False Knock I believe, How do I Overcome it?

Torchy

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OK So I am helping a friend out and my tuner wants a log before he tunes it. The car is basically stock. Mods below. The tuner wants a 3rd gear steady pull from 1100-redline and a WOT from 1500-redline. No problem so I log his car and I'm getting knock activity in both scenarios. I get under the car and give it a once over and pay particular attention to the exhaust and can't find anything. I am compensating for suspension travel and all and do not see anything that could be causing it/touching (nothing making metal to metal contact).

So I log the car again on a different day. Still seeing the same activity which it's pulling about .5 to 3 degrees of timing at partial and WOT. I get under the car a second time and fine tooth comb over the car and nothing. Soo I say hey lets go put good gas in it and see if that changes anything. So I put 8 gallons of 100 octane in the car (it had about 2-3 gallons of 91 still in it) log the car again. All knock activity was gone on partial throttle but it was still there at WOT. In fact it added as much as 6 degrees on partial throttle. It is still seeing .5 to 3 degrees taken out at WOT (with the 100 octane).

Car: 2014 CS A6 GT (stock tune)

Mods: GT500 AB, JPC OAP and JLT Oil Separator

Additional info: I'm doing this in the middle of the day in Las Vegas at 100 degrees ambient. A/C was on. Oil lvl was perfect. I didn't pull any plugs but the inside of the exhaust tips are like perfect. Zero oil is going though the motor.

The only other thing I can think of would be to log the car at night and see if the ambient temps are impacting it.


Anything else I should check? Help!:whine:
 

Gpcalero

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Even though the exhaust piping may not come in to contact with anything with your search, I would double check the bolts and clamps where the piping connects. This was my issue. my drivers side axle back clamp bolt was hitting the body (pan hard support bar).

Double check that and where the OAP connects to the mid pipe.
 

slick3

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Don't have my laptop in front of me but going off memory around 20-21 degrees with KS at 0.



That's what I'm thinking considering I saw big changes at partial with only changing fuel. I hope so.


-The fact that it reacted positively (adding 6 degrees) with the 100 octane, but took it away on the top end I would be willing to bet its not false knock...
-Start with whats aftermarket and work your way from the motor back.... 99 percent of the time its exhaust related from the posts I see, start smacking things and see if you can get any squeaks or thuds. Make sure the engine cover is snug too.

I would try it in cooler weather but with 100 octane it should not be knocking at all I wouldn't think


Side Note: I know Shaun had me go drive the piss out of mine with the 100 octane to clean up the motor a little and then relog the car. The little knock I did have never came back.
 
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