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Watercooled Parts & Upgrades

RSS Underdrive Harmonic Dampening Pulley & Wrench Kit 97-08 Boxster Cayman 911

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RSS Underdrive Harmonic Dampening Pulley & Wrench Kit 97-08 Boxster Cayman 911


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SKU: 608

The RSS Harmonically Dampened Underdrive Pulley is ideal for engines that are running light weight flywheels, engines that are built - bored/stroked, and engines that are driven hard. Porsche used a harmonically dampened crankshaft pulley on all 997 3.8 models, so we recommend them on all engines for both street and track use.

Offers improved HP & TQ by reducing drag from the power steering pump, A/C, water pump and alternator without detrimental effects on said ancillary systems. Dampens/reduces internal engine harmonics for improved engine performance, efficiency and longevity.

Fits on all Porsche 986, 996, 987, 997 models EXCEPT 2.9L (multi hole crank pulley pattern), DFI engines, GT2, GT3 and Turbo.

Installation tool (wrench) and new OEM Pulley Washer included:

Dyno Image shows HP & TQ gain on 2005 997.1 Carrera S:
Baseline Dyno Run Mods: OEM Crank Pulley, OEM Software, Cargraphic Headers, Hi flow 200 Cell Cats, and Medium Sound Cargraphic Sport Mufflers
Modified Dyno Run: Added RSS Pulley (Part #608) to baseline car with existing mods:
+16 HP / +8 ft lbs TQ

*NOTE: We recommend using/sourcing a new OEM Crank Shaft Pulley Bolt for your specific vehicle when installing the RSS Pulley. (Not Included with 608 Kit)

We recommend using the appropriate length belt RSS # 6PK (sold separately).


Additional Information

Brand RSS

Important Seller's Note

The Seller, hereby expressly disclaims all warranties either express or implied, including any implied warranty of merchantability or fitness for a particular purpose, and neither assumes nor authorizes any other person to assume for it any liability in connection with the sale of this part(s) and/or service. Buyer shall not be entitled to recover any consequential damages, damages to property, damages for loss of use, loss of time, loss of profits, or income, or any other incidental damages. In addition, expressly excluded is any liability for defects pertaining to safety or performance, by way of ‘‘strict liability’’, negligence or otherwise. In the event of non-payment, the Buyer agrees that the costs of collection including court cost, and reasonable attorney’s fees, shall be recoverable from the Buyer. The Buyer has read and with any transaction, agrees to all of the terms and conditions in connection with the Seller.

Terms: • All Returns/Exchanges Require Written or Verbal Pre-Authorization and RMA Number. • Positively No Exchanges Without This Invoice. • No Refunds On Opened Packages Or Used Parts. • Items Returned Must Be In Original Packaging. • No Refunds On Special Orders. • No Return On IMS Parts. • No Refunds After 30 Days. • 25% Handling Charge On All Returned Items. • No Returns On Electrical Parts. • Refund On Purchases Paid By Check Are Refunded After Check Clears. • Limited Lifetime Warranty on NSC plating provided by Millennium Technologies LLC and subject to their terms and conditions. • There is no warranty on blocks processed with the Nickies Lite direct plating process. • Any Damage Must Be Reported to the Shipper and LN within 24 Hours of Receipt.

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Questions or comments? Feel free to contact us before ordering. Open a service ticket, call 815.472.2939 or email