4-inch Underdrive Pulley

You will need access to the engine compartment.

• Boxster & Cayman – Remove the rear wall cover behind the seats.
• 911 Carrera – Disconnect your MAF sensor from the air filter housing. Remove your engine air filter housing.

Now you will see your engine drive belt. Locate the tension roller and turn it clockwise to release the belt tension. Remove the belt.

Remove the original crankshaft pulley using the Porsche crankshaft pulley tool (not provided with kit). The pulley tool can be picked up from any local Porsche dealer. Part number # 000 721 928 51.

Once you have the factory pulley removed, you will notice a boss protrusion. In order for your new pulley to fit properly, you must modify this protrusion. This is necessary – failure to do this step will cause damage to the new pulley and warranty will be voided. You can use a dremel, hacksaw or any tool you deem perfect for trimming down the protrusion. Below photos show the original crankshaft pulley (#1), and the boss protrusion that needs to be trimmed down after it is removed.

<< This is how the protrusion should be cut to have clearance for the new under drive pulley to fit.

Failure to cut this protrusion will not allow correct fitment.

Install the new under drive pulley in position. Make sure to use the new bolt that is provided with the kit, do not re-use the old bolt (discard it). Apply red thread lock to new bolt (supplied with kit). If you are missing these components please contact us.

The new bolt has a two-step torque process:

• Step 1 – Torque to 50Nm.
• Step 2 – Turn an additional 90 degrees.
• DO NOT OVER TORQUE.

In order to hold the pulley in place while tightening down the bolt to prevent the engine from turning follow these steps (if you do not have a pulley holder tool):

• Manual transmission cars – Put the vehicle into 5th gear with the handbrake engaged.
• Automatic transmission cars – You will need to lock the flywheel in place, this can be accessed from under the vehicle.

Install the new serpentine belt provided. The belt is specific length for vehicles with A/C (6pk2070) and without A/C (6pk1890). Your original belt will not work. Position the belt by removing the tension off the tension roller in a clockwise direction, install the belt and allow the tension roller to slide back to its position.

Crank the vehicle and ensure everything is working correctly.

Reinstall the rear wall cover and tighten (on Boxster / Cayman) / Reinstall the air filter housing & connect MAF sensor (on 911 Carrera).

Go for a test drive!