[Christ]

Originally Posted by JackMcCornack

I'd like to put an alternator cut-out switch on my 32 horse Kubota diesel that will disengage the alternator (electrically--it has a one wire alternator) at full throttle. Will this improve fuel economy? I think yes, 'cause I'm giving my car a removable roof this summer, which will add a bit of weight, and according to my back-of-envelope calcs this alternator mod could give me a (worst case) extra half horsepower at full throttle which means I won't need any engine mods to keep my present (limited) performance. Does this make sense to anybody?

Also, should I do this with a relay? Probably so (rather than have long current-carrying wires 'twixt alternator, foot switch, and battery), and hooked up as NC; so how much will the current draw for a relay negate the alternator disconnect advantage?

Innit like 1 or 2 watts for a starter solenoid (form of relay) to actuate the big copper plate inside against the terminals? I'd think there would really be no noticeable degradation of performance, although your lights might dim some (haha - dim sum) at full pedal.