Originally designed for about 100 horsepower, the factory cam gear to cam interface on the VW/Audi engines struggle when subjected to serious power. Larger camshafts and stiffer valve springs will add more stress on this area. Even with an ARP cam gear bolt, this interface can become taxed and allow the cam gear to slip around under high torque, and come loose. This leads to wear between the surfaces, and shortly thereafter complete failure of the bolts and joint. This ruins the cam gear and camshaft, and can even damage the surrounding components. In order to fight this we had EKagrip make some of their patented nickel and diamond coated friction shims. These shims increase the friction between the two components by up to 3 times what is seen with regular aluminum on steel contact. This greatly increases the load which can be carried. The shims are .008" thick, and do not cause any alignment problems with the cam/cam gear. An absolute must for any engine making 450+ ft-lb with increased stress on this interface from larger camshafts and stiffer valve springs Increases friction by up to 300% Fits 8V/16V/20V VW/Audi cam gears A must for high HP engines