Flake6899

Okay explain to my dad what a ud pulley does, why is it better than the stock one? And about how much horse will it add to a 1999 v6 3.8?

jthorn9

It doesn't add, they free up rwhp. U/D pulleys consist of a crank pulley, alternator pulley, and water pump pulley (for a V8) V6s only need the crank, and maybe the alternator. They reduce the size of the crank pulley which makes the engine up less hp to drive the outer accessories, which causes them to be underdriven, the hp that would be used to drive these pullies is sent to the rear wheels instead, this also will improve MPG. They'll free up approx 6rwhp on a V6. This will not cause any damage to the car, I have a 300hp GT with a 1400W+ stereo system and I'm 100% fine.

Flake6899

Thank you thats what I meant. Is it a noticeable gain?

jthorn9

Vaugely. You'll notice an improvement in MPG, other than that, you won't really feel anything other than the fact that the car will feel like it has more power up top, and that's because it will.