Unorthodox Racing 95-99 Pulley Review
The UDP (Underdrive Pulley) is an aftermarket replacement for the crankshaft pulley on the Maxima, which drives the accessory belts. The UDP replaces the stock crankshaft pulley with a smaller diameter and lighter weight unit which allows the engine to rev more easily. Unorthodox Racing has developed a pulley system which not only provides light weight but also operates in a very proper and well constructed manner. UR claims on their site this statement, "This version of our crank pulleys increases performance because they underdrive all the accessories (15-20% more power), unlike accessory only kits out there that do not include the crank pulley. This means one you air conditioning is on our crank pulleys give you more power back to the wheels by not letting the air conditioning compressor rob as much power." Lets see what's really going on..
Basing our review on our 1995 Nissan Maxima with Air Conditioning, Audio System, and Power steering still intact this will provide a complete understanding of how well this performs without sacrificing much if any drivability. This CAD designed & CNC'd from 6061 Aluminum billet pulley weighs in at a respectable 1.49lbs compared to the 4.84 lbs from the stock pulley. Due to the smaller radius and weight savings, this makes it much easier for the car to spin the pulley and frees up energy for other components of the car. The result is a faster revving engine, and a small HP gain. Since the pulley is underdriving some accessories, there are some speculations that the (Underdrive Pulley) UDP will have a negative effect on things such as the AC, power steering and electrical output. With our test it seems as though we are sustaining as much power to operate the car with full accessories as we did with the factory unit. If you have or plan to get a supercharger/audio system than this modification is not intended for you because you do not want to underdrive a supercharger/amplifier. UR has taken a note to that and created a Stock diameter pulley for just those application while still saving weight but keeping with the diameter of the factory unit.
None as of yet
95-01 Nissan Maxima
96-01 Infiniti I30
Gates belts, numbers K-060408 and K-040292
Crankshaft oil seal -- Nissan Dealer (part # 13510-31U00)
Crank Pulleys (Ultra S)
Unorthodox Racing, Inc.Dealer:
Unorthodox Racing, Inc.Contact:
Jim Lodding - Advertising & Marketing Director
Short and Long Extensions
With the belts removed and the bolt removed from the crank pulley, using a large flat screw driver or similar tool slowly but firmly pry the factory pulley from the motor making sure not to damage anything in the area you working. With the pulley removed you will see where the crankshaft oil seal can be replaced while you are in the process of this install. Line up the new pulley with the key on the crank and firmly press the pulley into its location. Reinstall the crank bolt and new belts and you are ready to go. Drive Spiritedly.