To get the full benefit of cylinder cut-out
you need to close the intake and exhaust valves
during operation too.

Since the 5.7 Hemi MDS system only saves about 10% 'real world'
without closing the valves on your V8 you might only save 4-6%

You can save more than MDS
by installing an overdrive that gets your driveline
so that it takes about 1000 rpm to go 40 mph

Chrysler knows that proper gearing saves more than MDS
but Chrysler also knows that customers want
'instant power'
for climbing hills and passing cars at interstate speeds
and are annoyed by shifting transmissions.
MDS is a customer pleaser, not the best MPG improver, but better than nothing.

If you want to use Chrysler engineering that already exists
to lower your cost of driving...by a lot...
find a compressed natural gas (CNG) 5.2 V8 Dodge van in a junkyard
and retro-fit the computer and drivetrain to your truck.
At a present cost of $7 to 11 per million btu's
natural gas is like buying a gallon of gasoline for 80 to 120 cents per gallon.

more tech info on cylinder cut-out pros and cons:

http://www.autoweek.com/apps/pbcs.dl.../1041/PHOTOS01

http://www.superchevy.com/technical/...dod/index.html

 

Oil flow would still be delivered to all the valves and lifters via the oil pump. shutting off an injector would not cause oil flow problems. however, you have a point about the new lifters. actually, however, they work the opposite way. these lifters act as a solid lifter under normal circumstances. when cylinder cut out is activated, a solenoid opens to deliver a high pressure oil supply to the lifters of the cylinders to be cut out. the oil pressure unlocks the pin, and allows the two separate parts of the lifter to move, preventing the valves from opening. i'm not able to do this on my engine, because it has hydraulic lifters. although it wouldn't hurt anything to run an engine with all the valves opening but no fuel, it would cause what is called pumping loss. pumping loss is power consumed by a dead cylinder. air is sucked in, compressed, and expelled. newer engines close the valves to create a type of air spring. power is consumed, but given back as the cyl decompresses. i think that my project is certainly possible, but after doing some research, i don't think it is very practical, as i would gain fuel mileage from cutting cylinders out, but the pumping loss would take up so much power i would probably not actually see and mpg gain.

 

Doesnt sound to good. You would probably more or less tear your engine up.;

 

Like Hank said, you would have to overcome (release) the compression in the dead cyliners so the engine isn't fighting them. Also, rather than just killing every other cylinder, I would look to the stroke configuration to achieve the best balance. Otherwise she may shake you right out of the seat! And as mentioned, I think 4 cyl. would be a little extreme. Shoot for 6 first if you try this.

 

the reason i would go to four instead of 6 is because it would be more balanced. a v8 trying to be a v6 would shake itself silly without more external balancing. and you would want to cut out every other cylinder to achieve the smoothest running engine. a v8 works the same as a four cylinder, it just has twice as many fires per two revolutions. it's kind of like a circle, instead of 2 revolutions having 4 hits, you have 8, just closer together. cutting out every other cylinder also would cut out 2 on each bank of the engine, keeping it better balanced.

 

"What I'm trying to find out is which four cylinders should I cut out to have the smoothest running engine? Also, what kind of mileage can I expect to gain and if it is even worth it? Anyway, tellme what you think or if anyone has tried something similar to this. Thanks!"

Then it seems you've already figured it out and know where to go. Should work like a charm!
I say go for it. What did you need our input for?

 

Not much input as to what you are doing. But I find this very interesting, if you do choose to go down this road, please please! Keep us updated, I would love to know the outcome.

Personally ive never known anyone to do this, so would like to know.