Well i took a short trip out to matt_95TGS's place to use his laptop and dataloger, to see whats goin on with my setup. We tested all at around 8 psi of boost. Here is what is happening. We started out doing third gear pulls, rpm's started out around 3000. I would hit 8 psi of boost, and i got .88-.89 o2 sensor voltage. Ok, too low fuel, need to up the pressure. Keep in mind, my fuel pressure was at least 105 psi on the gauge at 8 psi boost. So i adjusted the SFMU a little, then did another 3rd gear pull. I was hoping for better o2 voltages, but NO difference! My fuel pressure went up from last time to about 110 psi. So i adjusted the fuel pressure to about 120 psi at 8 psi boost, and still got .88-.89 o2 voltages. Then we did a 2nd gear pull. Check this out. In second gear at WOT at 8 psi, i got .93 o2 volgage. Hmmm..strange. We found out that there was a greater %of load on the motor when in 3rd gear, than 2nd. So the load on the motor has something to do with my o2 voltages. Interesting indeed. So all this comes down to is that i am maxing out my stock injectors at 8 psi, and maxing them at around 105 psi of fuel pressure. I had thought many others have run more boost on stock injects than 8, and got perfect .93 o2 voltages??? Can anyone explain this? Maybe my injectors are dirty? This also explains why my EGT's skyrocket a little past 1600 under WOT under full boost. I am going to get 30lb injects to remedy this very soon. Sucks, cause i was going to go to the track friday night :( Anyone have any input on the injector issue?? Also, is it right to tune your o2 voltages in third gear pulls??

I would be more worried about the egt's at redline than o2's. At the top of third gear, 1550* on the egt (when I'm tuned right), I have seen o2's as low as .84-.86. If that's where the car runs good and the egt's are in check, then I'd leave it. I also think that driving down the freeway and then doing a 3rd gear pull may not be such a great indicator of how the car is tuned. I am trying to tune strictly at the strip so that I hit 1500-1550 at the top of 3rd, but of course my egt's are very low at the the start of the run (~900*) unlike on the street (~1200*), so it would take less time to heat up to 1550* on the street. So that's my theory of the day. Anyone want to cut it up?

Well, I'm running ~11psi on the stock injectors and am running rich. I see about 120psi of fuel pressure, and my O2 voltage(in third gear, starting at 2500) will first be at ~.98 when I step on it(no boost), then as boost rises, when it spikes mine reads .88-.89(around 4K-5K), then when my boost levels off to around 11psi, I get .92-.94 to redline. My EGT's NEVER go that high, in a 1/4 mile run they get up to about 1450- at most. I drive this car like a mad man, and the highest I've seen my EGT's get is 1550, and that was at 150mph :) Try running some injector cleaner for the hell of it, it's not gonna hurt anything, and it may just help you. All in all, I'm not sure how I'm running this rich on stock injectors with 11psi, maybe it has to do with my lower compression......

Yeah i am thinking my injects are dirty, but the car runs excellent? I would think if i had dirty injects, that it woulnd't run so good? I'll will def try some cleaner to see if that helps. There is no way i could run 11 psi on these injects the way it is now! I was getting 120 psi of fuel and .88-.89 o2 voltages, and it makes sense of not enough fuel because my egt's always get up to 1600+ on long full throttle pulls, no matter if i'm going from a stop, or on the highway into full boost. Maybe its possible that the person who had the car before me replaces the injects with the smaller neon 190cc injects? Hell, i dont know, i just want to get this runnin strong at 8 psi for a good 1/4 mile run at the track, not to mention keeping the engine from blowing up :) .89 o2 voltage is wayyyy to low for me..I heard a little detonation also when the boost spiked to 9 psi..so it all makes sense that i dont have enough fuel gettin in there..

I took my car to get dyno tuned and I had 115 fuel pressure, and my injectors were getting maxed out at like 7 psi,
I thought it was weird too because I have always heard people talking about 8-10 psi...

Hmmmm...this is very strange indeed. Why would some people's cars run plenty of fuel through the injects at higer boost, while others cant even run a good 8 psi with enough fuel flow?? This just doesn't make any sense really. If you can run 10 or 11 psi on stock injects, and have plenty of fuel, then why am i maxing out mine at the same fuel pressures meant for 10 psi, at only 8 psi? Wierd...are we all positive that all years of our cars have the same 235cc flow rate injectors?? I'm going to get some injector cleaner asap also..we'll see how that goes..

Unless you get them cleaned and flow tested, it is not worth your time to run injector cleaner. Our local fuel injector place told us this, so I believe the experts.

Buy new injectors and be done with it. I was always worried about the stock injectors and that is why I changed them out. You might be able to go slightly larger than 30LB by lowering your static fuel pressure, but I would not chance it. My car initially idles rough when I start it for the first time of the day. You might be able to drop your idle pressure to 38psi w/30Lb injectors and have a easy starting car and able to run a solid 10 psi daily without any fuel problems.

In this heat (above 90), I had to turn my boost down to 8.5 psi to be able to max out 3rd/4th gears. I do a lot of highway pulls....LOL My egt is around 1550 in 3rd and 1570 in 4th at 7200 rpm. This is in the heat of the day.......damn hot ass summers. When it cools down in the late evening(mid 70's)I can run my normal 10 psi without going over 1600 degrees. We all know that I run the star kit, but you should be able to boost 10 psi daily even in the summer heat with the 16G.

I too have noticed that when going over 100 psi the curve for fuel is not linear. Injectors do not flow much more when pressure gets to 120 psi(rough guess).

IMHO

Well Ive got a question. I hear of people running 10psi w/ upgraded injectors and a stock bottom end and I was wondering if it is as safe to do that as it is to run 8psi with the stockers. I mean I know its more punishment on the stock bottom end, but if your EGT's are under 1600 is it still pushing it? TIA

Mine is leaning out too. I have always had a high egt when making highway pulls. I think you should be OK at the track though becuase you will starting out with the car cold. I need to get my 440cc injectors in my car as soon as I get my new MAP sensor. Should be here next monday.

Well i got some "Lucas" brand fuel injector cleaner at Napa today. Car feels a bit better already i suppose, but i only drove around for a bit with it in the tank. We will see what happens with another tank full with it in. BTW this fuel inj cleaner is an oil like substance, and it is supposed to clean out the entire fuel system, and it will also lubricate the upper combustion chambers and valve seats. Was about 8.50 at Napa, for a quart of it, enough to treat 100 gallons of gas. Napa said this stuff is damn good, and all the shops they deal with use this stuff...so we'll see how it goes, and i'll let you guys know if this helps...still gettin the 30lb injects though...

I myself am boggled by how rich my car runs at 11psi w/ the stock injectors. I was under the impression that I couldn't run more than 9psi without going lean, but my A/F gauge was reading .98-1.00V with 8.5psi. My EGT's never went above 1400, so I upped the boost a bit till I leaned down where I should be. Hell, I even leaned the car down a bit with the S-AFC to get my A/F to be around .93V at 11psi. Oh well, I own the car and am just as confused as you guys :rolleyes