I figure this hasn't been a huge subject in the past, but with gas the way it is, I decided it was time to make my Camaro live on the cheap gas. So I started a tuning project.

I made a datamaster log and generally drove around looking for the places I have knock counts/retard. What I found was at 2400-5500 in places, at WOT, PE, 95-100kpa, I'd have KR. This would enable low octane mode and cause KR at part throttle, even though I never saw knock counts there. I started pulling advance from 2400-5500, then I turned off low octane mode. Now my KR at part throttle is completely gone and the only thing that's left is some KR at WOT, in PE. It seems to be the most problematic at ~4000rpm, for whatever reason.

The thing is, I have the timing retarded to the level of a stock B-body LT1 (around 29° commanded), which had iron heads and ran on 87 octane. I've also pulled 4-6° out from stock in places. With aluminum heads, shouldn't the F-body LT1 do fine at B-body LT1 spark advance levels (or more)?

My latest tune is on my laptop but I can post either the total SA table or the difference (using tunercat's Compare feature) later today.

Here is a screenshot of datamaster. I've plotted spark retard on the screen (which really helps visually), so you can see it pull a lot of advance, then slowly feed it back, only to need to pull it again. I understand the best performance is had if it never has to pull any (since it takes a lot of retard to stop knock).

http://kmoore.phzero.net:8081/pictures/camaro/DM_KR.gif

Any help, advice, tips are appreciated.

 

This is a comparison of what I am running now versus the stock spark map:

http://kmoore.phzero.net:8081/pictur...o/87tune_3.gif

Here is the actual SA of my current 87 octane tune:

http://kmoore.phzero.net:8081/pictur...3_total_SA.gif

I have pulled out a little PE fuel.

[CODE]Stock was like this: And I changed to this:

2400 12.6 13.1
2800 12.4 12.9
3200 12.7 13.2
3600 12.5 13.1
4000 12.6 13.1
4400 12.5 13.0
4800 11.8 12.3
5200 11.7 12.2
5600 12.0 12.5[/CODE]

Should I put it back to stock? Might be one way to get rid of the knock counts, I guess.