Return or Returnless 818R?????

[Brd.Prey]

Which direction opinions with explanation wanted?

[Hobby Racer]

That depends. If you are going to stay with the OEM computer you should stick with the returnless setup so the ECU does not throw fits. If you are using an aftermarket ECU you can do either, but I would recommend a return type system. With a return type system you have better fuel pressure regulation (assuming you are using a quality fuel pressure regulator).

You can see some information in my build thread about it.

Return type system diagam (https://thefactoryfiveforum.com/showthread.php?23199-John-s-EZ36R-H6-818R-Build&p=291710&viewfull=1#post291710)

If you go with a return type system you can easily modify the factory fuel rails to work well.

Fuel Rail Modifications (https://thefactoryfiveforum.com/showthread.php?23199-John-s-EZ36R-H6-818R-Build&p=291660&viewfull=1#post291660)

[Brd.Prey]

Ok, went return with a surge tank.

[walt555]

Doesn't the wrx set up have a return line back to the tank after the regulator?

[Aero STI]

Every WRX or STI that I've owned has been return style.

[20boxer]

Every WRX or STI that I've owned has been return style.

yeah all 5 of mine had return style too....

[Bob_n_Cincy]

My NA impreza's have non-return. On big disadvantage of the non-return type is when you shut of the car you heat soak all the fuel lines on the engine. Then when you restart the is a chance of vapor lock.

The return type constantly circulates fuel to the engine which help to keeps the fuel system cool.
Bob