Kong Billet Dual Idler Belt Tensioner (LS9)

Although the Supercharged LS9 engine on the C6ZR1 has an 11 rib belt driving the supercharger, in many cases it is not enough to prevent belt slip. Smaller than stock pulleys, combined with inadequate belt wrap from the factory is a recipe for belt slip on the ZR1 that we have seen and been dealing with for many years. The best solution up to this point was fighting to install the tightest belt possible while frequently changing belts to keep belt slip to a minimum. 

Aside from belt slip, the OEM tensioners have been known to fail for a variety of reasons.

We took all of these issues into consideration and decided a new tensioner was necessary with a complete design overhaul. Performance, durability, and appearance were all taken into account during the design process to come up with the best possible alternative solution for a belt tensioner. See comparison which shows an additional 55 degrees of belt wrap in the middle of the belt travel. This massive increase in wrap will slow down belt wear, and allow for use of pulleys all the way down to 2.175"

Key Features:

• All 6061 billet constriction (much stronger than the stock unit). 
• Increased tension over the OEM tensioner. 
• Increased tensioner travel
• Lockout bolt for easy belt install.
• No modifications needed for install.
• Simple bolt on installation. (5-10 minutes)
• Reuses the factory hardware for mounting. (Three bolts)
• Lifetime Warranty

SMG ordering and fitment notes

This Kong Performance catalog item is supplied for the applications described above. Verify the exact vehicle, engine, supercharger, bolt pattern, finish, pulley ratio, and supporting hardware before ordering. Contact SMG before purchase when the combination is unusual or when the product requires machining, calibration, or another Kong component.

Processing and shipping

Processing occurs before shipping. Kong products may be special-order or vendor-fulfilled and can require additional handling time before carrier pickup. Expedited shipping changes transit time after shipment and does not shorten manufacturing, machining, or order processing. Any product-specific lead time or availability note above takes priority.

Installation responsibility

Performance components should be installed and calibrated by a qualified professional. The purchaser is responsible for verifying compatibility, safe operating limits, emissions legality, and suitability for the intended vehicle and use.