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Fuel pressure @ 18psi? + horrible track experience...


Jersey

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Hey all. What do you guys think fuel pressure should be @ 18psi, stock T3, 370cc injectors on a stock L28ET? I know thats pushing the T3 past it's efficency level but, that's all i have to work with right now :) I just took the Z out for a "spirited" run and she was coughing a bit up near 18psi. Fuel pressure was up at about 62psi. Pulled the plugs and they seemed a little white so i'm assuming a little lean. The bpr6es are gapped at 39 supplied by an MSD6a. I'm hoping to get to the track Wednesday night so i'm mainly concerned with WOT for now. Thanks.

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Thanks Yo. Any idea about the pressure i should be running? Damn i wish i had bought the LM-1 when i had the cash! I'll see if i can find the 7's and run them. After i posted last night, i pulled the plugs and re-checked the gap - 42. So i brought them down to about 40 and bumped fuel pressure up to about 39 @ idle (21hg vac) which worked out to be near 68psi at full boost, but i still have that little hiccup. I've had these plugs in there for a while now so that could be causing the problem as well. At 68psi of fuel pressure with the small T3 @ 18psi, i think that's plenty of fuel and probably a bit rich up top. I'll try a plug change and back the pressure down a little to see if that's the cure. Thanks again.

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Base pressure (37) + boost pressure (18) = 55 psi would be the standard answer, but set it to where it needs to be so you don't detonate. I would think you should bump the base up quite a bit - 18psi on a T3 is HOT HOT HOT.

 

a/f ratios have little to do with detonation. I can run 11:1 and still knock if timing and/or boost is too high.

 

I'd get that LM1, best tool I bought this year. I would also re-gap. No more than .030"

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Thanks Drax, Clifton. I just dropped new plugs in gapped @ .038". The originals that were in there were @ .042" for over a year and she never stumbled until about a week ago so i'm hoping the little bit of build-up was the cause. Figure i'll try and drop them down just .004" and see how she runs there. If not, i'll go with your suggestion and go way down to .030". Thanks. Time for a test run...

 

Keep ya posted.

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Yeah I'd try gapping the plugs down a bit too... even as low as 0.030.

 

Yep - don't even worry about losing any power from the reduced gap. You won't be able to tell the difference, except it might stop misfiring. :D Misfiring will cost you MUCH more power...

 

I generally run 0.030".

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Test ran it @ .038" and she coughed again at high boost. Back to the garage and cleaned the connectors - HTS, AFM, ECM, TPS - and all the grounds... now she breaks loose in 3rd instead of coughing :D:D:D

 

I just got in from loading it on the trailer (first time not driving it to the track but have a funny feeling i'll be breaking something tonight) and it's off to the track later tonight (Wed), shooting for an 11.99999999 LOL. Thanks again for everyones suggestions.

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Thanks Cygnusx1, but i just got back from the worst experience at a track i've ever had. I went to the "big time" strip here in NJ, Raceway Park, for the first time and it was bad. Got to the track and in line at 7pm. Not too too many people there but a bunch of pro cars. It was suppose to be street muffled time trial night but, ok, not big deal. After the pro cars kept running and running without letting any of "regular" performance cars run, i was getting pissed. Finally, 9pm rolls around and now they announce that only muffled cars can run now. Mind you, Track closes @ 10pm. More waiting. A few hondas sprayed some antifreeze on the track, more waiting. DSM blew an axle all over the track, more waiting. 10pm, my Z still sits in the same spot i parked it @ 7pm and they announce that the lanes are closed so dont bother coming around for another run. ANOTHER run??? We didn't get ONE run in yet! Fianlly, 10:20pm and i line up for my one and only run. Anxious, yeah, just a bit. Light drops, i pull a good light - .093 and really drop the clutch from 5k and she spins a little. Damn. Hit second gear hard and get a little slipchip. Damn but ok, not so bad. Shift into 3rd and now she's pulling like mad and i can see the end of the 1/4. Tach up to about 5800, shift into 4rth...ah..try again into 4th..ummmmm...try AGAIN IN 4th....one more time and i get it. Yup, you got it. I missed the 3rd to 4th shift 3 times. The easiest shift you can possibly make in the 1/4, my opinion, and i missed it 3 TIMES! Finally get it into 4th, slam the pedal to the firewall and run her a bit past the line in aggrevation. 12.9@104mph. Damn. pulled it around, loaded it back onto the trailer in disgust and just got home - 12:50am. What a horrible night. Sorry to vent but it just completly sucked. I'll be going to my usual track from now on that doesn't have all the bright lights and bullsh*t of Raceway Park. At least i can make as large a mistake as i did tonight and get at least 10 more runs in to try to do it right!!! ok, i feel better now :)

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7.88 @ the 1/8th. It was 8.061 when i ran the 12.4 and, this time i wasn't bleeding down boost anymore like i was when then so, who knows i guess. Seems like i would've pulled off a better time. This morning, i feel better, and worse. Pulled her off the trailer this morning, driving to work, went to shift and the clutch went right to the floor. Pedal cam back to the top but couldn't push it in anymore? Pulled over, popped the hood figuring the slave blew (again) but it was fine but, fully extended! Had to get to work so i drove it home 5 miles without a clutch and drove the suburban in. I'm figuring, hoping, it has to be the pivot arm that controls the throw-out bearing that bent or snapped. I'll get it on the jackstands tonight (need a JSR # :) ) to get a closer look. Im figuring it could either be the pivot arm busted, the throw-out bearing disintigrated or the clutch fingers melted. I don't think it's the fingers or throw-out because i didn't hear any unusual noise when i drove it home after she broke. That ACT PP that i complained about a year ago about having a MUCH harder pedal i guess finally took it's toll. Oh well. I feel better because maybe the 3-4 shift wasn't 100% my fault :wink: but, feel worse because now it's back on the jackstands :roll: LOL.

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