HomeSite IndexSearch Logo

Unorthodox Racing Underdrive Pulleys Stage 2

By Shell Black

This time we are installing the alternator and power steering pump pulleys. We already have in place the crankshaft and the water pump pulleys from Unorthodox Racing (click here for Stage 1). This set from Unorthodox Racing is a newer generation than what was installed previously. The new product from Unorthodox has four large circles in the disk for less weight on the power steering pulley (see the picture below). Whereas my water pump disk is solid, the new stock that Courtesy Nissan received has the four hole pattern. I am not sure when the design change occurred. The pulleys can be ordered in different colors. I continued with the red anodized units to match the other red accents in the engine bay.

I was able to get some weight measurements this time around. I used a digital postage meter to get exact weights (thanks to Wayne Cox for the idea!). The power steering pulley from Unorthodox weights in at 7.5 oz versus 14.7 oz for the OEM pulley. The alternator pulley from Unorthodox is a featherweight 4.0 oz versus 10.5 oz for the OEM pulley.

Installation was done at Courtesy Nissan and took about 2 hours. When I got the call at work that my car was on the rack, the power steering pulley had already been installed by the time I got there. The passenger tire was removed as well as the front passenger engine splash guard and front passenger wheel well splash guard to gain access to the belts and pulleys. The power steering pulley had unbolted without a fuss. The problem was clearance to remove the old pulley. Smitty, my mechanic at Courtesy, had to unbolt the motor mount on the left side of the engine bay and tilt the engine just slightly upward to get enough room to slide the pulley off its post. He did this by carefully lowering the car while on the rack so that the engine rested on a stand. The stand was simply a 4 X 4 post with a 2 X 4 "T" to displace the weight across the oil pan. Be sure to use the side of the oil pan and avoid the area near the sump pick-up (denoted by the big square pattern on the bottom of the oil pan). With the engine tilted slightly the pulley could slide clear and the new pulley could be placed on the power steering unit. A screwdriver was placed through one of the big four holes to hold the unit in place so the nut could be tightened.

To put the pulley on the alternator the alternator was removed completely with wiring harness attached. With the unit out of the engine bay it was quick work to swap the pulleys.

Surprisingly the belts remained the same from the first stage. This makes me believe the diameters of the pulleys did not change much this time around. I was running a Nissan belt 4PK845 on the power steering, crank, and water pump; and a generic K3906 on the crank to the alternator. Smitty commented that the power steering pulley looked to be actually a larger diameter than the OEM. At first this did not seem right, but when you think about it you want the crank to be a smaller diameter and the accessories to be a larger diameter in order to "under-drive" the accessories. Unfortunately, Courtesy did not have another set in stock for me to compare to confirm this observation. With the pulley already on the car when I got there, I could not get a picture comparison. When I stacked the alternator pulleys the Unorthodox Racing unit looked to be slightly smaller. I think the weight savings was more key on this pulley.

diagram_small.jpg (6125 bytes) A scan out of the Nissan manual. Just a reference for everyone.
pulleys1_small.jpg (6226 bytes) The power steering pulley on the left and the alternator on the right. Notice the four large holes cut into the power steering pulley. The newer generation water pump from Unorthodox Racing also has this feature.
pulleys4_small.jpg (6018 bytes) The backside of the pulleys. The red box on the far right is attached to the key (for scale), as the car was in service at Courtesy.
side3_small.jpg (5468 bytes) A side shot of the pulleys before installation.
installedtop_small.jpg (6742 bytes) Best shot I could get before the belt went back on. From left to right: power steering, water pump, crank. White Nissan Oil filter to the left and silver motor mount casing to the right for orientation.
installed1_small.jpg (7454 bytes) The pulleys from below installed.
stacked2_small.jpg (7461 bytes) A stacked comparison of the two alternator pulleys. The Unorthodox pulley looks to be slightly smaller in circumference from what I could tell. I think the weight reduction was more dramatic in this case than the size of the pulley.
alternator3_small.jpg (9240 bytes) The pulley installed ready to go back into the car.
alternatorin_small.jpg (7290 bytes) The alternator installed in the car with the new pulley. Notice the engine was still tilted from the power steering install - the motor mount is floating above the bracket.


Team Dynotech's Dyno on 5/8/99:

My last dyno runs BEFORE Stage 2 Pulley Upgrade but WITH the Stage 1 from Unorthodox was:

At Team Dynotech's Dyno on 5/7/98:

At Area 51 Performance's Dyno on 11/21/98

I'm up between 3.4 - 4.5 HP from just the stage 2 pulley upgrade!?! I know, hard to say considering the time between runs and different dynos - but I'm up in both cases! The only thing I can possibly attribute any other gain was switching to silicon vacuum hoses (a stretch but I know my gas mileage has increased slightly as a result).