Originally Posted by
VodeAn
The white flame from the ZR1 is different than the backfire we are looking for between shifts, when rpm drops.
If you look at the video Ihab posted and compare that to GM's video of the ZR1 you'll spot the difference in flame appearance.
The new zr1 "flame" is mostly a 'clean' hot flame (white flame, no orange as you get further from the exhaust tip)
They are not injecting fuel directly into into the exhaust or anything like that. You can see this flame on other vehicles as well, a lot of FI cars with undersized exhaust exhibit this effect (I am not suggesting the ZR1 exhaust is undersized, I'm sure they engineered it to be as big as needed to meet their many requirements) For example, a S480 turbo on a ls motor with a single 3" exhaust out the back will often show a blue/white flame under wot.
We aren't looking for a a visible flame under load, we are looking for a flame between shifts or on decel.
nsogiba, try running less timing, maybe 0 degree or even -5 degrees. Even on bone stock vehicles timing can go negative during TM events. Additionally, to the right of your highlighted point timing increases and then ramps down, you need to look at your timing tables and get it to hold the lower timing, not go from WOT timing to 5 degrees then back up to 20ish and slowly back down like it does in the log. Look at the idle spark tables, not just the main spark tables.