AFPR, what exactly does this thing do? Is it important?

[JoeyJigglesGSX]

ok you can see my list of mods in my profile, but for now i have an EVOIII 16g and and 255lph fuel pump. Now i have been trying to read up on these AFPRs, but i just cant seem to get a good enough answer.

What is this thing all about? What exactly does it do? I know it "regulates" fuel, but do i need it? will it make my car run better? please teach me, because im not sure on if i need one or not

 

[hellotbone]

Any DSM with a 255l pump needs an adjustable fuel pressure regulator. What happens is the big pump puts so much fuel to the rail the stock FPR becomes over run and in turn cann't get rid of the fuel fast enough. Making the fuel rail have a higher fuel pressure causing your car to run richer. An AFPR keeps your fuel pressure more consistant and can get rid of the excess fuel the stock one cannot. You should definately look into one if you are wanting to get any kind of a decent tune and performance from your car.

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[JoeyJigglesGSX]

Any DSM with a 255l pump needs an adjustable fuel pressure regulator. What happens is the big pump puts so much fuel to the rail the stock FPR becomes over run and in turn cann't get rid of the fuel fast enough. Making the fuel rail have a higher fuel pressure causing your car to run richer. An AFPR keeps your fuel pressure more consistant and can get rid of the excess fuel the stock one cannot. You should definately look into one if you are wanting to get any kind of a decent tune and performance from your car.

<<<<<<<<<<<<<<< Now look over there see the scales of justice at the bottom under my name yep those are rep points I thank you.

so are you saying that technically my car is not getting enough fuel because i am over doing it? or does that mean i could run more boost because i have soo much fuel?

 

[SBstar]

No you will not be able to run more boost. Your car is running to rich because the stock FPR cannot handle the extra load from the fuel pump. If you have a 255 LPH fuel pump you will need an AFPR and a fuel pressure gauge and adjust it back to stock fuel pressure. Stock pressure for your 2G is 43 psi.

 

[JoeyJigglesGSX]

No you will not be able to run more boost. Your car is running to rich because the stock FPR cannot handle the extra load from the fuel pump. If you have a 255 LPH fuel pump you will need an AFPR and a fuel pressure gauge and adjust it back to stock fuel pressure. Stock pressure for your 2G is 43 psi.

ok, now my questions may sound retarded but im new at this fuel stuff.

1) why would you want to run it at the stock pressure setting? wouldn't you have to raise it up a little with my type of mods?
2) how do you adjust it? can you do it with your car just sitting there running?
3) what is a good efficient AFPR to buy? something that will get the job done correctly

 

[hellotbone]

ok, now my questions may sound retarded but im new at this fuel stuff.

1) why would you want to run it at the stock pressure setting? wouldn't you have to raise it up a little with my type of mods?
2) how do you adjust it? can you do it with your car just sitting there running?
3) what is a good efficient AFPR to buy? something that will get the job done correctly

1)You want to run the stock fuel pressure because the regulator runs a 1:1 rise so 1 pound of fuel for every pound of boost you run. That is what the injectors require no more.

2)Yes you can adjust the fuel pressure on an aftermarket fuel pressure regulator thats why its adjustable.

3) A good one to guy is an Aeromotive one any of the site sponsors/vendors can supply you one.

 

[JoeyJigglesGSX]

1)You want to run the stock fuel pressure because the regulator runs a 1:1 rise so 1 pound of fuel for every pound of boost you run. That is what the injectors require no more.

so is 43psi the stock pressure? and is that were your injectors are maxed out? also what psi of boost should you run with stock injectors and a 255lph fuel pump?

 

[CanadianTSi]

43 is the pressure at Idle, I wouldn't run more than 15 on the stock injectors.

 

[JoeyJigglesGSX]

well i think it is just time to get an SAFC II and have it tuned. That is something i have wanted to get anyway to i can finally tune my car correctly with all of my mods. I will prob. be going to Turbo Trix. Thanks for all of your guys help.

 

[99gst_racer]

JoeyJigglesGSX - This thread might help you understand fuel pressure regulation a little better.

 

[andymoraitis]

ok you can see my list of mods in my profile, but for now i have an EVOIII 16g and and 255lph fuel pump. Now i have been trying to read up on these AFPRs, but i just cant seem to get a good enough answer.

I'm all for simple solutions so please take this with a grain of salt. The 255 is overkill for an EVO III. A 190 pump has powered cars into the 11's. By using a 255, you're adding another unnecessary link to the tuning equation. To see the most from your turbo, buy a set of 660cc injectors, get an EPROM ECU from DSM Chips with injector compensation, a leaner A/F and a bit more timing built in and swap the 255 for a 190. An AFPR will not be needed and you can still use an AFC to help you fine tune the setup. I've sent you a rather long PM with some recommendations.

As an aside, if you keep the 255 and don't buy an AFPR, an AFC will not help you with fuel pressure overrun (which you're experiencing now).

Drop me a line if you have questions.

Andy

 

[BlackbirdOfPrey]

No you will not be able to run more boost.

That is incorrect. You can run more boost, even without a AFPR. He is going to have bad gas mileage until he gets his fuel pressure corrected with a AFPR, but he shouldn't suffer any DRIVABILITY issues. The problem for him is injector size. He needs larger injectors to run more boost than stock boost with anything other than a stock turbo.

 

[SBstar]

I'm sorry I guess I should have clarified. What I meant is that he will not be able to run more boost only due to the fact that he has more fuel pressure. Its the added fuel that will allow for more boost.

 

[JoeyJigglesGSX]

ok, what do you guys think of a AFPR and SAFC II together and have it tuned for my set up?

 

[neuralracing]

The 255 is overkill for an EVO III. A 190 pump has powered cars into the 11's. By using a 255, you're adding another unnecessary link to the tuning equation.
Andy

Couldn't agree with you more... I don't know why "regular DSM'ers... be these people in the 12's or 11's" buy 255's in the first place. First you are spending more money... FPR... and you are adding tuning headaches.

I would ditch the 255 (sell it) and use that money to buy a 190. Use the money that you were going to throw at the FPR towards buying 660's or 720's (might be overkill).

 

[JoeyJigglesGSX]

ok, now please people bare with me. That makes sense neuralracing about getting rid of the 255. Now this 190 pump, i can run that and not have to upgrade my AFPR? because that would be awesome. What is this 190 pump like just the perfect fit for the stock AFPR?

 

[L2RTSiAWD]

A 190 generally will not overrun the stock FPR, however if you are seeing a non 1:1 rising rate on WOT runs you would still need to get an AFPR to balance that out.

 

[DGajre777]

A 190 generally will not overrun the stock FPR, however if you are seeing a non 1:1 rising rate on WOT runs you would still need to get an AFPR to balance that out.

In simple english that means you won't need a AFPR for the 190 pump for your EVO III 16G turbo

 

[Grimis]

is it ok for me to jump in here as well????

Any ways, i just got my Evo 3 turbo, and i was going to get 255lph and 660s, but the 190lph and 660s will be fine with an SAFC, and no need for an AFPR?? if i read this post right

 

[L2RTSiAWD]

Like i said in my post 190 will not need an AFPR in most cases. I would still invest in a fuel pressure guage to make sure.

 

[Grimis]

ok will do that, thats why I asked. Thanks, now if only the canadian customs would let my trans go.