setting up your fuel system

grumpyvette · Sep 22, 2008

when your setting up your cars fuel delivery system, you'll obviously need to know the physically requirements of the engine your about to feed,
For your older carburetor, equiped muscle car, this will generally be for most performance cars 5-6 psi of fuel pressure at the carb inlet port, a fuel pump should supply about 130%-to-150% of the minimum flow rates the charts posted lower in the thread , so a manual fuel pump rated at 90-130 gph is generally a good idea if your intent on making 400-550 hp, and taking the time and effort to accurately check your carbs float levels when you set it up!
and youll need to know not guess or assume that the limitations of the current fuel pump, pressure, and volume , so its able to supply your engine, having a small fuel pressure gauge mounted on the fuel rail helps and know the limitations on the current fuel lines, fuel filter and any restrictions to flow imposed by the fittings and connections to the filters and fuel tank, the fittings , lines internal cross sectional area,and the restrictions to flow that they potentially represent.
heat, inertial loads and distance all reduce flow rates.
as a basic rule carburetor engines will need about 6 psi at the carburetor inlet port, fuel rails or lines for fuel injection systems that feed , fuel injectors generally need between 40-60 psi at the fuel rail.
http://www.prpracingproducts.com/products-page/fuel-system-accessories/fuel-pressure-regulators/it makes no logical sense to run 1/2" or AN#8 lines to and from a fuel cell, or fuel tank, too a pressure regulator , or fuel pump or fuel filter,with restrictive AN#6 or 3/8" lines, if your intention is to make much over 500 hp so use a regulator , fuel filter and lines and fittings that all match, and allow max flow levels with little restriction, remember a chain is as strong as its weakest link, and a fuel delivery system will be limited by its most restrictive flow points..
one very common symptom, of a fuel system thats not keeping up with demand is a car that pulls hard through first gear and maybe second then power noses over as you go further, or a bad miss that develops in 2nd or third gear thats not there in first gear at the same rpm level.

http://www.eastwood.com/professiona...e=&network=g&gclid=CIe-y9b938cCFUhhfgodBkQCDg
heres a bunch of good info
http://www.aeromotiveinc.com/stealthdiagrams/

loss of third gear fuel pressure?

Hi all, I have a fairly healthy (~460hp) 406 SBC with a 800cfm DP Holley, a Carter M4891 (120gph) mechanical fuel pump and 3/8" hard line front to back with a 3/8" pickup. This fuel system has worked great for me the last three seasons of driving and ~30 passes down the quarter mile. But when...

garage.grumpysperformance.com

you DO understand that theres a very visable and meassurable difference between a O.E.M. style replacement fuel pump, designed as a replacement part that can be swapped in, that might provide a bit higher flow, and a true performance aftermarket electric fuel pump. right?
any serious fuel delivery system will require a fuel cell, or major changes to an existing fuel tank, and larger diameter fuel lines and a better fuel filter aling with a matched return style fuel pressure regulator and return lines, you can,t simply swap in a few components the whole system, (end to end) will need to be upgraded if you expect reliable fuel delivery by the time your exceeding about 550-600 hp.
Everyone initially, thinks they can simply put a larger fuel pump on the existing fuel lines the car came with,
inevitably they will be forced to accept the reality of the physics involved,
even if they don,t yet see the need yet
and those that don,t make the required upgrades,
will look far less knowledgeable if that issue is not resolved before damage occurs,
this is simply a watch them read links ,accept advice, and make suggested ,
changes or watch them gain knowledge, the hard & expensive way after replacing damaged parts that resulted

DON'T SKIP OVER/IGNORE THIS LINKED INFO

In Line Fuel Pump Diagrams – Aeromotive, Inc

Aeromotive_A750_EFI_dualfuelrail_13109_fuelsystemdiagram.jpg

Aeromotive_A1000_EFI_dualfuelrail_13101_fuelsystemdiagram.jpg

too much or too little fuel pressure?

Need advice. I have a 1956 Chevy truck. The problem I'm having is every time I put the gas pedal to the floor the truck gets up and takes off. After I let off the gas the truck sputters and dies. I open the hood and look at the fuel pressure regulator it reads zero and won't pressure up. I have...

garage.grumpysperformance.com

http://www.magnafuel.com/support/

VERY INTERESTING ADDITION TO THE POTENTIAL FUEL SYSTEM DESIGN
http://www.motoiq.com/MagazineArticles/ ... rvoir.aspx

the problem with all decent quality fuel line supply component parts is they cost more money, than the cheap low quality parts and generally take up more room and take a bit more time and thought to instal correctly
http://www.summitracing.com/parts/hly-12-841/overview/

http://www.amazon.com/Moeller-Separatin ... d_sbs_sg_1

http://www.summitracing.com/parts/edl-1792/overview/

yes the diagrams a bit confusing,pressure is a measurement of RESISTANCE to flow, the pump puts out , flow volume, theres no pressure until theres a resistance or restriction to flow,

potentially 6 -7 psi the true pressure is regulated to what ever the fuel pressure regulator is set too, IE, if the bye-pass spring setting is at 4.5 psi thats a high as the pressure ever gets, the fuel pressure potentially exceeding this forced the regulator to open,the spring resistance is over come and the fuel flows back too the tank, thus running out through the bye-pass, into the return line, limiting pressure.

I can easily see where the diagram may be confusing ,, and while that cheap holley return style fuel pressure regulator works
at maintaining fuel pressure on the inlet port and can be used its far from the better choice
this is the type of FP regulator you want in most cases,
and it comes in AN#8 and AN#10 sizes

its simply a strait through fuel flow with a pressure release that leads to the return line that opens if the fuel pressure exceeds a set level, thus it maintains that max pressure
https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/regulators/carbureted_regulators/parts/12-841

http://documents.holley.com/199r10575rev3.pdf

http://garage.grumpysperformance.com/index.php?threads/fuel-pressure-regulators.635/

http://www.daytona-sensors.com/engine-tuning-and-recommended-guidelines.html

one of the most common mistakes less than experienced performance enthusiasts, face and very commonly over-look, is the fact that the internal cross sectional area on many hydraulic and fuel line fittings are considerably more restrictive to flow that the fuel limes or hydraulic lines inside diameter they were designed to be used with, and it varies a great deal between different manufacturers, now ideally the fittings internal passage cross sectional area is both consistent and the same or greater that the tube or hydraulic line size, it listed to match, , so a 1/2" inside diameter fuel line, or hydraulic lines?hoses, for example should have components for the connections and fittings that have significantly smaller internal cross sectional areas, it does you very little good to use lets say, AN#8 or half inch fuel lines if the internal cross sectional area of the connections and fitting used with those lines is only 3/8" or smaller in cross sectional area,this is an area where dealing with a local hydraulic supply shop that has the correct tools and fittings to custom fabricate your fuel lines, coolant or lubrication lines is a very good idea!
talk to a local professional at your local hydraulic supply, measure accurately, take the time to explain what your trying to accomplish and take several pictures to show them what your doing, and get them too fabricate any high pressure fuel or coolant lines and related fittings

*
Up to 45 GPH= 3/4 GPM = 5/16" or -04 AN
*
Up to 90 GPH = 1.5 GPM= 3/8" or -06 AN
*
Up to 250 GPH =4.2 GPM= 1/2" or -08 AN
nearly ideal for transmission and oil coolers
*
Up to 450 GPH =7.5 GPM= 5/8" or -10 AN
*
Up to 900 GPH = 15GPM 3/4"or -12 AN

keep in mind that thats the minimum required, a fuel system has restrictions to flow rates like filters ,fitting and internal line flow restrictions requiring you to have a slightly higher actual supply volume and pressure

I don,t use aluminum, fuel line, because it fatigues quickly and it frequently rated under 40 psi., the best line is stainless steel hydraulic line you can usually get from a local hydraulic hose supply manufacturer or repair shop, its generally rated at 1000 psi or higher in 1/2" size I GENERALLY RUN ON PERFORMANCE CAR APPLICATIONS, shop carefully some places price that line like its made of gold, most are far more reasonable.
remember pressure and volume are two different measurements and youll need to supply both at a certain level to maintain a dependable power level, what works just fine in a fuel supply system idling in your drive way on a typical 350-400 cubic inch engine thats common in most cars ,built for performance,to feed the needs of an engine running at 1500rpm-3000rpm is a far cry from whats required at 6500rpm under 3/4 G acceleration loads.
that brass fitting you picked up cheaply some place that feeds the 3/8" inside diam. hose that has the 1/4" passage thru it , that allows a fuel pump rated at lets say 130gph to pump 70gph, won,t seem restrictive until the cars under full acceleration in top gear.
these links and sub links below should help, keep in mind in the tank electric fuel pumps tend to be cooled by sloshing fuel , so maintaining at least a 1/4 tank volume tends to prolong pump life span and pumps work far better with a return style fuel pressure regulator as that style tends to allow a consistent minimal fuel flow thru the pump to absorb and transfer heat out of the pump. the less expensive frame mount external electric fuel pumps tend to have heat related durability issues and tend to be louder as they operate. don,t forget a decent quality fuel filter that has the flow capacity to not be restrictive, a restrictive fuel filter can significantly reduce fuel flow rates.

adding a fuel pressure gauge.

I wanted to install a mechanical fuel pressure gauge on my 91 L98 TPI. Sometimes the car don't start (driven infrequently) and I want to know at a glance if I got fuel pressure. I wanted the gauge to be visible from the drivers side, and not interfere with removing the valve covers. ended up...

garage.grumpysperformance.com

http://www.amazon.com/Ti-Industries--Ca ... aulic+line

http://www.hydraulic-supply.com/html/pr ... tubing.htm
http://store.fedhillusa.com/cnf6.aspx

http://www.discounthydraulichose.com/Hy ... tm?Click=3

http://shop.hoseandfittings.com/catalog ... S-304.html

IF you decide you want a fuel cut off valve to make fuel filter changes less messy,
http://www.harborfreight.com/38-Full-Po ... 68255.html
while not ideal Ive seen these valves above used

http://www.brewershardware.com/1-2-Full ... Valve.html
I generally use AN#8 lines and stainless valves like this

viewtopic.php?f=55&t=7787&hilit=shut+off+fuel

viewtopic.php?f=55&t=211

viewtopic.php?f=55&t=1939

viewtopic.php?f=55&t=4381

viewtopic.php?f=55&t=1030

viewtopic.php?f=55&t=6105&p=18854#p18854

viewtopic.php?f=55&t=211&p=275&hilit=fuel+filter+drain#p275

http://www.copper.org/applications/auto ... brake.html

use steel hydraulic/fuel line its rated well over 1000 psi, it comes in 25 ft lengths in either 3/8" (AN#6) or 1/2" (AN#8)

READ THESE LINKS POSTED IN THE THREAD BELOW ALSO[/color]

https://www.centuryperformance.com/fuelish-tendencies.html

viewtopic.php?f=55&t=1378&p=3035#p3035

http://web.archive.org/web/200701062316 ... 1.htm#FPHP

http://www.duccutters.com/ConvertionCha ... bzyv5ytbP1

viewtopic.php?f=55&t=231

http://www.youtube.com/watch?feature=pl ... uIoAa5RRBs

http://www.stealth316.com/2-air-fuel-flow.htm

http://www.circletrack.com/enginetech/c ... _pressure/

http://www.smartfireinjectors.com/fuelflowchart.html

http://www.designatedengineer.com/FuelLineSizing.html

viewtopic.php?f=44&t=4912&p=14365#p14365

viewtopic.php?f=55&t=1939&p=5137#p5137

viewtopic.php?f=55&t=10664

e.com/viewtopic.php?f=55&t=231

For Dead-Head type regulators:

Multiply maximum horsepower by .23 to calculate minimum pump size in "free flow" GPH.
Example: 400 HP x .23 = 91 GPH "free flow"

For Return-Style regulators:

Multiply maximum horsepower by .17 to calculate minimum pump size in "free flow" GPH.
Example: 400 HP x .17 = 68 GPH "free flow"

The minimum fuel line size (from the pump to the regulator) is dependent on the horsepower output of the engine (and/or Nitrous system) regardless of the size of the pump. fuel pressure regulators are normally placed as close to the fuel rail or carburetor feed inlet port as possible to maintain most of the fuel feed lines under higher pressure to reduce vapor-lock, high g -force fuel starvation and to reduce the chance of air entering the carburetor ,or injectors and keep a constant flow of cool fuel reaching the injector's or carburetor, because theres a constant flow of new fresh fuel being forced up to and some bye-passed thru the system, and fed to the engine
keep in mind TPI fuel pressure regulators maintain about 40-45 psi while carburetors require about 4.5-6.5 psi MAX, but in most cases the fuel pressure at the carb inlet port NEEDS to read 4.5-5 psi MAX and you NEED to set the float levels per the carburetor manufacturers instructions, having the pressure at 6.5 psi will in many cases cause the needle & seat valve to constantly leak excess fuel, into the carburetor while the engine runs.
BTW any time you start having fuel delivery issue's check the electrical connections, fuzes, relays, and replace the fuel filter as those are frequently major factors in causing problems

Use these figures as a fuel line sizing standard: if your feeding a carburetor with the typical 8-10 psi fuel pump feeding to the fuel pressure regulator

* Up to 250 HP = 5/16" or -04 AN
* Up to 500 HP = 3/8" or -06 AN
* Up to 700 HP = 1/2" or -08 AN
* Up to 1000 HP = 5/8" or -10 AN
* Up to 1500 HP = 3/4" or -12 AN
many guys fail to keep the line size consistent, it does no good to feed a 1/2" or AN8 line from a 3/8" or AN6 fitting in your fuel filter or fuel pump are to try to suck fuel from the tank thru the stock lines and then feed larger lines, you'll need a fuel tank or fuel cell,and matching line adapters and fittings with the correct matched internal dimensions
fuel flow is restricted to the limitations imposed by the smallest cross sectional area of the smallest and most restrictive line or fitting, if a fuel filter restricts you to lets say 70 gph at 7psi hooking it to a fuel line that potentially flows 120gph at 7psi won,t increase the flow

In the automotive world, hose size is expressed by inside diameter. For example, a 3/8 inch has has a nominal (approximate) inside diameter (ID) of 3/8 inch. Not so with aircraft hose. Aircraft hose uses dash numbers to designate the hose size.

Dash size is in 1/16 of an inch. So

-2 (2/16) 1/8 inch,
-6 (6/16) 3/8 inch,
-8 (8/16) 1/2 inch and so on.

But be careful, this does not mean that a -6 hose has an inside diameter of 3/8 inch. In fact, it can be anywhere from .298 to .359 inch, depending upon the hose type.

Common aircraft hose dash sizes are:

-2 Smallest hose size. Used as an instrument gage line
-3 Also used as an instrument gauge line
-4 Common hydraulic line. Some smaller fuel line
-6 Common size for fuel delivery lines
-8 Fuel delivery and oil cooler lines
-10 Larger aircraft, oil and fuel
-12 Larger aircraft, oil and fuel
-16 Larger aircraft, oil and fuel

The inside diameter of each hose and fitting dash size is found in size charts. A common mistake is to think all hose of the same dash size has the same inside diameter. There not

A common mistake is to think that all fittings of the same dash size have the same inside diameter. They do not.

http://www.jegs.com/i/Russell/799/670353/10002/-1

and yes, use of a small handy and accurate fuel pressure gauge, mounted on the fuel injector fuel rail (0-100 psi for FUEL INJECTION)

or carb inlet port (0-15 psi for carburetors)is almost mandatory, they generally cost under $30

http://www.grumpysperformance.com/braidhose.jpg[/im
http://www.jegs.com/i/Moroso/710/65374/10002/-1

http://www.grumpysperformance.com/efisystem.jpg

having a gauge helps

A common mistake is to think that a straight -6 fitting and a 90 -6 fitting of used on the same hose should both have the same inside diameter. They do not. A hose with a straight fitting on one end and an angle fitting on the other end will have different inside diameters.

http://www.grumpysperformance.com/sizing-fittingthread.gif

http://www.grumpysperformance.com/sizing-anthread.gif
READ THESE THREADS ALSO
viewtopic.php?f=55&t=733&p=6470&hilit=fuel+cell#p6470

viewtopic.php?f=55&t=4381&p=11507&hilit=fuel+cell#p11507

If you use a return-style regulator, you will also need a return line from the regulator back to the tank. The size of the return line is dependent on the size of the pump you are using, regardless of the engine's horsepower output. The return line must have limited or NO pressure in it. In most cases, the minimum return line size will match that of the supply line, but a larger return line is sometimes preferred.

Use these ratings to decide your return line sizing based upon fuel pump output:

*
Up to 45 GPH = 5/16" or -04 AN
*
Up to 90 GPH = 3/8" or -06 AN
*
Up to 250 GPH = 1/2" or -08 AN
*
Up to 450 GPH = 5/8" or -10 AN
*
Up to 900 GPH = 3/4"or -12 AN

http://www.grumpysperformance.com/fuelsysxz1.png
E85 fuel requires larger lines and a bigger fuel pump
http://forum.grumpysperformance.com/viewtopic.php?f=44&t=10202']viewtopic.php?f=44&t=10202

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635']viewtopic.php?f=55&t=635

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=3172']viewtopic.php?f=55&t=3172

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=109']viewtopic.php?f=55&t=109

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1961']viewtopic.php?f=55&t=1961

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1442']viewtopic.php?f=55&t=1442

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=7787&p=26658#p26658']viewtopic.php?f=55&t=7787&p=26658#p26658

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1790']viewtopic.php?f=55&t=1790

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1030&p=1912&hilit=fittings#p1912']viewtopic.php?f=55&t=1030&p=1912&hilit=fittings#p1912

http://forum.grumpysperformance.com/viewtopic.php?f=62&t=1469&p=3303&hilit=+gauges#p3303']viewtopic.php?f=62&t=1469&p=3303&hilit=+gauges#p3303

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635&p=12710#p12710']viewtopic.php?f=55&t=635&p=12710#p12710

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=733&p=1030#p1030']viewtopic.php?f=55&t=733&p=1030#p1030

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635']viewtopic.php?f=55&t=635

http://garage.grumpysperformance.co...ir-ratios-that-gets-ignored.15506/#post-92064

http://www.chevyhiperformance.com/techarticles/0606ch_carbureted_motor_fuel_system/index.html']http://www.chevyhiperformance.com/techa ... index.html

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1939']viewtopic.php?f=55&t=1939

http://www.corvettefever.com/techarticles/corp_0908_corvette_fuel_systems/index.html']http://www.corvettefever.com/techarticl ... index.html

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635&p=849#p849']viewtopic.php?f=55&t=635&p=849#p849

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=733&p=3587&hilit=cell#p3587']viewtopic.php?f=55&t=733&p=3587&hilit=cell#p3587

most of the under hood gauges screw directly into fuel rails or fuel line fittings and read direct pressure, they are used for tuning and trouble shooting, direct pressure while accurate does pose safety issues inside the cars cab so they use remote electric sensors and wiring to in cab dash gauges for safety reasons, (you don,t want fuel leaks inside the cars cab, especially during a traffic accident, so get the remote dash gauges if its in the cab)
you should own a DEALER SHOP MANUAL for your car,that will provide the ideal fuel pressure info, but generally you'll want about 4.5-5.5 psi feed on carbs and about 40 psi on Chevy tpi or lT1 injection systems
read this first
https://www.centuryperformance.com/fuelish-tendencies.html

http://www.grumpysperformance.com/powra1.gif

http://www.grumpysperformance.com/AFR_Torque.gif

http://www.grumpysperformance.com/FuelFlowDiagram02a1.jpg
most electric fuel pumps last much longer if you follow three simple rules,
IF ITS INTERNAL TO THE FUEL TANK
(1)keep the fuel tank at least 1/4 full, so sloshing fuel cools the pump
(2) use a return style FUEL PRESSURE regulator, that allows a constant flow of fuel to cool the pump
IF ITS EXTERNALLY MOUNTED
(3) mount the pump low enough under the tanks fuel level so it self primes
BASIC CAR FUEL SYSTEM DESIGN
http://www.grumpysperformance.com/FuelFlowDiagram01.jpg
THIS WILL WORK
http://www.grumpysperformance.com/FuelFlowDiagramEdit copy123.gif

if your, looking at the diagram,and asking what pressure the fuel rail feeding the carburetor is pressurized too its obviously controlled by the fuel pressure regulator just beyond it in the diagram, which is usually located near the carburetor and fuel rail, to maintain the indicated 5psi, beyond that is the return line feeding back to the fuel tank and that should be close to zero, the main feed line from pump to the first fuel pressure regulator which ideally is located on the inner front fender or firewall maintains the 8psi-12psi the fuel pump provides , keep in mind a fuel pressure regulator can only control the pressure between it and its pressurized feed source, by bleeding off pressure above the peak its set for, it has zero control past it, it only controls pressure between it and its pressure feed source
OR
http://www.grumpysperformance.com/FuelFlowDiagram02.jpg
PERSONALLY, THE SIMPLER THE BETTER ,ID go THIS ROUTE

http://www.grumpysperformance.com/fpr123.jpg

http://www.grumpysperformance.com/EDL-1792.jpg
http://www.grumpysperformance.com/665-MP-6208.jpg

http://www.jegs.com/i/Magnafuel/665/MP-6208/10002/-1

http://www.summitracing.com/parts/EDL-1792/?rtype=10

ID be more likely to put something together that looked more like this but with a single fuel filter, and single fuel pump and two separate fuel pressure regulators all feed with two separate feed and return AN8 lines so you could have about 12 psi feed each fuel pressure regulator with 1/2" ID lines and run AN8 lines to the nitrous and carb fuel log and return lines
Ive had 750hp cars with a single 1/2" inside diam. fuel line loop from tank sump too pump too regulator and back as a return line that worked just fine BTW 1/2" inside diam. fuel line measures about 5/8"-3/4" outside, I buy mine from the local hydraulic supply house, SPECIFICALLY ask for HIGH TEMP,MID PRESSURE FUEL LINE with the metallic braided shield, 250-300F and 150PSI MINIMUM rated, measure VERY CAREFULLY then have them install the AN fittings with their hydraulic press that's designed to do the job correctly, and don,t get it near, or install it near hot engine or exhaust parts
ELECTRIC FUEL PUMPS PUSH FUEL FAR MORE EFFICIENTLY THAN THEY PULL FUEL, so place the pump low and close to the fuel tank, but inside the frame for impact protection in accidents
looks like this....
viewtopic.php?f=55&t=4381&p=11507&hilit=fuel+cell#p11507

http://www.discounthydraulichose.com/SAE_100R5_General_Purpose_Truck_Hose_p/r5-hose.htm

http://horsepowerperformance.com/c-7774 ... l-die.html

viewtopic.php?f=55&t=1030
AN4 or 5/16 id line will support up to about 420hp,
AN6 or 3/8 ID fuel line will support about 550-600hp if its correctly set up, youll want to jump to AN8 or 1/2" id line if your in the 550-800hp power zone

BTW THEY ALSO MAKE A SIMILAR FUEL LINE WITH STAINLESS BRAID on the outside

http://www.jegs.com/images/photos/500/555/555-100914.jpg
http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_752578_-1_10019

look thru this link I provided

http://www.robbmcperformance.com/produc ... msend.html

http://www.centuryperformance.com/f...tanding-fuel-pressure-and-volume-spg-140.html

and just because you've installed a bigger diam. line and a better pump that's not the end of the deal, you can still have problems if the fittings and routing are less than ideal or the filters restrictive, the fitting most guys use cause a problem because the passages thru those fittings are to small and restrict flow ,that may or may not be the source of your problem, you REALLY SHOULD install a return style fuel pressure regulator and a return line or the fuel flow rates won,t cool the electric fuel pump,but ID point out that fittings and routing effect results, most guys don,t understand that the return line is designed too have and supposed too have nearly zero resistance too flow back to the tank, the factory line is marginal,and restrictive at best. and of to small a diam. on even the stock engine in my opinion, a 1/2" feed and a 3/8" minimum,or better yet a 1/2" return line would be a far more realistic match in a performance application, and be aware that the cheaper fittings have smaller internal passages, adding a 3/8" return like does little good if a fitting in that line has a 1/4" or 3/16" internal passage like some do!
IF your getting inconsistent fuel pressure in most cases,
IF youâ€™re not using a RETURN LINE and a bye-pass style fuel pressure regulator that problems fairly common, itâ€™s NOT common with a decent 3/8" or larger fuel lines, (BOTH feed AND return lines) matched with a bye-pass style fuel pressure regulator.
dead head style fuel pressure regulators are famous for that crappy control.
naturally you'll need to verify the carbs set up correctly with the correct jets,power valves, float levels etc, also, but the problem of fuel pressure jumping around inconsistently and seemingly for no reason is far more common to the dead head fuel pressure regulator designs with carbs..

http://www.centuryperformance.com/f...tanding-fuel-pressure-and-volume-spg-140.html

http://www.centuryperformance.com/fuel-system-troubleshooting-spg-142.html
it does very little good to run a 1/2" fuel feed and return line and hook it up to the factory 3/8" or 1/4" fittings at the factory tank , if the flow gets restricted at any point you'll see problems

HERES ONE SOURCE OF FITTINGS

http://www.holley.com/division/Earls.asp#21

http://www.russellperformance.com/misc/ ... pdf/26.pdf

http://www.holley.com/types/Ultra-Flex Hose Ends (standard length nut).asp

generally when Ive added a sump to a tank Ive used a steady flush of CO2 shield welding gas to fill the tank and make it totally inert if I had doubts, or several pounds of dry ice stuffed in the tank to evaporate, will help make it totally safe to weld on, but several flushes with hot water with some dish washing soap mix generally removes the vapors/residue. then after your done welding, just let it dry out in the hot sun with the air compressor flushing the interior.
keep in mind you'll be drilling 4-6 holes in the tank and welding the sump over the holes so fuel dropping thru the holes is trapped in the sump under high G loads, you DON,T want to cut one huge hole it weakens the tank and makes it far more flexible, BTW if your not 100% sure all the pin holes in the weld seam are filled you can silver solder over the welds, or get cheap and dirty and use J&B epoxy as an exterior sealer, use something like this

http://www.kbs-coatings.com/KBS-Aut...UserID=1045409&SessionID=PoOgOUlfTTIo3wZCT7yV

to seal crud inside the tank

naturally if your bucks up, you avoid the work buy purchasing a aluminum fuel cell, http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-293220-S&N=700+115&autoview=sku

http://www.russellperformance.com/misc/ ... pdf/26.pdf

keep in mind its does little good to run larger 1/2" lines in a high hp application and then install fittings or filters ETC. with internal passages significantly smaller than the 1/2" lines feeding them. Ive seen many installs where decent line size was rendered nearly useless with fittings or filters of significantly smaller internal diam. rendering the line size almost immaterial to the flow restriction the fitting presented to the flow of fuel
a 1/2" fittings with 5/16" internal passages effectively make a 1/2" like flow at a 5/16" line rate
THE AN FITTINGS (like the two lower examples) WILL GENERALLY HAVE MUCH MORE CONSISTENT INTERNAL DIAM. AND HIGHER FLOW RATES THAN CHEAPER PLUMBING STYLE ADAPTER FITTINGS, MANY GUYS PICK UP AND USE FROM LOCAL HARDWARE STORES

I can assure you fittings like these restrict flow rates more than CORRECTLY SELECTED and SIZED /MATCHED FITTINGS LIKE THESE

if you ask the supplier of any fuel lines, you buy at any hydraulic supply house, in most cases they will know if the hose, lines they supply are compatible with current fuel, and at what pressures,but keep in mind current fuels have a bit of alcohol in many of the blends and hose that handles gas may not handle an alcohol blend /gas fuel long term...I see guys experience leaks from degraded rubber/synthetic fuel lines that held up fine with just gas, far more frequently with today's fuel lines than in the past

grumpyvette · Sep 23, 2008

what power level does a 6AN fuel line become a restriction
having a fuel pressure test gauge helps

"Grumpy, theoretically, what is the maximum horse power that a -6AN fuel line can support? Meaning -6 all the way from the tank to the pump and from the pump to regulator, regulator to carb. Is there a point at which the -6AN fuel line will not support XX HP, regardless of the pump used?

Thanks,

Phil??

Fuel Hose Sizes
AN Size Tube or Hose OD Tube or Hose ID
-6 3/8” .297”
-8 1/2” .391”
-10 5/8” .484”
-12 3/4” .609”

read this
viewtopic.php?f=55&t=211&p=1533#p1533

viewtopic.php?f=44&t=38&hilit=carb+spacer

http://www.russellperformance.com/misc/ ... pdf/26.pdf

http://garage.grumpysperformance.co...ubing-fuel-lines-and-flaring.1030/#post-35905

http://www.chevyhardcore.com/tech-s...ning-building-street-performance-fuel-system/

http://www.centuryperformance.com/fuelish-tendencies.html
For Dead-Head type regulators:

Multiply maximum horsepower by .23 to calculate minimum pump size in "free flow" GPH.
Example: 400 HP x .23 = 91 GPH "free flow"

For Return-Style regulators:

Multiply maximum horsepower by .17 to calculate minimum pump size in "free flow" GPH.
Example: 400 HP x .17 = 68 GPH "free flow"

These minimum pump sizes assume that the fuel system is equipped with fuel lines of adequate size. If the fuel lines are too small (or if there are a lot of restrictive fittings in the system) a larger pump may be required to satisfy the fuel demand of the engine. The minimum fuel line size (from the pump to the regulator) is dependent on the horsepower output of the engine (and/or Nitrous system) regardless of the size of the pump.

Use these figures as a fuel line sizing standard:

Up to 250 HP = 5/16" or -04 AN

Up to 375 HP = 3/8" or -06 AN

Up to 700 HP = 1/2" or -08 AN

Up to 1000 HP = 5/8" or -10 AN

Up to 1500 HP = 3/4" or -12 AN

If you use a return-style regulator, you will also need a return line from the regulator back to the tank. The size of the return line is dependent on the size of the pump you are using, regardless of the engine's horsepower output. The return line must have limited or NO pressure in it. In most cases, the minimum return line size will match that of the supply line, but a larger return line is sometimes preferred. You definitely want less pressure in the return line than the supply side line(s).

Use these basic ratings to decide your return line sizing based upon fuel pump output:

Up to 45 GPH = 5/16" or -04 AN

Up to 90 GPH = 3/8" or -06 AN

Up to 250 GPH = 1/2" or -08 AN

Up to 450 GPH = 5/8" or -10 AN

Up to 900 GPH = 3/4"or -12 AN

Ive seldom used fittings and lines that small,
on anything I intended to race,seriously ( I usually use 8AN size or 1/2" id fuel lines ) so I called the tech guys at EDELBROCK and at RUSSELL, both tech guys felt that if everything was optimal you could probably just barely get to 600 hp with the correct pumps, and ,filters and fuel pressure regulators,but things are seldom perfect in a fuel system so Id say around 500-550 hp is close to the limit on a 6an or 3/8" fuel line.
Ive frequently seen gains in power swapping to the larger AN#8 fuel systems on cars that only had 500plus hp, simply because theres almost always restrictions to flow rates in every fuel system, and all the fittings, filters and lines are rarely flowing at near ideal levels.
what works just fine in a fuel supply system idling in your drive way on a 350-400 cubic inch engine thats common in most cars ,built for performance,to feed the needs of an engine running at 1500rpm-3000rpm is a far cry from whats required at 6500rpm under 3/4 G acceleration loads.
that brass fitting you picked up cheaply some place that feeds the 3/8" inside diam. hose that has the 1/4" passage thru it , that allows a fuel pump rated at lets say 130gph to pump 70gph, won,t seem restrictive until the cars under full acceleration in top gear
with out testing theres now way to know if that particular application has a potential problem, but keep in mind that the carbs fuel bowls hold a certain amount of fuel reserve and the fuel pump is designed to feed fuel at a set rate or volume and pressure, usually at 5.5psi-6 psi measured at the carb fuel supply inlet port.
its entirely possible for your cars fuel system to be able to supply fuel at a rate,pressure and volume at lower rpms that keeps the carbs fuel bowls filled , but at some point the engines needs exceed the fuel supplied by the fuel entering the carbs inlet port, and the difference is being temporarily maintained by the volume in the fuel bowls, this is common, and in marginal systems tends to mask a potential problem that will rarely show itself due to the minimal time duration the engine is subjected to the conditions over taxing the fuel delivery systems potential as few of us do more than occasionally race for a few gear changes with friends on back rural roads, but if the car was ever pushed for more than 12-15 seconds at wide open throttle the condition would become far more obvious

the usual problems not the 3/8" or an 6 line size, it self , its that many common adapters and fuel line fittings REDUCE the flow and have inside diam. that are significantly under 3/8" ID,while its seldom an issue with the stock engine, if you double or tripple the engines potential with modifications it should be rather obvious that the fuel system in its original configuration may no longer be adequate, with out upgrading it also.
take the time and effort to carefully read the products informational instructional sheets that most manufacturers include rather than pitching them in the dumpster !
if your ordering and installing a new fuel pump, & fuel filter it will help immensely, to verify the fuel flow rating AT THE OPERATIONAL FUEL PRESSURE & VOLUME LEVELS at least slightly exceed the calculated needs of the engine at its max anticipated power level.
remember fittings, filters, and inertial G forces all reduce flow from the rated levels, and having an accurate fuel pressure guage to verify sure won,t hurt a darn thing.

example, heres a 3/8" barb/3/8 NPT fuel line fitting

inside diam. significantly less than 3/8" ID

an #8 is a better bet at 550 plus hp, and the fittings are designed not to restrict flow

autowize said:
Aluminum fittings need more wall thickness than steel. And you pay more because they are aluminum and anodized to boot. My suggestion will see you to steel fittings and none of these problems. It will cost you between $30-$60 per hose. Usually closer to the $30. The fittings they use at industrial supply stores are steel. usually left raw or galvanized/ rust coated with something at best. They are a tiny fraction of what you will pay for Russell or fragola or any other anodized aluminum fitting that is gonna have a smaller id because it is made of soft aluminum. If you grind out the center of the aluminum fitting until you have the wall thickness of a steel fitting, it will be weak and likely fail. The right solution is a thin wall steel fitting. And thankfully they are so much cheaper than what you are used to playing with. you just have to goto the right place to get it. And that is your local industrial hose / hydraulic supply store.

http://www.russellperformance.com/mc/hose/main.shtml

http://www.gre6.com/ansize

(Army-Navy) Fitting Thread Size Chart

AN Size

http://www.bgcmotorsport.co.uk/faq.html

Hose Size

as a rough guide, and assuming your running a carburetor equipted engine with the correct fittings and fuel pump etc
this is about the max hp those fuel lines can be expected to support

ASSUMING EVERTHING WORKING NEAR OPTIMUM LEVELS
AN4 (5/16")=375hp
an6 (3/8")=575hp
AN8 (1/2")=850hp

Thread Size
-3 3/16 3/8-24 SAE
-4 1/4 7/16-20 SAE
-6 3/8 9/16-18 SAE
-8 1/2 3/4-16 SAE
-10 5/8 7/8-14 SAE
-12 3/4 1-1/16 SAE
-16 1 1-5/16 SAE
-20 1-1/4 1-5/8 SAE

if you do a bit of research youll find that those combo water separator & fuel filter combos come in dozens of different configurations and flow ratings.
these are ideally mounted near the fuel tank where you can easily access and replace parts,
that particular one pictured first,below is rated at 90 gph which for the application is adequate.
youll find this type filter mostly listed in marine applications and for diesel fuel, but they can be used for gas in carb applications.
be aware that you must carefully read the fine print on specs ,some of these filters Ive seen ar 4" in diam. and 14" tall, some are 2" diam. and 4" tall making them more reasonable for automotive use, some have CLEAR fuel bowls with a drain, sone have a drain but you can,t see the fuel thru the filter, most cars use 1/4" or 3/8" NPT or smaller fuel hose fittings some of the marine filters have fittings up to 1" NPT which by automotive standards is HUGE!
http://www.highflowfuel.com/i-10388...rainers.html?gclid=COabwduFgs0CFZKGaQodbGQCOw

http://garage.grumpysperformance.co...-auto-elecrtrical-connectors.3105/#post-68805

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

https://www.delcity.net/store/Weather-Pack-Assembled-Pigtails/p_810525.h_810527
450 LPH EFI FUEL PUMP

http://www.amazon.com/Moeller-Separatin ... _sbs_sg_12

http://www.amazon.com/Moeller-Separatin ... d_sbs_sg_1

http://www.amazon.com/RACOR-500FG-EQUIV ... _sbs_sg_16

http://www.amazon.com/Racor-320R-Rac-Se ... _sbs_sg_11

http://www.jamestowndistributors.com/us ... 378&AMAZON

grumpyvette · Dec 13, 2008

FUEL PRESSURE REGULATORS DEADHEAD vs BY-PASS STYLE

dead head regulators seldom allow a stable fuel system pressure, you NEED a by-pass style system with the regulator mounted close to the carb, you can ignore the nitrous part of this diagram if your not running nitrous but the concept of the higher pressure feed bleeding off excess pressure at the regulator so that the carb sees a constant feed pressure is valid. it may help if you understand the difference in concept of how the regulators work

http://horsepowerperformance.com/c-7774 ... l-die.html

PRESSURE IS THE MEASURE OF RESISTANCE TO FLOW

THE DEAD HEAD STYLE REGULATOR
Works with a spring on a valve that allows the valve to open once the DIFFERENCE IN PRESSURE between the sides of the regulator valves fuel lines has changed
Think of it as a door that has 7-10psi on the feed side and you want lets assume 5.5 psi at the carb
as the fuel pump fills the line it eventually (fractions of a second) reaches the point where thereâ€™s a volume of fuel past the valve with enough pressure to allow BOTH the SPRING and the fuel pressure past the valve to close the valve until the fuel is reduced to the point that the SPRING and the remaining fuel pressure/volume beyond the valve can not hold the valve closed and the valve is force open and held open until, that difference in pressure is restored. now lets launch the car hard, the pump that had maintained 8-10 psi to the regulator, 5.5 psi past the valve and the spring in the regulator is now fighting the fuel in the line feeding the regulators inertia, and the sudden drop in pressure as the throttle drops full open in the carb, what the pump sees is the full 8-10 psi or MORE the regulator sees a sudden drop off to near zero and it opens wide, if the fuel pumps able too it tends to flood the fuel bowl for a second then the valve slams shut, until the pressure drops off as you hit each gear the cycle repeats, the result is a surge in pressure and a rapid drop off in volume then a rapid flood of fuel that rapidly cycles as you go down the track
if you had a accurate fuel pressure sensor at the carb youâ€™ll see a rapidly cycling pressure/flow
if some crud gets stuck in the valve it cant close and your carb FLOODS OUT, because it must fully close every few fractions of a second to work correctly

the by-pass regulator functions in a totally different manor
Assuming the same set-up but you replace the regulator with a by-pass style regulator, the by-pass regulator works by opening a valve too a much lower pressure path for the fuel to return to the tank, the open fuel return line. Anytime the pressure exceeds the 5.5 psi, youâ€™ve set it to, so the fuel line to the carb can only see a max at that 5.5 psi. now the pumps sitting there potentially supplying at 8-10psi just like before, but it can never exceed 5.5 psi because the bye pass regulator bleeds of any excess the pump supplies. but lets look at your launch, if the pressure drops to 6, 07 psi nothing changes at the carb, it it increases to 10 or 12 psi, nothing changes at the carb ,if it drops to 5.5 psi or less the valve to the bye pass line will close but thatâ€™s seldom a problem, it the sudden changes in pressure and over pressures that happen when you suddenly change the fuel flow required or the (G)loads on the system that potentially screw things up, the bye-pass regulator style regulator isolates the carb and maintains the desired 5.5 psi FAR MORE CONSTANTLY
Now let,s assume the spring get weak over time or the adjustment gets set at 4 psi in error, with the bye-pass style you,ll probably never notice, if you had a accurate fuel pressure sensor at the carb you'll see a rock steady pressure/flow
Should some crud get stuck in the valve and it can,t close NOT MUCH HAPPENS, because its normally OPEN not closed
If you check you,ll see MOST EFI systems are BYE-PASS regulated designs also due to control and reliability issues

But on the dead head the cycle just gets about 20% more erratic and more frequent in the cycles, further weakening the spring over time

http://static.summitracing.com/global/i ... -13301.pdf

http://garage.grumpysperformance.com/index.php?threads/fuel-pressure-regulators.635/

your carburetor inlet fuel pressure should be a consistent 5 psi-5.5 psi in most cases, once you get over 6 psi you'll find the carburetor float bowls tend to flood and under 3 psi the carburetor can run lean under hard acceleration.
keep in mind the internal port size is not all that large on the cheap holley fuel pressure regulators , so they work ok on near stock applications but NOT on anything close to a race application.

most people don,t understand that the return fuel line to the tank will ideally have very low restriction to flow for the fuel pressure regulator to function correctly, if theres a restriction to flow it reduces the bye pass fuel pressure regulators accuracy and consistency.
most guys use a smaller diam. return line thinking that theres less fuel flow due to the engine use of fuel, thats not generally 100% accurate because if the fuel pressure is to remain consistent at a set pressure & volume the fuel pump must produce more fuel pressure and flow volume even at peak rpms than the engine can burn and even under high (G) loads, meaning that the return line needs to be fairly large and unrestricted to reduce the resistance, to flow in the upper rpm ranges with manual pumps that work in relation to engine rpms and all the time with electric pumps

btw your fuel pump tends to run under less stress and run cooler with a by-pass style regulator also

viewtopic.php?f=55&t=3172&p=8673&hilit=fuel+filter#p8673

viewtopic.php?f=55&t=1939&p=5137&hilit=fuel+filter#p5137

viewtopic.php?f=55&t=231&p=275#p275

btw

before you get crazy chasing some problem your sure is an intermittent fuel delivery issue
(1) Do a compression test!
(2) verify your ignition advance curve, and verify the ignition systems working correctly , the spark plugs are new, properly gaped and the ignition wires in excellent condition visually and with an OHMS meter.
(3) adjust your valves, correctly
(4) carefully verify theres no vacuum leaks, in lines or gaskets
(5)Check the fuel delivery system, WITH A GAUGE, while the engines under real operational inertial loads to verify you have a consistent 5-6 psi at the carburetor inlet port
(6) change out the fuel and air filters, especially if over 3-4 months old
(7) actually check your exhaust back-pressure levels
(8) verify your return style fuel pressure regulator and fuel lines function as intended
(9)verify your using FRESH FUEL WITHOUT MOISTURE OR PARTICULAR CONTAMINANTS
(10) actually look for and read installation instructions and rated flow and pressure limitations on fuel pumps and filters
(11) If ALL of the above are normal, only then start looking at the carburetor, and tuning issues
most newer to racing people, use a fuel filter that's far too small & low in flow capacity, fuel pumps don,t suck fuel worth a darn, they are only efficient at pushing fuel, both these smaller filters below are a bit restrictive
read this
viewtopic.php?f=55&t=231&p=275#p275

http://garage.grumpysperformance.com/index.php?threads/is-backpressure-hurting-your-combo.495/

http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

something like this filter mounted between the pump and tank tends to work on applications like your describing

http://www.summitracing.com/parts/FRM-HPG1/

notice that a larger canister size promotes faster flow rates, notice the top filter is at 90 gallons per hour and this below at 18 gallons PER MINUTE (thats 1000GPH)[/b]
http://www.drillspot.com/products/66747 ... er_Housing

something like this is at times restrictive,especially if your engine has over about 400hp placed between the tank and pump, because its line size is too small and restrictive

http://www.summitracing.com/parts/SUM-G1512/

if you place the filter after the pump on the pressure side its slightly less critical, but a decent size fuel line and quality return style fuel pressure regulator are mandatory, naturally a compromise due to under car clearance and mount space is required

if youve ever wondered why Ive suggested no one use the cheap glass fuel filters, its because they are prone to leak, with less than safe results.

if your setting up your cars fuel system think it thru,theres not much gained using the correct size fuel lines and fittings if you use a restrictive fuel filter, one of these two above or a similar fuel filter....both designs are restrictive and the glass design frequently leaks or breaks so its basically an accident waiting to happen in my opinion

you'll be far safer and have less restriction with a better design
at a minimum on a carb Id suggest these but again you need to verify line size and flow rates easily exceed the cars fuel flow requirements , and both the pressure and line size do matter

http://www.jegs.com/i/JEGS+Performance+ ... 5/10002/-1

http://www.jegs.com/i/JEGS+Performance+ ... 7/10002/-1

HAVING A DECENT RETURN STYLE FUEL PRESSURE REGULATOR HELPS
diagrams

if your, looking at the diagram,and asking what pressure the fuel rail feeding the carb is pressurized too its obviously controlled by the fuel pressure regulator just beyond it in the diagram, which is usually located near the card and fuel rail, to maintain the indicated 5psi, beyond that is the return line feeding back to the fuel tank and that should be close to zero, the main feed line from pump to the first fuel pressure regulator which ideally is located on the inner front fender or firewall maintains the 8psi-12psi the fuel pump provides , keep in mind a fuel pressure regulator can only control the pressure between it and its pressurized feed source, by bleeding off pressure above the peak its set for, it has zero control past it, it only controls pressure between it and its pressure feed source

grumpyvette · Dec 15, 2008

THINKING OF CONVERTING TO A CARB, MOST GUYS INSTALL A SEPARATE ELECTRIC FUEL PUMP,and REPLACE THE IN-TANK PUMP WITH 18" of 3/8" fuel line , replacing the original pump
no one anywhere can accurately predict exactly what your particular engine combo will find to be the best tune-up specs but any good dyno operation or experienced shop will start with a basic known base line and tweak the combo to get the best results, you'll want a consistent 40 lbs of fuel pressure, you'll want to keep the coolant temps under 200 F
youll want the oil temps in the 200F-210F range
and youll ant the injector pulse duration to stay under 75%-80% at peak rpms , this may require larger injectors, and youll want significantly less than 3 psi of exhaust back pressure at peak rpms.
heres a basic tune

installing a fuel pressure gauge on your LT1 fuel rail will help provide a slightly higher fuel flow from existing injectors

an adjustable fuel pressure regulator allows you the option of feeding the injectors with more pressure which results in a slightly richer fuel/air ratio at any pulse duration.(at times this helps during a tune up)

THINK,
EFI works at higher pressures (a 1985-1991 TPI corvette as an example generally operates in the 38psi-42 psi fuel pressure range)
THINK,

fuel tank...to .fuel filter....to .-fuel pump....to feed into fuel rail& injectors. then out too....fuel pressure regulator...then too..return line to fuel tank

the vacuum line to the plenum drops under full throttle,
so the diaphragm and check ball,compensate, to maintain max flow rate to the injectors,
the diaphragm and check ball in the regulator become, or are just a tiny bit harder for the fuel pressure too force open,without the plenum vacuum above the the diaphragm and check ball
thus maintaining fuel rail volume and pressure before any of the fuel can exit the return line

it might help if you think, fuel pump provides fuel flow volume,
fuel pressure is a measure of resistance to fuel flow,
the fuel pressure regulator acts as a valve that opens if the pressure exceeds about 42 psi (YES some versions like yours are manually adjustable) but the reason its there is to maintain a consistent 39 psi-42 psi to do that you allow the fuel pump to stack or pressurize fuel in the fuel rail and in theory the fuel pressure regulator only allows excess fuel volume to flow back to the fuel tank through the return line if that fuel pressure exceeds the 42 psi, the pump is designed to provide a bit more than the required 42 psi too insure fresh cool fuel is cooling the fuel pump while maintaining that consistent fuel volume at the fuel pressure, when you tromp on the throttle the flow of fuel drastically increases, the regulator momentarily restricts out going fuel to maintain the fuel rail pressure and volume, until the flow demand drops enough, for excess volume and the resulting increased pressure that results to open the regulator again,

http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.com/index.php?threads/diagnoseing-tpi-lt1-problems.1241/

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/

http://garage.grumpysperformance.com/index.php?threads/replacing-a-c-4-fuel-pump.33/

http://garage.grumpysperformance.co...ard-starting-tpi-crossfire-or-lt1-vette.1401/
post your results and more questions

HERES AN ENGINEERING CHART ON FUEL FLOW, IVE GENERALLY FOUND AN#* lines to provide full power up to at least 700 hp, restrictions in the fittings used and pumping losses makes use of AN#6 lines rather restrictive once you reach 500hp or more, in my experience, so plan ahead!
if you experience a loss of power in a drag race application that starts in about 2nd or third gear thats usually a good indication of fuel flow restriction at some point
Approximate Maximum Flow Rates through Schedule 40 Pipe & Fittings for Selected Line Velocity
Pipe/Fitting Size 2 Ft/Sec. 4 Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
1 / 8” .269” ID 21.6 GPH 43.2 GPH 108 GPH 162 GPH
1 / 4” .364” ID 36.0 GPH 72.0 GPH 180 GPH 270 GPH
3 / 8” .493” ID 72.0 GPH 144 GPH 360 GPH 540 GPH
1 / 2” .622” ID 115 GPH 228 GPH 570 GPH 840 GPH
3 / 4” .824” ID 206 GPH 396 GPH 960 GPH 1,500 GPH
1” 1.049” ID 330 GPH 660 GPH 1,620 GPH 2,460 GPH
1-1 / 4” 1.660” ID 564 GPH 1,140 GPH 2,820 GPH 4,200 GPH
Table 1
Approximate Maximum Flow Rates through Fuel Hose for selected Line Velocity
Fuel Hose Size 2 Ft/Sec. 4Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
3 / 8 ~ .375” ID 36.0 GPH 72.0 GPH 180 GPH 270 GPH
1 / 2 ~ .500” ID 72.0 GPH 144 GPH 360 GPH 540 GPH
3 / 4 ~ .750” ID 180 GPH 360 GPH 900 GPH 1,500 GPH
1 ~1.000” ID 291 GPH 582 GPH 1,458 GPH 2,190 GPH
Table 2
Approximate Pressure Drop per Foot of Hose & Schd. 40 Pipe @ Selected Flow Rate and Line Velocity
2 Ft/Sec. 4 Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
Hose size
3 / 8 <.1 PSI @ 36 GPH .1 PSI @ 72 GPH 0.6 PSI @ 180 GPH 1.1 PSI @ 270 GPH
1 / 2 <.1 PSI @ 72 GPH .1 PSI @ 144 GPH 0.5 PSI @ 360 GPH 1.0 PSI @ 540 GPH
3 / 4 <.1 PSI @ 180 GPH .1 PSI @ 360 GPH .35 PSI @ 900 GPH 1.0 PSI @ 1,500 GPH
1 <.1 PSI @ 291 GPH .1 PSI @ 582 GPH .23 PSI @ 1,458 GPH 0.5 PSI @ 2,190 GPH
Table 3
Approximate Pressure Drop for 2 Full Flow Hose Fittings @ Selected Flow Rate and Line Velocity
2 Ft/Sec. 4 Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
Fitting-“
3 / 8 <.1 PSI @ 36 GPH .10 PSI @ 72 GPH .55 PSI @ 180 GPH 1.2 PSI @ 270 GPH
1 / 2 <.1 PSI @ 72 GPH .13 PSI @ 144 GPH 1.0 PSI @ 360 GPH 1.5 PSI @ 540 GPH
3 / 4 <.1 PSI @ 180 GPH .14 PSI @ 360 GPH 1.3 PSI @ 900 GPH 2.0 PSI @ 1,500 GPH
1 <.1 PSI @ 291 GPH .10 PSI @ 582 GPH .45 PSI @ 1458 GPH 1.3 PSI @ 2,190 GPH
DESIGNATED ENGINEER
954-562-7465
1 Hg" = .4912 PSI
1 PSI = 2.04 Hg" To find restriction from pressure drop PSI X 2.04 = Hg"

1 Foot of Lift of Diesel is equal to .886 of Hg" Restriction

https://www.powerperformancenews.co...00-hp-street-engine-big-power-means-big-fuel/

One 90 Degree Fitting is equal to 7' of Hose Run

2 Ft/Sec Flow may be to high and cause high restriction in some systems, and lead
to a short Primary Filter Life. (some Engines have a Max. Fuel restriction of 4 Hg" )
In calculating restriction, Total fuel flow GPH, fuel Hose ID, feet of fuel hose,
fittings, feet of lift or head of the fuel level, Type of Fuel filter must all be added in.

your TPI fuel pump produces 37-45 psi and the current fuel pressure regulator is designed to work at that pressure level
YOULL need to swap to a fuel system/pump that's designed to run at the 6-7 psi that a carbs fuel system are designed to run at. youll also want to run a decent single plane intake if your serious about the nitrous as dual planes seldom work as well with nitrous, don,t forget the HEADS, CAM, and EXHAUST need to match to get the full effect. BUT even WITH the low pressure 1984 pump that runs at about 14 psi you'll find a return style fuel pressure regulators MANDATORY with a carb

the TBI pump from the 1984 TBI vette runs at 14 PSI

THIS is a very good intake for use with a CARB AND nitrous plate

http://store.summitracing.com/partdetail.asp?part=HLY-300-110&autoview=sku

theres some info here

http://www.thirdgen.org/carbswap

http://www.chevytalk.org/fusionbb/showtopic.php?tid/49752/

viewtopic.php?f=55&t=1030

obviously when your talking about routing fuel lines, keeping them out of the passenger compartment , away from heat and shielded from potential impact damage as much as possible should be your prime concerns, use of rubber grommets,at reasonably close spacing to maintain support or clamps with rubber friction coatings are preferred.
the frequently over looked factor is the fittings and connections, they should be as few as possible, and carefully selected,as internal size and flow characteristics on many fittings will significantly restrict flow,and the in the tank sump pick-up and fuel line connections to the fuel pump and fuel filter and fuel pressure regulators will need to be taken into account, and a fuel cell will usually be the preferred route on a true performance application.on cars with frames its not uncommon to run fuel lines either along the inside lower surface or thru the frame rails, and place the fuel pump in an accessible location between the frame rail and tank, then run the fuel line forward and have it come up near the passenger side front frame rail, near the front of the engine, flex lines are normally limited to a short section near the carbs fuel manifold. If headers or electrical connections run too close the lines frequently get routed from the inside lower frame rail surface to the upper inside top surface of the forward frame rails or up along the firewall, then forward near the engines intake manifold.
SFI rated flywheels/clutches and LAKEWOOD explosion proof bell housings are a very good idea, as is having a CO2 fire extinguisher and a fuel pump shut off valve
viewtopic.php?f=27&t=867&p=5975&hilit=switch#p5975
remember that on any turbo or super charged engine application the fuel pressure MUST be indexed to the engine boost, to maintain the ideal fuel/air ratio, and you'll generally want most engines to run in the fairly lean 14.7:1-13.5:1 range at idle but be tuned to transition smoothly and consistently, to a fuel/air ratio closer to about 12.6:1 as the rpms AND loads on the engine are increased,
LOOK CAREFULLY AT THE CHARTS POSTED LOWER

without a fuel pressure gauge and an adjustable return style fuel pressure regulator with a return line installed your basically restricted to guessing, and chances are very good youll have major problems, you need the engine timing set correctly and you need to learn how to tune carbs and correctly read spark plugs
step one is getting the fuel pressure rock steady at 5 psi, then get the carbs floats and jets set correctly, so you get plugs that look like this

good

too lean

too rich

rdsk8ter · Jan 22, 2009

not sure if this is the best place to post this but you have a picture of what im thinking. I dont want to add a fuel cell to my car if i can avoid it. Im looking to add a sump to my current tank in my s 130 whats the best way to go about this? I see to weld it but is it better facing front back side etc etc I see them out the back all the time just not sure.

grumpyvette · Jan 23, 2009

they place them generally at the lower section of the floor of the fuel tank(that varies between car designs and clearance issues may limit choices) and sometimes at the rear of the tank so hard acceleration tends to stack fuel into them due to inertia, the big mistake many guys make is cutting one large hole in the fuel tank floor where the sump is located. thus hard braking tends to allow the fuel to flow away from the sump, your better off having several 1/2"-3/4" holes in the original tank floor located about center line on the sump, so rapid changes in direction still leave the fuel trapped in the sump, (SEE THE INFO EARLIER IN THE THREAD ON WELDING fuel tanks SAFETY)

http://www.centuryperformance.com/fueli ... g-140.html

base the nitrous jets on the fuel pressure you see spraying fuel,(for now) , if it drops (the fuel pressure) but the truth is if your seeing any drop in pressure the fuel system needs to be upgraded, you probably need bigger lines and a better fuel pump and better fuel pressure regulators.
and don,t forget to retard the ignition total advance and work up to the point in the ignition advance just before you get detonation indicators,

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=211

the problem with all decent quality fuel line supply component parts is they cost more money, than the cheap low quality parts and generally take up more room and take a bit more time and thought to install correctly, but you tend to get what you pay for in car part quality, and carefully matched parts will significantly increase flow volume, and stabilize the pressure.
you NEED a high quality ,return line style, fuel pressure regulator
http://www.summitracing.com/parts/hly-12-841/overview/

http://www.amazon.com/Moeller-Separatin ... d_sbs_sg_1

http://www.summitracing.com/parts/edl-1792/overview/
CARB PUMP BELOW

EFI PUMP BELOW

http://www.highflowfuel.com/i-10388...rainers.html?gclid=COabwduFgs0CFZKGaQodbGQCOw

450 LPH EFI FUEL PUMP

in this diagram the dead head regulators are some what optional, but the rest of the diagram holds true,

theres several decent manual fuel pumps available
http://www.summitracing.com/parts/EDL-1721/

http://www.summitracing.com/parts/SUM-EDL21/

once you expect to significantly exceed the factory horse power levels, you NEED the correct return style fuel pressure regulator, like those listed lower in the thread, and fuel supply and fuel return line lay out, back to the tank to get the consistent fuel supply required.
don,t be fooled into thinking you need a great deal more pressure, its maintaining the required flow volume to maintain the correct fuel air ratio,and control of that flow that maintains a consistent pressure of about 5psi-5.5psi at the carbs inlet port thats your key concern, not just a high pressure pump.

IF you suspect your fuel pump is not supplying the correct pressure or volume of fuel to the carb,
its fairly simple to verify or test.
verify your carb float levels, and check for vacuum leaks,and replace the fuel filter, first,
but to test the fuel pump,
you'll need a fuel pressure gauge

http://www.harborfreight.com/fuel-injec ... 92699.html

HF sell for under $20

to determine if your getting at least 5 psi ,use the test gauge, between carb and fuel pump, and if you are, then and if you are ,disconnect the fuel line from the carb , add a section of fuel line so you can easily let the pump push fuel into a large container like an empty milk or bleach gallon container you set on the floor and have a friend stand by with a fire extinguisher or at least a garden hose so that if you do manage to start a fire your ready to contain the resulting problem,have the friend hold the fuel line in the container while you start the car and time the test,if its a manual pump, allow the engine to idle on the fuel in the carb, and run for 30 seconds (YES TIME IT!)if its electric just turn on the pump for a timed 30 seconds,then measure the unrestricted fuel flow volume,with a large measuring cup, or quart container, like an empty oil container by pouring the resulting fuel flow you caught in the gallon container during the test,it should be no less than 1 quart minimum.

if your getting BOTH a minimum of 1 quart every 30 seconds AND 5 psi your marginal, but usually going to be ok for a basic street car, fuel supply.
if you get less than 5 psi or less than 1 quart of fuel in 30 seconds of unrestricted flow the pumps at least highly suspect or more likely faulty, and should be replaced, you should be getting at least 2 quarts, 1 quart in 30 seconds is PATHETIC AT BEST
in most cases you'll have closer to 2-3 quarts of fuel in the gallon container , if you have a decent quality fuel pump and have a pressure reading 6-8 psi and you'll need your friend to hold the fuel line into the gallon container or its likely to jump out and throw fuel around if un-restrained as the fuel jets out, so be aware of the potential spilled fuel/fire hazard

heres a few fuel pumps, notice the unrestricted flow is over a gallon a minute

http://www.summitracing.com/parts/EDL-1722/

http://www.summitracing.com/parts/EDL-1721/

http://www.summitracing.com/parts/CRT-M4530/

http://www.summitracing.com/parts/CRT-M6101/

http://www.summitracing.com/parts/SUM-G3136/

http://www.summitracing.com/parts/CRT-P4070/

http://www.summitracing.com/parts/MRG-95H/

naturally having a fuel pressure gauge mounted to the carb inlet feed makes diagnosing problems faster

http://www.summitracing.com/parts/MRG-2975/

http://www.summitracing.com/parts/HLY-26-504/

HERES SOMETHING FAR SUPERIOR, to stock fuel filters if you need something better

http://www.aemelectronics.com/universal ... ilter-1212

KEY FEATURES
Machined from 6061-T6 aluminum and hard anodized black
Flows up to 12.32 gpm @ 45 PSI and 2.63 gpm @ 6 PSI with -10 port fittings
Filters as low as 7 microns
Viton o-rings and gaskets ensure outstanding performance when using gasoline, alcohol or gasoline/alcohol blended fuels
End caps are machined with -10 AN female fittings with o-ring receiver groove
End caps have pressure intensifiers for greater sealing of end gaskets
2â€ OD x 10â€ length for easy mounting
Commonly available replacement filter cartridges
Laser etched with AEM logo, flow and filter replacement information

The AEM High Flow -10 AN Inline Fuel Filter is CNC machined from 6061-T6 Aluminum and Hard Anodized Black. AEMâ€™s engineers designed this filter with the racer in mind and with the intention of maximizing flow, filtration and ease of installation. The end caps are machined with -10AN female fittings with o-ring receiver groove that allow the filter to flow up to an astonishing 12.32 gpm @ 45 PSI and 2.63 gpm @ 6 PSI. All sealing o-rings and gaskets are made of Viton for outstanding performance when using gasoline, alcohol or gasoline/alcohol blended fuels. The commonly available replacement filter cartridges filter as low as 7 microns. The standard 2â€ OD allows for easy mounting virtually anywhere in the vehicle.
read thru the links and sub links

grumpyvette · Jan 29, 2009

FUEL SYSTEM REQUIREMENTS FROM EDELBROCKS TECH SITE

BRAKE SPECIFIC FUEL CONSUMPTION

BTW alcohol in fuel tends to cause aluminum to oxidize over time
http://video.foxbusiness.com/v/2000862202001/

Brake Specific Fuel Consumption is the ratio of fuel consumed (in lbs. per hour) to horsepower produced. This ratio is a direct indicator of how efficiently the engine converts fuel into power. Most factory gasoline type engines run approximately a .50 to .55 Brake Specific Fuel consumption (BSFC) range while a highly efficient normally aspirated race engine operates at approximately a .40-.45 BSFC.

Most common turbocharged or supercharged engine configurations run in the .55 to .60 BSFC range

For Methanol powered applications the BSFC is doubled (i.e. turbo/methanol: 1.10-1.20)

These factors should be considered when sizing & selecting injectors for your particular application.

LBS/HR = HP X BSFC

Generally BSFC = 0.50.

Example: How much fuel flow will you need to feed your new 440 hp E-Tec EFI
crate engine?
Lbs/hr = 440 x 0.50
Lbs/hr = 220

GPH = LBS/HR Ã· 6.0

Example: What is the GPH for the 440 hp crate engine?
Lbs/hr = 220 Ã· 6
Gals/hr = 37

Please Note: The above equations and rules apply only to four-cycle engines. The equations have been simplified for ease of understanding. Answers will be approximate but generally will be close enough for use as a guideline.

as a rough guide, and assuming your running a carb engine with the correct fittings and fuel pump etc
this is about the max hp those fuel lines can be expected to support

AN4 (5/16")=375hp
an6 (3/8")=575hp
AN8 (1/2")=850hp

Common Fuel Delivery Mistakes and How to Correct Them
by Barry Grant Inc. Â©2004

Fuel lines, filters, pumps, and regulating devices exist to deliver gasoline or alcohol from the fuel cell to the carburetor, and in a bypassing system return it to the fuel cell. Pressures and volumes vary depending upon the kind of fuel used (gasoline or alcohol) and the type of fuel system employed. With routine maintenance, a good fuel system will pay dividends; yet many cars are fitted with systems that fall below the necessary standards. With a little help from BG Fuel Systems of Dahlonega, Georgia, here is a list of the most common mistakes in competition fuel systems and a guide as to how to correct them:

1. Incorrect fuel lines
Do not use 1/4" - 3/8" o.d. lines on a racing fuel system between the fuel cell and the pump. Racers often joke about their first race car and how the fuel line was so small it functioned as the main jet. Ensure the fuel is supplied through lines that are of the correct size for the application. Remember fuel line size is determined by the system, not the vehicle! Push-Lok, stainless steel braided hoses, and aluminum tubing are the most common fuel lines used on race cars.

2. Right-angle hose-end fittings from the pump to carburetor
Avoid forged 90*elbow fuel fittings as much as possible. Although they are inexpensive and readily available, they're restrictive and frequently cause fuel flow troubles. Hose ends with angles of 90* & 45* should also be avoided if possible. Nonetheless, should it become necessary to use one, use radiused hose ends (90* bends) as they have much better rates of flow. They're manufactured from aluminum, equipped with swivel ends for a positive seal and are easy to install.

3. Fuel pumps unsuitable for alcohol
An alcohol fuel system differs from the gasoline alternative in several crucial respects. Fuel pressures in a gasoline system are typically maintained between 7- and 9-psi throughout the rev range, whereas alcohol carburetors require low pressures of around 4- to 6-psi at idle and 9- to 11-psi at fully open throttle. This is necessary to prevent the carburetor from flooding at idle and under light engine load, yet maintain the extra volume necessary for maximum acceleration. Engines producing around 500-hp can be fueled with a 15-psi mechanical pump in conjunction with a throttle bypass valve. However, for engines over 500-horsepower, a belt-driven system with a diaphragm valve, or poppet bypass should be considered. For overall reliability and performance, a belt-driven system is usually the better choice. When using a diaphragm bypass, BG Fuel Systems recommend it be installed close to the carburetor for faster response.

4. Incompatibility between bypass and pump
Throttle bypasses were designed to operate with block-mounted pumps and, similarly, diaphragm bypasses with belt-driven pumps. Never use a throttle bypass with a belt-driven pump - they must function in pairs and are not to be mismatched.

5. Unsuitable fuel filter
Fuel filters with conventional paper elements must not be used with alcohol. Because alcohol absorbs water, the paper and the bonding materials deteriorate quickly. As a consequence, particles can enter the float bowls, or get stuck in the needles-and-seats and main jets. Further, it's equally important on alcohol applications, to avoid filters with inadequate flow rates, and inlet and outlet sizes that are too restrictive.

6. Neglecting routine maintenance on an alcohol system
Although alcohol fuel additives can help prevent corrosion and provide lubrication for pumps and other components, alcohol can severely corrode metal objects, especially aluminum, if allowed to remain in contact too long. There is no substitute for a strict maintenance program, it will not only prolong the life of the carburetor and fuel system, but also keep it trouble-free. Alcohol will naturally absorb water from the air. This not only dilutes the fuel, but also adds to the corrosive effects of alcohol. After every race, the alcohol should be drained from the race car and stored in air-tight containers; a vented fuel cell is not considered an appropriate storage container. The fuel system and carburetor should also be thoroughly drained and flushed of any residual alcohol. Some racers will add gasoline to the empty fuel cell and run the engine until they are certain the carburetor is filled with gasoline. Other methods include removing the carburetor and flushing it with a cleaning solvent or lubricating aerosol sprays. Removing inlet and outlet fittings from the pumps, bypasses etc. and lubricating the internals is also an acceptable practice. Whatever the method, maintenance on an alcohol system is crucial; ignore it and the system will fail.

7. Failing to use a high-flow air cleaner
Race engines rely on receiving air as well as fuel, but are frequently starved by the use of thin, small-diameter air filters that are detrimental to their performance. If possible, use a filter that is 14"diameter x 4"tall. If clearance is at a premium get one with a recessed pan, which allows for deeper filter elements. Get a good quality air filter. If you're constantly cleaning lots of dirt from the surface of your race car the chances are your air cleaner is struggling to filter the dirt and debris from your engine.

8. Deterioration of foam-filled fuel cells
Modern military-spec foam-filled fuel cells, are compatible with conventional fuels, racing fuels and alcohol. However, alcohol can cause the foam to deteriorate and it must be renewed once a year. To check the condition of the foam, simply remove the cap and pinch it between finger and thumb. If pieces come away the foam must be replaced.

9. Not having proper linkage travel and return springs
Make sure that, at wide-open throttle, the butterflies of the carburetor are fully open. Use a minimum of two, good quality return springs - preferably of stainless steel and employ them, if possible, in two different places on the linkage. Ensure the linkage and the return springs operate without interference throughout the full range of throttle travel.

10 Failure to use an adjustable pedal stop.
It's amazing to consider the large numbers of race cars that have no form of throttle-pedal stop, and inexcusable that so many are permitted to compete. Excessive loadings on the linkage, carburetor shafts and butterflies can cause the mechanisms to distort and jam, and the consequences are usually grim. To avoid the inevitable, use an adjustable pedal stop and, at the fully open throttle position, synchronize the stop on the carburetor with the stop on the pedal.

11. Not having the proper size of carburetor for the application.
Having the proper venturi sizes for a given application ensures the carburetor generates sufficient air speed. Air speed creates the necessary depression (low pressure) to draw fuel through the metering systems and booster venturii into the air stream to be atomized. The Race Demon, which is equipped with removable venturi sleeves and boosters etc., overcomes most of the sizing problems.

12. Inadequate fuel cell venting.
If the fuel cell vent is too small the fuel system can malfunction. In extreme cases, inadequate ventilation can cause permanent damage to the system. As the fuel pump draws fuel from the cell it needs to be replaced by air. If the vent on the cell is too small the pump will try to draw the fuel from the cell faster than the air replaces it. This can create a vacuum in the cell, distort its shape, and starve the pump and engine of the fuel it requires.

13. Filtering of fuel cell vents.
Just as an undersized vent will adversely affect your fuel system, not having a filter on the vent will cause dirt and debris to enter it. As air replaces the fuel, the vent hose will attract anything that's in the air, including dirt, sand, or debris. These particles will eventually destroy a fuel system as well as an engine.

14. Fuel filter location.
To protect the fuel pump and carburetor, use a good filter before the pump, and filtered fittings at the carburetor.

15. Inspections.
Steel braided fittings and aluminum fittings have a life cycle. Over a period of time, the rubber bore will deteriorate causing the line either to collapse and starve the engine of fuel, or disintegrate and possibly block the passage. Radiator hoses and fan belts are routinely replaced and so, too, should fuel system components. Aluminum fittings will wear out over time and fail to seal properly. From a safety and performance standpoint regularly check the lines and fittings. Try to detect soft or weak spots by feeling the outside of the lines, and visually inspect the internals each season. Keep the connections tight.

16. Relays for electric fuel pumps
On cars equipped with electric fuel pumps, use a relay to ensure the pump is provided with the proper voltage in order to maintain proper fuel flow.

Barry Grant, Inc.

http://injectordynamics.com/articles/fuel-pressure-explained/

grumpyvette · Dec 27, 2009

now the question frequently comes up as to wheres the best location for the fuel pump and fuel filter, because fuel pumps (ESPECIALLY ELECTRIC FUEL PUMPS) push fuel far more efficiently than they PULL or suck fuel the obvious location is as low as practical, so they tend to self prime and as close to the tank as clearances and the application will allow.
but obviously it needs to be easy to access and easy to inspect, as it will need to be changed occasionally.
you also want it mounted where its NOT easily damaged in a fender bender type accident, as its potentially a fire hazard if its easily crushed.

READ

http://www.crankshaftcoalition.com/wiki ... Pump_Mount

http://www.chevyhiperformance.com/techa ... index.html

http://www.hotrod.com/howto/42519_nitro ... index.html

http://www.hotrod.com/techarticles/gene ... index.html

http://www.ehow.com/video_2328063_assem ... plate.html

viewtopic.php?f=55&t=733

the oil pressure switch might be defective, if the fuel pump won,t run, even if its new
and at $11-$35 Id just swap it out if your concerned
some early c4 vettes have the gauge and oil pressure switch on an adapter near the distributor base into the block

http://www.ecklers.com/product.asp?pf_i ... ept_id=153

http://www.ecklers.com/product.asp?pf_i ... ept_id=153

the single terminal sensor runs the oil gauge the dual connector runs the fuel pump ONCE theres about 5 psi of oil pressure but they do fail and they do leak oil when they fail and both are commonly located near the distributor

http://www.jegs.com/i/Holley/510/12-803BP/10002/-1

thats a dead head style regulator and its FAR FROM IDEAL, all QUALITY return style regulators that Ive seen, have THREE PORTS

(1)FEED from tank
(1)CARB feed line
(1)RETURN to tank
and a pressure adjustment screw, and a vacuum line connection to the plenum

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=211

if your running a carb, you need to have a correctly set up fuel system, one of the more common complaints is related to fuel pressure at the carb inlet port, many fuel pumps produce 6-12 psi of fuel pressure at higher rpm levels , some even provide that at idle speeds, that much pressure tends to flood carbs and make float adjustment difficult or useless, only 7-9 psi will almost always overcome the needle & seat and constantly flood the carb, that is probably the source of your major problem, install a RETURN STYLE fuel pressure regulator, and a line back to the tank or at least back to a TEE thats located before the pump intake point

http://www.jegs.com/webapp/wcs/stor...wd=Fuel+Line&gclid=CNrLsez3opkCFQudnAodtC_cpQ

yes the diagram says 8PSI your far better off with 5 psi in most street car applications

these cheap ones, that are dead head style seldom work well

http://www.jegs.com/p/Holley/745059/10002/-1

much better
http://www.jegs.com/i/Mallory/650/4307M/10002/-1

http://www.jegs.com/InstallationInstructions/600/650/650-4307M.pdf

http://www.summitracing.com/parts/MAA-4309/

High-flow for your fuel system.

When using high-pressure fuel pumps, a fuel pressure regulator must be installed to prevent carburetor flooding. These Mallory fuel pressure regulators feature housings fully machined from 6061-T6 billet aluminum, and specially designed high-flow fuel passages. These features, combined with a quick-acting diaphragm assembly, make them extremely efficient. A mounting bracket is provided to allow quick and easy mounting.

http://www.summitracing.com/parts/MAA-4307M/

http://www.summitracing.com/parts/AEI-13351/

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635

brngrhd · Dec 27, 2009

how would you do a system that runs one pump with EFI and nitrous? say 45PSI on the EFI and 6psi on the nitrous?

grumpyvette · Dec 27, 2009

If I did that..and I,m not sure I would as its potentially got a few problems,.... ID probably use the return line on the 45 psi efi regulator to feed a second 6psi regulator with a return line to the tank, but you would need two fuel pressure gauges to verify it functioned correctly

fuel tank>>>>filter>>>>high pressure fuel pump>>>>>efi fuel rails, feeding injectors>>>>fuel pressure gauge>>>>45 psi regulator>>>>>low pressure return line>>>>>nitrous feed solenoid>>>>fuel pressure gauge>>>>6psi regulator.>>>>zero pressure return line>>>>>back to fuel tank

if you have a wide band oxygen sensor youll generally want to try to get into the 12.7-13.5 fuel/air ratio band, any leaner tends to get into detonation, any richer tends to get into ignition problems,but supercharged and turbo engines tend to run better on the rich end of that fuel air ratio, and many issues are related to not enough spark energy and heat or incorrect spark timing
but start by getting the ignition advance curve consistent.
then verify your getting both constant fuel pressure and volume, as a drop in either can cause problems.
maintaining a rock solid and consistent fuel delivery is a frequently over looked issue.

viewtopic.php?f=70&t=4683

viewtopic.php?f=55&t=635

viewtopic.php?f=55&t=109

viewtopic.php?f=55&t=211

viewtopic.php?f=55&t=1961

grumpyvette · Mar 13, 2010

obviously the answer, to where youll mount a fuel filter is dependent on both its size and design, it is also dependent on your options as cars and trucks vary wildly and in most cases youll want to mount it as close to the fuel take and before the fuel pump if possible but of course that's not always an option, a few guys I know with pick-ups mount them on the frame near the rear of the cab most guys choose the fire wall or inner fender or radiator support , you'll need to find a location that's easily accessed if you run that type of filter , but it has distinct advantages over the more common low quality filters

generally a decent option

http://www.holley.com/EarlsCatalog/Cata ... eNumber=59

these glass filters are in my opinion a HUGE POTENTIAL fire hazard and are known to be restrictive to fuel flow rates required once you exceed about 400hp

Ive found these type to be restrictive

HERES SOMETHING FAR SUPERIOR, to stock fuel filters if you need something better

http://www.aemelectronics.com/universal ... ilter-1212

http://www.summitracing.com/parts/rus-650103/overview/

grumpyvette · Apr 14, 2010

selecting a fuel pump for your horsepower delivery becomes fairly straight forward.
Weight of fuel:
The average advertised weight of a gallon of premium fuel is 6.34 lb/gallon.
Brake Specific Fuel Consumption or B.S.F.C.
Brake Specific Fuel Consumption or B.S.F.C. is the amount of fuel required to produce 1 HP for 1 hour. This means that an engine with a B.S.F.C of .5 will burn 1/2 or .5 lbs of fuel to produce 1 HP for one hour. Determining exact B.S.F.C for a specific engine is complicated and requires an engine dyno.
Based on industry standards the B.S.F.C for:
Normal Aspirated Engines is .45 - .55
Supercharged Engines is .55 - .60
Turbocharged Engines is .6 - .65
Fuel Pump Pumping Losses:
Fuel pump pumping losses is the difference in fuel pressure measured at the fuel pump exit and that of the fuel pressure at the exit of the fuel rail. Friction, fuel line inside diameter and turns or bends in the fuel line is the cause of the pressure difference which can be as high as 4 - 10 PSI.
Fuel Pressure Regulator or FPR:
A fuel pressure regulator or FPR is a piece of equipment that mechanically or electronically controls fuel pressure. Without getting to technical, the FPRâ€™s purpose is to raise or drop the fuel pressure from a preset point by the same amount the pressure in the intake manifold changes. Lets say the FPR is set to a base pressure of 43.5 PSI and the manifold pressure goes up by 1 PSI the FPR now should control the fuel pressure at 44.5 PSI.
About injectors and boost:
Most fuel injector flow rates are advertised statically at 43.5 PSI. This means that fuel flow is measured while the injector is kept open fully and fuel is pumped threw the injector at a pressure of 43.5 PSI into atmospheric. To maintain advertised flow rates the fuel pressure should be raised or dropped by the same amount the pressure in the intake manifold raises or drops. If static fuel pressure is set to 43.5 PSI and manifold pressure raises to 20 PSI fuel pressure should rise to 43.5 + 30 = 73.5 PSI. Max HP supported by an injector is calculated to flywheel power.
How much fuel do I need for a 4 cylinder turbocharged engine making 500 HP to the crank at 30 PSI?
First we need to calculate total fuel pressure.
(Base fuel pressure) + (Total Boost) + (Pumping Loses) = Total Fuel Pressure required
43.5 + 30 + 5 = 78.5 PSI
Now we need to calculate fuel required:
Target Hp * B.S.F.C. = Fuel required in lbs/hr
500 *.6 = 300 lbs/hr
Most fuel pumps flow rate is advertised in gallons per hour:
Lbs/hr / fuel weight per gallon = gal/hr
300 / 6.34 = 47.32 gal/hr
To make 500 crank HP at 30 PSI of boost we need a fuel pump that will be able to supply 47.5 gal/hr at 78.5 PSI.
From the selection chart on the bottom we can see that a Walbro high pressure 255 ltr/hr at 13.5 volt will supply enough fuel for the HP requirement

Walbro fuel pump flow rates and current draw at 12 volts
Pressure
(psi) 190 ltr/hr
fuel pump
(gal/hr) 190 ltr/hr
fuel pump
(amps) "high pressure"
190 ltr/hr pump
(gal/hr) "high pressure"
190 ltr/hr pump
(amps) 255 ltr/hr
fuel pump
(gal/hr) 255 ltr/hr
fuel pump
(amps) "high pressure"
255 ltr/hr pump
(gal/hr) "high pressure"
255 ltr/hr pump
(amps)
0 56 2.6 53 2.8 75 4.7 76 4.4
10 52 3.2 50 3.5 72 5.2 73 4.8
20 48 4.0 48 4.3 67 6.1 68 5.5
30 44 4.8 44 5.0 62 7.2 63 6.3
40 40 5.7 41 5.9 58 8.2 59 7.1
50 36 6.6 38 6.8 53 9.3 54 8.0
60 32 7.6 35 7.8 49 10.6 51 8.9
70 28 8.6 31 8.8 40 11.8 46 9.9
80 22 9.7 29 9.9 29 13.3 41 11.0
90 12 10.8 25 10.9 0 14.6 32 12.0
100 0 12.5 21 12.0 22 13.2
110 17 13.5 11 14.5
120 11 15.0 1 15.8
Walbro fuel pump flow rate and current draw at 13.5 volts
Pressure
(psi) 190 ltr/hr
fuel pump
(gal/hr) 190 ltr/hr
fuel pump
(amps) "high pressure"
190 ltr/hr pump
(gal/hr) "high pressure"
190 ltr/hr pump
(amps) 255 ltr/hr
fuel pump
(gal/hr) 255 ltr/hr
fuel pump
(amps) "high pressure"
255 ltr/hr pump
(gal/hr) "high pressure"
255 ltr/hr pump
(amps)
0 63 3.1 60 3.3 82 5.2 85 5.0
10 61 3.5 58 3.9 81 5.9 82 5.2
20 57 4.2 56 4.5 76 6.5 79 6.0
30 52 5.0 52 5.3 71 7.8 73 6.8
40 49 5.8 50 6.2 68 8.6 70 7.5
50 46 6.6 47 7.2 62 9.8 65 8.2
60 42 7.5 45 8.0 58 10.8 61 9.1
70 38 8.4 41 8.8 50 12.0 56 10.2
80 32 9.4 38 9.8 39 13.3 51 11.1
90 22 10.3 34 10.9 11 14.4 43 12.1
100 14 11.5 31 12.0 1 15.0 32 13.2
110 12.7 28 13.2 20 14.3
120 22 14.5 11 15.7
130 18 16.0 17.0

grumpyvette · Apr 14, 2010

lets say youve got a 450 hp sbc and your looking for a decent mechanical fuel pump, the choice is between two in your catalog , one pumps 35 gallons per hour and one pumps 80 gallons per hour, but costs a bit more, so you want to know if the smaller pump will work?

The average advertised weight of a gallon of premium fuel is 6.34 lb/gallon.
Brake Specific Fuel Consumption or B.S.F.C.
Brake Specific Fuel Consumption or B.S.F.C. is the amount of fuel required to produce 1 HP for 1 hour. This means that an engine with a B.S.F.C of .5 will burn 1/2 or .5 lbs of fuel to produce 1 HP for one hour. Determining exact B.S.F.C for a specific engine is complicated and requires an engine dyno.
Based on industry standards the B.S.F.C for:
Normal Aspirated Engines is .45 - .55
Supercharged Engines is .55 - .60
Turbocharged Engines is .6 - .65

need to calculate fuel required:
Target Hp * B.S.F.C. = Fuel required in lbs/hr
450 *.6 = 270 lbs/hr
Most fuel pumps flow rate is advertised in gallons per hour:
Lbs/hr / fuel weight per gallon = gal/hr
270 / 6.34 = 42.6 gal/hr
but remember there are inevatably going to be pumping losses, fitting and line and filter induced flow rate restrictions, and a fuel pressure regulator and youll need to think through and fabricate a well designed matched,return line fuel feed system design, with matched flow requirements ?
well on a mechanical fuel pump that supplies about 7psi at the pump, getting more than 4-5 psi at the carb, under hard acceleration is going to be a challenge, due to flow restrictions, pumping losses, etc. youll find that the 80 gallon pump matched to a quality fuel pressure regulator,is about the minimum required, and a 100-110 gallon flow at 7 psi would be a nice option http://www.centuryperformance.com/fuel.asp

diagrams

this basic fuel system, and line size will work to over 650hp or more with the correct pump and regulator, youll want a MINIMUM of AN #6 or 3/8" fuel lines on both the feed and return lines on a 450 hp engine

grumpyvette · Jun 25, 2012

now in this thread and its related sub links we discussed fuel line size and the fact that quality AN#8 fittings, are far less likely to pose a significant restriction to fuel flow rates in most performance applications and that a quality fuel filter must be used rather than the cheap off the shelf plastic or glass fuel filters you occasionally see used.
be aware that the cross sectional area of both the fuel lines and fuel filter medium,
and the fuel pressure regulator and return line cross sectional area all effect the fuel delivery efficiency
and fuel delivery consistency is critical,, you need a certain, dependable,
fuel volume available, pressure increases only go so far in correcting lack of required fuel delivery issues,
and you might get by with a cars stock 3/8" lines on a dyno , but once your dealing with inertial loads,
and longer duration, high power runs a 3/8" line is usually hopeless on a 750-1000 hp engine

We’ve created three abbreviated charts pulled from Aeromotive’s data. These pressure drop charts are based on rubber-lined AN fuel hose. If you were to use hard line or smooth PTFE line, the pressure drops would likely be slightly lower. Note the major effect hose length has on pressure drop. While hose diameter is critical for volume, it’s obvious that length adds to the load that the fuel pump must support.

A quick way to equate lbs/hr to horsepower is to divide flow by the bsfc. Example: 600 lbs/hr / 0.50 bsfc = 1,200 hp. This example uses a normally aspirated, gasoline bsfc. As you can see by the charts, it would not be wise to plumb a 1,200 lbs/hr system with -8 line through 15 feet since that would generate a fuel system pressure drop of 14 psi.

Clow also pointed out that making the fuel line too large as an over-compensation for pressure drop can also cause problems. He mentioned that some big race teams have discovered that oversized fuel lines/fuel rails can kill flow velocity, which should be 3 to 12 feet per second on the pressure side of the system. An overly large fuel line will develop excessive fuel pressure fluctuations. Big may be good, but bigger is not always better!

One further check to ensure the fuel system operates at maximum efficiency is to pay close attention to the electrical side of the pump. As you can imagine, amperage demand also increases with higher fuel pressures. This places an increased load on not only the charging system to supply the necessary current and voltage; it also requires reviewing wire gauge to ensure it can handle the current and prevent voltage drop to the pump.

The above chart lists the wire gauge size recommendations depending upon the combination of the pump’s current draw and the length of the wire running from the power source to the pump. This chart assumes no more than a 3-percent voltage drop. Always use the same gauge wire for the ground circuit.

We’ve included a chart listing Aeromotive’s brushless pumps all pushing against a 60-psi head pressure. The smallest of the pumps requires just over 11 amps while the big pump spikes the load to 24 amps. At full song it might be necessary to employ a charging system capable of 100 to 140 amps to handle ignition, fans, accessories, and the fuel pump to ensure the voltage remains stable.
Once the charging system is spec’d, even a small pump demanding 20 amps over a 15-foot length of wire will benefit from an 8-gauge wire to minimize the voltage drop. The best way to ensure the entire system is sized properly is to perform a dynamic voltage drop test. This could be done with a volt meter, or better a data recorder monitoring the voltage at the fuel pump under max load. If the voltage drops below 13.5 volts yet it shows 14.3 volts any other time, you then know you have a 0.80-volt loss and there is work to be done to bring that drop closer to 0.40-volt or less.

In Conclusion

Maintaining voltage at the pump is critical since voltage is torque to an electric motor and torque is what keeps the pump from slowing down as pressure rises. Aeromotive pump flow curves plot both 13.2 volt (battery only) and 14.4 volt (alternator-equipped) applications. It’s obvious looking at the flow curves that keeping voltage at 13.5 volts or better is important to maintain expected fuel flow volume. Of course, higher voltages (14.5-16.0 volts) will make the pump run stronger. This is the idea behind voltage-boosting boxes that bump the system voltage to the fuel pump. While this does increase pump output, it comes at the price of reduced pump lifespan.

While it may appear that choosing a fuel pump is a complex process, hopefully we’ve illustrated that it’s not black magic and that with careful planning you can design an efficient fuel system for virtually any engine. Making power means paying attention to the details. When that happens, your efforts make success look almost effortless.

Based on this NHRA rule

Lines: All non-OEM fuel lines (including gauge and/or data
recorder lines) must be metallic, steel braided, or NHRA-accepted
“woven or woven-pushlock.” A maximum of 12 inches total (front to
rear) of non-metallic or non-steel braided hose is permitted for
connection purposes only; individual injector nozzle and motorcycle
fuel lines are excluded. Fuel lines (except steel braided lines) in the
flywheel/bellhousing area must be enclosed in a 16-inch length of
steel tubing, 1/8-inch-minimum wall thickness, securely mounted as
a protection against fuel-line rupture. Fuel lines may not be routed
in the driveshaft tunnel. It is mandatory that fuel lines passing
supercharger drive belts be steel braided, NHRA-accepted woven
or woven-pushlock, or be enclosed in protective steel tubing. A
current list of NHRA-accepted woven or woven-pushlock fuel lines
is available on NHRA.com. All NHRA-accepted fuel lines must use
ends that are specifically designed for the type of fuel line being
used. No hose clamps allowed on NHRA-accepted fuel lines.
Pumps/Valves: Cars with non-OEM-type mechanical fuel pumps
must have a quick-action fuel-shutoff valve within easy reach of
driver and located in the main fuel line between the fuel tank and
the carburetor and/or injectors. Fuel recirculation systems not part
of normal fuel/pump system prohibited. All cars in Stock, Super
Stock, Competition, and Pro Stock must be equipped with a
positive-lock drain valve located between the fuel tank and the
carburetor(s) or fuel injector to facilitate removal of fuel samples for
fuel-check purposes

http://www.youtube.com/watch?feature=pl ... uIoAa5RRBs

but Id point out that routing your fuel pressurized and return lines away from the exhaust header heat or in areas potentially impacted by a failed drive shaft or an exploding clutch assembly only makes good sense, and a bit of ARMORING in areas you cant avoid by running lines thru a larger short section of 1"-1.375" section chrome moly tube,thats a minimum of 1/8th inch thick, that will weight less than a lb or two, to act as a shrapnel deflector makes a great deal of sense.
a 24"-to-36" section of custom bent armor tube thats solidly clamped to the frame ,protecting the fuel lines run thru it in the area near the headers and bell housing can save you a great deal of damage or the car catching on fire if the armor prevent fuel lines from being cut in a clutch of converter failure

http://www.onlinemetals.com/merchant.cf ... &top_cat=0

RELATED INFO, with lots of optional , and useful info, failure to take the time to read thru the linked info could eventually cost you far more than the time it takes to read the links

viewtopic.php?f=55&t=211

viewtopic.php?f=55&t=6105&p=18854&hilit=fuel+filters#p18854

http://www.hotrod.com/techarticles/engi ... ewall.html

viewtopic.php?f=55&t=1939

viewtopic.php?f=55&t=635

http://www.boydwelding.com/?gclid=CIuGs ... 7Aod-BAANg

viewtopic.php?f=55&t=733&p=1614&hilit=fuel+cell#p1614

viewtopic.php?f=55&t=4381&p=11507&hilit=fuel+cell#p11507

http://garage.grumpysperformance.co...ks-and-welding-on-fuel-tanks.6178/#post-61230

Transporting Limited Amounts Of Fuel, Or Waste Oil

I don,t know how many of you gentlemen have shop welder/generators or other lawn mowers or similar equipment that requires you to buy and transport a bit of fuel for thier use, but Ive noticed that finding a well designed structually strong 5 gallon fuel transport container thats rather leak and...

garage.grumpysperformance.com

Indycars · Oct 10, 2012

grumpyvette said:
HERES SOMETHING FAR SUPERIOR, to stock fuel filters if you need something better

http://www.aemelectronics.com/universal ... ilter-1212

Using the link you provided above.....on the AEM web page they give other filter
elements that will fit their filter housing. The Wix 24004 works in their filter
housing, but Wix also sell a filter housing at 1/2 the cost.

$43.95
http://www.summitracing.com/parts/WIX-24003/

$87.27
http://www.summitracing.com/parts/AVM-25-201BK/

BTW, it's also used inline at the gas station pump nozzle.

grumpyvette · Oct 10, 2012

great find! Ive found similar filters in the past and I would not be a bit surprised to find some company's relabel and charge a good deal more for identical filters

Indycars · Oct 11, 2012

There seems to be 3 different styles of electric fuel pumps:

1.) Internally regulated to about 7psi, no separate pressure regulator needed.
2.) Puts out 14 psi and requires a dead head type pressure regulator.
3.) Puts out at least 14 psi and requires a return style pressure regulator.

Can all 3 styles of electric fuel pumps be used with a return style pressure regulator ???

grumpyvette · Oct 11, 2012

Indycars said:
There seems to be 3 different styles of electric fuel pumps:

1.) Internally regulated to about 7psi, no separate pressure regulator needed.
2.) Puts out 14 psi and requires a dead head type pressure regulator.
3.) Puts out at least 14 psi and requires a return style pressure regulator.

Can all 3 styles of electric fuel pumps be used with a return style pressure regulator ???

not only is the answer YES they can, the answer should be yes they should be, because only a return style regulator can maintain the consistent 5psi-6 psi most carburetors work best with.

viewtopic.php?f=55&t=635

viewtopic.php?f=55&t=10665&p=46016&hilit=flex+line#p46016

bytor · Oct 11, 2012

Grumpy, whats your thoughts on using swagelok fittings in fuel line builds? Seems like an valid option for those of us who aren't tubing flaring experts.

Related links:
http://www.swagelok.com/search/find...NWD&item=20b6dcb5-5a04-42f1-9df7-a5d3fd3672c3

http://www.youtube.com/watch?v=FdthSQDH8qk

http://forums.corvetteforum.com/c6-...nyone-installing-aftermarklet-fuel-rails.html

grumpyvette · Oct 11, 2012

http://www.swagelok.com/downloads/webca ... 13-151.pdf

http://www.duccutters.com/ConvertionCha ... bzyv5ytbP1

they look like a great option, but Ive got to admit Ive never personally used those,
Ive found that if I carefully measure the length and diameter of any fuel lines, transmission fluid cooler lines or oil coolant lines , I need and have the local HYDRAULIC SUPPLY fabricate exactly what I need with the correct swagged ends. I usually specify AN#8 and of course depending on the application, you let them know exactly what you intend to use the fluid transmission lines for, for something like fuel, you obviously would specify the lines for fuel, and able to handle at least 120 psi.
for hot transmission lines I specify 300 psi and 350 F temp range.
Ive found the prices and quality excellent,having the local HYDRAULIC SUPPLY SHOP FABRICATE LINES, and they make anything I want while I wait

one factor I see guys ignore at times is when a in tank fuel pump goes bad, guys read the instructions about dropping the fuel tank to get access to the in tank fuel pump to replace it, which in some cars makes the replacement procedure a HUGE P.I.T.A. and start thinking ,...hey Ill just tap into the fuel line and install one of the outside mount electric fuel pumps and avoid all that work, FORGETTING that the defective in tank fuel pumps going to significantly restrict fuel flow, as its still in the fuel line in the tank

setting up your fuel system

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