I can't remember what it is called when on the highway up to speed the engine stop using a number of cylinders to increase mileage. Anyone know if this can be retrofitted and does dodge/cummins have this in new trucks?

 

On the Hemi, Dodge calls it MDS, Multi-Displacement System. It shuts down 4 cylinders to improve mileage when the power isn't needed. Not available on CTD. There is more to it than just computer programming. I'm pretty sure you don't want to shut down fueling to 1/2 of the cylinders on a CTD.

 

Thanks for the answer I figured it was something like that

 

i dont think it would run very smooth

 

on variable displacement engines, the valve train on the engine uses electric solenoids and/or linear actuators for the push rods, or on the Lexus system there is no cam, the valves are completely moved by actuators. This gives variable dwell, valve timing and displacement. The valves are held open so as not to require power to compress the air in the cylinder that is not being used. Not much to go wrong on those systemes eh?

 

Remember when Cadilac put out the 4-6-8 back in the 70s?? Nobody could make it work right and they dumped it. But with todays computers and the electronic actuaters instead of cams it should be more succesful. Untill the actuaters start to go bad. But then injectors work.???

 

The Hemi "C" motor does have a cam..

http://www.allpar.com/mopar/new-mopar-hemi.html

 

All those in favor of saving fuel raise your right foot.

 

Second what Boatnik said!!