944 Trigger Wheel (redux for MS3)

[argiopeweb]

I'm beginning planning of a multi-phase upgrade to my 1987 Porsche 924S (which has the same 2.5L I4 as the more common 944, hence the title). I'd like to ensure that everything I'd like to do is possible and get the community's input on the most cost-effective way to go about it. This doesn't appear to have been discussed on the forums for the MS3 (though the MS2 and MicroSquirt have both been done, albeit not recently), but please feel free to direct me if I've missed it.

My primary goals for the project are taking small enough steps that it minimizes downtime on the car, keeping cost to a minimum wherever feasible, and using proven stock systems wherever possible.

Phase 1 is relatively basic (and probably the source of most of the challenges): Fuel via MS, ignition from the stock ECU. Distributor/rotor/coil setup remains as-is. I'd prefer stock injectors (low-impedance) and stock trigger wheel (dual VR setup with 130 teeth on the flywheel + 1 tooth at TDC). I've heard of high voltage issues from this wheel causing cut-out around 5krpm and requiring modification on the v2 MS2, but I'm unsure of whether this has been improved on the v3 boards. I've also heard that MS2 doesn't like non-integer tenths of degrees per tooth.

Phase 2.1 moves ignition to the MS via the stock distributor with (as close as I can get to) the stock ignition maps and deletes the stock ECU and MAF. Significant modifications to the spark advance would wait for Phase 2.2 with wasted spark COP. I'd prefer to run the coils with the MS rather than e.g., the standalone EDIS controller.

Phase 3 is sequential injection with a cam signal from something like this Clewett product. This introduces a third trigger signal, which might be an issue.

Phase N is forced induction, but I'm pretty sure that modifications through even phase 2.2 will be plenty to make FI into a run-of-the-mill experience.

Can MS3 do all these things? Do I need the MS3X board? Can I get away with an MS2 or MicroSquirt with the v3 board?

Thanks for your input!

[billr]

Hmm... this must be my day for being "Mr. Grinch"! My son raced (amateur) a 944 for a while, it doesn't seem to be a particularly inexpensive or durable engine. Point is, a lot of money is going to go into this project, pay the extra $200 to start off with MS3, the most versatile MS available right now, it will be a trivial cost and yield considerable benefit.