Some time ago I was wondering about disconnecting my alternator from my race car just during a quarter-mile drag run. The lesser friction on the motor's drive belt system would be ideal. Then I realized that spinning the alternator itself is not that much of a problem, it spins pretty freely. Spinning it while it is charging a load though, that is what's in question. I'm sure nobody would really know, but I was wondering what kind of force it would take to spin the alternator while charging the car's electrical system. Not the car's system when the lights and accesories are on, just when the battery is pretty much charged up and there is no other significant loads on the engine. The idea then came to just put a switch on the alternator, and turn it off during a track use. It would be easier to flip a switch than to dismount the alternator, and even if the gains are very minimal, we are talking about one relay and some wiring here. A buddy of mine who worked at a tuning shop was going to test the idea for me by dyno'ing a stock acura integra and then dyno'ing it again with the alternator electrically but not mechanically disconnected. Just wondering if anyone else has had this idea or anyone with dynonameter access could try this out for me. My buddy never got around to doing it.