Belt slip has been a problem for superchargers since they were first introduced to internal combustion engines decades ago. There are solutions out there, old tricks included changing to a cogged belt, or adding more belt tension. These days specialized belts, and advanced tensioner designs reduce belt wear and breakage. Having the right supercharger pulley can make all the difference in this area as well.

This past summer the guys over at VMP Tuning introduced their no slip, 2.40-inch supercharger pulley for Shelby GT500’s. This pulley when combined when installed properly, allows for consistent results throughout the boost curve.

VMP recently sent us a video of their installation and testing of this pulley on a 2007 GT500. Using VMP’s supercharger pulley tool, swapping this pulley takes only a few minutes. WIth a new tune loaded, and their Dynojet also setup to monitor boost pressure, the cammed and modified GT500 put down a very healthy 754 hp to the rear tires, and 746 ft-lbs of torque, this was a gain of 22 hp and 12 ft-lbs over the previously installed 2.50-inch pulley.

Proving out that their pulley does not slip when everything is installed correctly, the boost curve is tidy and smooth, belt slip would be indicated by sudden dips in the curve showing a loss of boost due to belt slip. The car gained 1 psi of boost overall in this test, and made more boost significantly earlier in the RPM band, meaning more power under the curve where it’s used the most. According to VMP’s Justin Starkey the shape of the boost curve is also dictated some by the cams installed in this car, which allow for more airflow at higher RPM.

The VMP 2.40-inch pulley for 2007-2012 GT500s is part number VMP24PTVS and priced at just $169.99. They also carry this pulley for 2013-2014 GT500s, as part number VMP24-2013 which runs just $149.99. VMP can also package the pulley with their pulley tool for making easy swaps and changes, that is part number VMP24W90TOOL and runs $249.99 for 2013-2014 GT500s.

For more information, check out the VMP web site, and be sure to check out their Facebook page and YouTube channel as well.