fuel pressure - Newbies Forum

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fuel pressure
Tuesday, February 19, 2008 7:17 PM
hey i just signed up!! i tried looking through other forums about N/A fuel pressure. i have a 3" intake with a col air extension ran to the front bumper (plenty of air!!). i have an obx 4-2-1 header with a 2.5 exhaust and twin dual canister mufflers. i just bought the split second air/fuel calibrator and a fuel pressure regulator. i have a 2.2 LN2 with only 20,000 on the motor . its a 2001 with a manual transmission if that makes a difference. the fuel system is completely stock for now. pretty much my question is what is a good fuel pressure that i should set my FPR to? im about to move to eastern nc from panhandle flordia towing a trailer so any reliable hp and torque i can get would be HIGHLY appreciated!

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Re: fuel pressure
Tuesday, February 19, 2008 8:18 PM
stock. you have nothing done that you'd need to play with fuel pressure/injector size yet.



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Re: fuel pressure
Wednesday, February 20, 2008 6:41 AM
correct me if im wrong, but any time you make an alteration from the stock setup allowing the engine to breathe better, your changing the afr. ive allowed the engine to bring in more air as well to expell it. i know it definately wont be a drastic change but with more air you need more fuel correct?

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Re: fuel pressure
Wednesday, February 20, 2008 7:14 AM
Yes you have allowed the engine to breathe easier, but you have not changed the amount of air flowing into your engine enough to need to change your A/F. Besides the computer already is compensating for it.

The only thing with the FPR is that you can bump up your fuel pressure for better atomization and a better more complete burn. I doubt you would notice it.



Re: fuel pressure
Wednesday, February 20, 2008 11:27 PM
i know that im not increasing air flow by that much, like i stated before, i knew it wouldnt be a drastic change. im slowly build up the engine for a turbo kit. the fuel system is the first on my list. thats when the fpr will really come in handy when used with a fmu. im just starting to build for it, so i was wondering what a recommended setting would be since ive already got it. if you got, use it you know. i think the factory psi is 32, but i might be wrong. thanks for the input, not tring to sound like a know it all cuz i know i dont!!

SMILE!! YOUR ON CAMERA
Re: fuel pressure
Thursday, February 21, 2008 4:46 AM
Just set it to factory to start and maybe play around with it by bumping it up slightly and see if it affects your fuel economy. I dont think it would noticeably affect your horsepower. I plan on building my car for a turbo in a year or so. But im just gonna grab a spare engine and just build it in one shot.



Re: fuel pressure
Thursday, February 21, 2008 8:33 AM
Your fuel economy right now will be higher on the highway than it was. The low end, however, will have had a drop.


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Re: fuel pressure
Thursday, February 21, 2008 8:42 AM
our cars (and just about every car) tend to run rich. its safer to run rich than lean.

generally, when you put an intake and exhaust on a car, it brings the car closer to lean, but it will generally still run a touch rich. the fpr will help you later in your mods, but i dont think you need it right now. if your going to be towing a trailer, it wouldnt be a bad idea to put it in before you go though. with the extra weight, if you notice the engine starting to ping and pre-det, you can bump up the pressure a touch.



1997 Cavalier Z24 - 16.3 in 1320 and falling...
Re: fuel pressure
Thursday, February 21, 2008 7:20 PM
thanks for the info, does anyone know the actual psi of the factory regulator? does anyone have a fpr on a 2.2 ohv with factory fuel rail. looks like fun. any one have any good suggestions (with out welding, wont have my welder back till i get to NC), any are appriciated.

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Re: fuel pressure
Sunday, February 24, 2008 11:28 AM
You should have between 53-59 psi key on engine off. this is the only thing ive been able to find on the internet so far as an actual number. i would assume that it would be a similar figure when the car is running. ive gotten a couple of replies to my initail question, but this is really what im tring to find out. i still appriciate the replies. if anyone has a different number, i would like to hear it. thank you

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Re: fuel pressure
Friday, February 29, 2008 7:35 AM
last time i checked all data, i think it said 47-51 psi if im not mistaken but i can double check when i go to class again for you. as far as having an adjustable FPR i just did a write up on what im making, its basically an adapter i made for a universal FPR that will slide right into the factory fuel rail and even use the same mounting hole. The are adjustable FPR like from an LT1 but that will run you around 170 bucks.

here is the link:
AFPR on LN2/2200






Re: fuel pressure
Friday, February 29, 2008 10:06 AM
thanks luis, thats the most informative reply ive had yet. i have to work on a montero sport this weekend which has a fuel problem, so ill probably just rent a fuel gauge and check it before i install it. that adapter looks good, but what are you going to use to secure it to the rail so it doesnt pop out from pressure. i dont have access to a laith, but i was thinking of going to a junk yard and getting a used oem fpr, and chopping it up to make one. cutting everything off except the mount and the nipple, then tapping the nipple to accept a fitting. like i said earlier, im moving on the 5th to nc from fl, so im limited on time. i dont have the time to mess with a machine shop. let me know how the install goes, and when i get the actual psi off my car, ill be sure to post it. thanks again.

SMILE!! YOUR ON CAMERA
Re: fuel pressure
Saturday, March 01, 2008 1:41 PM
well that pic was when i had just took it off of the lathe, now i grounnd it down so that the edge is not a sharp and wont cut through the hose but i left the edges rough so that the hose has stuff to grip to even with the clamp instead of leaving it smooth. Im making a flat plate with two holes and then feeding the adapter through and welding it, if your interested i would be able to make you one maybe during spring break in two weeks. I like the idea your going with on cutting up the old one, but one problem is that the fpr uses vacuum pressure to pull fuel and raise fuel pressure and sealing it might be too much of a hassle. I should be posting install pics soon along with pics of the complete adapter.





Re: fuel pressure
Saturday, March 01, 2008 8:59 PM
ok, i didnt know you were making a mounting plate for it, you didnt mention that in your writeup. sounds like that would work good. as far as what i was talking about with the adapter im making. i think your thinking that im going to have a lot more of the original fpr left then there will be. im talking about cutting the fpr in half long ways, then cutting off everything but the center section that contains the oem nipple and mounting bracket. then taking a threaded to hose adapter like the one thats on the adj. fpr and threading it into the oem nipple. who knows, i might be able to thread it right into the fuel rail itself. i dont know if the junk yard is open in pensacola on sunday, but if they are, im considering working on that tomorrow. im tring to get it on the car before i move, cuz im pulling a trailer with my cavi. i dont know if you ever pulled a trailer with a cavi, but any free horsepower is more than welcomed. the trailer hitch is well hidden in side my rear bumper (aftermarket), you would never know it was there. when you connect the hose from the new fpr to the return line to the tank, are you going to try to attach to the hard line, or use a hose couplin lower down on the rubber part of the oem fuel line. i was curious if autozone carried a flairing tool for hard metal lines. if you were to make an adapter to sell, bout how much would you sell it for? i think my idea will work, but probably wouldnt be the prettiest thing in the world. do you know of anyone that makes a hi flow rail for the 2.2 LN2? i wonder if you could switch to a 2.4 intake manifold and injectors with out to much fabrication?

SMILE!! YOUR ON CAMERA
Re: fuel pressure
Saturday, March 01, 2008 10:12 PM
by the way, this is my project, well 4 years ago, and yes i got new tires since then!! the 5 1/2" driving lights were rewired with #8 thhn with independent grounds, im an electrician and a light finatic, what can i say.


SMILE!! YOUR ON CAMERA
Re: fuel pressure
Saturday, March 01, 2008 10:12 PM
2 years ago, sorry, wrong button

SMILE!! YOUR ON CAMERA
Re: fuel pressure
Tuesday, March 04, 2008 4:35 PM
^^^^^ ok your picture didnt work

when i attach the hose, im going to do it to the hard line and use a flaring tool to make sure that the hose stays put.

Autozone does carry a flaring tool for metal lines, it cost up front to rent it but after your bring it back you get a full refund.

If i do make the adapters then they would be about 30 bucks or so, maybe 35 shipped.

As far as the high flow rail, no one makes one that im aware of. Modifying a 2.4 manifold and fuel rail to fit would be a big hassle plus i dont think you need to worry about flow on our rails they really arent that bad. Where you would need to concentrate would be injectors to get more fuel into the system.

i think your idea would work but it would take alot of cutting. What i have seen before is someone taking a 90 brake fitting with both male ends and threading it on how you were explaining and then using steel braided line to go to the afpr. Good luck with your project and get some pics up and ill update mine soon.





Re: fuel pressure
Tuesday, March 04, 2008 7:20 PM
oh by the way the fuel pressure per all data is 41-47 psi all the time.





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