Detonation at WOT???????????

[93svt#981]

I have a friend with a 03 vert that is detonating at wot. He has had several different tunes put in it but nothing helps. He replaced the fuel pumps and the fuel filter yesterday and still the same. The car has a built bottom end, stage 4 steig ported eaton, 60 lb injectors, kenne bell boost a pump, and the car has been dyno tuned, also has after market maf...any ideas or suggestions? Car seems like its leaning out to me but we had the tuner put a "fat" tune in it and still the same thing..

THANKS IN ADVANCE!

 

[96stanggt]

What plugs is he running, octane, max timing? Who tuned the car and what was the AFR?

 

[93svt#981]

plugs are ngk at .32, 93 octane fuel, 22 degrees timing(he thinks). Amazon tuned it. they have been great trying to help this too btw, my car was tuned there as well and is issue free...he doesnt remember the afr

 

[96stanggt]

Huh, how does he know it's detonating? It's pretty hard to hear it on these cars with the blower and exhaust, has he checked the plugs for signs?

 

[93svt#981]

Huh, how does he know it's detonating? It's pretty hard to hear it on these cars with the blower and exhaust, has he checked the plugs for signs?

he just replaced the plugs and the others looked fine...at wot it falls on its face and pops nice and loud...:shrug:

 

[01SaleenS281]

Huh, how does he know it's detonating? It's pretty hard to hear it on these cars with the blower and exhaust, has he checked the plugs for signs?

From my experience with mine you can really tell your car is detonating up top by the cackling sound and lack of power. The sound was very noticeable even in my vert with LTs, O/R midpipe, and Borla catback.

When this happened to me it was due to a failing fuel pump. Had it changed and the problem was solved.

 

[96stanggt]

he just replaced the plugs and the others looked fine...at wot it falls on its face and pops nice and loud...:shrug:

If it was detonation he should be able to see little specs on the plugs. He needs to datalog the car and see what the fuel looks like.

 

[SLEEPERSTATUS]

dont know if this helps

Spark Plugs

 

[93svt#981]

If it was detonation he should be able to see little specs on the plugs. He needs to datalog the car and see what the fuel looks like.

we are hooking the laptop up as we speak...thanks for all the help guys...hopefully we can figure this thing out :dw:

 

[JB]

...The car has a built bottom end...

Did he replace pistons with something other than stock?

If so, what compression ratio does he have now?

 

[93svt#981]

Did he replace pistons with something other than stock?

If so, what compression ratio does he have now?

yes, it is all aftermarket because whatever this issue is caused the first motor to die...

 

[93svt#981]

ok guys...just drove this thing and it is not detonating...runs great till u go wot then it spits and sputters and falls on its face hard...it also is smokin like a freight train when under any boost.

 

[csbrown]

White or light gray smoke means your friend probably has a head that is lifting under boost. New headgasket time.

Black smoke means something is causing the car to go super rich. The comment about the "fat tune" usually means the car was set up rich.

All depends on the color of the smoke.

 

[93svt#981]

White or light gray smoke means your friend probably has a head that is lifting under boost. New headgasket time.

Black smoke means something is causing the car to go super rich. The comment about the "fat tune" usually means the car was set up rich.

All depends on the color of the smoke.

yes I agree, but here is where it gets weird...the smoke is black as a diesel but the log said it is losing fuel pressure at wot....I sent the log to rick at amazon...I will post up when I get a diagnosis :??:

 

[Steeda30]

It sounds much more like a fuel / spark issue / blowout to me, maybe even a slightly torn FRPS diaphram?

Detonation doesn't result in pops from the exhaust and a lot of black fuel smoke, that sounds like the plugs aren't firing well enough to ignite the AF mixture when he goes WOT. Detonation sounds like a lot of crackling/BB's in a can, kind of hard to describe, but you'll hear it, especially if you get into the throttle next to a dividing wall on the highway, it just doesn't sound very clean, sounds kind of "airy".

I experienced it not too long ago after I got a bad batch of gas.

For plugs, I recommend NGK Iridium TR7IX's btw.

 

[Quicktime_GT]

I'd back the timing off some... My GT would detonate occasionally at 21 degrees with a procharger and much cooler air coming in..

I was ended up making the most power out of it with the 21 degrees of timing but it took a shit ton of fuel to cool things down

 

[trmin8ter03]

Had the same problem a while back. Turned out to be the i/c pumps wasnt working all the time. Hook up your handheld and keep an eye on the iat2 to see if the pump is working. If they are too high the comp will pull timing but cant compensate enough it only pulls 5* i believe.