When you're looking for more performance out of your late model muscle car you can spend your time and a lot of your hard earned dollars for a few more horses under the hood. Most bolt-on mods are simply trying to increase the engine's air-flow capacity and efficiency, usually resulting in marginal gains. But what if you have already done all of that? What's next? A super charger? Nitrous? How about freeing up some of the horsepower that is already there, but being consumed by your car's accessories driveline?

Steeda's Underdrive Pulleys may just be the answer you have been looking for. Reducing the size of the motor's crank pulley allows accessories such as the alternator, air conditioner compressor, power steering pump and water pump to operate 25% slower than their original speeds. This saving in parasitic accessory drag increases your vehicle's horsepower and torque to the wheels, resulting in a gain of up to 10 horsepower and increased fuel efficiency.

Steeda has done their homework and was the first aftermarket manufacturer to achieve SFI approval of their underdrive pulleys for all 4.6L engines. According to Steeda, their underdrive pulleys are the only pulleys engineered through a partnership with the OEM Manufacturer. This means the pulleys have been designed, from the ground up, with the proper torsional vibration dampening characteristics for the engine.

The Installation

Before we start the installation there are a few things to note. You will need a calibrated torque wrench, high temperature silicone sealer, and a three prong puller to complete the installation. If your car is an automatic transmission, you will also need an impact wrench to get the crank shaft pulley retainer nut loose. The directions also state that you should jack the car up to perform the installation, but I found that was not required once I removed the cold air intake (CAI) from the throttle body.

1: Verify that your kit has all the parts included. The kit comes complete with a smaller iron crank pulley, an oversized water pump pulley, a new mount bolt, a longer seating bolt, a replacement alternator bracket bolt and the instructions.
2: Remove the air intake, this step isn't required but makes for a much easier installation when you are not fighting the OEM rubber intake tube or a cast CAI tube.
3: With the car in gear and the hand brake applied, remove the crank pulley retaining bolt.
4: Next, loosen the bolts that hold the water pump pulley to the water pump. Note: Steps 3 & 4 must be done with the accessory drive belt installed, unless you using an impact wrench.
5: Using a half-inch socket driver or breaker bar, apply downward force on the belt tensioner to release pressure on the accessory belt.
6: Maintaining pressure on the tensioner, slide the belt off of one the pulleys and then remove it from the engine bay.
7: Remove the retainer bolts for the water pump pulley and then remove the pulley from the water pump.
8: With the water pump pulley removed, loosen the alternator's lower right retainer nut and remove the stud. A 7mm socket is required to remove the stud.
9: Replace the alternator's retainer nut and stud assembly with the supplied alternator bolt and washer from the Steeda underdrive pulley kit. Note: In the example image the black bolt from the kit is missing the washer, which was added later.
10: Using a three prong puller, start removing the crank pulley from the crank shaft. Note: Verify that your three pronged puller is positioned properly on the crank pulley. This will ensure nothing is damaged during the pulley removal process.