Unorthodox Racing Ultra Street Pulley Sets are CNC-machined from lightweight 6061-T6 aluminum billet. Premium 6061-T6 aluminum billet ensures the consistency of the material's strength and balance. Tolerances for each crank and accessory pulley are held to within .001". In addition to the numerous machining steps taken to ensure the crank pulley is the lightest possible design, each accessory pulley is also lighter than the factory piece it replaces and includes lightening holes where possible.
Unorthodox Racing pulley sets on average can provide gains of 8 to 15 HP and 6 to 10 lbs.-ft. on normally aspirated engines and 10 to 18 HP and 10 to 20 lbs.-ft. on forced induction engines. Higher gains can be realized on vehicles that are modified.
Unorthodox Racing Ultra Street Pulley gains are obtained in two ways. First, and most important, is the weight loss. There is an average of 2.7 HP gained from every pound lost off the crank shaft. With the lighter accessory pulleys, as much as 15% to 30% more power can be found. 85% of our gains are from weight loss.
The rest of the gains are from underdriving, which accounts for about 15% of the total gains. We do not push underdriving for two main reasons. Our main reason is to keep charging systems, air conditioning, power steering, and water pumps moving fast enough for every day driving. Second, not much horsepower is gained from extreme underdriving.