2G Fuel systems, Return or Returnless?

[BayState300GT]

I need some opinions/input. Im getting close to finishing my car and have been currently setting up the fuel system. I have the STM tank to rail and and STM FPR kit. I still have my stock return line on the car but ive been debating whether or not to run returnless. What are the advantages/ disadvantages. I know return can help keep the fuel cooler. Also a friend was tellling me i need to run e85 but theyre arent many places in my area that sell it, more than a 20 mile hike. Ive also heard with a returnless system you dont need to run a FPR.

 

[GRAVEDIGGER]

The only returnless system I know of with these cars is on the 2g non-turbo 420a engine. Every turbo application I have seen returns the fuel and I believe that is the best way to do it. I think you are mixed up in saying that a return system keeps the fuel cooler though. It actually heats it up by sending the fuel back to the tank after is has come from the heated engine compartment and fuel rail. Also there is still a fpr with a returnless system, but it is located inside the tank near the pump, so you won't see it out on the rail.

 

[boost97gst]

Return-less fuel systems (like in my Lincoln) use a pressure sensor on the rail in conjunction with ECU commands and a driver. It uses pulse width modulation to maintain a constant pressures. On a turbo system this would be a dumb idea basically. The driver for the pump would have to be heavy duty and you have more parts in the system. More parts to do the same job is always a bad thing, more things to go wrong.

With the DSM its constantly applying voltage to the pump and the only real problem you can get is a torn diaphragm in the AFPR. That's pretty rare.

With a PWM pump the sensor can fail, driver goes bad, ECU can screw things up.
Which one sounds better?

 

[jw4free]

I don’t believe this question was answered properly.

Does any DSM’r have experience with the fuel supply setup as sketched?

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