jreynish

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https://www.rx7club.com/showthread.p...=1#post4027018
Have a read reply here or there
Anybody have a similar experience or make more power?

jreynish

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Here for people too lazy to click the link
Well it turns out that I have officially maxed out the stock fuel pressure regulator on our cars.
I am running a TD07-25 Turbocharger and a Haltech, with stock 550cc primaries, 1600cc secondaries, Walbro 255lph Fuel pump. and so far the stock fuel system so I am on the road tuning and with my G-Tech RR Properly calibrated and Actual weight of car inputed. And datalogging on my laptop. I was on the Highway doing 5th Gear tuning for high load, and then I notice that my EGTS start climbing so I adjust timing accordingly, and notice the egts went down a little but not significantly so I look at my afr's for that run in the datalog from the haltech and it turns out that the afr's went into the High 12's.... so I in turn add fuel in that area of the map and it did not good, there just isn't the fuel pressure to run the 1600's and the 550's.
Anyways the system started to top out at 15.5 PSI on my large turbo and according to the G-Tech that translates into 348 RWHP. So If anybody is looking to go much above this with your stock fuel pressure regulator, I strongly suggest upgrading to an aftermarket FPR.
I just happen to have an Aeromotive and -6AN fittings sitting in my garage ready to install I just wanted to see when the stock fuel system maxed out. And voila I have fount it approx 350 HP and 15 PSI on a larger single Turbo.

jreynish

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And todays results.
ok so I installed my -6 and lines and my Aeromotive Fuel pressure regulator today and went for a couple of runs on the highway and Zip Tied a Digicam with video recording to the FPR in the Engine bay.
so here is what I found.
at iddle 32 PSI
at 0psi boost is see 40psi
at 15.5 psi boost I see 55 psi.
and Lone Behold I am now rich in that area of the map....
So now I see 10.8 AFR at 15psi in 5th Gear.
and on a HP test with the G-Tech in 3rd I managed to pull off a 365 HP
So I do suspect that it was the Fuel pressure Regulator buecause nothing else was changed.

Snook

iTrader: (12)

Great info!

I wonder what it is for the fd? Nobody has ever complained about the fpr and I've seen 435rwhp on it I'm not sure if that is the most. I really wonder how safe that is because you do run lower fuel pressure with less boost correct? It's probably not made for so much pressure?

maxcooper

Keep in mind that it might just be that jreynish's stock FPR may simply have gone bad.

-Max

Carl Byck

Also, running 1600/anything is going to need an FPR with at least a 1:1 gain when turning up the boost. In other words I have never seen someone with a single upgrade/stand alone, and the stock FPR (before today) ... It's a simple ~125.00 upgrade, i thought everyone did when they upgraded their fuel system.

pp13bnos

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Running a 850/1300 combo and my stock FPR did fine at 400+rwhp. CJ

jreynish

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I had already purchased it and had it sitting in the garage but I was just cheking to see what exactly the stock FPR could handle. I was paying close attention to all of my gauges while tuning, as anyone should as to not blow my engine, and to see when I started running out of fuel.

Maxcooper, has a good point it could have been that my Stock FPR was on it's way out. But either way I figured that my findings would be usefull to someone.

Carl Byck

At what boost? Also what pump? Most of the pumps being used only run~40-45 psi+/- at WOT(without an aftermarket FPR), that leaves almost no room at all figuring~12psi system loss, and the pressure differentials needed for correct fuel atomization. Assuming ~16-20psi that most commonly used turbos need for 400rwhp, you might get away with it, but you are well below your systems potential with an aftermarket FPR. For reliability sake a rising rate FPR would bean excellent addition to your system. I see guys run 20 psi on pump gas, that does not make it a good idea. If you had a large turbo, and did not need much boost you could do it as well. For the average person reading this the aftermarket FPR is the way to go.

jreynish

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Carl are those questions dirrected toward me or pp13bnos?

Carl Byck

Sorry, they are for pp13bnos. If he was PP, and NOS, or had a large turbo that would be more in line with his fuel statement.

pp13bnos

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I'll clear some stuff up. I'm not running a peripheral motor on nitrous anymore.....and it was never turbo charged. What I was talking about was my 3rd gen.

As some of you know, I'm running a SR stage II. The car made 396rwhp on a mustang dyno at 16psi (Add 10% for dynojet numbers.) The fuel pump is a Groundzero (Ralph or Xcessive on the forum.) pump. When the car was on Ralph's dyno we where running the fuel pressure into his dyno. There was'nt any fuel pressure drop with boost upto 16lbs of boost. Or anouther was of saying it was that the boost to fuel pressure where bolth climbing at the same rate. This was not on pump gas but low lead 100 octane. CJ

maxcooper

Also, so long as you have it hooked up, either direct or through the stock solenoid (that simply hides vacuum under some conditions other than under boost), the stock FPR is a 1:1 unit. I agree that it generally makes sense to use an aftermarket FPR with 1600s and a custom rail, but the stock FPR seems adequate for many stock-secondary-rail setups as long as you want to run stock fuel pressure levels.

-Max