Quote:
Originally Posted by jpnovak
So... If you are having trouble running leaner than 12.5 you need to add more timing. A rich mixture is slower to burn - up to a point.
General rule of tuning is that to run more lean, you need to add more timing. This rule especially holds at light load and cruise. This is why you see Motronic (3.2 and 964) cars with lots of light load timing. In some cases, higher than 40 BTDC.
Increase the timing at light load and see if that helps you increase the AFR to run more lean.
And yes, Always give the engine what it wants... In some ways you tune by feel/sound.
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For some reason I had in my head the leaner mixture burns more slowly and thus the need to start the combustion process sooner?
I think Chris and I are in the same place, timing-wise. I have a max of about 32 degrees in the mid-range, tapering down to 30 degrees at the torque peak. I have no means to determine load with the system I have (no vac advance) but am thinking of adding one back in. Maybe adding a 123distributor so I can map timing to vacuum.
My car seems to like closer to 12:1 for best power although that's seat of the pants at this point and not really what I'm spending most time on these days.