[Z06] Pre-Ignition? Detonation? last night
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Melting Slicks
Joined: Aug 2000
Posts: 2,568
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From: Miami Fl
Pre-Ignition? Detonation? last night
Going home last night I finally got on a strip on freeway that allowed me to get on it on 3rd gear. I heard the dreadfull sound of small rocks in a can coming from the engine bay at WOT.
I had been in stop and go traffic for about 30 minutes, coolant temp was 192, oil was 210. Is that detonation or pre-ignition, or is it the same thing? I've run my car at the track for hours and raced a bunch of 1/4's and hadn't heard this.
My car is obviously modded and tuned.
I had been in stop and go traffic for about 30 minutes, coolant temp was 192, oil was 210. Is that detonation or pre-ignition, or is it the same thing? I've run my car at the track for hours and raced a bunch of 1/4's and hadn't heard this.
My car is obviously modded and tuned.
Heel & Toe
Joined: Apr 2004
Posts: 19
Likes: 0
From: Cleburne Texas
My 03Z has been doing the exact same thing for over a year. I really don't know what it is. It is rarely consistent when it occurs. Sometimes when the car is cold, sometimes hot, and at other times, not at all. The only consistent element is that when it happens it ALWAYS occurs at WOT and 4,000+RPM. Like you said, "Rocks in a can" is the best description of the sound. My car has been lightly modded, and the sound seemed to manifest several months after I had it dyno tuned.
My theory, which is purely speculative, is that I'm running lean at high RPM and detonating. The AFR from my dyno tune is at 13.0 from 4,500 RPM to redline (my baseline was 11.5). However, one road test that people told me to try to test for detonation was to put her in sixth at low speed and floor it. This test resulted in no unusual sounds.
It is my limited understanding that Detonation/Pre-Ignition are the same thing and can ultimately lead to engine failure. Anyway, my warranty is about to expire so I am contemplating taking it to different tuner and pay for an engine inspection and another tune. If the inspection comes back clean, I'll just chalk it up to another strange Z06 engine sound and stop worrying about it. If it isn't clean, I will have to find out if I can get it fixed under warranty.
My theory, which is purely speculative, is that I'm running lean at high RPM and detonating. The AFR from my dyno tune is at 13.0 from 4,500 RPM to redline (my baseline was 11.5). However, one road test that people told me to try to test for detonation was to put her in sixth at low speed and floor it. This test resulted in no unusual sounds.
It is my limited understanding that Detonation/Pre-Ignition are the same thing and can ultimately lead to engine failure. Anyway, my warranty is about to expire so I am contemplating taking it to different tuner and pay for an engine inspection and another tune. If the inspection comes back clean, I'll just chalk it up to another strange Z06 engine sound and stop worrying about it. If it isn't clean, I will have to find out if I can get it fixed under warranty.
Drifting
Joined: Jun 2004
Posts: 1,936
Likes: 0
From: Las Vegas NV
My '02 has done that since I bought it - infrequently when cruising in 6th gear at low rpms after having been either on it real hard or stuck in traffic and the oil temp has gone up. I'm having all the valve springs replaced tomorrow because I'm tired of reading about those breaking and wondering if mine will and I'm going to follow that with ignition wires when I get it home and I'll report back if it still does that. I would tend to agree with the running lean causing it - but it could possibly be the stock plug wires as well.
