mechanical constant flow injection

Discussion in 'Intake Systems , fuel systems and related' started by grumpyvette, Jan 25, 2011.

  1. grumpyvette

    grumpyvette Administrator Staff Member

    I was at a local guys house recently and he was discussing the fact that hes always loved how the older STACK injection systems, looked but he had heard they were miserable to tune and not nearly as precise as the newer EFI systems.
    well I guess if your totally non- experienced with something anything you don,t fully understand is intimidating, but honestly, having grown up using that type of injection I really prefer them, as they really are fairly simple to tune once you understand the basic concepts.
    with experience you can exactly match the engines air flow and fuel needs and INTAKE RUNNER LENGTH to PRODUCE RAM TUNED PULSE STRENGTH to maximize power
    , its the ability to change intake runner stack length and exactly ram tune the intake to maximize power under a specific set of conditions that gives stack injection a pronounced advantage in torque curve produced.


    theres several basic components, the most obvious is the manifold with the individual stacks feeding each individual runner, each has a throttle butterfly that needs to be adjusted so it exactly duplicates the other 7 angle and degree of opening, these butterfly or throttle plates restrict air flow into the engine just as the similar ones in a carburetor do. this is frequently done with a vacuum gauge but experience is required to get it tuned correctly

    below the butterfly throttle plate is an injector,the injector size can be changed,like carb jets, this this injector sprays fuel in a fan or or fogger type pattern,
    [​IMG]
    similar to a nitrous system, but the amount of fuel depends on the fuel pressure and volume of fuel reaching it produced by the mechanical fuel pump, the injector size and the pill or return jet that cycles excess fuel to the fuel cell, some systems have a high and low speed return jet system, most have a barrel valve and adjustable ratio linkage

    theres an adjustable mechanical linkage connecting all 8 throttle plates thats also linked to a linkage controlling a valve that controls how much fuel enters the common distribution manifold that all 8 fuel injector lines feed from that is adjustable, as to when and how rapidly it opens, this can be but is not necessarily directly proportional to the throttle plate position

    theres a mechanically driven fuel pump,[​IMG][​IMG]
    http://www.kinsler.com/index.php/pumps/mechanical-pumps

    http://www.kinsler.com/index.php/pumps/electric-pumps

    that pumps fuel at volume rates approximately similar to the engine rpm, I.E at 1000rpm if it pumps X amount of fuel, at 7000rpm its pumping approximately 7x times the fuel, this fuel flow feeds the valve that feeds the common distribution manifold that all 8 fuel injector lines feed from

    theres a bye-pass jet (PILL) thats used to bleed off a controlled amount of the fuel pressure and volume that feeds the common distribution manifold that all 8 fuel injector lines feed from,
    [​IMG]

    http://hilborninjection.com/tech-support.asp

    thru lines from the common manifold to the individual injectors
    [​IMG]
    the LARGER the opening in that jet or (PILL) the LESS the fuel pressure and flow volume that reaches the common distribution manifold that all 8 fuel injector lines feed from, and the leaner the jets feeding the individual injectors in each stack flow.
    theres a quick access pill holder
    [​IMG]
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    [​IMG]
    [​IMG]

    you will occasionally find older CROWER, HILBORN, ENDRL injection intakes and components for sales, these can be either a huge bargain or a bottomless money pit depending on condition and what parts are needed to rebuild them, so before jumping into a "bargain' be aware of the limited part support, limited parts, few skilled repair or tuners and the fact its part art and part science,and that it takes some experience to tune one correctly, and it won,t be cheap...you can make excellent peak power over a fairly limited power band, but unlike the current electronic control mpfi injection that uses sensors to measure and control air and fuel metering,constant flow mechanical injection is very unlikely to run well at both low and peak power levels
    and the PILLS or JETS
    on some systems theres also a vacuum controlled bye-pass circuit that makes fine adjustments to the bye-pass flow of fuel.

    basic operation means selecting the injector nozzles that flow the correct amount of fuel for Wide Open Throttle operation, as the rpms increase the fuel pump rate of flow increases fuel flow supplying the flow necessary to compensate for the increased air flow as the engine rpms, increase
    selecting the correct pill to get the correct fuel pressure for mid and upper rpm fuel curve, allows you to customize the effective flow feeding the valve that feeds the common manifold and further adjusting the throttle linkage to provide a smooth transition,allows some more control on the rate of fuel sprayed into the stacks,in most cases low or at idle operation tends to be a bit lean, or richer than ideal, based on the choices made in linkage adjustments or bye-pass pill size,but these systems can meter fuel very well in the mid to upper rpm ranges, once you learn how to tweak the system to get the fuel flow you want, at the rpm ranges you want. its certainly easier than most carbs once you get a good feel for how it works, but your efficiency is concentrated near W.O.T and your fuel air ratio will not be precise at part throttle or under low loads.
    if you want to pass emission testing, or get better mileage, the newer electronic controls with the oxygen and map,temp sensors will prove to be superior,but if raw peak hp is your goal the constant flow systems cam provide that.


    Can I run a mechanical fuel injector on a street car?

    A mechanical injector is classified as a constant flow system and was designed to operate at WOT under load. As a constant flow system, yes properly set up and tuned correctly mechanical injection can both look great and produce excellent power and torque over several thousand rpms , but it must be exactly matched to the application.
    fuel pressure is controlled by the fuel pump which increases the volume of fuel as the rpms increase and fuel volume being delivered to the injectors is controlled by the main jet,which you can change that allows a semi predictable percentage of fuel to flow back to the fuel cell and not to the injectors , known as a pill, along with pump speed (engine rpm) and nozzle size. The barrel valve, also controls fuel reaching the injectors ,which controls idle fuel and transitional fuel from idle to WOT, can be compared to a ball valve much like the one that turns off the water in your house.
    The basic design and lack of fuel control of a barrel valve does not allow us to precisely control the fuel at part throttle,as well as an oxygen sensor and injector pulse changes on modern EFI, but properly set up it can do a remarkably good job, especially on lower load part throttle, or peak power at wide open throttle under load. If you consider the fact that an engine's fuel requirements are based directly set on max power at full load, and that we can have many different loads at different rpms all at the same throttle angle, the lack of fuel control for street applications becomes apparent. A mechanical system does not employ enough fuel control in the operating range where you drive your street car and, therefore, is not recommended for street use.

    Of course we have all heard the stories of mechanical system working on the street but few if any actually worked correctly. The use of a dial-a-jet, additional bypass valves, and home center ball valves have all been used to provide fuel control for adequate street use, but fall far short of the fuel control required as part throttle load is constantly changing. The constant manual adjustments needed, as one guesses the current fuel requirements of the engine, leaves very little time to actually drive the car and, at best, is incredibly inaccurate. Blown applications appear not to be as affected by the lack of fuel control of mechanical injection, possibly due to the load placed on the engine to drive the blower, but is still not recommended for those looking for the best all around drivability.

    The use of alcohol helps because of it's large tune-up window, but fails to provide drivability due to loading up, mileage (in gallons to the mile) and severe oil dilution. Claims from those that run injected engines on stands or dyno's stating they can make mechanical injection streetable, are unable to simulate a fraction of the different part throttle load scenarios your engine will see, nor provide the required fuel control. Interestingly enough, engineers have devised a way to electrically control these valves and bypasses...it's called electronic fuel injection.

    [​IMG]
    [​IMG]

    [​IMG]
    intake runner stack length changes, and to some extent cam timing can be used to tune the torque peaks, but cross sectional area of the runners and head ports will dictate a great deal of the air flow speed and where the restriction to flow occurs


    http://www.hotrod.com/how-to/engine/hrdp-1010-what-you-need-to-know-about-mechanical-fuel-injection/

    http://www.kenlowe.com.au/LFS_book_intro.htm

    http://www.hilborninjection.com/PDF/installation.pdf

    http://www.koehlerinjection.com/enderle-fuel-injection-pumps-shutoffs.html

    This is from Hilborn:

    A Hilborn mechanical injector is classified as a constant flow system and was designed to operate at WOT under load. As a constant flow system, pressure and volume are controlled by the main jet, or pill, along with pump speed (engine rpm) and nozzle size. The barrel valve, which controls idle fuel and transitional fuel from idle to WOT, can be compared to a ball valve much like the one that turns off the water in your house. The basic design and lack of fuel controlof a barrel valve does not allow us to control the fuel at part throttle especially no load part throttle. If you consider the fact that an engine's fuel requirements are based directly on load, and that we can have many different loads at different rpms all at the same throttle angle, the lack of fuel controlfor street applications becomes apparent. A mechanical system does not employ enough fuel controlin the operating range where you drive your street car and, therefore, is not recommended for street use.
    Of course we have all heard the stories of mechanical system working on the street but few if any actually worked correctly. The use of a dial-a-jet, additional bypass valves, and home center ball valveshave all been used to provide fuel controlfor adequate street use, but fall far short of the fuel controlrequired as part throttle load is constantly changing. The constant manual adjustments needed, as one guesses the current fuel requirements of the engine, leaves very little time to actually drive the car and, at best, is incredibly inaccurate. Blown applications appear not to be as affected by the lack of fuel controlof mechanical injection, possibly due to the load placed on the engine to drive the blower, but is still not recommended for those looking for the best all around drivability.
    The use of alcohol helps because of it's large tune-up window, but fails to provide drivability due to loading up, mileage (in gallons to the mile) and severe oil dilution. Claims from those that run injected engines on stands or dyno's stating they can make mechanical injectionstreetable, are unable to simulate a fraction of the different part throttle load scenarios your engine will see, nor provide the required fuel control. Interestingly enough, engineers have devised a way to electrically control these valves and bypasses...it's called electronicfuel injection.


    on the better 23 degree SMALL BLOCK AFTERMARKET HEADS THERE'S ABOUT 5.5 INCHES OF INTAKE PORT LENGTH ON AVERAGE FROM INTAKE GASKET TO THE BACK OF THE INTAKE VALVE AT THE FAR EDGE
    READ THESE LINKS


    you should read this related info also

    http://www.vetteweb.com/tech/vemp_1303_ ... n_systems/

    http://www.hilborninjection.com/PDF/installation.pdf

    http://www.kinsler.com/page--Constant-Flow--14.html

    viewtopic.php?f=55&t=10909

    http://www.morrisonoz.com/ChevManifolds.html

    viewtopic.php?f=55&t=6841

    http://www.hilborninjection.com/tech_mech_overview.asp

    viewtopic.php?f=56&t=789&p=1143#p1143

    http://www.pelicanparts.com/techarticle ... TipMFI.htm

    http://www.hilborninjection.com/category.asp?Id=187




    1. / One Formula: David Vizard's Rule for IM Runner Length

    The general rule is that you should begin with a runner length of 17.8 cm for a 10,000 rpm peak torque location, from the intake opening to the plenum chamber. You add 4.3 cm to the runner length for every 1000 rpm that you want the peak torque to occur before the 10,000 rpm.

    So, for instance, if peak torque should occur at 4,000 rpm the total runner length should be 17.8 cm + (6 x 4.3 cm) = 43.6 cm.

    Vizard also suggests that you can calculate the ideal runner diameter by the equation :

    SQRT [ (target rpm for peak torque x Displacement x VE)/ 3330 ]

    SQRT = square root

    VE = Volumetric Efficiency in %

    Displacement in Liters


    eg.

    So if we want peak torque at 5800 rpm at 95% VE in a teg, VE = 0.95


    SQRT [ (5800x 1.8 L x 0.95)/3330]

    = 1.73 in. or 43.8 mm (1,73 x 25.4 mm/in.) is the ideal runner diameter.


    2./ Another Formula to Calculate Runner Length for a Specific Peak Torque RPM: from Steve Magnante at Hot Rod magazine


    N x L = 84,000

    where N represents the desired engine rpm for peak torque and L is the length in inches from the opening of the runner tube to the valve head.

    3./ Website Calculator

    Or you can forget the formulas and just plug in the numbers and this calculator will crunch out the numbers for you:

    http://www.rbracing-rsr.com/runnertorquecalc.html


    II B.) Helmholtz Resonator Calculations

    Remember at the start of the article I mentioned that the dimensions of 3 parts of an IM can affect where peak torque can occur? Well here is another way we can calculate estimates for our IM dimensions for the peak torque location we want.

    A Helmholtz resonator is an acoustic resonance chamber (as described by our plenum above) that modifies the acoustic frequency of a sound wave like a spring oscillating with a mass attached on the end.


    http://www.team-integra.net/images]

    http://www.automotivetech.org/photopost/data/500/171imhelmholtzequationgrafico.gif



    where f = the rpm at which you get peak torque ( the natural frequency of pressure oscillations in the acoustic chamber ) , c = the speed of sound (= 340 m/sec.) , S = runner area, L = runner length, V = displacement per cylinder

    A simplified version of this is using the Englemann formula for the above which also takes into account static CR of the engine:

    RPM for peak torque =

    642 x c x [ SQRT (S/[L x V] ) ] x [ SQRT { (CR-1)/ (CR+1) } ]


    = 218,280 x [ SQRT (S/[L x V] ) ] x [ SQRT { (C)/ (CR+1) } ]


    For a more detailed explanation on the application of Hermann Ludwig Ferdinand von Helmholtz's acoustic resonator theory applied to intake systems, please check out:

    [URL]http://enaf1.tripod.com/teche.html#helm[/URL]

    [URL='http://www.mecc.unipd.it/%7Ecos/DINAMOTO/risuonatore/risuonatore.html%3Cbr%20/%3E']http://www.mecc.unipd.it/~cos/DINAMO...ore.html<br />[/URL]

    A Helmholtz resonator is used not only in an automotive induction sytem but also in the designing of exhausts to suppress sound and many other non-automotive designing that involves amplifying sound like in the music industry.

    [B]III. RAM INTAKE TUBE DIMENSIONS[/B]

    What are the best intake tube dimensions for the IM that we have just designed for a particular peak torque rpm?


    [B]III a./ INSIDE DIAMETER (D) of a RAM INTAKE TUBE [/B]


    [U]First Method[/]:


    D in inches = SQRT [ ( Displacement x VE x Redline) / (V x 18.5) ]

    Displacement = Total Displacement in Liters, VE = Volumetric Efficiency in %, V is the velocity of the air flow in the IM plenum for resonance (usually estimated at 180 ft/sec max.)


    eg. SQRT [ (1.8 x 85 x 8500) / (180 x 18.5) ]

    = SQRT [ (1,300,500)/ (3330) ]

    = SQRT (391)

    = 1.98 in.

    [U]Second Method[/U]:

    Throttle Body Size is Determined by IM Plenum Size.

    [IMG]http://www.team-integra.net/images/BAEC1978-D3A7-4405-AB2D-2761DC15A96D/articles/tuan/manifold_calc/TBoverboreafter.jpg


    Quote:
    from the Dave Thompson of Thompson Engineering and Endyn: http://www.theoldone.com/archive/int...old-design.htm

    The plenum volume is critical on N/A engines, and a basic rule of thumb is: The smaller the plenum, the lower the rpm range, and bigger means higher rpm. The throttle body size and flow rate also affect the plenum size: Bigger TB, smaller plenum, small TB, larger plenum.
    The best way to find out if your TB is too small for your IM plenum is to determine what the intake manifold absolute pressure (MAP) sensor is reading (in the plenum) when you are at full throttle ( or wide open throttle (WOT) ) while the car is accel using a datalogger. The MAP should be equal to, or close to, atmospheric pressure. If it isn't or there is a MAP drop at WOT, then your TB is still too small.

    A 70mm (at the intake side or TB opening) to 65mm bore (at the plate side) ITR taper bore TB: More than enough for most big N/A Teg engines.

    [​IMG]

    Once we have determined the optimal TB size for our IM, we can then determine the best intake inner diameter.

    The ideal diameter for an intake is when the intake has 25% more cross-sectional area than the TB's bore cross-sectional area . Your TB diameter (overbored or not) dictates your intake diameter.

    Remember that the area of a circle (your TB bore) is pi x radius squared and the diameter = 2 x radius. If you calculate your TB's area and then multiply it by 1.33, you will determine the intake's area. Then, use the area of the circle equation to determine the intake's radius.

    Therefore, for example, with a 64mm (plate side bore) TB, the calculated "best" intake diameter is 2.8 in. ID.

    III. b/ LENGTH OF RAM INTAKE TUBE

    A suggested starting point for the length of a tube with peak torque at 6000 rpm is 13 in.

    You add 1.7 in. for every 1000 rpm that you want to move the peak torque below 6000.

    Or subtract 1.7 in. for every 1000 rpm you want to move the peak torque above 6000.

    For more info on specific intakes (short rams versus CAI's etc.) please refer to my intake tech article over at hondavision.com :

    http://www.automotivetech.org/forum/...5&pagenumber=1[/U]
     
    Last edited by a moderator: Sep 25, 2016
  2. grumpyvette

    grumpyvette Administrator Staff Member

    http://www.hotrod.com/techarticles/engi ... ewall.html
    [​IMG]

    http://www.kinsler.com/hand31.html

    http://www.hotrod.com/articles/hrdp-1201-mechanical-fuel-injection-breakin-the-rules/

    http://blp.com/cart/index.php?main_page=index&cPath=73_127



    [​IMG]

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    even back in the early 1960s they were well aware that long intake runners on race engines provided a significant inertial ram tuning benefit that increased mid range torque
    [​IMG]
    [​IMG]
    [​IMG]

    http://www.kinsler.com/072707/Cat56Pg_Whole_LR.pdf

    http://stackinjection.com.au/

    http://eightstack.com/

    http://foxinjection.com/

    http://www.force-efi.com/stacks.htm

    [​IMG]

    http://alkydigger.net/proddetail.php?prod=ENEFI427

    IF you know what your looking at and what parts are easily replaced youll find theres a few deals available on older constant flow injection intakes, many can be converted to EFI and MAP sensor control if your good at fabrication and welding aluminum, but keep in mind the main advantage of individual runner EFI conversions of older constant flow mechanical injection is the retention of the ability to change stacks and effective runner lengths the newer intakes with a common plenum and throttle body can,t be as flexible but they will be much easier and cheaper to work with, and while the mechanical injection can be tuned to make exceptional power over a narrow rpm band the newer EFI with computer controls and sensors will be much more efficient over a wider rpm band and fuel economy will tend to be better, as will be ease of low rpm operation and a computer control can be easier to tune for those guys UN-familiar with the art of jetting tuning and reading spark plugs

    http://www.summitracing.com/parts/EDL-7136/?rtype=10
    [​IMG]

    [​IMG]
    IF YOU EVER WONDERED WHY SOME BIG BLOCK CHEVY MECHANICAL STACK INTAKES, USE DIFFERENT INTAKE STACK LENGTHS,
    its to compensate for the basic BBC cylinder head design that has two intake runners on each head direct flow toward the cylinder bore center-line (GOOD PORTS_ while two other intake runners direct flow toward the bore walls (BAD PORTS)

    [​IMG]
    BBC good vs bad port, notice how one intake runner directs air flow toward the bore center-line vs the next that forces flow toward bore wall.
    thus the reason for different intake runner lengths and changing stack lengths to compensate to equalize flow at the same rpm level


    http://garage.grumpysperformance.co...ical-constant-flow-injection.4502/#post-49554
    [​IMG]

    I wish ID never sold my bbc crower injection when money got tight!
    I loved the look and performance of those older mechanical FUEL injection stack systems and once converted to true EFI they are even better.
    neither of these pictures above do the properly set up and maintained injection system any justice , both look like crap compared to a well cleaned intake with the optional stacks, (the top intake looks like has the cheaper non-chrome powder coat versions)

    btw for those guys that don,t know a big block chevy has 4 intake runner ports that empty into the center of the cylinder and 4 that empty into the cylinder wall the different length stacks on the injectors change the charge inertia and enhance the volumetric efficiency, and yes IT DOES HELP, and YES changing the stack lengths can change the torque curve a bit


    [​IMG]
    picture blood red injector bells, chrome stacks and black powder coated intake base
    thats what I had on my race 496 BBC for years
     
    Last edited by a moderator: Apr 11, 2018
  3. grumpyvette

    grumpyvette Administrator Staff Member

    keep in mind theres more intake manifold options available in MPFI intakes that the old single vertical stack designs, and many of the older constant low intake injection manifolds can be converted to the newer EFI design or are factory available as EFI now
    some research and parts swapping can allow a self tuning MPFI config.
    individual runner fuel injection has a rather unique feature in many intake designs not found in most intakes, and that the ability to easily change the runner length, changes in stack heights can noticeably change the engines torque curve , thru inertial ram tuning, its fairly easy to boost the ram effect on a single stack runner intake to produce over 100% cylinder fill efficiency, over a fairly narrow rpm band, but one you can tune for and predict, with experience,you can actually feel the change in the seat of your pants in many cases.


    viewtopic.php?f=55&t=8957&p=31913&hilit=holley+control#p31913

    http://www.kinsler.com/page--Manifolds--6.html

    http://www.kinsler.com/page--EFI--4.html
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  4. bytor

    bytor Well-Known Member

    Good info, I have wondered how the mechanical injection setup worked. So there's no individual injector sequencing or timing, they are all always spraying fuel?
     
  5. grumpyvette

    grumpyvette Administrator Staff Member

    [​IMG]

    [​IMG]
    [​IMG]



    yes constant flow injectors
    [​IMG]
    CONSTANTLY fog fuel into the intake runner , but the volume of that fuel flow changes and is controlled and adjustable, just like a carburetor allows fuel to flow out of the carburetors venturie boosters, air flow and differences in pressure drag fuel out of the carburetors, venturies where its atomized, at a rate controlled by the jets,selected and installed, in the carburetor plus further enriched,by the vacuum drop opening the secondary power valve enrichment etc.

    viewtopic.php?f=55&t=5229

    but like a carburetor. theres a rotary valve that controls the volume of fuel thats potentially flowing AND unlike current MPFI theres no constant fuel pressure, feeding the injector nozzles, as the rpms increase the fuel pump supplying the constant flow injector nozzles increases boosting the volume of fuel, thus theres three factors controlling the amount of fuel, a injector flow size, a sliding pressure curve and a return (PILL) or jet that allows fuel to return to the fuel tank supplying the mechanical fuel pump.

    on the more modern EFI , multi port injection theres a constant supply of fuel and pressure at the fuel rail and the injector, if its properly sized can supply 100% of the engines fuel needs at a 70%-75% pulse duration,but that pulse timing and duration is controlled by sensors measuring unburnt fuel/oxygen ratios in the exhaust, air flow rates and temperatures, or put a different way, if the solenoid in the injectors getting power for 75%-80% of the time, because the sensors control the fuel/air ratio and check and correct that every fraction of a second it can potentially flow fuel as its needed,and it will more than adequately flow that level of fuel needed.

    on the older mechanical flow injection your balancing five owner adjustable controls, or flow curves,
    (1)first the injector jet or nozzle in each intake runner which controls max fuel flow,
    (2)next the rotary valve that controls fuel flow from the pump that can reach the injector nozzle from the fuel supply lines, was adjustable for both minimum and max flow
    (3)next the pump volume is adjustable in some designs as the cog belt pulley diameter between the crank drive and the pump are selected to give a known
    pressure curve and pressure,the diameter of these belt drive pulleys were something you select from a chart.
    and
    (4)volume reaching the nozzles is also controlled with the size of the return jet, that routed excess fuel back to the tank,
    the larger the jet the more fuel bye-passes back to the tank .
    (5)on most system there was an optional second return jet mounted near the rotary control valve.

    this may sound complicated but with a good understanding of the process and how the parts interact tuning the system is remarkably fast, consistent ,repeatable and accurate, you just need to understand what your doing!
    it took me several weeks to fully understand how and why I should make changes and what I was doing and you darn sure learn a great deal about reading spark plugs and how you need to understand ignition advance curves and how cylinder temps are used as an indicator of some of the burn conditions in the cylinders.
    THERE WERE dial adjustable return jets that made changes to get close to ideal very fast and easy, fine tuning from that point involved secondary jet changes, changes to the injector stack length, and adjusting how far the barrel valve opened, timing advance changes and other minor tweaks you leaned over time, you also very quickly lean that METHANOL IS CORROSIVE on aluminum if not properly cleaned, and that you were better off running high octane race gas if you were not into constant cleaning.

    BTW
    with the properly matched cam timing, and a tuned set of headers with a low restriction exhaust the inertial ram tuning of a single runner per cylinder intake injection system and an anti reversion exhaust can frequently give very noticeable torque gains , Ive frequently seen guys who get everything tuned correctly see 40-70 ft lbs of torque at some point in the power band that a common plenum single carb intake manifold can,t duplicate because those intakes can,t provide the true inertial ram tuning that the combo of stack injection and a tuned anti reversion exhaust can produce.
    if you think about it the TUNED PORT INJECTION (TPI) INTAKES

    [​IMG]
    used similar technology using long intake runners to boost low rpm torque with inertial ram tuning, but unfortunately they used about 1.5" diameter intake runner cross sectional areas designed to maximize torque under 4000rpm on a 305 displacement engine, if you do the calculations you quickly see thats going to be very restrictive on a 350-406 SBC at anything close to max potentially useable rpm levels, which could easily reach or exceed 6400rpm with PROPERLY SELECTED and matched, performance components


    related info
    http://www.kenlowe.com.au/LFS_book_intro.htm

    http://www.hotrod.com/techarticles/engi ... to_03.html

    http://www.kinsler.com/Cat_32_Pgs/Cat_32_4_09_Pg_72.pdf

    http://www.hilborninjection.com/tech_mech_overview.asp

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

    grumpyvette Administrator Staff Member

    1st to 4th Harmonic Intake Tracts CFD
    "Here are two animations of intake tracts , I found posted else ware. showing the pressure and velocity dynamics and how it differs in various length tracts.

    The lengths are: 26.5, 15, 10.4 and 8.2
    The animation runs for 63 frames.
    Each frame is 15 degrees of crank rotation
    The 1st frame is the beginning of an intake stroke
    Frames 48 to 62 would be a 2nd intake stroke but I intentionally left the velocity out so that the waves can be seen unaffected.
    This is simulation of an engine running at 10,000 RPM
    Each frame is at an interval of 0.0025 seconds.
    The motion of the air is defined by velocity at the cylinder end and an opening to atmosphere on the runner opening.
    1 degree taper per side was used.
    The blend radius is 0.25"

    ID also point out that torque curve could easily be enhanced with individual runner stack injection

    [​IMG]

    [​IMG]
    Enjoy"
    notice how the longer length runner has a more pronounced and stronger inertial pulse strength and duration
    [​IMG]

    [​IMG]
     
    Last edited by a moderator: Apr 13, 2018 at 1:23 PM
  7. grumpyvette

    grumpyvette Administrator Staff Member

    If youve ever wondered why I've repeatedly suggested individual runner fuel injection intakes have advantages look closely at the dyno chart I found and the two different torque curves, and why comparing only the peak horse power is so misleading on the true advantage of a significantly more robust torque curve of the stack injection, theres easily 60 plus foot lbs, of additional torque gained with the stack injection over a noticeable part of the rpm band
    [​IMG]
    http://www.hotrod.com/cars/project-vehi ... am-tuning/

    [​IMG]
     
  8. 87vette81big

    87vette81big Guest

    I would like to find IR Stack Injection for a Pontiac V8 Grumpy.
    I would try it out.
     
  9. grumpyvette

    grumpyvette Administrator Staff Member

  10. Grumpy

    Grumpy The Grumpy Grease Monkey Staff Member

  11. 87vette81big

    87vette81big Guest

    Resurrected Grumpy .
     
  12. Grumpy

    Grumpy The Grumpy Grease Monkey Staff Member

    constant flow injection was and is a system that cam be tuned to provide excellent peak horse power AND IMPRESSIVE TORQUE over a fairly limited rpm range,
    the ability to change the stack length and in some cases cross sectional area to exactly match the engines needs makes the system very useful.
    yeah it might be old school and the more modern MPEFI has lots of advantages and can be much more flexible under lots of conditions , but having old school stacks sticking out of your car hood does look impressive
    [​IMG]

    THE most common mistake, most guys make when doing calculations is use of the wrong data , you may have sellected two 750cfm carbs on a tunnel ram and expect them to flow 1500 cfm, but the fact is each of the two carbs now shares a comon plenum on one engine so the vacume each individual carb venturies sees is reduced significantly, OR
    if you were to sellect individual runner mechanical or EFI stack injection, when you select
    "Individual Runner fuel injection"in the calculation , each runner feeds a single cylinder, again this fails to use the correct calculation, individual runners acting as a ram tub must be significantly larger because they induce a pulsed or ram, inertial flow.
    you can,t use the carb cfm, info, thats simply failing to use the correct flow calculations
    [​IMG]
    this is the result of failing to realize each
    Individual Runner,
    easily flows easily 320cfm to 450 cfm
    (depending on each individual ram tube and throttle bore size )
    UNLIKE a carburator which will have a listed
    (and basically useless flow rating)

    thus the minimum CFM youll use in the calculations is more than likely in the 320 x 8 or 2560cfm-to-3600 cfm flow range
    so put 2600 cfm in for a SBC and 3200 CFM in for a BBC individual runner FUEL INJECTION INTAKE CONFIG

    read link
    http://www.hotrod.com/articles/hrdp-1010-what-you-need-to-know-about-mechanical-fuel-injection/

    http://www.borlainduction.com/200094-v8-kit-chevy-big-block-35mm-air-horn.html

    heses a typical chart showing SBC intake gasket sizes
    notice 1.3 x 2.31 is the largest size thats roughly 3 sq inches
    [​IMG]
    NOTICE THE BBC FUEL INJECTION LIST A 3" BORE thats 7 SQ INCHES
    trust me the larger bore flows significantly more air
    [​IMG]
    [​IMG]
    https://www.kinsler.com/index.php/gm

    http://hilborninjection.com/product/big-block-chevy-fuel-injector-3-bore/

    it helps if you understand that most INDIVIDUAL PORT INJECTION EFI intakes are single plane because a single plane intake design is the least restrictive and allows the most direct route for the air flow to enter the cylinders, and they don,t have to be concerned with fuel droplets falling out of the air flow as the injectors mist fuel in a cloud directly behind the inlet valve.
    [​IMG]

    the tunnel ram is the most efficient single plane design for higher engine speeds as it allows a direct strait line path from carb base to the back of the inlet valve, but remember its properly timed EXHAUST SCAVENGING, displacement, cam timing and compression ratio and port cross sectional area, that has the most effect on intake runner flow rates
    [​IMG]
    [​IMG]
    one reason a properly port matched tunnel ram intake flows efficiently is a strait path to the intake valve, in the cylinder head from the plenum
    [​IMG]

    USE THE CALCULATORS, YOULL, QUICKLY FIND THE LIMITATIONS
    http://www.rbracing-rsr.com/runnertorquecalc.html
    http://www.wallaceracing.com/chokepoint.php
    http://www.wallaceracing.com/header_length.php

    [​IMG]
    [​IMG]

    reading through these links would be helpful

    http://garage.grumpysperformance.com/index.php?threads/carb-intake-test.58/

    http://garage.grumpysperformance.com/index.php?threads/mechanical-constant-flow-injection.4502/

    http://garage.grumpysperformance.com/index.php?threads/tuning-a-tunnel-ram-intake.5175/#post-67680

    http://garage.grumpysperformance.com/index.php?threads/calculating-header-design.185/

    http://garage.grumpysperformance.com/index.php?threads/calculating-required-exhaust-pipe-size.11552/

    http://www.wallaceracing.com/header_length.php


    useful RELATED INFO you might want to read

    http://www.wallaceracing.com/runnertorquecalc.php

    http://www.pontiacracing.net/js_header_length1.htm

    http://www.superchevy.com/how-to/en...-0902-chevy-engine-port-variations-measuring/

    http://garage.grumpysperformance.com/index.php?threads/port-speeds-and-area.333/

    http://garage.grumpysperformance.com/index.php?threads/calculating-ideal-port-size.624/

    http://garage.grumpysperformance.com/index.php?threads/sellecting-cylinder-heads.796/


    single stack injection with an individual injector per cylinder is the best potential intake design as it ,
    if properly designed and correctly matched to the engine size,
    cam timing and exhaust scavenging can provide over 100% cylinder fill efficiency ,over a narrow rpm band through inertial ram tuning.


    [​IMG]
    [​IMG]
    [​IMG]

    [​IMG]
    intake runner stack length changes, and to some extent cam timing can be used to tune the torque peaks, but cross sectional area of the runners and head ports will dictate a great deal of the air flow speed and where the restriction to flow occurs
    I wonder how many people read through that info, and might grasp the concept that if you matched the displacement,
    compression ratio, cylinder head port cross sectional area, and took the effort to calculate matching intake runner length ,
    with a well tuned stack injection induction,
    and matched the header primary lengths,
    too the cam duration and lift and LSA that you could significantly enhance cylinder scavenging efficiency,
    over a limited but predictable, 1000-rpm-1500-rpm, rpm band,
    by creating one hell of an efficient, cross flow in the cylinder head's during the over lap period,
    when both valves were off the seats at the same time, thus getting one kick in the butt torque curve boost ,
    certainly something you feel in the drivers seat as the engine passes into that rpm band


     
    Last edited: Aug 31, 2017
  13. 87vette81big

    87vette81big Guest

    60 Ft/lbs gain is a lot Grumpy.
    To get that gain SBC With limited header selection such as a Corvette you would have to go 383 ci to 434 ci.
    Results be unpredictable .

    A Gain of 60 -80 ft/lbs in Pontiac you would have to stroke a 455 to 477 -484 ci.

    Constant Flow mechanical injection was used by Mickey Thompson on his Record setting Pontiacs 1959-64.
    Normal Aspirated & Roots Supercharged.

    No modern EFI System still can give such gains with a Bolt on and a Tune.

    Will be searching.....SBC, BBC, & PONTIAC V8 Constant Flow Mechanical Stacks.
    I don't want EFI.
    Want Raw Olds School HP & TORQUE.
     
  14. Grumpy

    Grumpy The Grumpy Grease Monkey Staff Member

  15. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    Just the Cats Azz Conatant Flow Mechanical injection I think.
    Work great with Twin screw Superchargers as done in the past.

    Be nice to use with Turbocharging & a Vertex Mag Grumpy.
     
  16. Grumpy

    Grumpy The Grumpy Grease Monkey Staff Member

  17. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    I just tried one of links Grumpy.
    Wallace Racing Header tube length.
    Used my TA Hooker Super Comp 4202's.
    Explains why besides the cam it worked at high danger zone RPM.

    Headers made for it.
     
  18. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    Velocity IR stacks I like.
    Just screwed if it rains and on the Highways here.
     

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