Had this to do for a long time, finally the movies of my new to me 99SS's first couple trips to the track. This one is from the very last day of the year the track was open, weather cancelled the weekend after this one. It was second pass of October 15th, 8th official track pass for the 99SS total including 3 from the day before, Sat the 14th and the prior Sundays 3 passes. No dyno tune, tuned it on the street and straight to the track so the 13.2, 13.0 and 13.0 from the very first day did surprise me .The next and last weekend brought lean spikes in different gears but worst in 4th. A 0.4 spike in AFR when already running on the edge with 13.0 commanded AFR meant 13.4 brought a couple degrees of knock retard out of my 29* advance timing and you could feel it nose over while it was happening. It ran 13.337 on this pass, even with issues in the tune. The prior pass was real rough traction wise on a cold track, so I couldn't get a good read out of it and the day before the AFR spike would only occur around shifting. After looking at the datalog of this pass I backed down the commanded to 12.6 while I could figure WTF was going on because everything else was looking good. The day before the lean spikes only occured bad in the last pass and I thought maybe an 1/8 of a tank might have been not enough gas. 13.4 was just too lean for my liking, so I richened it up so the spikes only went to 13.1 but I never figured it out that day, it was weeks later. I was trying to learn the HPT scanner logs and actually selected all the proper pids, but a someone more familar with HPTuners and GM's had to point to the codes that showed my Evac system gas tank purge cannister was releasing unmetered air right while I was blasting a gear for whatever cool day reason or whatever. There is no real way to just turn the Evac system off without a realtime tune, which kinda sucks.
stock LS-1 M6 with 4.10 gears, original clutch, Nitto DRs, full weight, my tune
13.337 15th October LVD second pass - 99SS-2006-1015-13337_102.wmv
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Originally Posted by shawnsvtcobra
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