Do i really need a FPR

[Kmiller86]

Hey, ive looked and i cant find the answer that im looking for. I have a 255 fuel pump and FIC 850cc injectors and a whole lotta other mods. I am on a tight budget and was wondering if it is really worth getting one or is it one of those things i can wait till later to get.
thanks Kyle

 

[MattnGsx]

Yes good thing to get, if you want a proper tune, otherwise your fuel pressue will be all over the board. If you buy one, make sure you can get on that can lower, and raise fuel pressure.

 

[jott5555]

i think i remember reading somewhere that 1g na's had a nigher stock fp or something so you are able to put one temparaly on a car equipt with a larger pump and run a decent stable fuel pressure..

other wise i suggest you get a afpr.. go with the full throttle one or a used charged air one.. it should be manditory

 

[2.4 turbo Hyped]

I would like to swim against the current and say no you dont need one. All you really need is a reliable fuel pressure, which is provided by the stocker. I have proved this using a cockpit mounted fuel pressure gauge. I have tried several different aftermarket regulators and all of the ones I have tried seemed to be affected by the underhood heat. The springs inside them heat up and the pressure drops off after the underhood temperatures reach a certain point. None of the stock regulators I have tried do this. I use an n/a regulator off of a 90 laser and it sits at 49-50 psi base pressure. Good enough for a 2.4 liter motor with a 60 trim turbo. Sean

 

[Kmiller86]

yeah thats what i thought i have read that somewhere too. in fact, sean, i think it was you telling somebody that. 1 question though, the lazer fuel reg is it a direct fit for a 1g rail?

 

[2.4 turbo Hyped]

Yes its a direct fit and the great thing about it is if you do alot of hood popping people will always ask you why you dont "waste your money" on all of that aftermarket fuel line crap. I usually just smile and say "what for". Its a great sleeper mod.

 

[jott5555]

the problem your overlooking is that a base 1g turbo runs 37psi ( i beleive) and 2.4 is going to naturally use more fuel because of the larger displacement.. running 50 psi on the stock regulator is going to probally over run it.. that may be fixed by switching to a na regulator but then you may have 49-50psi, which is going to make you run very rich.. and would altimetly be harder to tune.. I beleive.. now granted im not a noobie.. but im also not a pro.. just my .02

 

[2.4 turbo Hyped]

Theres a couple of 2 liter guys running them also and they work just fine. As long as you have a source of tuning such as an safc or a maft you should be ok.

I dont believe in overrun. I have never seen it or experienced it with any fuel pump or regulator. Sean

 

[fostytou]

AMS is about to do my 6 bolt swap. Eric #1 said he runs his 500hp 2L with the stocker and that I shouldn't need one. We both have walboro 255 and 680cc injectors i think.

 

[jott5555]

now see i have seen a stock fpr over run.. with 720's and a 255. it would do ok up to 3500 or 10lbs.. put under wot of over 10psi it would stumble all over and act like crap. the car belonged to chaey on tuners here..

he put a charged air afpr in and it ran 100% until his b16g ate crap 1000 miles later.. so.

 

[David15151]

would it not be a good idea just to get a AFPR for tuning purposes i mean if you are getting close to maxing out your injectors you can just turn the fuel pressue up a bit to get the duty cycle down.

 

[dave99gst]

how bout we start with .. do ya got a f/p gauge ?
if not your all just guessing.

is the f/p a 255 or 255hp ? is it re-wired ?
if the answer is yes to both then you are over-running your stock FPR
btw - 2g fpr's handle the pressure then 1g's not the other way around.

 

[Kmiller86]

Thanks for all the input. Could i just get a fuel pressure gauge and tape the fuel rail or the feed line to see what my pressure is at and go from there? or just spend some more money and just get a regulator?

 

[AMS stampy]

People toss around the FPR all the time as a proper tuning tool on mildly modded cars. We dont toss an FPR on a car unless we are overworking the stock fuel system. on my personal car with a 2.3 GT35R 880 cc injectors and EMS I run a STOCK FPR and my tune is DEAD ON! So to answer your question No you do not NEED an FPR on the car. Yes it can help fine tune it some more but any proper wideband and AFC will get you where you need to be. The FPR can help ballance out Fuel economy and what not but if you worried about gas milleage you are in the wrong hobby.

Eric

 

[Kmiller86]

wow u can measure gas usage in miles with your car? any way i think ill just see what i can do with out it and if i have a prolem then i may need to get one.

 

[99gst_racer]

Thanks for all the input. Could i just get a fuel pressure gauge and tape the fuel rail or the feed line to see what my pressure is at and go from there? or just spend some more money and just get a regulator?

Yes, find out what your fuel pressure is right now. And that will determine if you should get a AFPR.

 

[Clipso 1]

he put a charged air afpr in and it ran 100% until his b16g ate crap 1000 miles later.. so.

How did your friend get his charged air afpr to work? I have had one for months and I keep going back to the stock one because it doesnt seem to make any difference at all.

 

[AMS Eric #2]

The term "overrunning" the stock FPR is being misused in this thread. The only time the stock FPR can be overrun is when the car is idling. The fuel pump in your car runs the same speed all the time, and pumps the same amount of fuel. At idle, your injector pulsewidth is very small. Your FPR has to return most of the fuel back to the tank to maintain proper pressure. With big pumps and small regulators, the pump will push more fuel than the regulator can return, causing pressure to build up in the rail.

Most of the time, we dont see problems with 255lph HP pumps and stock regulators. If you rewire the pump, or use a supra pump, especially on a car with a 2g rail and fpr, the pressure will get quite high at idle. If you have any doubts about your fuel pressure, we sell the banjo bolt replacement for the fuel filter that has a 1/8" NPT fitting in the top of it. You can perminatly mount a small mechanical liquid filled gauge(which we also have) there to check idle pressure, or temporarily run a hose to a gauge and put it under your wiper blades and go for a drive. I dont suggest routing a mechanical gauge into the car for the risk of fuel getting all over the interior on accident or the possibility of a fire.

If your running into fuel pressure problems under WOT, you should really look more closely at fuel injector capacity, fuel pump, or tuning. Ive never seen a car with a stock regulator fail to maintain pressure under WOT that was actually caused by the FPR.