Formula934

iTrader: (4)

I just recently added two degrees of timing across the main spark tables and WOT 95-100 KPA ranges on my friends stock 95 camaro. The car runs excellent, smoother in drivability, Wot there is definately more power. What im wondering is, using Free Scan, Its logging my Wot spark timing anywhere from 39-41*. However, my Wot timing is set for 35* -95kpa and 37* -100 kpa. Any ideas where the inconsistancy is coming from? Could it be the logger is off or is it that the pcm just can't be dead on accurate with the spark timing? Any ideas?

Appreciate it

-Jeff

ss.slp.ls1

iTrader: (36)

I think there is a tuning subforum...might be more helpful to you.

infinitebird

iTrader: (11)

What you read on the datalog is always a few degrees higher than the commanded advance in TC. I have no idea why this is but its been that way on every car I've seen.

infinitebird

iTrader: (11)

Most the the tuners there are LS1 guys.

spudnick3119

I've run into this as well. I've logged timing as high as 41* when I have not changed the spark tables yet. It sounds like the PCM puts extra timing into the table at certain RPMs. Tunercat responded and said that they have not found the table yet, if it even exists. Here's some good info:

http://cz28.com/forums/showthread.ph...+timing&page=2
http://cz28.com/forums/showthread.ph...mystery+timing

Unfortunately, you probably have to tune around it. I would love to find out why the PCM does this though.

Btw, are you seeing any knock retard with timing being set so high?

Formula934

iTrader: (4)

I logged the car for a good 15-20 minutes at all driving ranges and recorded 0 knock with the timing set at those levels. Prior to changing any timing, I had made adjustments to WOT A/F and put 12.4 across the board, and that alone cause alot of knock up top, so i know the knock sensors doing its job.