There's one thing supermodels and racers are always concerned about--losing weight. However, unlike a rabbit food-munching, two-pack-a-day-smoking, bulimic supermodel, your everyday gearhead is constantly trying to find ways to make a car lighter and faster. Racers have gone to extremes to shave weight, purchasing titanium connecting rods, knife-edging crankshafts, titanium valves and retainers, etc. These options lead to performance gains, but they're often very expensive.
Unorthodox Racing, Inc., which has been researching and developing lightweight underdrive pulleys since 1995, found huge benefits with lightweight pulleys. In-house testing revealed 85 percent of performance gains came from reduced weight and 15 percent came from underdriving. So Unorthodox Racing concentrates on manufacturing lightweight pulleys instead of just underdriving the pulleys.
Most of the Unorthodox Racing pulleys feature only a 15- to 20-percent underdrive. All Unorthodox pulleys are constructed from billet aluminum, which are then machined on computer-operated CNC machines to .001-inch tolerances.
For our testing, we chose a 2003 Nissan 350Z track model equipped with an Invidia exhaust, AEM intake and Sun Automobile Hyper Ground System. The 350Z baselined at 238.8 rear whp on the Dynojet chassis dyno. Installation of the pulleys requires new alternator and air-conditioning belts due to the smaller diameter crankshaft pulley. It's a direct R&R affair.
The Unorthodox crank pulley is only 1 pound 5.2 ounces, compared to the stocker's 6 pounds 3.2 ounces. The Unorthodox alternator pulley is 3.0 ounces, while the stock measured 6.8 ounces. And the water pump pulley came in at 7.6 ounces vs. the stock of 14.0 ounces. That's a total weight savings of 5 pounds 8.2 ounces. On the dyno, the reduced weight, along with the pulley's 15 percent underdrive design, resulted in a gain of 6.1 peak hp as Peak output checked in at 244.9 hp. At 5500 rpm, we witnessed a gain of 9 hp.
The increase in output was noticed in quicker revs and a stronger pull to redline. At $399 for the pulleys and $35 for a new drivebelt, the Unorthodox pulleys are a must-do performance modification. Lighter is better.