Return Line in fuel system?

55C150

Well-Known Member
Is it possible to plumb the return line of the fuel system to the fuel filter near the gas tank or in the feeding fuel line via Y fuel block? I thought about the Y block to not interrupt the fuel flow like when using a T block.
I ask that because my original gas tank (1955 Chevrolet) has no plug for a return line and I don't want to drill a hole in it.
I the near future I want to install a fuel pressure regulator. After reading here all the information abaout fuel system and regulators I want to use the return style regulator instead of the dead head version.
 
yes its not only possible, but done rather commonly, and while this is not ideal it will work, and function.
be aware that air trapped in the line will cause the fuel pump to have priming issues until all the air is expelled ,
thus you'll want too disconnect the feed too the carb,
and run the pump with the starter, spinning the engine, or intermittently refilling the carburetor fuel bowls,
so the engine will run for a minute, or so to purge any air in the fuel lines,
after the new return line configuration is installed, and fuel feed, lines are re-routed until,
you get a solid flow of pressurized fuel.
both the fuel pump and the internal diameter of the fuel lines and fittings used can restrict fuel flow rates ,
so Id certainly suggest use of 3/8" minimum (about 9.5MM) on any performance car, to avoid fuel flow problems,
and ideally 1/2" internally, (about 12 mm)
if your car engine once modified makes over 470 hp.
your carburetor inlet 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 3-4 psi the carburetor can run lean under hard acceleration.
If your current fuel tank or fuel lines can,t keep up with the engines demands, can you remove the current plate and fittings and drill and soldier in a larger dual fuel fittings

fuelplate1.jpg

http://www.tanksinc.com/index.cfm/p...t_id=100/category_id=167/mode=prod/prd100.htm

Tankconnect1.jpg

http://www.jegs.com/c/Fuel-Carbs-Intakes_Fuel-Cells-Fuel-Tanks/10297/10002/-1

http://garage.grumpysperformance.co...es-restrict-fuel-flow-rates.12859/#post-66683

tankfity.png

FuelFlowDiagram02a1.jpg


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

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

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

http://garage.grumpysperformance.co...ss-fuel-pressure-regulators.12776/#post-65958

http://garage.grumpysperformance.com/index.php?threads/input-on-electric-fuel-pump-selection.10664/

http://garage.grumpysperformance.com/index.php?threads/fuel-line-sizing-return-vs-feed.3067/
fls1.jpg


Fuel System

The TPI Fuel System comprises the following components:

  • Fuel Tank
  • Fuel Pump
  • Fuel Pressure Regulator
  • Fuel Lines
Fuel Pump
In the original GM applications, the fuel injection pressure pump is installed inside the vehicles fuel tank. Adapting this pump has never seemed to us a practical solution, unless you are installing the TPI system on a vehicle that utilises the stock GM gasoline tank. This would allow for the installation of an internal tank type pump. If you are installing the TPI system into a vehicle that was originally equipped with carburettors, or even a throttle body fuel injection system, it WILL be necessary to install a compatible high pressure port fuel-injection type pump. Any number of fuel pumps will serve the purpose. We can recommend the fuel pump from a 78-80 and 82-85 Datsun 280Z. The Nissan part number for this pump is 17011-P7211. In addition, these pumps are usually readily available from wrecking yards, as are similar units from BMW, Mercedes Benz, Jaguar and many other late-model port-injected vehicles.

The electric fuel pump used should be capable of maintaining at least 50 psi under full throttle, and a return line MUST be plumbed back to the fuel tank/tanks if there is not one installed on the car!

IF THE FUEL TANK IN YOUR VEHICLE DOES NOT HAVE PROVISION FOR A RETURN LINE, IT IS NOT NECESSARY TO MODIFY THE TANK!
By installing the appropriate size tee-fitting into the fuel supply line from the tank to the inlet side of the fuel pump and connecting the return line into this suction line at the newly installed tee, the need for a return line can be met without removing and modifying the fuel tank.

If you are installing your TPI system in a vehicle which was originally equipped with a carburetted engine and a mechanical fuel pump that was equipped with a factory installed return line, BE AWARE, that many of these systems have a restriction in the return line. This restriction should be removed to eliminate the possibility of unnecessarily high pressures in this portion of the fuel system. These restrictions are often contained in the return line fitting on the gas tank sending unit mounting flange. If it is inconvenient to access this flange to remove the restriction, the return line can be re-routed to the fuel pump inlet line, as described above.

Fuel Regulator
A fuel pressure regulator is mounted on the rear of the right side of the TPI fuel rail. This non-adjustable regulator controls fuel pressure, to maintain it at about 41 psi under high vacuum conditions, such as idle, and up to 47 psi under low vacuum conditions, such as full throttle operation. Adjustable fuel pressure regulators are available through a number of after-market suppliers, for high performance applications.

Fuel Lines
Because of the high fuel pressures involved, we prefer to use braided stainless fuel lines with threaded connectors, as opposed to just using hose clamps and rubber hose, when making the connection between the TPI unit and the fuel pump! The pressure inlet of the TPI system is the fitting with the larger I.D. A return line MUST be connected from the petrol tank to the smaller I.D. fitting. If you are utilising braided stainless hose and fittings, it will be necessary to purchase after-market adaptor fittings which thread into the hose connections, or the TPI manifold, to allow the use of these improved hose and fitting assemblies, since the OEM connections utilise metric threads and O-ring type seals. These adaptor fittings are available, either in a male configuration for installation into the fittings on the fuel rails of the TPI or, into the ends of the stock rubber hoses which attach to the body/frame mounted steel fuel lines that come forward from the fuel tank, or in a female configuration, for installation onto the end of the engine mounted steel tubing extensions, which are a part of all factory TPI fuel line installations.

The above-mentioned items are all that could be considered separate elements of which are component parts of the TPI installation. Simply stated, the system will not work at its designed level of performance if any one of the above items is deleted! The following information will include some additional items which, while not required to make the system functional, are items that are utilised in the factory installation to make everything work as originally designed, and which may be used, as necessary, or deleted if so desired, with no functional effect on the real world operation of the unit.



FuelPumpCircuit01a.jpg


related info (reading links is very helpful)and frequently will prevent mistakes and wasted time and money

http://garage.grumpysperformance.co...-the-rabbit-hole-with-alice.10933/#post-66925

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

http://garage.grumpysperformance.com/index.php?threads/return-line-too-small.10665/#post-46016

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

http://garage.grumpysperformance.co...ss-fuel-pressure-regulators.12776/#post-65998

http://garage.grumpysperformance.com/index.php?threads/fuel-line-sizing-return-vs-feed.3067/

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/
 
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always glad to help! btw ,
posted links, and sub links on this website,
almost always hold a great deal of additional detailed info
and if you can add any useful info to any thread you read, please do so!

those aluminum finned tube coolers work, are reasonably cheap, very durable ,but a bit restrictive

https://www.summitracing.com/parts/mor-41205/overview/
MOR-41205.jpg


but they don,t cool trans fluid or oil no where near as efficiently/fast as the larger fan equipped coolers with the AN#8 line size
and in either case finding a place to mount any cooler where you can keep it out of sight and still easily access fresh outside air flow,
is usually a problem for most people

https://www.summitracing.com/parts/der-15850
der-15850_w.jpg


https://www.summitracing.com/parts/der-15950
der-15950_w.jpg

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



fitr1.jpg

fitr2.jpg

fitr3.jpg

*
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 :D
*
Up to 450 GPH =7.5 GPM= 5/8" or -10 AN
*
Up to 900 GPH = 15GPM 3/4"or -12 AN

fitcr1.jpg

fitcr2a.jpg

fitcr3.jpg

fitcr4.PNG

 
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Is it possible to plumb the return line of the fuel system to the fuel filter near the gas tank or in the feeding fuel line via Y fuel block? I thought about the Y block to not interrupt the fuel flow like when using a T block.
I ask that because my original gas tank (1955 Chevrolet) has no plug for a return line and I don't want to drill a hole in it.
I the near future I want to install a fuel pressure regulator. After reading here all the information abaout fuel system and regulators I want to use the return style regulator instead of the dead head version.

You sir, have a brain and know how to use it. Welcome.
 
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