I just installed the racetronix lt1 fuel system (walbro pump and plug and play harness). It is very nice and easy to install kit.

Since I have installed the kit, my fuel pressure has been roughlly 2-3 psi higher than with the stock pump. I still have the stock FPR. Do I need to get an AFPR to turn it back to 43.5 psi @ WOT? I think I run a little rich @ WOT already and this will probably make it worse. Why won't the stock fpr keep the pressure the same as it did befere?

Thanks
Dustin

 

Your new pump produces a higher volume of fuel.

 

I know it produces more volume, but the pressure relief valve in the fpr should still open at the same pressure right? With a higher volume pump you should just have a higher volume flowing back to the tank. I don't understand why the pressure would increase unless the return system is incapable of flowing enough fuel back to the tank.

Does this happen to everyone that installs this pump?

Dustin

 

When I did my install, my fp did not go up. But I have an ACCEL afpr, so I don't know if that would change things. It shouldn't.

 

The factory regulator is not 100%. Most regulators will allow a small pressure rise with a substantial increase in fuel volume.

 

Stock FPR's wear out too. How many miles are on it? I ended up replacing my FPR with a new stock one when I did my Racetronix pump install last year. If the spring and seal in the stock FPR are worn it can allow to much fuel pressure to pass through.

 

What he said. Same concept as a torque converter. Double the power, and it'll stall a little bit higher.

Double the fuel, and it'll allow a small pressure increase