Tuning Help..Longshot here but WTF hehe

4Jenna

Founding Member
Sep 12, 2001
4,326
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AZ
On the dyno at around 5800rpm my car kicked out 3 puffs of grey/black smoke and the power fell off hard. No noise (typical det) from the motor (marbels rolling around) and the motor is still in one piece.
It was like puff..puff...puff small pause in between.

This was around 20psi, so I'm thinking the motor def woulda been hurt or heard some unhappy noise from the motor if this was detonation. My tuner is dead set on detonation because he can see detonation from the exh (new to me) but I think it was spark blow-out.
I was on Auto-lite 3923s (2 ranged colder than stock) gapped @ .035. This was around 550rw with (total timing) 14*@4k, 12*@5k, and 10*@6k on a 9.82 or so a/f no methanol. This was only on 91 octane (yeah I know) but in order to tune for methanol you have to get the car somewhat tuned in on pump gas.

Need some help.
I plan to take some boost out of it, bring my gap down to .026, and possibly try a colder plug. I am done messing with methanol and have 10 gallons of 109 Sunoco GT plus waiting to go in
Any input

Chris
 
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Danger is my middle name..hehe The boost was plain stupid I sure wasnt expecting that.
The car had no timing, and LOTs of fuel..you would think that was much safier, but infact that was scary low for the timing/af
Either way somethin wasnt right..tryin to run this down
 
Probably was detonation - the puffs of grey smoke are the telltale sign. You can't always hear it with engine noise. I blew a HG on the dyno once on my car (for trying something very stupid) and we had three people listening for detonation - only one person heard it, but I saw the grey smoke, then POP!! I've done stupid things in the past on my own car to test things out and seen the grey smoke and never hurt anything - but not this time.

I've seen this before on several other cars too - sometimes at the track you can hear detonation in the stands - and see the grey smoke at the same time.

That said, spark blow-out can act very similar sometimes too. I run a 0.028 gap with that much boost - and NEVER run 91 octane. My best guess is detonation - that much boost is strictly race gas territory.
 
Never can tell..day at a time on these levels


Don thx for the help, I guess I am knocking all possibilities out in one go with the idea of tightening the gap up and running the good gas, and of course lowering the boost
 
haulbalz said:
threads like this worry me. I have a stock block with forged internals. not to rob the thread but with a vortech s trim and a 2.95 pulley and power pipe, am i gonna blow anything up?
You should be fine depending on the boost, but it's all based on how you drive it and how it's tuned....timing, AFR, etc.
RC
 
haulbalz said:
threads like this worry me. I have a stock block with forged internals. not to rob the thread but with a vortech s trim and a 2.95 pulley and power pipe, am i gonna blow anything up?
that is impossible to say. depending on a proper tune, what rpm's the motor sees, and the correct balance of the rotating assembly, it is anyones guess as to how long it will hold together. without knowing anything more about your combo and tune, it is pointless to even try to guess. as far as what you did on the dyno, you are insane chris. with my setup and the stock block with the s-trim, im going to be scared of 12psi. definitely a higher octane fuel and less boost is the right way to go. the tighter gap will also help assuming it actually was blowout. why did you decide on stopping the meth injection though. the cooler air charge couldnt do anything but help you at this point (aside from jumping the power up even more being that you are already in block splitting territory).
 
Nothing against methanol it has always worked great for me. This is my reasoning..for one you need to get the car to 12.1 a/f min on pump gas before you can tune the alky....not gonna happen on my combo unless I run like 5psi haha, my motor/blower is a lil much to try that on 91 octane..not enuff octane in the tank is why. The second reason is the "what-if" factor..I am takin enuff risk as is with this block..I dont want another risk added to the equation, what if my pump fails mid pass, what if I get a clogged line, what if the ground wire for the varible controller frays all those=a melted motor for me. With yummi gas in the tank I know I have NO octane worries, and race gas burns cooler so I will still make WAY tomuch power for my block just wont have to worry about some component failer (in the alky kit) ruining my motor.
 
And yes Roger I agree..that was insane, stupid, crazy, and all those other names. I never imagined the car would make that kinda boost..whew that T-trim is no joke.
 
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