RedStang510

I do hate to ***** up the forums... but I'm new to engines etc. (friend got me hooked on cars a few months ago, im still learning) Another friend with an '02 3.8 V6 mustang was talking about getting Underdrive pullies. what exactly do underdrive pulley systems do, and what brand should i go for?

mattdel

they slow down your front mounted accessories to reduce drag on the belt system, which the manufacturers will have you believe will free up HP, but it does not. Don't waste your money.

Dj_Seph

Brand really doesn't matter since they're all the same thing basically. Possibly March or MAC? I went MAC but just because I loved their exhaust system.

As for what they do, they make the belt travel less. Can't give you much more than that. Maybe someone more knowledgeable will chime in.

Dj_Seph

Indeed. Not really any hp gain but the responsiveness is way worth it in my opinion.

ttocs

the biggest problem that you will have with underdrives is that it will slow down the alt and the water pump. We just finished a discussion with someone that was wondering why his voltage would keep dipping below 12 v at idle. If you have any kind of stereo you will be killing the alt slowly to gain a couple of HP. I had a set of underdrives and put the stock pullies back on and sold them for $50 to the next sucker.

ALMOST STOCK

I've said it before and I'll say it again I've never had a problem with charging or over heating problems with the March Power & Amp UD pulleys, but they've only been on my car for 10 yrs so any day now I waiting for those problems to occur so that I can join the masses and say how they cause charging and over heating problems.

luckythirteen13

waste of money, get something else. use that money towards some gears so something else that youll actually notice

NoGo95GT

Didn't notice any power increase.