@Michael Pickett posted:This update addresses how to adjust Speeduino for a type 1 engine with individual throttle bodies and air conditioning. Probably an edge case, but maybe someone will need it.
....You can identify the optimal spark advance at idle speed by adding advance and watching the MAP gauge drop. At some point, the MAP gauge will stop dropping and will start rising again. In my case, that's at 42* advance and MAP=57 at 1200 rpm (amazingly high, eh?).
I know this is a FI thread but I wonder if the principle might apply to any of us backward MFs running carbs along with programmable ignitions. Right now my off-throttle (high MAP) ignition timing numbers at idle are much, much lower: my "trough" is at 800 rpm at maybe 8 degrees (I'd have to hook up the computer to check the table). I'd thought the trough should only be a degree or two. You're saying it can be more pronounced?