Turning stock FPR into an AFPR

[mike96]

this concept has been used else were. Honda Acura B&M Style Fuel Pressure Regulator Kit although this website only displays usage on Honda and acura there are quite a few e-bay'rs that have this brand marketed for DSM's. i have thought of doing something like this on my car but i need to get it back on the road first. i am curious to see what changes there is to stock fuel pressure if you were to just cut off the stock return line, remove the stock restrictor and thread on a new return line. this alone should be enough for most people who have problems with fuel pumps overrunning the FPR. something like this perhaps....

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or this would give you something with a nice smooth end to seal against like you were talking about with the bolt... and it is only $3 where as the copper one is like $17

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[eclipsh]

Time for an update.

I decided I wasn't happy with the fluttering fuel pressure so I dug into the regulator you see above, tapped some more threads going up into the regulator body, center bored an 8 mm bolt with a 3/32" hole and threaded that up in to give the valve a better seat and more restricted flow to even out the pressure. I made the bolt short enough that I could thread my pipe fitting back onto the end and stick it back into the car. It evened out my pressure so the needle was barely wavering at idle (I'd estimate less than 1psi of flutter which is comparable to the stock regulator or an after-market one).

I ran with that for a while but decided I really wanted to make something cleaner. So I gave the idea in post #20 another shot. I center bored another much longer bolt, polished the end for a nice mating surface, stuck a jam nut onto it, wrapped it in teflon tape and threaded it up into the regulator. I left enough of the bolt sticking out that I could slide the return line hose on over the end and clamp it down. Once it was in the car I adjusted the bolt in/out until I had the pressure where I wanted it and tightened down the jam nut. Before tightening the nut there was a little fuel leaking out while I adjusted the bolt. Once the jam nut was tight the fuel leak disappeared. I dried the regulator off and ran the car for a bit to see if any more fuel came out. I didn't get a drop and couldn't smell any gas leaking out. Just to be safe though I went ahead and soldered around the jam nut so nothing more could come out. I've been running that regulator in my car for a few days now. It is holding pressure better and starts up much easier. It takes less cranks than the Aeromotive AFPR I had on my 1g took to get going so I'll call that a victory. I still need to run my pressure gauge up onto the windshield and go boost it to see what happens but I'm sure it'll rise at a 1/1 ratio since I didn't mess with much of anything besides the center bore.

Here's what it looks like in the car.

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Of course if you try this you do it at your own risk, I am not encouraging you to do so, just showing what I did. If your car burns to the ground it is your fault, you did it wrong and failed to properly test the regulator before installation.

 

[95'RS-T]

nice job man! So does it work with the 1:1 ratio?

 

[eclipsh]

I haven't stuck a gauge up on my windshield yet but I may not. I went out and did some tuning yesterday. I use Jackal running native WB02 so I can log my real AFR along with everything else. My enrichment tables and measured AFR were working perfectly together and both have a curve as smooth as a baby's butt. The lack of noise in my enrichment table and my AFR lets me know my FPR is at very least adjusting smoothly through the boost range. That's good enough for me to call this a total success.

 

[the_mork]

I just wanted to reiterate that this is really cool and thank you for your work on this. I may play around with this at some point but for the moment I have a lot of other things to get to on my car first and it is always good to have someone else do this for a while first to work the bugs out .

 

[eclipsh]

Thanks mork, glad you like the mod. With more time spent running this regulator I still have no leaks and the regulator holds pressure for quite some time. Pressure drops very slowly now, at about 1-psi every minute or so. Polishing the mating surface at the end of the bolt is a must for getting a good seal.