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Knock retard @ cruise

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Old 10-13-2011, 04:04 PM
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Default Knock retard @ cruise

I've been noticing quite a bit of "bumpy" KR while at just about any cruise speed usually past 50MPH is where I see it most. Not really sure where to start looking, I've read around and I've heard altitude can play into it, load, being over advanced of course. I do live @ altitude, around 4400 feet varying hundreds of feet over a matter of miles. I've tested the KR out by the salt flats where it's flat for miles and miles and it's still present. I've been going down the list and can't come up with anything. The spark tables aren't over advanced those cells are stock, I've tried with and without DOD/AFM, same results, I have a half range cooler plug installed TR60 vs TR55 to take the additional heat from added timing. Probably could go back to the 55s honestly since I'm losing so much cylinder pressure and heat from altitude gain. Anyways..I found a bad motor mount on the front bottom side, replaced that, still knocking, headers don't seem to be loose..

Other things to consider my baffles are gone with the roller rockers installed, the blow-by getting back into the intake manifold is probably considerably higher...but that shouldn't impact cruise though I wouldn't think.

Haven't tried the obvious which would be reduce timing, I just don't see why that would be the case @ altitude...pressure/heat are lower and you usually get a few "free" degrees up here because of that. My WOT cells are advanced considerably higher without KR than they could be at sea level, so IDK.

Any other ideas or thoughts on WTH is going on here?




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