2013 5.7 HEMI’s and up have VVT. All it does is drop down to 4 cylinders for supposed to get better fuel economy. I’ve had both VVT and none VVT and all I can say is VVT is a joke. When it goes to 4 cylinder mode the running 4 cylinder that are running have to drag the non running cylinders plus the weight of the truck/car. On top of that. Half of the motor will wear faster than the other half do to VVT. The VVT has a split cam. When your VVT equipped HEMIs are at idle that’s why they sound funny. It’s only idling with 4 cylinders.
Not quite.
VVT is variable valve timing and refers to the ability of the engine to adjust valve timing on the fly to a certain extent via the cam phaser. All 2009 and up 5.7L Hemis have VVT. These versions of the 5.7 do not have exhaust gas recirculation (EGR) like the 2003-2008 5.7s do because NOx emissions can be controlled via valve timing.
The cylinder deactivation you are referring to is called MDS-multi displacement system. This is entirely different from VVT and is found on versions of the 5.7 in the Dodge/Chrysler/ Jeep cars and SUVs with automatic transmissions. There are two versions of the 5.7 that have VVT and not MDS-they are in the HD Rams, and the Challengers with the 6 speed manual transmission.
Furthermore, Ram 1500s have had MDS since 2006,
before the 5.7 had VVT.
So:
-MDS and VVT are different
-MDS debuted in 2005 in cars and 2006 in trucks
-HD trucks have never had MDS in the 5.7 (6.4s in the HD trucks do)
-VVT debuted in 2009 in the 5.7
-There are 5.7s with MDS that do not have VVT
-There are 5.7s with VVT that don't have MDS
When 4 cylinders are deactivated (MDS is engaged), the only difference is the injectors don't fire for those cylinders, the lifters disconnect for those valves, and the spark plugs don't fire in those cylinders. The valvetrain and pistons continue to get oil and the pistons continue to reciprocate; so no, it doesn't "wear out half the engine twice as fast." I am not sure what you mean by a "split cam" but I am going to assume you didn't mean that there is a preload ramp built into the lobe profile on the MDS lobes to take out slack from the deactivated lifters as is actually the case. Lastly, MDS is disabled:
-When ERS mode is engaged to lock out certain gears
-Above 85 MPH (good luck keeping a light enough load on the engine at those speeds for it to engage anyway)
-Below 15 MPH; so again, no, trucks with MDS do not idle on 4 cylinders, they idle on 8.