Turbolarry, I tossed on a 3" cat-back last night, then got together with ldstang50 to do some tuning. I was supposed to have my Hallman so that we could do some REAL tuning, but instead, it was just some light tuning, since the exhaust didn't invoke a need for many changes, nor did we have to worry about setting boost at a certain level. I already had the S-AFC tuned in really well to begin with, so we only made some minor changes, but I have now gotten to the point where my 02s are beautiful, and my timing advances wonderfully, but I'm afraid it's advancing too far. What are the ramifications of timing advancing too far? I originally worried that it would potentially raise my EGTs, but after reading on EvoM, I see that increased timing LOWERS EGTs, which at least relieved me for the moment. Take a look at these 2 logs, and let me know if you have any suggestions on some changes. I'm not sure how to keep the O2 curve flat while advancing the timing steadily without going over 20. I keep hitting 21 at 6700rpm or so...
RPM 02 Tmng AFC
3820 93 3 +3 (4000)
4199 93 8
4570 91 9 +2 (4500)
4929 91 10 0 (5000)
5273 93 9
5636 93 11 -1 (5500)
5953 93 14 -2 (6000)
6285 93 16
6597 93 17 -5 (6500)
6898 93 20 -8 (7000)
7164 93 20 -12 (7500)
Now, for the 2nd log, I tried to take the timing dip out of 5273 while leaning out 4500-6000 to the point of hitting .91. Above 6000, I wanted to stay at .93v all the way to redline just to be safe. I haven't been losing timing, so I didn't see a need to push the AFR in street mode.
RPM 02 Tmng AFC
4023 93 4 +3 (4000)
No reading
4593 91 10 +2 (4500)
5128 91 10 0 (5000)
No reading
5605 93 12 -3 (5500)
6000 93 15 -3 (6000)
6394 93 17
6718 93 21 -5 (6500)
7015 93 22 -8 (7000)
7308 93 23 -12 (7500)
I actually didn't even pay attention to the richness and suppressed timing at the 4k level, because it is usually leaner, but I think the turbo is spooling up sooner then hitting full boost sooner, so the 3800-4000 o2/timing needs to be addressed. I'm going to take a little fuel out of my 4k setting for next time, so that I get the timing advancing sooner and so that the o2 is .91v. After 5500, I still have a lot of room, but I am hesitant to pull out more fuel on the road. I'm happy with the power, and everything is running nice and smoothly. I could get the 5500-6500 down to .91, but then wouldn't the timing advance even more? What's the downside of having my timing go all the way up to 23 near redline?
Btw, thanks for all the help, Liam! Can't wait to go for a 12.4@110.
