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'88 911 Carrera 3.2
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Discussion Starter · #1 ·
So I've recently gotten tuned by Dent Sport. I've got my FSP EJ22 project putting about 120-130 awhp out. It was 122 on the dyno, but we were unable to adjust ignition timing at all due to my own wiring issues. Now that I've adjusted them, I have added another 10lb-ft of torque or so in timing (measured with G-Tech), so that's about where I am for power right now. More details, if you're interested, at http://www.jenandneil.com/28fsp.

Anyway, we noticed on the dyno that torque really really drops off after 5200RPM or so. By "really really" I mean that it goes from about 120lb-ft of torque to somewhere in the 80s. It's pretty sad. The fuel injectors are running overtime with about a 92% utilization rate and mixtures are really rich no matter how lean we tried to make it. We suspect the injectors aren't actually closing, so fuel is basically just spraying non-stop into the cylinders after 5500 or so.

So I'm trying to rectify this. I've got the stock fuel pump (??lph), stock injectors (280cc), and stock fuel pressure regulator and I want more fuel. I'm curious how others have approached this problem. I haven't yet hooked up a fuel pressure gauge anywhere to see how the fuel pump is keeping up and I can't find anywhere even an estimate of the flow capacity of the stock pump.

1. I could get a new fuel pump and assume that fuel pressure is dwindling at the top end. I don't suspect this is the case, but I'd love to hear someone else's experienced opinion here.
2. I could do a fuel pressure regulator, increase fuel pressures, and consequently lower the injector durations to get the fuel into the cylinders faster and allow more space between injector pulses.
3. I could replace the injectors. 440cc WRX would certainly flow more than the 280cc ones I've got and I could decrease the injection duration to accomodate that. It's not such a big jump that I expect to have any idle troubles with that and it's not a daily driver, so even some idle issues are just fine by me.

Anyone have any valuable experience I could learn from?

Can I assume that any top-feed Subaru injectors will fit or are there fitment issues with certain injectors?

Should I just assume that all options will require a new bigger fuel pump?

Does anyone have any good experience with electronic fuel pressure gauges that I can run inside the car or is that not worth the effort/money?

Thanks in advance!
-N
 

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overdeveloped beater
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First, put a mechanical gauge on the feed line so you get a baseline fuel pressure reading at idle. Then disconnect the vacuum line at the regulator and see what the pressure goes to (cap off open vacuum line).

Once you do this, you can slowly crimp the return line so the pressure jumps up 5psi. Repeat your tests until you get the most power/tq with decent IDC's. Once you know the best pressure, you can either crimp the stock regulator to match it or use an adjustable unit to get you to the right amount.

What did you use to bump the timing? PP6? Nice numbers for an EJ22....you got power on me for sure!
 

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Discussion Starter · #3 ·
First, put a mechanical gauge on the feed line so you get a baseline fuel pressure reading at idle. Then disconnect the vacuum line at the regulator and see what the pressure goes to (cap off open vacuum line).

Once you do this, you can slowly crimp the return line so the pressure jumps up 5psi. Repeat your tests until you get the most power/tq with decent IDC's. Once you know the best pressure, you can either crimp the stock regulator to match it or use an adjustable unit to get you to the right amount.

What did you use to bump the timing? PP6? Nice numbers for an EJ22....you got power on me for sure!
That sounds not so bad/random. Maybe I can do that after all - it sounds so much more scientific. Can I trust that a crimped return line will be stable enough as time goes on?

As for timing, I'm using an eManage Ultimate for tuning. I decided against the PP6 only because I wasn't confident that it could do as much for tuning as I wanted and I had a good line on an eManage Ultimate. As for power numbers, I'm pretty happy with them. Now that I've got timing adjusted (G-Tech tuned too, so I'm sure it's not exactly great), I think I'm doing about 130-135 lb-ft of torque to the wheels and the horsepower numbers ought to be a lot higher (135+?) if I can get this fueling issue at high speeds figured out.
-N
 

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turbocharged mayhem
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neilschelly what do you 2.2 injectors look like? I also thought i was having fuel issues with my car. I tried to put in rs injectors, but they were a different kind of top feed.
2.2 injector on the right, 2.5 on the left
 

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Discussion Starter · #5 ·
From everything I've read, the RS and 2.2 ones are both 280cc injectors anyway, so that shouldn't be much of an upgrade. Mine look like the ones on the right in your picture though. The RS injectors in your pic look like they have the IAC functionality in them to mix in some air for idle in the neck of the injector, yes?

Which leads of course to one of my questions though. Can I assume that any Subaru top-feed injectors will fit? Clearly not, but what can I assume will fit?
-N
 

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GF OBS-T, GM RS EJ20, SF EJ20
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The greens from the 2.2 are 267cc, the greys are 306cc - I had both flow tested.
You can actually use the entire 2.5l intake manifold on the MAP 2.2's - I did.

MAF 2.2's with the 1.8 style v-covers & side feed injectors have an entirely different intake manifold so the above WILL NOT WORK.
 

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The Stock 2.2 ECU does not mind the Grey injectors so you will not get a Rich CEL like you may with the WRX injectors.
 

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Discussion Starter · #8 ·
So you're saying that I can use the gray ones above from an RS if I can find them and that will give me an injector size boost? I'm already controlling fuel, so I'm not worried about getting a CEL. They just don't look like they'd fit to me. Am I missing something? Were those injectors used on all 2.5RSs or only certain years?

I'm not interested in using the intake manifold from and RS - already spent enough on mine to make it worth getting injectors that will fit in it.
-N
 

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Yeah you are missing the part were I used the 2.5l intake manifold & fuel rails to make this work - everything else was the stock 2.2l bits (T-body + all other sensors), between your old manifold & a 2.5l one from the J/Y you'll have all of the parts to make this work!
 

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Discussion Starter · #10 ·
Got it... well, does anyone know if there are any other injectors that will just fit? Or am I stuck with the stock ones? I suspect I'm going to go Storm's route at increasing pressure right now anyway. I like that idea a lot and it sure sounds cheap.
-N
 

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Opps, I did not read the part where you said you wanted to keep your I/M.

I don't think the greys will fit but did buy a set of 470's from Marren Fuel Injection in CT that did fit my old 2.2L I/M.

The return line pinch is an old trick that works well & will allow you to increase fuel pressure for the cost of a hose-clamp!
RC engineering has the pressure Vs flow equation that will allow you to predict what your injectors will flow @ a given fuel pressure level.
 

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Discussion Starter · #12 ·
So I have been trying to get to this forever. I finally got everything together and am at a loss again. I tried putting a hose clamp in the return fuel line, but I can't get it to register on the gauge as any increase. I can't find any smaller hose clamps, but I imagine it would be tough to get them around the hose to begin with too. I'm shopping McMasterCarr now and not finding anything smaller. Am I missing something?
-N
 

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Discussion Starter · #13 ·
And I'm stubborn, so I went out again with another idea. I used a standard worm-drive clamp this time and put some extra rubber between it and the fuel hose to keep the edges from digging into the hose. I successfully got the fuel pressure to rise by tightening the clamp. I could not stabilize the pressure though. It seemed decently stable just under 50psi where I was aiming for.

Then the cooling fan kicked on (as per normal) and the fuel pressure jumped to over 65psi. I dialed it down again to 48-ish and then the fan stopped and pressure dropped back to stock. I adjusted slowly up again to 48-ish. The cooling fan came on again eventually and pressure stayed stable. Then the fan went off and the pressure dropped back to stock. I turned it up a bit more and got it up to 48-ish again. Cooling fan came on and pressure jumped into the 60s again. I left it alone to see what would happen and it dropped to stock again when the fan stopped.

So in the end, it seems that any given position of tightening can translate to anywhere between 43 and 65 psi of pressure. The only exception is running without any crimping on the fuel return, which stays steady at 43-ish stock.

I guess my next option is some bigger injectors. I saw someone selling some of the RS injectors with special rubber or something that would make them fit an EJ22. Does anyone know anything about that?
-N
 

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overdeveloped beater
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That's weird....... I put '00 EJ25 manifold next to my '00 EJ22 manifold and they are identical. Both have grey injectors, identical again. I even swapped them out, trying to get rid of a nagging WOT/launching misfire.

I've crimped my return line to the point where some clamps under the car started to leak! virtually zero flow on the return, no fans came on, nothing..... (didn't help my misfire either). I've never seen the green injectors.......

Neil, pull the vacuum line off the FPR and cap it at the manifold. See what the pressure reads then....and note if the fans kick on.
 

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Discussion Starter · #15 ·
That's weird....... I put '00 EJ25 manifold next to my '00 EJ22 manifold and they are identical. Both have grey injectors, identical again. I even swapped them out, trying to get rid of a nagging WOT/launching misfire.

I've crimped my return line to the point where some clamps under the car started to leak! virtually zero flow on the return, no fans came on, nothing..... (didn't help my misfire either). I've never seen the green injectors.......

Neil, pull the vacuum line off the FPR and cap it at the manifold. See what the pressure reads then....and note if the fans kick on.
I know my injectors are green - they were on my '99 motor and on my '00 motor that I use now. But you're right that the manifold should be identical to an RS. In fact, I initially ordered the wrong phenolic spacers for my car from GrimmSpeed because I ordered the EJ22 ones instead of the EJ25 ones - the '99+ EJ22 intake ports match the EJ25, not the earlier EJ22s.

And I did pull the vaccuum line on the FPR. When first I turned on the car with the fuel pressure gauge hooked up, it came up to about 35psi or so. When I pulled the vac line, it jumped to 43-ish. As for the fan, it just came on as is normal for the car to do after sitting idling for a long time. It wasn't as a reaction to fuel what I was doing with fuel as far as I can tell. But it coming on and off certainly had something to do with the fuel supply somewhere. I can't explain it because as far as I can tell from electrical diagrams, the car has no fuel pressure sensor and no ability to "correct" the fuel pressure except the FPR, but it proved damn good at defeating me nonetheless.

Ugh.
-N
 

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Ugh is right....... Short of putting a voltmeter on the fuel pump and seeing if it changes when the fans come on, I can't think of any reason why the jump in idle (fans cycling on) will cause the pressure to jump like it does.......

Maybe you just need to upsize the injectors slightly. I know the ECU can pull them back for daily non-WOT needs. I'd be willing to split a set of 8 injectors with you since it's usually cheaper to buy 'em that way......
 

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Discussion Starter · #17 ·
Yeah, the more I think about it, the less it makes sense. Even if there was a jump in the fuel pump voltage, that still shouldn't make the fuel pressure go jumping so high when the idle goes up. Tapping the throttle doesn't have the effect of making pressure jump so drastically. The FPR, if doing it's job, should be taking any excess pressure from the fuel pump and sending it back. Perhaps somehow, the return line was getting completely stopped up and 65-ish PSI is just what the maximum pressure the stock fuel pump will do? That might explain it.

Anyway, I can't find the info on the RS injectors that I was looking for. I was thinking of trying out the dimpling of the fuel pressure regulator as an alternate means of increasing pressure. I know it works for WRX/STi folks and I know my FPR has a dimple on it. Has anyone done that to increase pressure or is that something that only some FPRs allow?

I guess if that's not going to work, I'd go in for 8 injectors if you want, but then I'd worry about getting the right ones. Do we know which ones fit? And does yours accept the same ones as mine? I think you're running a Phase 1 EJ22, right? Sounds like that might be different, especially if I've got the green ones pictured above.
-N
 

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The fuel pressure went crazy because the cars voltage changed when the fans kicked on - ? if the Alt does something to compensate for the fans being on - which sounds kinda silly.

? if a capacitor from a car audio system will stabilize voltage, but if you have an old one laying around i'd try it.

I also had the green injectors on both '99, & a '01 2.2l both of which wer MAP cars.
I got the greys from a SOHC 2.5l.

Since you are raising the fuel pressure you can get a cheap MSD 1:1 rise with boost 5/16" barb fitting FPR for about $52 from Summit Racing.
This can be plumbed into the return line, but will only allow a increase in Fuel pressure when installed inline with the factory FPR - which is what you want anyway.
 

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Discussion Starter · #19 ·
I can't find that on Summit Racing. Got a link? Is that an adjustable FPR?

I have been looking at that too. There's a pretty one on NASIOC for sale for $100 right now, though it doesn't appear to have the right fittings on it for this application, so if a universal one here is designed to work with the stock FPR, maybe that is a good thing?
-N
 

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The price went up to $72 on these, but the part # is MSD-2222.

This is an adjustable fuel pressure regulator for use on fuel injected cars (? the working PSI Range but a Summit tech could help with that), 1:1 rise with boost, + 5/16" barbed fittings so you don't have to spend $50 on fittings like I had to with my Aeromotive FPR.
 
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