ignition timing and A/f Options

[ncgalant]

Alright, lets get down to it. I'm looking for power. Given that, which is better, a little richer and more ignition timing, or leaner and less timing? Currently I'm working toward the latter, but want some input from some that run fast.

Also, which is better for spool, lean or rich. I can't get my pre-boost #s into the rich range. If I do a 3rd gear pull from 1500-6500. My O2s will read .08 until 3500 or so when they jump up to .8 and then .9 around 4000. My setup is working, but I want it to be the best it can be. I can post up my SAFC settings if you guys want too. Their F'd up.

[natedogg]

I'm pretty sure I have the map sensor (3 bar if I remember right) and casing that you need to run your SAFC off boost rather than throttle position. I was going to do this back when I had an SAFC. I'll check the garage when I get home.

If you have to choose between the two, leaner and less timing, vs. richer and more timing, I would choose the former as far as power goes. As far as engine safety goes the latter is probably your best bet. It just sucks that you can't see how much knock you are running with the OBDII set up. When Marcus and I would log his car and my old fwd, they both always felt quicker while running leaner on more boost and with less timing (due to knock readings causing the timing to get pulled). Not really the safest for the engine, but that's the rub.

If you want the best of both worlds try some xylene, toulene, or some 100 oct. I just logged my car on the way to work this morning and saw 27 to 30 degrees of timing at 26 psi and 0 knock while running 100 oct. My wideband 02's were reading right around 13.5:1 AFR. You will rarely if ever see a perfectly stoichmetric ratio on a turbocharged engine at WOT. Its just too lean. Hell, I think the 13.5 that I'm running is too lean, but she's not knocking and if I richen her up she just sputters and chokes on the extra gas.