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FPR v/s RRFPR


nocab72

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Talking FRP's in general, my application is SX in particular.

 

1) My instincts tell me that a FPR, like the SX FPR allows one to set the base fuel pressure, the "regulator" just keeps that fuel pressure constant.

 

2) A RRFPR, would do more than regulate fuel pressure at a base rate, and raise the fuel pressure based on boost (manifold) pressure, typically 1:1.

 

I have the SX FPR, BUT it has a vaccum line which goes to the manifold...this tells me its reading the manifold pressure for SOME reason, and I assume it's to raise the fuel pressure based on manifold pressure, but that contradicts my instincts from #1.

 

I guess my real question is, does SX make two different fuel pressure regulators, one FPR and one RRFPR, and if so, what are the specific features of each? Their website doesn't have jack for info...

 

Thanks in advance!

 

K

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I think I found my answer.

 

http://www.srmotorsports.com/srfuel.html

 

An adjustable raising rate fuel pressure regulator is another important part of the system.This will compensate for boost in turbocharged cars.(It gives you a 1-1 ratio of boost psi and fuel psi increase) We also sell an adjustable rising rate regulator (R.R.R.) which will add more fuel per pound of boost (sometimes up to 4-1 ratio) to allow you to run higher boost safely.

 

FPR = 1:1

RRFPR = 1:1 or > 1:1

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You found your answer. Typically, a RRFPR is used as a fueling device with undersized injectors to add more fuel as boost increases.

 

A "normal" FPR simply raises pressure with boost so that net pressure remains constant. If your injectors have sufficient flow for your horsepower level, you stick with an FPR.

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I sized my injectors for 550rwhp with plenty of cushion, but in the colder temps plus the extra 1000rpm I've got now (9000rpm redline) I've seen INJ duty cycles hit 100%... :eek:

 

I'm either

 

1) > 550rwhp (doubt it at only 17psi)

2) the cold temps really chew up the fuel

3) my fuel pressure needs turned up a tad...

4) I'm gonna need larger injectors, soon...

 

My educated guess, 2 & 3. 4 is certain.

 

K

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