Book fest

Just got my book by Jeff Hartman, basically an MIT text book for Advanced Mechanic students. If you like differential calculus you will love this book. Its a nice 600 page tomb.

Lucky the book uses the maths to demonstrate the text, though at times I think it just gives up and explains things with long physics formula. Anyway very interesting so far. That will keep me busy over the holidays.

Anyway, my tune continues to improve. Im not convinced with "Lean Cruise" and have reduced the factory lean out by 50% as I had to put my foot down quite a bit to get it to maintain cruise speed. This was backed up by some comments from Delco at chipmaster in oz, an amazingly helpful pro tuner who seems to live and breathe GM PCM's. I understand he wrote some of the code for EFIlive.

Ive left DFCO on as I like the engine braking it creates. I also wiped out PE mode by setting map to 110kpa. I will use table B3647 to command enrichment instead and see how that goes. The main reason for this was that PE came in at 64% Throttle and I could feel the engine slump at this point. I was assuming that it was PE cutting in. Either that or the richer fuel.. or maybe lower spark advance. Anyway stage 1 test is to see if turning TPS and PE off makes a difference. If not Ill look at the enrichment settings. Basically 13:1 going to 12.8 at max torque then back to 13:1.

My commanded fuel is more gradual, though ramps to the same settings.

So Im summary my low end and mid range feels great. Im not so happy with the higher RPM range and believe it to be either PE or spark that is the cause. I got a little KR around 0.60g/cyl and 4000rpm, so have pulled timing there down to around 26deg.

More updates once I see how the recent changes go.

Im starting to read up on idle tuning in anticipation for some tuning action when the new cam comes in.