Underdrive pulleys?

[ryangt]

do underdrive pulleys stand to make me any power off my stock d15 hf rex?
pro's con's anything helps
are they worth the price?

 

[B16RacerN2NR]

don't waste your time, especially on a daily driver, and a hf motor at that.

 

[posol]

they are not harmonically balanced.

unless you plan to re-balance your entire roating assembly, it could lead to oil pump breakage and a shitty feeling motor (vibrations like an off-blanced wheel)

 

[spydy43]

pro's you might get 3 WHP if your lucky
Con's in my case was a spun bearing on my daily driver leading to a pricey rebuild or buying a new motor. Definetly not worth the small hp gain.

 

[dohcvtec_accord]

They won't help you until you're making huge amounts of power.

On my turbo 2-liter, a lightened (not underdrive) crank pulley got me some pretty large gains after it was tuned for. On a stock or near-stock engine, you won't see much at all.

 

[integraslut78]

They are just not worth it stright up. I would be surprised if you got 1whp.