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PRO/SPORT Underdrive Damper - Chevy LS Series
PRO/SPORT Underdrive Damper - Chevy LS Series

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Technical Specs

PRO/SPORT Under Drive Dampers & Pulley Kits feature :

  • 25% Underdrive
  • SFI Spec. 18.1 Bonded Harmonic Damper
  • High quality ńAll Steelī construction
  • Robust outer ring retention design
  • Spin tested to 12,500 rpm
  • 60° precision engraved timing marks
  • Clear baked paint finish

The PRO/SPORT Under Drive Dampers

Accessory drive systems have been made more compact on Late Model V8 engines like the Ford 4.6L and the GM LS1 by machining serpentine belt grooves on the OD of the crankshaft damper. The crankshaft damper functions as a combination crank damper and crank pulley on these engines. Under drive dampers are smaller in diameter than stock production crank dampers which slows the speed of the accessories and reduces the HP required to drive them. Since performance and racing engine applications generally run at higher RPM, the water pump, alternator and power steering pump speeds can be reduced to save HP and still meet engine cooling, electrical and vehicle steering requirements.

The trick is to reduce the crank damper diameter without losing the torsion control capability required to prevent engine vibration and possible damage. The PRO/SPORT Under Drive dampers have been specially tuned to control crankshaft torsional vibration to stock production levels.

Dynamometer tests of the PRO/SPORT 25% under drive damper on a 2005 Mustang 4.6L 3V engine at Livernois Motorsports in Dearborn Heights, Michigan produced a 13 HP gain over a stock production damper.


  • 25% Under Driven front Poly-V groove accessory drive
  • 22% Under Driven rear A/C Poly-V groove on 98-05 Camaro & Firebird & 04-06 GTO LS1 & LS2 models
  • 7% Under Driven rear A/C Poly-V groove on 97-06 LS1, LS2 & LS6 Corvette models
  • Steel Alternator Pulley finished in black powder coat (where supplied)
  • Keyway

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Harmonic Balancers > Chevrolet - LS-Series V8
Make > Chevy