LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Questions about Knock retard

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Old 04-29-2007, 10:26 PM
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Default Questions about Knock retard

I just got datamaster and went to the track saturday. My car is an 1994 A4 Camaro and has a 3000-3500 stall converter, CAI, catback 3.73's and the transmission has been rebuilt. When looking over the runs, it seems like i get a lot of knock retard on the shifts, anywhere from 1 to 6 or 7 degrees, but then after the shift it goes away slowly. I know the LS1's have like torque management that retards timing on the shifts, do LT1's have that too? I also noticed that at the top end it also started pulling a little bit of timing. It was like 2 or 3 degrees most of the time, but i saw as much as 6. I'm planning on ordering the LT4 KM and seeing what happens. Any info would be great!
Old 04-30-2007, 03:17 AM
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There's a thing called "burst knock" in the lt1 computer that can sometimes cause this. It retards timing whenever there is a sudden change in certain parameters. You can delete that if you get a tune, the LT4 module might help, and also desensitizing the knock sensor with a tune.
Old 04-30-2007, 09:03 AM
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ok...i'll have to look into that. I've searched and i seem to come up with a P/N 16214681 for an LT4 knock module from GM. Does that number seem right?
Old 04-30-2007, 11:22 AM
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Originally Posted by mean_greenz28
ok...i'll have to look into that. I've searched and i seem to come up with a P/N 16214681 for an LT4 knock module from GM. Does that number seem right?
Yes thats the correct part #. I need an LT4 KM myself.
Old 04-30-2007, 01:13 PM
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I notice this as well in my 6 speed but i seem to get like 12 * of knock. is there any amout of knock this is normal? like just crusin around sometime ( not all the time) i get like 1 to 2 degrees of knock?
Old 05-11-2007, 08:39 AM
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I get a fair amount of knock retard on mine right now, because my exhaust is hitting in a few places and I think it is mostly false knock. I have some race gas that I am going to try after I get some of the obvious noise issues fixed. If there was real knock taking place, as long as the knock count isn't incrementing should you be ok in terms of engine damage if your not running lean? I understand the performance is hindered by the pulled timing, but if the KR is taking place yet no KC is incrementing are you still causing damage?
Old 05-11-2007, 08:42 AM
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You might want to go to the tuning section and read the documents on tuning your car. I was able to remove all knock retard from my system using LT1Edit.
Old 05-11-2007, 09:15 AM
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Yeah, I've seen in tunercat where you can change the amount of KR and recovery rate and stuff in the PCM. I was just curious if the KR itself with no KC is hurting the car any, besides performance.
Old 05-13-2007, 01:53 PM
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i just came across the same exact problem with my shifts as much a 10 degrees of retard. i will be getting the LT4 KM but how would i adjust my tables using Tuner Cats? i think this is a wide spread problem among the LT guys and a write up might be able to help alot of people myself included.
Old 05-13-2007, 06:00 PM
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This is how I removed KR using LT1Edit. It will be different with other software, but the steps should be similar.
1) I went to the PCM Diagnostics and Tuning section and printed out the document from the link Tuner Software - Tuning 101. I read through section 4 Eliminating Knock Retard. This doc was written for EFILive, I believe, so a lot of translation was required.
2) I made several runs with my car, using AutoTap as my data logger. LT1Edit does not have any logging capability (grr).
3) I analyzed the data, and saw where the KR was being applied.
4) I went into LT1Edit. In the Ignition section, It has a subsection labeled Knock Retard. In ther are 2 tables, Attack vs. RPM and Decay vs RPM. I started massaging these tables, making many, many runs. It took a long time, but I was able to eliminate KR by doing this. This is discussed in section B of Eliminating Knock Retard in the tuning document.
I don't know how it is done in other software, it has to be easier. Hope this helps.
Old 05-13-2007, 09:31 PM
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Originally Posted by koolaid_kid
This is how I removed KR using LT1Edit. It will be different with other software, but the steps should be similar.
1) I went to the PCM Diagnostics and Tuning section and printed out the document from the link Tuner Software - Tuning 101. I read through section 4 Eliminating Knock Retard. This doc was written for EFILive, I believe, so a lot of translation was required.
2) I made several runs with my car, using AutoTap as my data logger. LT1Edit does not have any logging capability (grr).
3) I analyzed the data, and saw where the KR was being applied.
4) I went into LT1Edit. In the Ignition section, It has a subsection labeled Knock Retard. In ther are 2 tables, Attack vs. RPM and Decay vs RPM. I started massaging these tables, making many, many runs. It took a long time, but I was able to eliminate KR by doing this. This is discussed in section B of Eliminating Knock Retard in the tuning document.
I don't know how it is done in other software, it has to be easier. Hope this helps.

thanks looks like im going to have to hit up the company printer tomorrow.
Old 05-14-2007, 10:16 AM
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are there any consequences to eliminating the KR completely? If thats done I assume am LT4 Knock Module wont be in need?
Old 05-14-2007, 10:47 AM
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I believe this is a question best posed in the tuning section. All I did was follow the document; it was my understanding that this is a required step in the tuning process. But I am just a student of tuning, not an expert.
From section C of the eliminating knock retard section:
Scan again and verify NO knock retard is present. If still present (work again to eliminate it).
Old 05-14-2007, 01:25 PM
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well if you eliminate the KR feature(if you can) when you have real KR you can chip pistons. Is there a tuner kit that works as a scanner too? Where could i get one that does if they make one? thanks much guys good luck, i'd love to scan mine to find out how much i have if any...
Old 05-14-2007, 01:48 PM
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Please do not misunderstand. You do not disable or eliminate the KR feature. You make adjustments to the PCM tables to reduce it to zero. That is what they mean by eliminate. There is a HUGE difference in the two concepts. KR is there for a reason, don't just turn it off (if that is possible). Again, if you read the document, you will understand what they are talking about. Read it, please.

Last edited by koolaid_kid; 05-14-2007 at 02:27 PM.
Old 05-14-2007, 07:13 PM
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i read the document it was slightly helpful. i also read the lt1 edit help document from the carputing website it was also helpful even though i have tunercats.



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