- The first power pulleys for American, Asian & European Modern Muscle.
- The litest pulleys for the biggest power gains & most fuel savings.
- Perfect balance, no wobbling or hopping.
- 100% designed & made in America.
- 5 year warranty for peace of mind.
- 18+ years of use from street to strip to rally to road course.
UNDER DRIVE PULLEY (UDP)
Definition: The reduction in speed of the accessories (a/c, alternator, p/s & w/p) by making the crank pulley smaller or the accessory pulley bigger. Under drive is usually expressed as a percentage of reduction versus the stock diameter.
Increases engine output by slowing the accessories. Power previously wasted over spinning the accessories now goes straight to your wheels. When UR uses under drive the reduction is adjusted for each application and accessory to fully maintain factory specified output/function. It also allows for upgraded stereos of up to 600 watts (RMS) without charging problems. UR under drive makes up to 10% more power than UR stock diameter.
STOCK DIAMETER PULLEY (SDP)
Increases engine output by significantly reducing the engine's rotational weight. Power wasted turning the extra weight now goes straight to your wheels. Stock diameter is also important for engines with factory or aftermarket superchargers to maintain factory boost levels. High wattage aftermarket audio systems also need stock diameter as many audio competitions require voltage to remain at a specific level.