2009+ 5.7 Hemi Eagle

Interesting read on the phaser limiters:

"Chrysler 5.7L and 6.4L engine cam phasers, how they work, their limitations, and how COMP uses them for making more power
What are cam phasers?
Chrysler’s cam phasers are specially designed, computer controlled cam gears that have the ability to adjust camshaft position while the engine is running. They are used on all 2009 5.7L and 2011 6.4L newer engines.
How do they work?
Engine oil is pressure fed through a series of passageways in the cylinder heads and camshafts, out to the cam phasers. The engine computer controls a pair of solenoids that adjust this oil flow into, and out of, a series of chambers inside the cam gear. Located inside these chambers are vanes, attached to a spring-loaded central hub. The hub is directly attached to the camshaft, and as oil is allowed into and out of these chambers, the position of the cam can be retarded up to 38 crankshaft degrees.
Why did Chrysler put them in the engine?
Chrysler’s primary reason for using cam phasers was to increase the engine’s efficiency by reducing its pumping losses. Basically, when the cams are retarded 15-30 degrees, during part throttle engine operation, it takes less power to turn the engine over. This helps to increase the engine’s fuel efficiency, but an additional power benefit is also realized by being able to position the camshaft for maximum power, regardless of what rpm the engine is running at. This results in an engine that makes more torque and horsepower and extends the high rpm power-band by an additional 800-1000 rpm.
Why should I modify the cam phasers with COMP’s limiter kit?
If there is a downside to the cam phaser as designed by Chrysler, it is that they have such a wide range of movement. Since the cam can theoretically be retarded by up to 38 degrees, there is very little piston to valve clearance in the engine. This minimal piston to valve clearance limits us to fairly small cam profiles with very little overlap; not the best for making maximum power or achieving an aggressive idle sound.
What does COMP’s cam phaser limiter kit do?
COMP’s Cam Phaser Limiter is a precision made spacer that installs into the cam gear’s oil chambers. This spacer takes up excess volume that would normally be used by the factory cam gear for movement. By installing cam phaser limiter, the cam design window opens up, allowing you to install big, powerful camshafts with safe piston to valve clearances. At the same time, by keeping up to 14 degrees of movement available, all of the wide-open throttle benefits of the cam phasing can still be retained. The normal maximum retard the cams see at wide-open throttle is only around 9 degrees with factory programming.
Why can’t I just reprogram the ECU to limit cam phaser movement?
Since Chrysler’s factory engine computer is programmable, the question arises as to why you can’t simply program in the limits and not bother with mechanically limiting the cam phaser. Theoretically you could do that, but a problem arises if something happens that would cause the engine’s rpm to shift faster than the cam phaser controls can react to. For example, if you ever missed a shift, broke a driveline part, did a clutch dump on a sticky set of slicks, or anything that could for a split second cause the cam phaser to get out of its programmed limit, the valves could crash into the pistons. By
mechanically limiting the maximum movement of the cam phaser, total engine safety is assured when running a big performance cams in these engines.
Do I have to reprogram my engine’s computer after installing COMP’s Cam Phaser Limiter Kit?
Yes, you MUST have your engine’s computer reprogrammed for the engine to operate properly after installing the cam phaser limiters. The Chrysler factory computer does a diagnostic sweep test of the cam phaser upon start-up. If the computer cannot get the cam phaser to reach their programmed maximum limit, an error mode occurs. When reprogramming your computer; just make sure that the maximum retard amount entered for any of the cam phaser tables in your tuning software does not exceed 14 degrees."

http://www.challengerforumz.com/archive/index.php/t-83250.html