Check these sites out, it tells how Displacement on Demand works. It is amazing that it can do this seemlessly..I wondered how it worked..

http://www.superchevy.com/technical/.../0405sc_gmdod/

http://www.greencarcongress.com/2005...ands_depl.html

 

GM tried this 30 years ago on the Cadillac and it failed miserably. PCM's have come a long way since then and make this process able to work now. Although IMHO I don't like it and don't trust it. You don't buy a V-8 or big V-6 for gas mileage. If you do, then you're buying it for the wrong reasons. Just my .02 worth but good article none the less.

 

I agree with Cain45 in the above post. I also read a review in a Popular Mechnics magazine or a similar magazine which explained how much extra internal wear DOD or similar so-called gas mileage saving techniques created on engines. Honestly, I believe it. It's the same thing that happened on the early-mid 80's Cadillac V8-6-4's. They just added to the amount of wear on those engines by switching from 3 modes instead of 2 like the Monte SS engine.V8 mode, to V6 mode, then finally to 4-cylinder mode. Plus, unless you have the Cruise Control on, the cylinders will continuously keep stopping and starting again with the changes in throttle inputcreating even more premature internal wear on the engine. Alot of Caddy V8-6-4 owners disconnected some type of wiring harnesswhich made the enginestay in V8 mode constantly. I wonder if the same can be done with the 5.3L DOD engines in the Monte, Impala & GXP. I'd like to know since despite it having been tested 2 decades ago,DOD cylinder deactivation isstill relatively new and not the most proven piece of technology IMO.

 

I think this may just be the start of it. Lets face it tones of people want to have sports car speed, but don't want to pay the gas.

I'm sure this won't count for my Future Telling merit badge, but I forsee gas prices starting toraise higher in the next few years. The truck market has been taking a nose dive as it is with people purchasing SUV's and being denied options. I would personally love a full sized truck to help me tow the boat and a few other things, but I make due with my Blazer. If I could get that kind of V8 power when I needed it and dropped down to 4 when I don't need it - going to work every day - I would gladly use it.

I'm sure this is just in it's test phases right now on the general public and will make it's way into trucks shortly. For the Monte's I would like to see more continued use of turbos for these functions. Lets face it the supercharger has way too much parasitic loss; the turbo can produce more power and save gas in the long run.

 

I am a GM tech, and this system is completly different from the old system. I see a tremendus advantage over the Cady system. I do not see where you would get any extra internal wear and tear on the engine. Everthing still moves except the valves. It is hydraulically controlled, not mechanically as the Cady was.

When it switches modes, you do not even know it. The only way to tell is by the use of the scan tool.

 

I totally agree with Red Baron, it is a seemless act. The only way you know that the car switches is if you get on it and it switches out of 4 cyl mode. Or you are like my **** retentive *** and watch it in instant economy all the time.

 

The advancements made in this technology are part of the reason why GM has now added their 7yr/100K warranty. I can't see them warrantying a vehicle with that kind of tech if they didn't think it was ready.

I'm of the same mind too. I hate to have too many frills on a vehicle, not a big fan of the "all options" wave. Power seats, sun roof, all that kind of stuff.I prefer manual seats and the like. I was even perturbed when I bought a new stove recently and the oven controls were digital sensors on the screen, not a physical ****. I like to be able to adjust things manually. Power door locks and windows is about as far as I will go.