perfect thanks,great idea i think this would be a good way (as most application r have SAI). on my injector circuit i could add a opto-isolator, low pass filter the PWM or a voltage comparator with error amplifier to triangle wave signal to drive my Hbridge driver (this will add the progressive bit) , that should work, the way i want. But yeah sounds like SAI is a good starting point for a nitrous safety switch, or for the watermeth engagement, im going to get an arduino and see what i can come up with, i wonder if things like engine load could be sent though can bus and then read by am arduino with extra inputs outputs, would be a neat project (i wonder if you could add wide band to arduino then send the "current lambda" back to a narrow band ecu, not sure how much info and at what speed the can-bus works, im ordering a roadrunner and will play around, i got El-Mouktari-Engineering on my skype (he is so good and nice) but i dont want to bother him with all my questions, and im always looking for good suggestions so i know where to focus my efforts.
ecu sends actual load via canbus
and ofcourse you can read it with arduino can-bus shield
