I've got a 200A alt in my FC.. at idle im 11.5v at about 2200 im at 14.8, will this affect the output of the megasquirt or does it have a voltage regulator, worried about tuning it right and the possibility of it overclocking on me.

 

i dont think so. because when you test megasquirt with a stimulator you use a 9v battery. key on engine off, you should have 12v. which is fine. when the alternator goes full field it puts out about 14v. so i think it be be allright.

 

Megasquirt will work fine in those voltage ranges. A drop in voltage could potentially affect fueling, though. At lower voltages the injectors open more slowly, so even though the electrical pulse width hasn't changed, the actual time spent open and squirting fuel drops with voltage. MS has a tuning constant built-in to correct for this.

On the constants page you'll see a 'Battery Voltage Correction', in ms/V. This value is added to the calculated pulse width at low voltages, and subtracted from the pulse width at high voltages to compensate. Without some detailed testing, it'd be hard to know the specific correction factor for your injectors. Most folks just use typical values in the 0.1 to 0.2 ms/V range.