SabrToothSqrl

Ok, so in the new Tahoe it switches between 4cyl and 8 on the fly, when needed...

my question is, can you force it (through wiring or other) to stay on 4cyl?

Say a switch to 'auto' or 'stay in 4'... I just think having more control is neat...

I wonder if it could actually move.... or if its just gonna not lol...

In bumper to bumper under 15 MPH, does it stay mostly in 8 or 4?

Big D

I think the engine can only run on 4 cylinders for a limited amount of time or it will overheat due to some cylinders running and the other ones not. ZX will probably chime in and give us the technical details.

73shark

It will only stay in V4 mode continously for ten minutes then has to switch to V8 mode to equalize temps per ZX. It drops out of V4 below about 25 mph and won't go in to V4 at all if you select Drive.

ZX1100F1

You can not force the AFM system to stay in 4cylinder mode.
These are heavy vehicles that require an 8-cylinder (not a 4 or a 6) engine to function properly, there are however certain conditions that allow for half of the cylinder banks to be disabled.

The ECM looks for just the right conditions to occur where operation in 4-cylinder mode will save fuel and not induce drivability problems, if the AFM is not in 4 cylinder mode it is because either there is too much load on the engine or the RPM's are too low and there would be no benefit.

Some people have the common misconception that operating in 4-cylinder will always save fuel in these heavy SUV’s and nothing can be further from the truth. Companies like Honda and Suzuki produce 4-cylinder SUV’s if you can’t afford a Tahoe or the gas for it.

SabrToothSqrl

Thank you for your information, I will look into those vehicles.

Personally I just like to control settings; its a quirk I guess.

For example; my girl friend's tribute is an 'automatic AWD' that uses electric couplers or so (sorry, I haven't found any good info on it, only the manual) to engage the rear when the front slip.
So, asI was driving in the snow, it did just that; but it does it so 'silently' and smoothly that you never really notice; other than the fact that you keep moving...

I don't know, there is just something reassuring about grabbing a lever and 'putting' it in 4WD... call me old fashioned

Going back to the 10 minute thing, is that true? It doesn't seem very useful if its only for 10 minutes, they way they advertise it it would seem to be in 4 on the highways all the time...

My cousin has a Silverado LT w/this feature, and its neat to watch...

You would think that idling at 4 cyl would be more effecient, unless its not enough to move say the power steering and alternator / etc...

I was reading that GM had this on a caddy long ago that would go from 8 to 6 to 4, however the technology wasn't as good as it is now, and it failed for several reasons.

Did you guys see the new E85 studies?

http://blogs.moneycentral.msn.com/to...ience-mag.aspx

schorner

What the study fails to mention (and maybe I didn't read all of it) was what impact ethanol could have on our dependance of foreign oil and whims of speculators at controlling oil prices. With all of the oil companies sporting record profits, one has to question who is behind the research. Remember when we were all mad that gas shot over $2.50/gallon? Now we would gladly pay $2.90 and think we got a deal.

RonH

Don't know if you have read the latest on ethanol, but studies are now coming out that indicate that the production of ethanol will result in more polution over a couple of decades.

And since I'm paying about $2.70/gallon for gas now, I don't think $2.90 is a good deal at all.

ZX1100F1

Go out and unplug 4 spark plug wires on your 95 Tahoe then start it and let it idle then come back here and report back your findings.

schorner

Still paying $3.18 down here in SW Florida....[]

From the limited amount I have read, Sugar based ethanol is supposed to have a much smaller carbon output that the corn based ethenol the corn lobbyists are trying to sell here in the states. It is hard to get at the truth of the matter with all the propaganda out there.

I do believe there is a car out there that runs on water, but the government doesn't want you to see it.

73shark

What about the 100 mpg carburetor that the oil companies won't let anyone make?

The worst thing about ethanol is we are using a foodstock to run are vehicles. [] As the price of corn goes up (and it has), the price of pork, beef, Coke, tacos, etc go up. A hundred years from now, they'll look back and just shake their heads at a civilization that used up their food to run their cars. I remember back in the 70s "energy crisis", it was projected that we'd run out of oil in 20 years. Proven reserves are about the same now as then.