do I need fpr or afc with my setup?

[khartley]

This is my setup as of now, some of this stuff isn't on the car yet, but I have it all.

full 3" exhaust
K&N open filter
mbc set at 16
14b
2g exhaust manifold
3000gt vr4 fuel pump
510cc injectors
water injection kit (might put on, might sell, not sure yet)
2100 ACT clutch and stock flywheel lightened approx. 5lbs
I have a datalogger, but it has a crap program

also considering getting a cheap FMIC or a supra sidemount with a better upper intercooler pipe

My question is this: I know I will need fuel management, but I don't really understand how it works. What is the difference between afc and fpr? Which do I need with my setup, or should I have both? Which is better?

 

[DarthBulk]

An fpr is a fuel pressure regulator. You need one of these when you use a bigger fuel pump, because a bigger fuel pump can "over run" your stock fuel pressure regulator. This means that not enough fuel gets bypassed back to your fuel tank, and you get too high of a fuel pressure at your fuel injectors. Remember that when you get a fpr, you need one that raises fuel pressure with boost pressure. This allows the fuel pressure differential across a fuel injector to remain constant when under boost.
An afc is a totally different device, that allows you to adjust how much fuel gets into your engine by adjusting how long your fuel injectors stay open. It does this indirectly by modifying the signal that tells your ECU how much air is flowing into the engine. If your ECU is tricked into thinking it is seeing more airflow, it will open the fuel injectors longer to add more fuel. Or, if you installed bigger fuel injectors, the afc will trick the ECU into thinking it is seeing LESS air, and so open the fuel injectors for a shorter time. Because they are bigger injectors, you still get more fuel. Make sense?

So in short, if you are installing a bigger fuel pump, you need an fpr. If you are installing bigger injectors, you need an afc. Since you are doing both, you need both of them.

 

[JayRolla]

You will not need a FPR with that pump, but to get the car to run right with the pump and injectors fuel compensation is 100% needed.

 

[khartley]

Ok. Which ones have good reps? I know the Apexi AFC is probably the most reputable in that area, what about the FPR, which ones are good there? I'm looking to go relatively inexpensive, but I don't want garbage either. Will I need to buy any gauges?

Advice is appreciated. Thanks for the help.