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Unorthodox Racing Underdrive Pulleys

By Shell Black

red_triangle.gif (202 bytes) Check out the Stage 2 pulley install here

I have found in the heat of Dallas in summer that at a stop light your AC will run weak due to low rpms... goose it up a few 100 rpms and you will run cooler.  With the car in motion the AC is fine.  At night the car blows ice cold.  I also have not had any cooling issues though I do not have a Consult or Techtom to verify.  I also have the Nismo radiator so I didn't expect a cooling issue.  The belt is a 6 groove 390 length (I hope I translated that right - Courtesy Nissan has the belt number cross referenced).  Only reason I know that is last weekend the alternator seized, chewed up the belt, and left me stranded.  Luckily with an Optima battery you can drive that 4 cylinder a long time! - at least back to Courtesy!

I have been running the set-up for about a month.  Installed and bought from Courtesy Nissan - $199 for the pulleys + 2 hours labor. I walked in and they had one set on display.  The car was on the rack the next morning.  John at SERious Performance is an Unorthodox dealer and put the bug in my ear at the last Texas Rally at Austin.  I believe his price was a bit more competitive - $180.  The only dyno run I was able to make was at Team Dynotech in Dallas.  I rushed over there on a blistering day with AC blasting.  I was supposed to be on the way to my brother's graduation and tried to squeeze a run in.  With the car completely heat soaked (no cool down time and no fan to put on engine or cold air intake) I managed a 1 HP gain (133.3 vs 134.2) and 1 lb ft torque (129.0 vs 130.0).  Also to note I disconnected the Stillen Fuel Pressure Riser for this run.

underdrive1_small.jpg (18218 bytes) Good shot of the crank pulley, with water pump belt on and the alternator belt off.
underdrive10_small.jpg (19714 bytes) Shot from above with motor mount and alternator out of the way to get a clean picture.
underdrive2_small.jpg (17500 bytes) Shot directly below up into engine showing the 2 pully set-up.
underdrive6_small.jpg (18216 bytes) Extreme close-up of crank pulley installed.