Re: How to adjust a "set" RRFPR thats too big.
 

If you want to run out of fuel pressure sure.

A check valve will not let the FPR operate correctly under boost. if you boost 15psi with a check valve in place, the resulting pressure differential across the injectors will be decreased by 15psi.


NOT THE CORRECT WAY.

Re: How to adjust a "set" RRFPR thats too big.
 

You still havent told us what engine/car you are talking about. SRT4??? scooby? what??? Did you knock the caps off the 550s??

820cc injectors and a 3-1 RRFPR? I assume you are using some kind of piggy back since you said you pulled sig. from the mass air sensor.

And a very clever idea it was. MY point is that you shouldnt have had that problem in the first place.

MOST people seem to install regulators because someone else told them that they needed it, even if they didnt.

Only 3 reasons to install a FPR (notice I didnt say RRFPR)
1. Upgrading the whole fuel system, reg becomes a restriction.
2. Highflow fuel pump "outruning" the reg/weak reg. (common on dsms)
3. To maintain an accurate and predictable LINEAR pressure to ease tuning.


Im not saying that you cant make power with whatever setup your running. Im saying that you might want to rethink the way your tuning it. The more signal you pull out of a MAS the less accurately the ecu is going to be able to control fuel and timing. Hince the running rich even while tricking the ecu. The more you lie to it, the more it will NOT run right.

You should also consider that with a properly running fuel injection system, if your hack your MAS signal to lean out the mixture, 99% of the time, the ecu is going to ADD timing. Richen it up, and it will pull timing. You will hit your knock limit sooner.

Good luck with your setup. (no sarcasm i swear)

Re: How to adjust a "set" RRFPR thats too big.
 

CC-Fab anyone?

Re: How to adjust a "set" RRFPR thats too big.
 

ROFL :y

Re: How to adjust a "set" RRFPR thats too big.
 

see were talking about the RIGHT way, as in ohhh, i dont know, an engine management system that works. if you have injectors big enough to handle the amount of boost your running at the correct psi of fuel pressure, you dont need to ramp up fuel pressure under boost. the computer will see the boost, via map or maf, and supply the correct amount of fuel. the only reasons i run vacuum to the FPR is because a) its not insanly unsafe like adding fuel pressure is and b) with huge injectors sometimes you can't shorten the pulse with enough to not have your motor idle rich as ----.

so as you can see, this is the correct way. if were refering to correct as the absolute best and safest way

Re: How to adjust a "set" RRFPR thats too big.
 

http://www.vincentfurniture.com/phot...llingRRFPR.jpg


I don't get it.


1-1 is fine cause thats what EVERYONE uses.

But 1.1-1 will blow your motor up, cause fires and rape you mother.

God forbid you go to 1.5-1 rate!

What about a turbo that only boosts to 8 psi. The fuel pressure goes up 8.

Another turbo boosts to 24 psi, ie fuel pressure rises 24 psi, 3 times the amount.

Will the first motor blow up in a fiery death because he decided to use a 3-1 RRFPR (for whatever reason) and also raised his fuel preassure 24 psi?

Not.

Re: How to adjust a "set" RRFPR thats too big.
 

You don't get it even after I explained it. The FPR has to see boost. That way it cranks up the fuel pressure to compensate for boost pressure. ie 1:1 FPR.

If you have 40psi of fuel pressure, and then add 10psi of boost which putting pressure on the output of the injectors, the resulting pressure across the injectors will be only 30psi.

rail pressure - boost pressure = effective fuel pressure (just simple physics here, nothing complicated)

Now your fuel maps would be funky and ramping up to compensate for the pressure loss.


Now imagine boosting 30psi. Now the effective fuel pressure would only be 10psi. You would need some massive injectors to compensate.

With the FPR seeing boost and you have 40psi of fuel pressure combined with 30psi of boost. Now the rail pressure will be 70psi and the resulting effective fuel pressure will be 40psi. Now no matter the boost pressure you will have a predicable fuel pressure and normal looking fuel curves.