MS2 upgrade

I upgraded the chip in my megasquirt from MS1 to MS2.

It is amazing what the programmers managed to get out of the MS1 chip, it was designed to run fuel injection, but with the megasquirt extra code, it runs ignition and fuel injection, this means that the timing precision required is around 100x more challenging (i.e. instead of a squirt or several per revolution, ignition requires precision of a degree or so per revolution).

I had been running into the limits of the MS1 chip for a while. It couldn't keep up with my 36-1 trigger wheel, so I converted the wheel into a 12-1 and it was fine, although sometimes the rpm went a bit funny at 10500rpm (perhaps the rev limit coming in early, not sure). Additionally I was limited with acceleration enrichment (you can do MAP or TPS based with MS1, but with MS2 you can blend the two). Next the TPS resolution was a bit of a problem with MS1, so I added a parallel resistor to improve the resolution at closed throttle positions. Finally, when I changed to secondary injection, then it was not possible to gradually ramp in the secondaries while the primaries ramp down. All in all it was time for a change.

So, Ms2 comes as a daughter card, which replaces the chip on the megasquirt board. You have to be careful to follow the instructions to the letter to avoid blowing it up. The megasquirt maps all need re-writing, but fundamentally much of this is copying from the old maps and settings.

After some messing around I managed to get the car running, and preliminary results suggest it to be much smoother and nicer. I think the ignition timing wasn't so good with the MS1, and injector timing is much better with the new chip.

Going for a 10minute drive sorted out the fueling map, so I am very pleased with it. Even on the tuning run where it was overfueling like mad (AFR of 10.5-11.0 when it should be 13 or so) it went very nicely. So I am very optimistic of how this is going to turn out.

Actually everything about it is awesome with no ned to reflash the memory to do things like updating the sensor scaling values (temp for example).

No pictures, sorry.