Quote:
Originally Posted by hawk02
Well if it's any consolation, the LT4 in my ZL1 makes the same noise on cold startup. Just like everyone else, it only happens when the engine hasn't been started for 24 hours or longer.
I thought it might be the supercharger pulley squealing but since none of you have superchargers, that obviously can't be it.
I first noticed it around Christmas (cold temps) after my car had sat for more than a week without starting. Definitely something to do with cold startup.
I found a similar post to this one over in the C7 Z06 section of the Corvette Forums. I contacted the OP to see if he found a fix. He replied back that he never found a fix and has just learned to ignore the noise. Says his Z06 runs great, so whatever it is, it doesn't seem to affect performance.
I've been meaning to make a recording of the noise to post over in the ZL1 section to see if other ZL1s are making the same noise. If I get around to recording the noise, I'll post it here as well.
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Good to know, it defiantly doesn't seem to be belt/pulley related even though it does sound like that. Like you said, it only does it on a fully cold start for about 60 seconds...and it's so exact with how it does it, it must be something going on, then off. My guess is some emissions related thing to heat up the cats quicker...or possibly a DI related thing. If it's normal (which is seems to be), I am okay with that, but man, I wish they isolated the noise better for OCD folks like us lol...
I wonder if a tuner (EFI Tim?) who works on these car may know if it is emissions related of some sort? If so, if you were tuned you could potentially tune it out...