rcwilbur

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.

redtan

iTrader: (5)

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.

rcwilbur

Thanks. The AFR is set to 12.5 and I run 93 octane. I am getting about 4 deg of knock retard at wot so I plan to back off timing to eliminate.

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.

flattusmaximus78

iTrader: (1)

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.

bene

iTrader: (16)

I set mine at 24ish. To be realistic set it to where its not making anymore power and not retarding.

rcwilbur

Thanks Bene.

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

rcwilbur

Thanks Bozzhawg. I appreciate your help. I was leaning toward several small increments and seeing where we are.