Cherokee Nation

Hey guys: What does a UD or OD pulley do for performance or?..I have a 2008 cam,headers,ported TB,intake and tune for street use.Thanks for any inputs.

jaybee924

I'm not a pulley or car expert by any means at all. But Underdrive slow down the accessories to make more power that sounds like what you need for your setup if you get one. It will make the care rev faster also.

The Overdrive pulley I know is for people with high power stereo systems and I want to say people with supercharged applications but I could be total wrong about the Overdrive pulley.

Blk 08 C6

UD gives you quick throttle response.OD mainly us for Forced Induction.

kevinkar

It does nothing you can really feel. On a 400HP engine, increasing it 5-7HP or so is only 1-2% and that's probably only at peak power way up in the 5000RPM range. Pretty high up there where you're really not sitting hours on end. There's no way you can feel that though it might show up on a dyno curve.

If you've changed your cam, intake, injectors, exhaust, heads, etc. and you've taken your 400HP LS2 up to 599HP and need that extra 1 to get you to 600, by all means do it. But if you are expecting actual performance gains, you'll be disappointed.

But if you're buying some nicely anodized colorful ones to pretty up the engine, there's no harm in also getting an underdrive set just for the heck of it.

All Stock Ls2

I’ve got an UD pulley and it’s a pain because it almost always triggers the service charging system code on your car unless you get a high-output alternator. Please take it from somebody who had one and don’t get it! Please don’t I don’t wish this annoying problem on my worst enemy you will NEVER feel the power difference.. best of luck to you brother!

Cherokee Nation

Is it he balancer pulley we are talking about?

Chiselchst

Primarily to spin the blower faster by increasing the HB to blower pulley ratio...maintains the same belt wrap on the blower pulley to.

Dano523

Short version, either slows down the spinning of the OEM alternator to cause charging problems at idle, or over spins the OEM alternator at top RPM's to cause it to crack a coil winding cage, taking out the alternator instead.

Also to point out, if you have heating problems as idle now, slowing down the water pump spinning at idle is not in your best interest as well.

As for super chargers, 99% of the time you can resolve that with just the pulley on the SC alone to either create more or less boost isntead.

In some instances with a TVS-2300 that you are trying to max out at top RPM(ring as much pressure out of the unit), you can only use so small of a pulley on the SC, and then have to over size the lower HB pulley. If you are using the stock oem alternator, then change the pulley on it to get it spin normally with the larger HB pulley so you don't under spin it at idle to have charging problems, or over spin it at max RPM as well.