fuel presure regulater

[ukdave]

my fuel pump or my fpr is going out. im not sure what is a good afpr? im gonna get the walbro 255lph and im gonna get a afpr but i just wanna know what is a good one thats not gonna brake the bank.

 

[eclipsh]

Are you planning on a turbo/injectors big enough that you'll need a 255? A 190 or Evo 9 pump will go a long way and could save you money on an AFPR. One of the wisemen also says the Evo FPR can handle bigger pumps with no issues and will fit our cars. He's also said the stock FPR can handle bigger pumps fine if it is a new one. I haven't seen hard numbers to back this up. You may want to do some research on these options if you want to save money.

EDIT: Here's a link or two:

http://www.dsmtuners.com/forums/newbie-forum/366433-honda-fpr-dsm.html

http://www.dsmtuners.com/forums/bolt-tech/337163-evo-parts-compatible-1g-2g-dsms.html

The second thread suggests it is voltage change that helps the EVO with fuel pressure. I haven't looked into it further because I've modified my FPR and don't need a new one.

 

[ukdave]

yes i will need the 255lph, but thanks for the link

 

[95blackGsTurbo]

You can either purchase a new 2g one or new EVO one. They are ~$60 from Mitsubishi. There are lots of people who are running stock regulators with big pumps. The EVO's do have a system to regulate fuel pump voltage but it isn't what everyone thinks. I have seen stock 2g regulators hold 255lph, Supra pumps, Aeromotive A1000, dual 255lph and Bosch 044's no problem. In my opinion AFPR are a waste of money on a shiney object.

 

[eclipsh]

You can either purchase a new 2g one or new EVO one. They are ~$60 from Mitsubishi. There are lots of people who are running stock regulators with big pumps. The EVO's do have a system to regulate fuel pump voltage but it isn't what everyone thinks. I have seen stock 2g regulators hold 255lph, Supra pumps, Aeromotive A1000, dual 255lph and Bosch 044's no problem. In my opinion AFPR are a waste of money on a shiney object.

How was their pressure? Was it consistent or was there a lot of flutter/spiking/non-1:1 rise going on? That return line hole is tiny.

 

[95blackGsTurbo]

I have run both on my car and run a stock 2g one on my car with a 255hp pump with no issues. Have a gauge mounted on my fuel filter and it holds steady at 43psi.

 

[ramsack]

i think people that think because a 1g overruns that a 2g will too. the 1g regulator has a return port that has a 1/16" orifice inside. i haven't taken apart a 2g one but i'd assume since people are actually having success with them they have a larger orifice. the problem i see with the statement with a AFPR is a waste of money is that once you start upping boost, you also up fuel pressure. more fuel pressure means the diaphragm has to hold more force, and oem ones are weaker, and not rebuildable. i'd think this is why they make replacement diaphragms for AFPRs.

 

[eclipsh]

i think people that think because a 1g overruns that a 2g will too. the 1g regulator has a return port that has a 1/16" orifice inside. i haven't taken apart a 2g one but i'd assume since people are actually having success with them they have a larger orifice. the problem i see with the statement with a AFPR is a waste of money is that once you start upping boost, you also up fuel pressure. more fuel pressure means the diaphragm has to hold more force, and oem ones are weaker, and not rebuildable. i'd think this is why they make replacement diaphragms for AFPRs.

You would assume wrong there. The return line hole on 2g FPR's is equally minuscule. I don't think the diaphragm has to hold any more pressure than base at any time. The increased pressure in the vacuum chamber should counter balance the increased pressure in the fuel chamber. That is how it compensates for changes in intake manifold pressure.

95black, do you have any info on how the regulators are handling higher pressures? I'm just curious because you're going against what a lot of prior information says.

 

[ramsack]

then how do people not overrun on a 2g? i have taken apart my fpr that was seeing 60 psi of base pressure after a few months of running and the diaphragm was bent permanently. the fpr was good when i put it on. i just don't hold true that an afpr is a waste of money.

 

[95blackGsTurbo]

i think people that think because a 1g overruns that a 2g will too. the 1g regulator has a return port that has a 1/16" orifice inside. i haven't taken apart a 2g one but i'd assume since people are actually having success with them they have a larger orifice. the problem i see with the statement with a AFPR is a waste of money is that once you start upping boost, you also up fuel pressure. more fuel pressure means the diaphragm has to hold more force, and oem ones are weaker, and not rebuildable. i'd think this is why they make replacement diaphragms for AFPRs.

Regulators DO NOT overrun. The diaphragm is just old and weak. If FP is irradic, get a new regulator. You have a 19-20 year old seal and spring. It's gonna be weak.

 

[ukdave]

i need one like soon but the parts stores around here told me today the they cant get a fpr, they told me to go to a dealer for one. and will the stock fpr work with 1000cc injectors? ### i will be getting some soon.

 

[ramsack]

it may or may not. it is well understood by many why the stock regulators overrun. the more fuel you actually pass through the injectors the easier the stock fpr can handle a big pump. you will just have higher idle and vacuum fuel pressure. my broken regulator was ruined by my 255hp, and it held steady fuel pressure. it also didn't dump any fuel into the vac line. sure someone can get a brand new factory fpr, it will just prolong death over a used fpr.

i don't get how a hole smaller than 1/16" is supposed to dump fuel back to the tank correctly when you are putting a pump on that can flow 255 lph at a higher fuel pressure. it has been well covered elsewhere and i guess there are just tons of people out there who wasted their money, and people that are very knowledgeable who are just making stuff up. also, if the diaphragm and/or spring are weakened from use, then fuel pressure would be lower. and a diaphragm can break. the only way the forces can counteract on both sides of the diaphragm are if the fuel pressure and boost pressure are the same. since there is a base fuel pressure of an example 40 psi, and you throw 30 psi of boost at it, fuel pressure will be 70 psi. there is still 40 psi of fuel pushing on the one side of the diaphragm.

it's not like afprs are that expensive, and if someone doesn't want link and wants to use something like an afc, then it is a good tuning tool to lower pressure and not have to take as much signal from the airflow signal. also the factory manuals have a range the fuel pressure should be, and then an fpr spec. why not just be able to adjust it EXACTLY to what it should be?

 

[eclipsh]

Ramsack, what I was saying is even when you're at 30psi of boost and fuel is at 70 psi the pressure differential the diaphragm is seeing is still the same 40psi it was seeing at idle. No matter what it should always be getting that. Well, unless it is getting overrun and pressure is rising faster than boost/vacuum. I still think overrun is entirely possible based on my own tear-down. There are pictures of what 2g FPR guts look like in my thread linked below.

http://www.dsmtuners.com/forums/custom-fabrication/346146-turning-stock-fpr-into-afpr.html

 

[ramsack]

i was reading that yesterday. quite cool. have you been able to tell if it's 1:1 in boost?

 

[ukdave]

ok some of you say the stock will work just fine and some say it wont. what about a cheap ebay one or a meganracing one to get me by tell i can get a good one.

 

[eclipsh]

i was reading that yesterday. quite cool. have you been able to tell if it's 1:1 in boost?

I guess I'd better run my gauge up onto the windshield and confirm it. I'm confident it is. Pressure is holding for hours now too. I can go start the car up after it sitting for half a day and it fires up with one quick crank.

ukdave, if you are confident you need an AFPR why buy two and waste your money on the first one? I'm all for saving funds wherever possible (just look at my various tech articles and threads) but I'd suggest you buy the right tool the first time and be done with it. You'll save money in the long run. That said, you can always watch the classifieds and eBay for a quality used AFPR.

 

[ukdave]

well the obd2 reader read fuel pressure solenoid so i guessing that would be the fpr and i need one with in the next two weeks

 

[95blackGsTurbo]

I actually installed an SMP aftermarket cheap one. OE replacement for $41 at Autozone. Holds fine. Of course after 10+ years the regulator and spring will be weak. But think about this, how long have you seen an Aeromotive or AEM one last? 3-4 years and your rebuilding that one as well. Seems to me a new OEM unit is a much better deal.

 

[ramsack]

except you're on a 2g, which all of the cars have 43.5 (3 bar) regulators. 1gs do not have a 3 bar fpr at all. automatic turbo is 42.7, manual turbo is 36.3, and non-turbo are 47. i would need to get a 2g rail for a 2g fpr to fit. so for me with an obviously overrun regulator, an afpr would be the best approach.

ukdave, the fuel pressure solenoid is there for warm starts to try to prevent vapor lock. it raises fuel pressure to lessen the chance of vapors in the fuel system resulting in a hard start. if you need an AFPR the 2 kind of AFPRs people run are the aeromotive a1000 or fuelab 515, 525, or 535/545 mini.

 

[95blackGsTurbo]

This applies to 1g's tooo. And how do you know you are overrunning it as you like to put it? Do you monitor fuel pressure? There are 2 guys in AZ running stock OEM regulators on 1g's with big pumps. One has a dual 255lph setup and the other an inline Walbro with a 255lph in tank and guess what? 37psi rock solid. You can run an AFPR but except to have to rebuild it twice as often for double the cost of a new OEM unit. And what does a 2g rail run? $10.00? You can probably get one from someone who upgraded their rail and regulator setup for $20.00. Tuning for the extra fuel pressure is pretty easy as long as you have something to adjust fuel.

 

[95blackGsTurbo]

FYI the OP has a 2g.

 

[95'RS-T]

Aeromotive a1000 kit from EXTREME PSI : Your #1 Source for In Stock Performance Parts - Aeromotive "A1000" Complete Fuel Pressure Regulator Kit w/ Gauge: Mitsubishi Eclipse 90-99 I'm very happy with this kit so far.

 

[ramsack]

actually i do. it is mounted on the rail right near the fpr.

 

[ukdave]

what do i do if the fuel pressure solenoid is bad, the part stores cant get one. is it safe to just bypass the fuel pressure solenoid

 

[ifeelubu]

I dont know about not using a stock regulator almost every person that I spoke to that has alot of knowledge when it comes to dsm has told me to use an afpr not the stock jeff from dsmchips is one of the guys i asked that question and he told me definetely to get afpr and I think he knows what he's talking about