Tuning Timing tables?

[Sunburst_SS]

Just wanted to see what methods you all used to tune timing? Pretty much advance it until it will knock then back off??

Example, I had a guy who has a supercharged cobalt who put some higher compression pistons in the car. The fuel was pretty easy to set. But I kept getting a few degrees of knock higher up in the RPM's on a full throttle pass. I pretty much used a histogram I had set up to read knock retard.....and copied and then went to the editor and did a paste special and subtracted the amount. Is this an alright way of doing it? Any tips?? Also, I had to put a little block in that area down to about 10 degrees to eliminate the knock I was seeing......will the surrounding areas be affected much without changing them?? Or is some smoothing required?

[Ec0tec]

The method I used, was First a buddy of mine copied my low octane tables into my high octane tables. From there I then removed 4 degrees in general from both tables. Next I subtracted another complete degree and a half from the table I had in the low octane table. Works Like a charm. The most advance I see under Full Boost is around 15 degrees. People tend to use various methods but I rather keep my timing tables low. At most on my current tune in a complete run the most knock retard I See is 0.5.

[PSYKOSTEVO]

There are different theories. I like Sunbursts method better. If you set the timing too low then there can be high EGTs. And you don't want hot exhaust temps because that could melt your pistons. Most people don't take that into consideration.

Best Idea in my book is to copy high to low, histogram a few good runs. Copy/Paste Special the knock over to subtract. Only downfall to doing the timing adjustments ONLY under WOT in the proper gear is that you will have too much timing for a novice driver or for a 4th gear dyno pull. You essentially build a progressive tune, where you have to be in the right gear at the right RPM range to go WOT.

[Ec0tec]

how low would you consider too low?

[TotheNthRPM]

best method:
advance till you stop making power (or you get knock).
in our cars, our timing is boost limited (ie, you'll get knock before you get to the peak timing). n/a cars can run 30* timing, but make max power at 26*

[Baldturbofreak.com]

More CYL pressure = faster flame propagation = less required lead to make peak cyl pressure coincide with optimal crak angle.

your method is viable and pretty much standard practice, if you can get detonation out of the way (race gas or water/alky) you'll find on the dyno that best power and most timing possible are 2 different things.

[Onyx Dragon]

More CYL pressure = faster flame propagation = less required lead to make peak cyl pressure coincide with optimal crak angle.

your method is viable and pretty much standard practice, if you can get detonation out of the way (race gas or water/alky) you'll find on the dyno that best power and most timing possible are 2 different things.

Yup. I was seeing power, but it seemed a bit flat on the dyno. Turned out I had a little knock. Cut back the timing one degree, and the power actually went up.