Our last power product is an Unorthodox Racing lightened front pulley. We had great success with Unorthodox Racing pulleys in the past and felt the KA engine could benefit from one too. Constructed from billet aluminum the UR pulley is substantially lighter than the stock cast steel unit. The UR pulley tipped the scale at a feathery 1.5 lbs while the stock unit weighed 6.5 lbs. Besides being lighter the UR unit also slightly underdrives the accessory units (A/C, P/S, alternator and water pump).
Installing the UR pulley is a straight R&R affair with the only difficult part being the removal of the 24mm front pulley bolt. Once the bolt is loose, remove all the belts. The UR pulley will require new, shorter belts due to the under driving. The instruction sheet lets you know what belt lengths you need. Once the UR pulley is installed, pop on the new belts and it's party time.
The key to power production is to not over-tension the new belts. Too much tension on the new belts will increase drag causing a lower power output. Trust us, we checked it out and you will lose power if the belts are too tight. Once we adjusted the new belts to the proper tension it was time for another dyno run. With the new pulley in place we recorded an increase of 1.8 peak horsepower and 3.7 lb-ft of peak torque. We figure once the new belts wear into the grooves of the pulley we should see an even greater power increase over the stock pulley.
Peak output now stands at 148.8 horsepower and 159.9 lb-ft of torque. Pretty impressive numbers considering a stock 1994 to 1998 240SX only makes about 125 horsepower to the wheels. We are now generating 20-plus more horsepower than a stock engine.
Just for fun we thought it would be interesting to see how much power the Blitz silencer, if any, would rob compared to the un-silenced system. To our surprise, with the silencer installed the Nissan made nearly identical power numbers, losing only 0.1 horsepower and 0.3 lb-ft of torque. Our guess for the identical power numbers is that the 80mm piping diameter flows much more than what the naturally-aspirated 2.4-liter can produce.
Now the Nissan has more grunt off the line and instead of falling flat at the top-end it pulls to redline. Although the 240 is nowhere in the performance range where we ultimately expect it to be, it is, however, a start in the right direction. If we are lucky maybe we can even break the 200 horsepower barrier in N/A. Dare we say, SR20 owners beware.