Early Review of the 2011 GMC

[timswi]

As I said, both have great sound but the Flowmaster system has a little better bark. The bad part is they both do not sound good when the engine management system cuts out half the cylinders for economy and you're only running on 4 cyl. Guess I'll just have to keep my foot in it. Maybe in the spring I'll figure out how to disable that feature.

I don't have the engine management system....All 8 all the time. My brother has it and feels that it does nothing for fuel economy..He's getting the same as he got on his 2000 GMC 5.3

 

[Diamondpilot]

I don't have the engine management system....All 8 all the time. My brother has it and feels that it does nothing for fuel economy..He's getting the same as he got on his 2000 GMC 5.3

I have heard the same thing from some of my GM customers but the Dodge guys swear it works. The main complaint I hear from the GM guys is it only works up to or about 57 mph. Any faster and its back to all 8. Now that is on 2-3 year old trucks and all as far as I know have the 3.73 gears so maybe they have ironed it out or perhaps different gear ratios act differently since the RPM's will be different.

Chris

 

[Lt CHEG]

I don't have the engine management system....All 8 all the time. My brother has it and feels that it does nothing for fuel economy..He's getting the same as he got on his 2000 GMC 5.3

I can't say as I ever noticed it working on my 2009 either. I actually got slightly lower fuel economy on my 2009 5.3 with 3.42 gears than I did with my 2005 5.3 with 3.42 gears. Everything else was the same on the trucks except for the fact that one was a Chevy Silverado, and one was a GMC Sierra, and also the 2009 had the 6 speed auto and the 2005 had the old 4 speed auto.

 

[CinderSchnauzer]

I can't say as I ever noticed it working on my 2009 either. I actually got slightly lower fuel economy on my 2009 5.3 with 3.42 gears than I did with my 2005 5.3 with 3.42 gears. Everything else was the same on the trucks except for the fact that one was a Chevy Silverado, and one was a GMC Sierra, and also the 2009 had the 6 speed auto and the 2005 had the old 4 speed auto.

Depends on the DIC (Driver Information Center) installed on your vehicle. On my LTZ, if "Instant Fuel" is selected it shows when the engine is in V4 mode.

If I try to hold a steady speed with just my foot and note the instant MPG and then engage cruise the MPG figure will improve and as light load situations occur it will register V4 and then switch back if the load increases.

I suspect there is some algorithm that controls the function so that as others have noted it doesn't go to V4 very often as speed increases - probably a function of load and RPM's

 

[MossRoad]

That's very impressive milage for such a big engine. Did you do the math on it by measuring the miles you drove devided by how much fuel you bought to fill up the tank? or was that based on the onboard milage computer?

My experience with Ford has been that those onboard computers are not very accurate compared to doing the math at the gas station.

The 4.8 GM engines that I've looked at in their half ton trucks are rated for 14 mpg city and 19 mpg highway on the sticker at the dealer, but those were 2010 trucks.

Thanks for the review, I'm looking and still unsure what I want to buy.

Eddie

I don't know about Ford, but the little computer in my 2000 Chevy Impala has always been spot on for mileage. Even after 147,000 miles. Just checked it yesterday. It was exact. :thumbsup:

 

[MossRoad]

These tires aren't the greatest but I did climb a 45 degree incline, ice covered driveway that is 1/8 mile long with them. Did OK..My Wild Country XTX's did a little better on the 17's...I can adapt.

1/8 mile long 45 degree driveway???

 

[Diamondpilot]

I don't know about Ford, but the little computer in my 2000 Chevy Impala has always been spot on for mileage. Even after 147,000 miles. Just checked it yesterday. It was exact. :thumbsup:

I always log each and every drop of fuel I put into my trucks and both my Fords and for the at matter the dozen or so I have owned with computers that calculate the fuel have been well within .5mpg. Most of the time it may be .2mpg. Example I calculated 16.9mpg last tank and the computer had it right at 17.0mpg For that matter its been the same with my only GM product that had a DIC and the other makes we have owned such as Honda, Lexus, and Nissan.

Thats close enough for me.

Chris

 

[deerefan]

I always log each and every drop of fuel I put into my trucks and both my Fords and for the at matter the dozen or so I have owned with computers that calculate the fuel have been well within .5mpg. Most of the time it may be .2mpg. Example I calculated 16.9mpg last tank and the computer had it right at 17.0mpg For that matter its been the same with my only GM product that had a DIC and the other makes we have owned such as Honda, Lexus, and Nissan.

Thats close enough for me.

Chris

Same for my F250. It was always within a tenth or two. My wifes 2011 Traverse is accurate also. Do not know about the 2011 Silverado, haven't filled it up yet.

 

[timswi]

1/8 mile long 45 degree driveway???

Just about 1/8th mile a darn close to 45 degrees...Sould have seen us pouring the concrete for that.

 

[Diamondpilot]

Just about 1/8th mile a darn close to 45 degrees...Sould have seen us pouring the concrete for that.

My college roomates uncle lives in Brown County Indiana and has a gravel drive like that. We tried to make it up in a Lumina back in the 90's and slid all the way back down till we hit a tree. Nothing but 4x4 trucks and SUV's can make it up even in the summer. Just too steep. When they built the house he had to rent a large farm tractor and had a 1000' piece of 1/2" cable to pull up all the supply trucks, concrete trucks, ect.

Chris