COMP Cams Cam Phaser Limiter Kit 2009-Present GM Gen IV VVT Engines Includes:

Cam phasers are specially designed, computer-controlled cam gears that automatically optimize camshaft timing based on engine RPM. They are currently used in all 2005+ Ford Modular 3V and 2007+ GM Gen IV VVT (Variable Valve Timing) engines, as well as 2011+ Ford 5.0L DOHC Modular 4V V8 Ti-VCT engines. Engine oil is pressure fed to the phasers through passageways in the cylinder heads and cams. The engine's computer controls solenoids that adjust oil flow into and out of the phasers control chambers, giving the ability to retard the cams.

While this technology provides fuel efficiency and the ability to always be in the best position for maximum power regardless of engine RPM, it does present some limitations when it comes to performance cams. With such a wide range of valve timing movement, there is very little piston-to-valve clearance, which limits you to small cam profiles with little overlap.

Comp Cams Cam Phaser Limiter Kits for Ford Modular 3V engines and 2007-Later GM Gen IV VVT engines restrict the range of cam timing movement (20° for Ford and 22° for GM), thus providing the necessary valve clearance for serious performance cams with tighter lobe separations (while still utilizing the benefits of VVT technology). Cam Phaser Limiters for the 2011+ Ford 5.0L 4V Ti-VCT engine limit the cam phasing to 25 crank degrees (12.5 cam degrees) while the Cam Phaser Locks for that same engine allow fully adjustable locking over the OE phaser range (50°). The resulting upper-RPM gains from using Comp Cams Cam Phaser Limiters or Locks are some of the largest from a camshaft swap without sacrificing any bottom end or mid-range performance.