Displacement On Demand...

[98 Z71 SLT]

I'm just getting "up-to-par" on the '07 NBS pickups. I'm a little leery on the DOD system.

Can it be manually turned off? Possibly thru the D.I.C.??

[HuntingEd]

nope, i dont think it can.

 

Outta Curiosity, what makes you so leery of it?

[redvett]

The Active Fuel Management system is more internal in the engine. The oil system unloads the selected lifters & the PCM shuts off the injectors to these cylinders at the same time.

Cutting your fuel economy would be fuelish.

[98 Z71 SLT]

As far as beeing leery of it??

 

YES, I KNOW technology has come a long way...but remember all those early-80's Cadillacs with the digital fuel injection?? Remember...they would cut off to 4 cylinders on the highway?? Remember all the problems with all that stuff??? Seems like they were always towed to the shop...

 

...running on just 4 cylinders

[redvett]

Boy Where have you been? Computers have much more memory & speed. The 80's cars were crude by todays standards infact the new GM vehicles have a faster computer than probably your personal PC. Those old computers couldnt tell if something was wrong & now the OBD2 can diagnose almost everything even if its gone bad its self.

If your worried about computers being bad/slow you better get rid of everything you have thats run by them. PC's,Ipods,TV's,GPS, and much more is run by computers.

This is the modern world and technology marches on.

[overlord1]

Boy Where have you been? Computers have much more memory & speed. The 80's cars were crude by todays standards infact the new GM vehicles have a faster computer than probably your personal PC. Those old computers couldnt tell if something was wrong & now the OBD2 can diagnose almost everything even if its gone bad its self.

If your worried about computers being bad/slow you better get rid of everything you have thats run by them. PC's,Ipods,TV's,GPS, and much more is run by computers.

This is the modern world and technology marches on.

 

This is all true but the improvement in fuel efficiency is neglible compared to non-DOD trucks as I understand it. I honestly don't see how the miniscule MPG improvement is worth the potential failures, especially when one is out of warranty and has to foot the bill. I see this more as a gimick than anything else. Now if the improvement in fuel economy were 50%, then I'd be a believer too

[redvett]

With the greenhouse gas issue hot on everbodys minds the MFR,s are out of cheap options the improve emissions/fuel economy and dont be suprised if down the road in a couple of years all the MFR's will have to charge at least $5000 a year for enviromental costs. Horsepower increases are just about over. GM has delayed all RWD passenger programs for the foreseeable future.

[caddycruiser]

Really, there's nothing about the system to be leery about anymore, and in all reality, it only kicks in few enough times to even think about it--except your mileage will boost a tad when it does.

 

In theory, there may be a possibility to detune it from working, but it would likely be quite involved--there's so many other parameters tuned to work with the AFM/DOD--that it would take some work, or at least a lot more so than just unchecking a box on the PCM program.

 

If you haven't driven a new truck so equipped, do so, and if you have, you probably noticed there's not even a single tell-tale sign of when anything has changed. They log millions of hardcore testing miles and revisions, and the chance of there being any related failure is really slim to none.

[HawkeyeOC]

I have nearly 10,000 miles on my '07 NBS Sierra with DOD. No reason to be leary. I fact if it were not for the display on the DIC telling me whats going on, I would not even know it's there.

 

Get used to it...it's showing up in a lot of new cars and trucks!

[Mr.Dizzleman]

I think it has the biggest impact on highway driving. last weekend i drove to my parents house which is about 40 miles from Phoenix. and i got 18.8 miles per gallon. i get like 14.5 around town driving. it works best in highway because it kicks in when you coast on good flat piece of road.

[pm26]

I'm just getting "up-to-par" on the '07 NBS pickups. I'm a little leery on the DOD system.

Can it be manually turned off? Possibly thru the D.I.C.??

 

Yes, it can be manually turned off. When you shut off your engine.

[pm26]

Cutting your fuel economy would be fuelish.

 

Fuelishly foolish!!!!!!

[pm26]

Boy Where have you been? Computers have much more memory & speed. The 80's cars were crude by todays standards infact the new GM vehicles have a faster computer than probably your personal PC. Those old computers couldnt tell if something was wrong & now the OBD2 can diagnose almost everything even if its gone bad its self.

If your worried about computers being bad/slow you better get rid of everything you have thats run by them. PC's,Ipods,TV's,GPS, and much more is run by computers.

This is the modern world and technology marches on.

 

This is all true but the improvement in fuel efficiency is neglible compared to non-DOD trucks as I understand it. I honestly don't see how the miniscule MPG improvement is worth the potential failures, especially when one is out of warranty and has to foot the bill. I see this more as a gimick than anything else. Now if the improvement in fuel economy were 50%, then I'd be a believer too

 

My sentiments exactly. I have made very similar comments on this system a while ago. Fuel savings are not worth the increased mechanical complexity and higher failure probablity and increased maintenance down the road.

[pm26]

As far as beeing leery of it??

 

YES, I KNOW technology has come a long way...but remember all those early-80's Cadillacs with the digital fuel injection?? Remember...they would cut off to 4 cylinders on the highway?? Remember all the problems with all that stuff??? Seems like they were always towed to the shop...

 

...running on just 4 cylinders

 

Those were the 1981 models only.

1980 models had a simple carburated 6.0 liter V8 engine with a 4 BBL carburetor, good for only about 150 HP(my father had one of those). Then, in 1981 they introduced the DoD system, which was new and very crude, and a source of constant problems. Fortunately, there was a way to deactivate and remove the system, which is what was ultimately done to most of these vehicles. Believe it or not, they even had an optional 4.0 liter V6 engine with a 4 barrel carburetor and a whopping 110 HP available in that car! And what a joke it was! The car was so underpowered, it barely got out of its own way. In their quest to improve fuel economy and retain some semblance of performance, in 1982 they got away from the DoD concept altogether and introduced the small displacement V8 - 4.1 liter or 250 cu in version. These cars too were woefully underpowered with this engine becuase it only put out something like 125 HP.

 

I thought you would enjoy a litle history on Caddilac attempts at creating a well performing fuel efficient car in the early 80's. Then GM made another tragic mistake: they converted a regular 350 engine block into a diesel engine, which was a very major fiasco and basically killed the passenger car diesel engine reputation was years to come. I believe only Cadillac Seville was ever offered with this diesel engine as standard equipment.

[HuntingEd]

I only see a big improvement on the HWY as well, it really does help, boosts my mpg up to 18+ w/ a 6.0L, and thats impressive.

 

As far as DOD, you dont pay a premium for it. Its included w/ the engine (at least the 6.0 and i think the 5.3) so if you need those engines for more power, pulling etc. it doesnt matter, you get it regardless. Now if it were an option i woulda considered not getting it. So the topic is kinda a moot point, if you dont want it get a 4.8L or buy something else ;)

 

 

But so far im happy w/ DOD, I'll take whatever boost in MPG i can get.