rrfpr and fuel regulator question.........

[awsomeears]

Whats the point/advantage of running a rrfpr and a fuel regulator together on a Fuel System vs. just running a rrfpr ?

[DurtyKurty]

There is no advantage. You usually see both regulators being used because of circumstance. For example, on my car, no one that I know of makes a direct replacement rising rate regulator to replace stock regulator. So the only alternative is to leave the stock one in place and use an in-line rising rate regulator after the stock one. You could remove the stock one, but it's usually just easier to leave it in because they're typically integrated into the fuel rail.

If a company makes a direct replacement rising rate regulator, then that would be the preferred way to do it.

[awsomeears]

I see, well right now I'm running a Walbro 255 fuel pump with a Cartech rrfpr going into a AEM fuel regualtor and a return line back to my fuel pump.

I'm just trying to understand Fuel Tech more, It's not a strong area but ill learn it.

[spindler27]

there really is no reason IMO, with the RRFPR just connect a good, NO VACUUM boost source to it, the "coldside" IC pipe is generally the best place for it

[awsomeears]

there really is no reason IMO, with the RRFPR just connect a good, NO VACUUM boost source to it, the "coldside" IC pipe is generally the best place for it

Umm I always thought this is accomplished by using the manifold vacuum/pressure to drive the fuel pressure up as the boost rises

Few other things I found while searching the .net


a 1:1 dosnt add extra fuel.

A 1:1 increases the fuel pressure to maintain the same pressure differential across the injector so that fuel delivery remains consistent at a given pulse width. ie 5 msec will deliver the same fuel at 20 inches as it would at 20 psi of boost.

[spindler27]

Umm I always thought this is accomplished by using the manifold vacuum/pressure to drive the fuel pressure up as the boost rises

Few other things I found while searching the .net

well, if you attach the vac line to a source that sees vacuum there is the possibility of reducing your static pressure, and if you use a boost only source, your static will always stay the same, example would be my car was at 30psi static with the 750cc injectors, but once i hit full boost i was at 62psi

[Russ Jerome]

Whats the point/advantage of running a rrfpr and a fuel regulator together

A FPR will only allow a 1/1 rate of gain, a RRR can be adjusted
for both onset and overal gain, 1/1,1/2,1/3, ect ect.

Traditionaly before we had $800 stadalone systems available
we would start with as little as 35psi base fuel and as
boost crept to 20psi we could run as high as 90psi FP.
FP has a big effect on the inj flow during duty cycle.

RRR are pretty much old school, you see them on Jap
show cars but I would put money on the fact they are
simply dialed down to 1/1 rate of gain, standalone
systems can adjusted inj duty cycles so fine now there
is no need for more rate of gain fuel keeping the EGTs
down and good AF ratio.

[Syclone0044]

I agree with Russ, adjusting the injector duty cycles directly is obviously the best method of tuning the fuel (along with everything else). Doesn't your car offer some way to reprogram the ECM/PCM? My shit's all 20 years old and I can reprogram it as easily as any F.A.S.T. system with about $400 worth of electronic tools & software.