I came across an issue and I'd like to get some input form someone whos more familiar. I got my swap camaro running pretty good with the 6.2/10l80 then I wanted to start tuning for flex fuel and I had this issue arise.I'm going to attach two tunes/logs, one before flex fuel and one after.
Prior to doing the flex fuel tune I was fighting torque management while upping my shift points. My tune did not like me ramping up so fast with my 3.70 gear so I zerod out the acceleration threshold and disabled to the use predicted torque under the cuttoff tab and it seemed to fix the TM issue. Now with only activating the flex fuel options and adjusting the EQ the car hits TM again at high RPMS. I see if more in 3rd to 4th shifts and the TM comes on sooner but my log pull started in 4th and its seen in 5th gear. Also something else is altering the timing as I only get about 10 degrees at WOT. After seeing this I went back to my old tune and there are no TM issues and the car runs more timing at WOT.
The car is running 2018 tahoe OS and currently only on 93 octain, I wanted to get things lined up with the flex fuel enabled prior to adding e85. The fueling is off a little here and there but I plan on dialing it in before I start to lean it out and add timing, just need to figure out the TM going on. The motor is only has long tubes. FYI, I hooked up my wideband on the flex fuel log to see if it matched and it didnt seem to be an issue according to the gauge.
Thanks for the help, see attached logs and tunes. Any recommendations would help!
Your cyl airmass goes to .86-.88 g/s at WOT on the E85 tune. You're also getting some timing removed by the IAT vs Spark table. Those rows are set to 12-13 degrees timing now.
You'll want to increase the Spark on those rows of the High Octane Spark table to achieve the desired timing. I typically copy that table over to the Low Octane Spark table and just remove 5 degrees of timing.
If the TM gives you problems, The DD tables can be increased on the bottom 2-3 rows to help that issue.
You might increase the VT tables a bit on the last couple columns. You might be surprised at the changes that this will make with your shifts.
Thanks Kevin! Forgot to mention I've only been dabbling with the tuning aspect of things for about 6 months so some of this obvious stuff is new to me. I get what you are saying about the timing being at 10 degrees. My high octane table is set to 13 degrees but with the IAT temp spark table its pulling 3 degrees making it 10. So is your recommendations the most common rather than adjusting the the IAT spark table? I've seen post about people zeroing out a bunch of the spark modifier tables but did not do it.
Is there anything in particular that stands out that would cause the throttle to shut from 100% to 40% and pull 16 degrees of timing? TM doesnt like something. Is this what you were talking about with the DD and VT tables?
What amount would you increase the bottom 2-3 rows in the DD table?
I got the car running a little better with not TM issues anymore. After filling up about half e85 I see that the Alcohol PID consistently reads 9% and is not adjusting the EQ at all. Theres another PID for ethanol content and it reads 43%. Shouldn't these work together in a way, why would only one be reading? Either way could someone check out the tune and see if I missed something somehow?
See attached tune and log file of me sitting in the driveway. The car has been run for about 15 minutes total since adding the e85. 9-10 tune lean WOT.hpt
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