how much knock is ok? Need advice.. and what about 180* thermostats?

[arubenstein]

Hello,

I am tuning a 2010 GMC Yukon XL 2500. It comes with a L96, which is a 6.0L iron block, aluminum heads, with VVT but no DOD. It has a MagnaCharger TVSS 1900 on it with an intercooler.

Attached is a small log file from a recent WOT run. I note that I have two areas of KR that occur. Some happens occasionally at medium throttle, low RPM (say, 1600 to 2000 RPM at .40 to .60 grams/cy), and then occasionally at WOT (which is upwards of 1.09 grams/cy).

So, the question is -- how much KR is ok? I am only seeing about 2 or 3* at most, if ever. Do I chase this, or do I let the ECM do its job?

Second question: currently running a stock thermostat; there is lots of talk to put a 180* in. Are there any long term affects of doing this? If not, why don't manufacturers do this?

9539

[Taz]

Regarding your thermostat question ... take a look at the thread below ...

http://forum.efilive.com/showthread.php?14382-160-Deg.-Stat-Fan-Settings


Regards,
Taz

[WeathermanShawn]

If it is legitimate KR, then the correct answer is no KR is acceptable. Usually the KR threshold is determined in your OS..mine is B6223..which anything over 1 degree of KR will activate the Octane Scaler.

Problem with 'waiting' until you detect KR and let your PCM/ECM pull timing is that the KR has already occurred. Better to have a run with 0 KR.

As far as the 180F Thermostat, as TAZ indicated it has been well-discussed on this and many forums. IMO, the thermostat argument is a little old. Its a lot of debate over ~ 1% in power differences. As long as you are not consistently running over 210 -220F, probably not a big deal. A 180F is a good compromise.

Good luck..