Hmmm......what sort of help with the SD equation. Would be interested either on or off list, whichever you prefer. Walt. >Pretty simple, isn't it? What method do you like? :-) To me, it >depends on MAF accuracy, and on the other side, the routine used to >calculate air mass in the cylinder. My SD code needed help in the >equation, but I'll save that for another post. > >Scot Sealander >