Timing at WOT?
Thread Starter
Teching In
Joined: Sep 2012
Posts: 48
Likes: 0
Timing at WOT? I have a 99 Corvette--LS1 with M6 transmission. I recently put on TSP 5.3 heads and a 224R cam. In addition it has LG streets and blackwing filter.
I took if for a spin after install and everything ran great. I hooked up HP Tuners and logged some data and see that there is knock retard at WOT. I looked at the stock tables and it looks like timing is as much as 28-29 in some areas of WOT. Just wondering what generally the timing should be. I read somewhere 23-25 is a general rule of thumb for WOT. I will of course look at the actual retard amounts to see how much timing is being pulled, but as I pull some timing was wondering what others may have experienced.
Thanks.
I took if for a spin after install and everything ran great. I hooked up HP Tuners and logged some data and see that there is knock retard at WOT. I looked at the stock tables and it looks like timing is as much as 28-29 in some areas of WOT. Just wondering what generally the timing should be. I read somewhere 23-25 is a general rule of thumb for WOT. I will of course look at the actual retard amounts to see how much timing is being pulled, but as I pull some timing was wondering what others may have experienced.
Thanks.
Without a dyno is almost a crapshoot, especially with more efficient heads and a cam.
I would set your desired AFT at WOT then see the max timing that you can run without getting knock. Then backoff 1-2* depending on how safe you want to be.
I would set your desired AFT at WOT then see the max timing that you can run without getting knock. Then backoff 1-2* depending on how safe you want to be.
Thread Starter
Teching In
Joined: Sep 2012
Posts: 48
Likes: 0
I thought (probably mistakenly) that the stock timing would have been pretty conservative and heads and smallish cam would not have required much adjustment to timing.
Every car is differn't. I have 5.3s on my mine not tsp heads though. 27 * I had knock retard, but it was due to oil in the intake. Was your knock audible at all?
EDIT: AFR'S are 12.5 as soon as the pedal hits the floor, maybe sees 12.7 up at 6500.
EDIT: AFR'S are 12.5 as soon as the pedal hits the floor, maybe sees 12.7 up at 6500.
Last edited by flattusmaximus78; Mar 18, 2013 at 02:28 PM.
Thread Starter
Teching In
Joined: Sep 2012
Posts: 48
Likes: 0
The stock files had about 28-27 degrees at WOT and knock retard was taking away as much as 4 degrees.
Question: Is the knock retard amount somehow proportional to the level of knock? If I got 4 degrees knock retard should I take out four degrees or start with two and see how it does first? Thanks again
Thread Starter
Teching In
Joined: Sep 2012
Posts: 48
Likes: 0
The best way to do it is log a run in VCM Scanner, also look at your histogram after reviewing the run, in the histogram look at #2 main spark-knock retard (A) average(I also look at (L) last value) . Compare the histogram to your chart, then pull your timing in 1-2* increments. Start low. Make sure to smooth the areas around the areas of knock.
If you find that you are pulling and pulling timing and there is still knock, you have another issue.
If you find that you are pulling and pulling timing and there is still knock, you have another issue.
