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Upgrading Fpr: Worth It?

cobrAA

By cobrAA,
in Engines & Forced Induction

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cobrAA Mentor

cobrAA

Posted
Posted

Little background : 400awhp, sard 700c, bnr32 oem fuel rail.

What is the advantage of running an aftermarket FPR? and I heard the only bolt-on ( to fit on the OEM fuel rail) was the nismo one. Is it worth upgrading my oem FPR to the nismo one if I plan to hit the 500awhp?

Please let me know your experience because, after a 30 minutes, it seems useless.. lol

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KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Sorry to highjack....Didnt want to start a new thread. But can anyone tell me the symptoms of a faulty FPR?

Insufficient fuel (running lean). Test with a fuel pressure guage. Should be about 3 bar at idle and rise an amount equivalent to the increase in boost.
PM-R33 Grand Master

PM-R33

Posted
Posted

The only reason to "upgrade" the factory FPR is really in three instances:

1. When your injectors are starting to max out, but you don't want to upgrade them, so you bump up the rail pressure with the aftermarket adjustable fuel pressure regulator to push them a little but furthur. Obviously this isn't ideal and most people don't recommend it. Just buy the correct injectors to start with.

2. When you are running huge amounts of boost and the factory fuel pressure regulator can not keep up the 1:1 fuel pressure ratio. Therefore you will need an aftermarket fuel pressure regulator that can handle this high amount of boost pressure and keep up the 1:1 ratio.

3. The factory fuel pressure regulator has failed so you may choose to buy an aftermarket one however still run it at factory fuel pressure.

So as you can see, not many people fall into the second category because a lot of people don't run 2+bar of boost through their car. A few do fall into the first category because they may be on a budget and don't want to upgrade the stock injectors so they choose to bump the rail pressure up instead and obviously a few will fall into the third category.

However there is a fourth category that you will find 90% of people with aftermarket fuel pressure regulators fall into:

4. They have no idea what an adjustable fuel pressure regulator does, but they got told to buy one by a mate or read about one somewhere.

For your situation assuming that you are not running E85, your 700cc injectors should be fine for between 400-500HP therefore you do not need an aftermarket fuel pressure regulator.

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rondofj Veteran

rondofj

Posted
Posted

LMFAO at your point in NO.4 below, I was one of those people, thanks to you, now I wont buy an aftermarket FPR.

The only reason to "upgrade" the factory FPR is really in three instances:

1. When your injectors are starting to max out, but you don't want to upgrade them, so you bump up the rail pressure with the aftermarket adjustable fuel pressure regulator to push them a little but furthur. Obviously this isn't ideal and most people don't recommend it. Just buy the correct injectors to start with.

2. When you are running huge amounts of boost and the factory fuel pressure regulator can not keep up the 1:1 fuel pressure ratio. Therefore you will need an aftermarket fuel pressure regulator that can handle this high amount of boost pressure and keep up the 1:1 ratio.

3. The factory fuel pressure regulator has failed so you may choose to buy an aftermarket one however still run it at factory fuel pressure.

So as you can see, not many people fall into the second category because a lot of people don't run 2+bar of boost through their car. A few do fall into the first category because they may be on a budget and don't want to upgrade the stock injectors so they choose to bump the rail pressure up instead and obviously a few will fall into the third category.

However there is a fourth category that you will find 90% of people with aftermarket fuel pressure regulators fall into:

4. They have no idea what an adjustable fuel pressure regulator does, but they got told to buy one by a mate or read about one somewhere.

For your situation assuming that you are not running E85, your 700cc injectors should be fine for between 400-500HP therefore you do not need an aftermarket fuel pressure regulator.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

lol yes plenty in the 4th.

i ran 24psi, 370rwkw, factory reg.

current car has 20psi, 350rwkw, factory also.

i know many other cars in the 20-25 range all perfectly fine.

fuel regs fall into the same category as BOV's, turbo timers and my fav... AFR gauges that run off the factory O2 sensor... pointless!

Crans Mentor

Crans

Posted
Posted

I too hate turbo timers monitoring narrow band is pointles BOV should recirculate or not be there at all.

I will be installing a sard fuel reg on my car purely for the fact that it gonna take along time for me to save for injectors, and it will help me squeze alittle more out of my fuel system

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