You're ready to tune your Hemi, or you already have your Hemi tuned. All is great, but what about that cam phaser thing? What is it? What does it do? How can you use it to your advantage? When Dodge started utilizing Variable Valve Timing (VVT), it was for various good reasons, and during our tuning process, we can use that for our own good reasons, too. Of course, the number one being more power!
One, what is Variable Valve Timing? VVT is a process many manufacturers use in their internal combustion engines to improve emissions, fuel economy, and power output. There are all kinds of versions and ways to do this, dating back into the ’80s on Asian vehicles. A series of mechanical and hydraulic pieces tailored with solenoids controlled by the PCM takes care of this action.
Two, VVT controls the camshaft(s) in internal combustion engines. The VVT Phaser replaces a simple camshaft sprocket. So, now the camshaft has the option to advance or retard the mechanical timing. Thus, giving us the option to 'phase' the cam for our own power benefits. At certain times the vehicle could benefit from advancing the camshaft to create higher TQ numbers. In higher RPM’s, it might be beneficial to retard the mechanical timing to get better HP.
A time not too long ago, we could get one or the other, retarding the camshaft, or advancing it, so we only got one benefit: better TQ or better HP. You had to choose one. Now, we can phase that camshaft both ways, giving us the option to decide and find out what is best for the application during the tuning process.
Three, during the tuning process we adjust things such as our fueling, ignition, throttle controls, and more. But now that we have the option to adjust VVT, it adds to the list of things we can adjust to maximize engine power. Our “Dodge Tuning Guide” teaches what you can do with VVT, and offers a process to use that is safe, repeatable, and can get the desired extra power. Take a look at the dyno graph below.
This is a before and after a run for a 6.4 Hemi with VVT adjustments only using our process. The black run is tuned, but no VVT adjustments at all. The red run is the same tune but adjusting the VVT Phaser with our Dodge VVT Tuning Process. You can notice some significant gains from one single adjustment in the tune.
Once upon a time, that was a gain no one could get, but now…. it's free for the taking!