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Old 10-02-2020, 05:11 PM   #9 (permalink)
backman_66
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Join Date: Nov 2019
Location: US
Posts: 64
Drives: 2012 G37
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Quote:
Originally Posted by SG4247 View Post
My car would knock at the exact same rpm, in the same gear everytime, no matter what fuel was in it (even E100), or timing used. All the logs showed the same knock at the same point. This is engine noise picked up by the knock transducers.

Based on this data, I was convinced it was ghost knock. I had the tuner raise the threshold on knock detection and been happy ever since.

I have had the engine light flash (mil gauge highjack knock indicator) a couple times on 89 cheap gas when pulling away from a stoplight with light throttle. If I see that, I pull timing on the oil temp gauge with the cruise toggle, and go add some 93 oct.
Good info! Thanks for that. I'll be getting more datalogs to see if I can reproduce the knock and see at what rpm's it happens at. I'm still in the tuning optimization process for normal driving conditions so I have a lot more datalogs to collect, but I always make sure to do some pulls while I'm at it.

Someone on the myg37.com forums said that G's in the 330whp+ range often have to raise the thresholds a bit to make the car happy, so maybe that's just a common issue.

My car only has 42,500 miles on it so I would assume the internals, plugs etc are all in good condition. When I replaced my factory intake manifolds with ported ones, I didn't notice excessive blow-by in the intake tracts but who knows if that is affecting knock or not?

Last edited by backman_66; 10-02-2020 at 05:17 PM.
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