Last Updated: 05/22/2021 @ 11:26 am
Member Credit: 96sleeper
I just wanted to put this info out there. When I first did my 3.5 swap I did the fuel setup the way that others had done with the Tee. It satisfied the VQ35 engine by leaving it returnless, and also satisfied the car with the return line.
Ever since running higher boost, I have been battling a little bit of a lean condition at higher rpms in the higher gears. I have tried just about everything, turning the pressure up, added a boost-a-pump, SAFC adjustments, etc. Nothing would fully fix the problem. I thought I had it narrowed down the the fpr not rising 1:1 with boost, but I fixed that and I still had the problem.
I decided to remove the damper on the end of the fuel rail and make it return style and eliminate the tee from the system. Now the fuel has to pass through the fuel rail to be returned to the tank. This seems to have fixed my problem. I can be as rich as I want now at the upper rpms. I don’t know if it was a volume problem flowing through the tee, or if it was just the setup allowing fuel to be returned to the tank without ever seeing the engine. This could have been a problem if the fpr was acting up.
Here is a simple diagram showing before and after.