ok, i've heard people say before that removing odds and ends like the a/c, pwr steering, air pump will not signifigantly affect power. if this is true, why do underdrive pullies add 4-8 hp (guess, i've seen them add that much on dyno charts for other cars). sure it's not a huge difference, but removing them instead of underdriving them would further that effect wouldn't it? the alternator can't be the only source of parasitc loss can it? i'd like to hear some opinions on this. personal expirience would be great too. i can't really test this theory, because my base has no a/c or ps, and now no air pump.

 

For teh short, don't underdrive a street car.

IMO it just cleans **** up. The A/C pulley is idle and doesn't really have any "parasistic loss", at least nothing measurable in the scope of hundredths of hp. Different story when the ac pump kicks on...

As for the power steering, same deal, just an idle pulley unless its being used.

All it really does is make working with the engine a hell of alot easier. If you don't like sweating your *** off (even in canada), or don't like struggling manuevering your car in parking lots, keep the stuff there.

If its a track car, remove all that **** and underdrive.

 

yeah, i'm not thinking of underdriving at all, the alt barely handles the amp as is. i'm just surprised that the alt creates so much drag that an underdrive pulley will dyno test in the previously stated range. although i guess the water pump may also be a factor too, i just realized that.

 

Yep kenteth is correct.

A/C is only on when the A/C is on, there is almost no loss when it is off.

The power steering is off at anything above 40 mph, and only at half load between 15 and 40.

The fan is only on when the engine air temp is above normal operating temp and pretty much freewheels at highway speeds.

Under drive pullies only work on the water pump and Alt, things that are needed all the time just to run the car (unlike the A/C, and power steering pump).