Tuesday, May 09, 2006
Which Megasquirt do I need?
I had originally tried to divide things up by categories, but that got repetative and unnecessarily complicated. I found that it's easier to reduce this to a few rules of thumb.
1. The V3.0 board with an MS-1 processor will control virtually any engine with minimal hassle. Use MSnS-E firmware if you need spark control.
2. You are much better off with a Stimulator board. Buy one unless a good friend has one you can borrow.
3. If the original chassis is not wired for fuel injection, I recommend a Relay Board. I'd use one if I had to do my installation all over again; my homemade substitute cost more and looked uglier.
4. It really doesn't matter if you are using a throttle body injection system or forced induction, unless you want to run very high amounts of boost. Running over ~21 psi of boost will require a higher pressure MAP sensor, but no other mods to the Megasquirt.
5. MSnS-E can control most ignition systems using the factory sensors by now, including distributorless ignition. If controlling a factory distributorless ignition seems intimidating to you, consider grafting on a Ford EDIS system - you just need to find a way to mount the Ford trigger on your crankshaft pulley.
6. Got a motorcycle, ATV, or small watercraft? Consider waiting for Microsquirt.
7. You'll need a 9-pin serial cable to connect it to your PC.
All right, now those are the basic rules. Now on to advanced ones - if you just want a simple way of running, skip this, and order a V3.0 board with the standard processor and the recommended extra hardware.
There are very few installations that actually need a MS-2 processor. But you might want to use it in the following cases:
1. You are running very large injectors and want the best idle quality and drivability.
2. You want to use a stepper motor idle control. Running MS-1 if you have one of these means having to find another fast idle controller. How do you know if you've got one of these? Check the connector on the idle air control valve - if you see four pins, you've got a stepper motor.
3. You are interested in one of the upcoming add-ons to Megasquirt, such as the GPIO board or MegaShift.
4. You just plain want the latest and greatest.
5. You want a flex-fuel engine that can run on any mixture of gasoline and ethanol.