Dumb question - removing alt belt for dyno?

SadbutTrue

Founding Member
May 1, 2002
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Granada Hills, California
************* says you can probably pick up some power on the dyno by disconnecting the power steering and alternator belts. The P/S is obviously not a big deal, but I was wondering if about the alternator.

My head says that, for the purposes of a dyno run or two, you could run no alternator without killing the battery and without ill effect, but I have talked to some gearheads and everyone i've talked to isn't sure.

So yeah... when I re-dyno my car in a month or so, can I disconnect the alternator belt? I really want 300 at the wheels and am willing to do any little thing that helps to get there :)
 
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Why, you'd put it right back on when you left, and wouldn't be an accurate number I don't think. Plus you'd have to rig something to get the water pump to spin. Or you could leave them all off. Bet that water pump soaks up some power, lol:stick:
 
************* says you can probably pick up some power on the dyno by disconnecting the power steering and alternator belts. The P/S is obviously not a big deal, but I was wondering if about the alternator.

My head says that, for the purposes of a dyno run or two, you could run no alternator without killing the battery and without ill effect, but I have talked to some gearheads and everyone i've talked to isn't sure.

So yeah... when I re-dyno my car in a month or so, can I disconnect the alternator belt? I really want 300 at the wheels and am willing to do any little thing that helps to get there :)

Yeah, probly only worth a couple of horsepower, but won't hurt anything. I once fried an alternator in Ohio and drove all the way to New Jersey with the belt off.
 
Like already mentioned. It's only a 2 or 3 HP gain.

And again as mentioned... are you doing this for bragging rights, or to actually get an accurate measure of the HP you are producing?
 
************* says you can probably pick up some power on the dyno by disconnecting the power steering and alternator belts. The P/S is obviously not a big deal, but I was wondering if about the alternator.

My head says that, for the purposes of a dyno run or two, you could run no alternator without killing the battery and without ill effect, but I have talked to some gearheads and everyone i've talked to isn't sure.

So yeah... when I re-dyno my car in a month or so, can I disconnect the alternator belt? I really want 300 at the wheels and am willing to do any little thing that helps to get there :)
I've always beena little baffled by this thinking. Hey, we'd all like a car with a ton of rear wheel ponies, but what's the point? I'd rather have a car that can knock out a quick e.t., and that's something the dyno can't do. Use the dyno to maximize your combination, not to give you a false sense of superiority. Think I'm full of it? As yourself how good that dyno sheet is gonna look when and if you actually take it to the strip.
 
back in the late sixties and early seventies a lot of guys would put a switch in the field wire circuit so that when they ran in competition they could shut down the alternator and pick up a couple of horse power. the reality of that situation was that it made no difference except in the mind of the person doing the driving.
 
rbohm - I just had a neat idea - how about wiring in the the field wire into a WOT switch - when at WOT, alt isnt chewing juice!

That gives you a mod that you can leave on the car all the time! And if it does give you 1 or 2 hp, its the cheapest 1 or 2 hp you will ever get.
 
rbohm - I just had a neat idea - how about wiring in the the field wire into a WOT switch - when at WOT, alt isnt chewing juice!

That gives you a mod that you can leave on the car all the time! And if it does give you 1 or 2 hp, its the cheapest 1 or 2 hp you will ever get.

interesting idea, but personally i dont like disconnecting the alternator when the engine is running. all you would need is a marginal coil or ignition box or battery and you now have a miss that seems unexplainable.