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RSS Road Sport Supply

RSS Road Sport Supply

RSS Road Sport Supply Underdrive Power Pulley Kits for Porsche Engines

RSS underdrive (power) crankshaft pulley kits offer improved horsepower and torque by reducing drag from the power steering pump, air conditioning compressor, water pump, and alternator without a detrimental effect on ancillary systems for M96/M97 and 9A1/MA1 models. RSS also offers the only harmonic dampened crankshaft pulley for 1997 through 2008 Porsche Boxster, Cayman, and 911 models, providing reduced internal engine harmonics for improved engine performance, efficiency, and longevity.

What are the pros and cons of using an underdrive pulley on my Porsche Boxster, Cayman, or 911?

An underdrive pulley increases engine horsepower by slowing down the engine's accessories including the power steering pump, a/c compressor, alternator, and water pump, all of which sap power at higher rpms. On a street driven car, this can result in poor battery charging, increased steering effort at low speeds, or even increased operating temperatures. However when you track your car and operate the engine at higher RPMs, an underdrive pulley can reduce parasitic drag and improve component life. If you track your Boxster, Cayman, or 911, adding an underdrive pulley, especially one of Road Sport Supply's harmonic dampening underdrive pulleys is an easy upgrade that provides one of the cheapest returns on investment for increasing engine performance with measurable horsepower gains. Just remember, if you use one on your street driven Porsche, the battery will likely not charge at idle and they are not recommended if you drive your Porsche in hotter climates or if driven regularly in traffic as engine cooling is reduced at low engine speeds.

Why do 1997 through 2008 Porsche Boxster, Cayman, and 911 vehicles have issues with their power steering pumps when tracked?

When tracked, Porsche Boxster, Cayman, and 911 models tend to overdrive the power steering pump, resulting in overheating of the power steering fluid. This can result in the power steering reservoir melting and loss of power steering fluid (and steering assist). Worst-case scenario, this can result in an engine fire and serious damage to your vehicle. Installing an underdrive pulley slows down the power steering pump at higher engine speeds to reduce the likelihood of a power steering pump failure.

Why should I use a harmonic dampening underdrive pulley when there are cheaper non-dampening units available?

Starting with the M97.01 3.8, Porsche added a harmonic dampening crankshaft pulley. The purpose of a harmonic dampening crankshaft pulley is to reduce engine vibration. Every time a cylinder fires, that force applied to crankshaft causes it to twist and also causes vibrations. At certain frequencies, resonance can make vibrations even worse, even in a horizontally opposed engine that is inherently balanced. A harmonic dampening pulley absorbs these vibrations. Porsche must have thought it was needed even with M96 and M97 engines having dual mass flywheels that also help cancel out harmonics that can cause engine damage and it is for this reason we recommend using either a factory 3.8 harmonic dampening pulley or an RSS harmonic dampening underdrive pulley.