My question is, i dont know if it matters but a 90 turbo rx7 with the stock fpr on the secondary fuel rail. When and why does a person need a aftermarket fpr? i was looking in the new modified magazine and that drift car didnt seem to have one and he was pushing 400whp@21 psi but with 4x1000cc injectors. or is a fpr needed when going to really big injectors like 1680cc secondarys and having to get a new fuel rail with the fpr?



Thanks

At that point I feel its really best to put in a fuel pressure gauge to make sure its within specs. I had 850/1200 with a cosmo fuel pump running 18psi on a decent sized turbo, and my fuel pressure was just fine.

Basicly, you want to go aftermarket when you start running higher than stock boost levels.

I have the cosmo pump and a greddy fuel pressure gauge. upgrading my turbo as well. I'll install the fuel pressure gauge and go from there, thanks.

Hummm, I'm running 12 psi of boost, on stock injectors, K&N Air FIlter and MSD fuel pump; do I need an aftermarket fpr? I was also wondering about lowering to 10 psi as I'm on stock injectors (been thinking about those 720, but then I'd need an S-AFC to manage them......)

Any ideas?

That is simply not true. As I previously stated, I was running 18psi on a T-62-1 with 850/1200 with a cosmo pump and my fuel pressure raised accordingly with each pound of boost.

The stock regulator will work fine in every situation I can think of. The only reason I can see to get an aftermarket FPR is if say your injector size is maxed out on the PFC and you need more fuel. At that point a regulator would help.



More importantly than the regulator would be a Fuel Pressure Guage. This will let you know if you pump is big enough to to the job or not......or if the pump is broken.

Bingo.

What is the fuel pressure supposed to be at normally? Is it ever supposed to move if you hit the gas or anything? You guys know how I've got my problem, that's why I ask. :P

Yes the fuel pressure is ever changing. It will increase with boost and decrease in vacuum. If this is not happening then the regulator is broken or the vacuum hose is not connected or has a large tear in it somewhere.



At idle should be setting around 2.8~3kilo......sorry never used PSI for this



It will raise 1kilo for every one kilo of boost.