Getting Knock?
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Intermediate
Joined: Mar 2015
Posts: 45
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Getting Knock?
Getting Knock? I have a 2002 zo6 with pcm for less tune car is headers,intake only mods..I have hp tuners and was logging last few times I was driving the car and when getting on it around 5-6 thousand rpms I was seeing 2-3 degrees of knock.I put a new set of tr55 plugs in it gapped at .040 noticing a little bit of detontation on the porcealin espically back pass plug #7 I believe.Should I try a colder plug tr6 or pull a little timing out of the car up top?
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Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Do you actually hear the engine pinging ??? It is very common with LT headers to get "false knock" because of the thinner exhaust tubes will make the knock sensors pick up some new noises that they will interpret as knock when in fact there isn't any---
What do you mean by seeing detonation on the porcelain ??Typically knock is caused by too much timing-----Old school plug reading says to determine if you have to much timing is by not looking at the porcelain but rather by looking on the plug strap
Ideally the best timing is achieved by having the color change on the plug strap to the "bend" of the strap----The further the color change is towards the threads indicates too much timing-----If the color change is more towards the strap tip would indicate not enough timing-----Of course you cannot read plus correctly if they are old or even driven on the street too much---You need to read the plugs most accurately by installing a new set
Finally the tr55 or tr5 is the best overall heat range for 90% of all applications
The only time I use a TR6 is on a high compression engine---A boosted or turboed engine or an engine using NOS
What do you mean by seeing detonation on the porcelain ??Typically knock is caused by too much timing-----Old school plug reading says to determine if you have to much timing is by not looking at the porcelain but rather by looking on the plug strap
Ideally the best timing is achieved by having the color change on the plug strap to the "bend" of the strap----The further the color change is towards the threads indicates too much timing-----If the color change is more towards the strap tip would indicate not enough timing-----Of course you cannot read plus correctly if they are old or even driven on the street too much---You need to read the plugs most accurately by installing a new set
Finally the tr55 or tr5 is the best overall heat range for 90% of all applications
The only time I use a TR6 is on a high compression engine---A boosted or turboed engine or an engine using NOS
Thread Starter
Intermediate
Joined: Mar 2015
Posts: 45
Likes: 3
No i dont hear any engine pinging..I did put a fresh set of plugs in it then read them.I know the strap tells me timing seems a little over timed timing mark is past the bend.But the porcealin does show some speckle dots on it from detonation.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Many other things can cause the speckling on your plugs -- like bad or cheap gas---a very lean WOT fuel mixture- Normally with too much timing you'll see the the results on the tips of the plugs or the strap---
If your ECM is removing timing and you cannot hear any audible detonation at WOT then most likely the KR is "false" most often due to LT headers or even a noisy valve train---
This false KR can be eliminated by desensitizing your knock tables in your tune so the sensors don't mis interpret the noisy engine as knock---
What is the actual timing final you are seeing with data logging ? I don't mean the commanded or asked for timing but rather the final timing the data logger shows ??
Typically with pump gas premium (91-93) you should be in the 24-28 range actual timing for best results ( with stock LS1 or LS6 compression)
If your ECM is removing timing and you cannot hear any audible detonation at WOT then most likely the KR is "false" most often due to LT headers or even a noisy valve train---
This false KR can be eliminated by desensitizing your knock tables in your tune so the sensors don't mis interpret the noisy engine as knock---
What is the actual timing final you are seeing with data logging ? I don't mean the commanded or asked for timing but rather the final timing the data logger shows ??
Typically with pump gas premium (91-93) you should be in the 24-28 range actual timing for best results ( with stock LS1 or LS6 compression)
