new 07 tahoe

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Originally Posted by agjohn02

anyone know how that displacement on demand works? seems like it would be pretty negligable unless the valves deactivate. its still a pushrod valvetrain isnt it?

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i was wondering the same thing...Fred?

:flipoff2: :flipoff2: give him a minute to look it up on the internet. then he'll chime in. :flipoff2: :flipoff2:

uh-oh, beat ya to it, but i still dont know how it does it. solenoid driven valves?


Enabled by GM's powerful electronic powertrain controls, Displacement on Demand saves fuel by using only half of the engine's cylinders during most normal driving conditions. When loads are light, the control system automatically closes both intake and exhaust valves for half of the cylinders, cutting off their air and fuel supply. The fuel supply resumes and the valves are reopened to provide all-cylinder operation when the driver needs it for quick acceleration or for hauling heavy loads.

I don't know how it works but I know fred does without looking on the internet, he has been talking about it for months. They did it back in the day but it sucked, you're not supposed to be able to even tell this one deactivates cylinders.

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Originally Posted by Fredo

not to offend you david, but I still hate the way the 03-up pickups look. This front end is how they should have done it.

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I like the 'chevy scowl'
this thing looks like just another SUV

all you need to know...

http://www.popularhotrodding.com/fea...0405phr_gmdod/

It's been a couple months since I read the article on it in Engine Masters, but from what I remember, it is all dependent on the lifters. It's got this oil passage control manifold thing that is in the lifter valley cover and basically what it does is shut off the high pressure oil supply to certain lifters. It still has a low pressure trickle but it doesn't allow enough valve lift for operation of that cylinder. To keep the lifters in place it has low tension springs to keep the lifters from floating out of the bore when they are inactive. Besides that, it shuts off the fuel injectors to those cylinders.

I may have not gotten all of that correct, or forgot something, but I've drank a lot of beer and slept since I read that article.

every time chevy comes out with a new body people ***** but give it a few weeks and you will probably like it more. Unless you are one of those people who lack taste and think dodge has done a good job styling there trucks. :flipoff2:

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Originally Posted by Fredo

It's been a couple months since I read the article on it in Engine Masters, but from what I remember, it is all dependent on the lifters. It's got this oil passage control manifold thing that is in the lifter valley cover and basically what it does is shut off the high pressure oil supply to certain lifters. It still has a low pressure trickle but it doesn't allow enough valve lift for operation of that cylinder. To keep the lifters in place it has low tension springs to keep the lifters from floating out of the bore when they are inactive. Besides that, it shuts off the fuel injectors to those cylinders.

I may have not gotten all of that correct, or forgot something, but I've drank a lot of beer and slept since I read that article.

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when i started reading i figured the same thing. interesting that the high pressure oil de-activates the lifter. i guess this is a failsafe so that if the DOD system fails the lifters will be stuck in v8 mode rather than the other way around.

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Originally Posted by agjohn02

when i started reading i figured the same thing. interesting that the high pressure oil de-activates the lifter. i guess this is a failsafe so that if the DOD system fails the lifters will be stuck in v8 mode rather than the other way around.

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oh yeah, it is the other way around isn't it. I had forgot about that. Good failsafe though.

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Originally Posted by Fredo

not to offend you david, but I still hate the way the 03-up pickups look. This front end is how they should have done it.

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No offense taken. Not my favorite either, but it still beats the hell out of the alternative.

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Originally Posted by Matt Conlee

every time chevy comes out with a new body people ***** but give it a few weeks and you will probably like it more. Unless you are one of those people who lack taste and think dodge has done a good job styling there trucks. :flipoff2:

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Ohhhhhhh! Two SNAPS up for Conlee. :gigem:

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Originally Posted by bburris

It looks like the front clip of the Canyon or Colorado or whatever that gay pseudo-mini truck is called. Fugly. The rest of the body looks good, though.

Dave - have you driven a 05 or newer F-series truck? There are about twice as many buttons on the steering wheel as any Chevy I've seen...

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Aren't the buttons on the back of the wheel? My 04 doesn't have any, but I wish it did. I thnk only the lariats and fx4s got that option

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Originally Posted by davido

No offense taken. Not my favorite either, but it still beats the hell out of the alternative.

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seconded

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Originally Posted by JBrown89

Aren't the buttons on the back of the wheel? My 04 doesn't have any, but I wish it did. I thnk only the lariats and fx4s got that option

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No, my brother has a 2005 F350 FX4 Lariat and it has the same radio controls that my Chevy has, plus the controls for the 6 disc CD changer, the primary a/c controls and the cruise control crap that Ford has put on the steering wheel since ~95.