Steeda Underdrive Pulley Set Mustang 4.6 2V 2001-2004

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  • Slow Down By About 25%
  • Reducing Parasitic Drag
  • Increase Up To 10 Horsepower
  • Increased Gas Mileage

Steeda Underdrive Pulley Set for 2001-2004 GT Mustang with a 4.6 Liter 2V Engine.

Steeda's underdrive pulleys slow down accessory speed by about 25%, reducing parasitic accessory drag on the engine. This drag reduction results in an increase of up to 10 horsepower and increased gas mileage! Get back the horsepower and torque your belt driven accessories steal and start enjoying better performance and gas mileage today! Steeda uses the latest technology directly from O.E. sources. Steeda's crank pulley is a one piece nodular iron, injection molded rubber design.

Features & Benefits:
- Slow Down By About 25%
- Reducing Parasitic Drag
- Increase Up To 10 Horsepower
- Increased Gas Mileage

Please Note: Midway through the production run for the 2001 model year Ford changed the design of the water pump on the 4.6L engine. The older style pump produced from 1996 to mid 2001 had a longer shaft. In January of 2001 the design of the pump was changed to a shorter shaft. This necessitated a change in the design of the pump pulley.

California Residents: Proposition 65 Warning

Note: This item is not CARB (California Air Resource Board) exempt and is not legal for sale or use in the state of California.

Installation Videos

Video Transcript

Underdrive pulleys have always been a popular way to add a few extra horsepower to your Mustang. Basically, what they do is underdrive your accessories, by doing that it slows down the parasitic drag on your engine and in turn creates horsepower. We’ve already done quite a few basic bolt-ons to our 2003 Mustang GT. Today we’re going to continue that trend by installing these Steeda underdrive pulleys.

The underdrive pulley set consists of a water pump pulley, an alternator pulley and in the case of the Steeda a completely new crankshaft damper. There’s a lot of kits on the market that just use a bolt-on pulley which isn't as safe as using an entirely new SFI proof damper, so we’re going to go with that with our installation.

You can use all of your factory hardware with the exception of this bolt. This is designed just to get the crank pulley started before reinstalling the factory bolt which we’ll explain during the installation.

This particular kit’s going to fit your mid-2001 through 2004 two valve GT. The installation for the ‘96 through mid-01 is exactly the same, but the difference is the water pump pulley. If your factory water pump pulley is concave like this aftermarket pulley is that’s going to use the mid-01 and up style. If it’s actually higher up where the bolts are actually extended beyond the face that’s going to be the ‘96 through early ‘01 style.

For this installation you need a lift or a jack and jack stands, impact gun, ½ inch ratchet, 3/8 ratchet, 24 mm socket, 19 mm deep socket, 18 mm deep socket, 10 mm socket, swivel, torque wrench and a pulley puller.

We’re going to be replacing the alternator pulley, the water pump pulley and then the crankshaft damper. We’re going to start by loosening up the pulleys; then take the belt and then go underneath the car to remove the damper.

Now, we’ll loosen the water pump bolts. Now, you can use the 3/8 ratchet to remove tension from the tensioner and just slide off the alternator pulley. We’re going to remove the bolts and remove our water pump pulley as well.

Now you’re going to install your new alternator underdrive pulley. You want to take a look in the center of the pulley. Sometimes when they get powder coated powder coat gets in there and it may not slide over the alternator easily if you have to just clean that out first then it’ll slide right on.

We’re going to install the Steeda water pump pulley. Just make them hand tight and make sure you remember to tighten them back up once you put the belt back on. Now we can move under the car. We’re going to remove the bolt that holds on our harmonic balancer. If you have an automatic transmission car you’ll have to actually hold the torque converter so the engine doesn’t spin. On a stick shift car you can simply put a wrench up in there and remove it.

To remove the crankshaft damper you will need a puller. These are available pretty inexpensively at any parts store; you can also rent them at a lot of places. Before you try to remove the crank pulley a lot of times it’s easier to put the factory bolt only back in then we can push against that to pull off the pulley.

Once you get the crank damper off then go back and remove the bolt. You can see the supplied Steeda bolt next to the factory bolt. This bolt is just to get the crank pulley started. You want he use it to get it seated; once it's seated you’re going to remove this and reinstall the factory bolt.

Before you install the new crankshaft damper you want to put a dab of a high silicone gasket and sealant right inside the key way. Line the key way up, again, use the original washer and the Steeda supplied bolt. Now, we can start to tighten it down. You’ll see the pulley start to walk on towards the block. Once you get in a little bit, maybe a quarter of an inch, you can remove this bolt and reinstall the factory bolt. Now, we’re going to install the factory bolt with the factory washer. Make sure you get a bunch of threads and know its right.

Once you get the factory bolt threaded in you’ll want to grab your torque wrench. Ford revised the torque specs for the crank. The new torque specs for ‘98 through 2003 is tighten it to 66 ft-lbs, one full rotation loose, then re-tighten it 37 ft-lbs and a quarter rotation tight.

You want to get the belt roughly back in place where it’s going to go. Now, we’ll go up top release tension from the tensioner and put the belt place. Make sure everything is seated on the pulleys where it needs to go. We’re going to put tension back on the belt and make sure everything’s lined up where it belongs. Now, we can tighten down our water pump bolts and our installation’s finished.

Underdrive pulleys are a great way to add some extra horsepower without any real side effects. In the case of this install, I would suggest keeping your stock pulleys though. A lot of times when you upgrade people throw the stock parts away. In the case like this If you would ever go to a centrifugal supercharger you’re going to need your stock pulleys back. The installation’s pretty straightforward, probably take you around in hour and should be back on the road in no time.

Vehicle Fitment

This product will fit the following Mustang years:

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