Megasquirt talk (split from robokills project thread)

[BenR]

piggy backing an ECU to run a higher overlap cam on throttle bodies will lead to pretty poor running.

When it comes to making an engine drive smoothly and loveingly, its all about the ECU's capabilities (and you get what you pay for) and the mapper.

In my experience, if its a high rpm engine i wont use anything less than 25x25 breakpoint map, anything less and you just asking too much in terms of interpolation which will simply lead to 50% of your engine running on averages between two mapped points, which is not really what we are trying to do when we spend all this time and money mapping to make sure every rpm of the engine is running spot on for fueling and ignition.

Tuning ignition timing is another grey area. When i see people simply advance until they get knock then retard a little, i cringe. This is not the best area for peak BMEP. You will want to monitor knock, AFR and EGT minimum. And EGT must be from 3-4" behind the exhaust port, not at the collector as you want to collect true data of the combusiton temps and see if the mixture is burning correctly. Ideally you will want to see 12.9-13:1 AFR and 1300-1350 degrees F for EGT.