2007 4.8L Tahoe reports 20 mpg

[Machine]

Hi –

 

I read an article in the Fort Worth Star Telegram that mentioned the 2007 Tahoe’s 4.8L with displacement on demand produced an observed 20 mpg. What they neglected to mention was if this mileage pertained to city or highway. GM also stated that when the new model was on the drawing board they predicted gas prices to be at $2.00 at the time of launch. With that said, I read the fine print for a Tahoe advertisement in Cigar Aficionado that positioned the current 4.8L Tahoe getting an estimated 16 city and 18 highway.

 

Three things came to mind about this information:

 

How many people actually drive a current Tahoe w/ the 4.8L option. The most popular / current Tahoe configuration comes w/ the 5.3L. To date, my best highway mpg is about 17.3 and was obtained by going 65 on a relatively flat portion of TX highway. My average highway mpg is somewhere around 15.9. This is from a 5.3L Suburban, so I do expect a decline in economy compared to a Tahoe.

 

Why didn’t the reporter specify the 2007 mpg as city or highway? This leads me to suspect that the 2007 reported mileage is Highway mpg. If this is the case, I’m a little disappointed that GM made only a 10% improvement in mpg over the current model.

 

Even if GM’s prediction came true and gas was at $2.00, why did they come to the conclusion that this marginal increase in mpg for the new model would be a great place to stop? Did they ever consider that the 2 year sales decline of thirsty SUV’s is primarily due to rising fuel prices and poor SUV economy? I suspect the answers are: if GM forecasted gas at above $2.50 they would have most likely scrapped a replacement model, or, better yet, built a newer model that would provide even better mpg’s.

 

It’s great that GM refreshed everything on the 2007 lineup of SUV’s, but it really sucks that, once again, US automakers only extend themselves far enough to just get by. I think GM is going to get raked over the coals with lackluster sales on the new 2007. A minimal increase in mpg is not an improvement for a standard 4.8L when gas is pushing the $3 price point. The price may go down, but $2+ gas prices are here to stay. I can only imagine what the new 5.3L, 6.0L, and 6.2L will have to offer as far a mpg’s are concerned.

[Zane]

I want to remember that the 20mpg is a "combined" rating. Thus, the average of City and Highway. Which would put Highway well over 20. I think thats a pretty good improvement.

 

You gotta think, an SUV no matter which way you shape it is going to have the aero of a brick, so to get over 20 without being a hybrid is good. I'm interested in what they can get with the hybrid system.

[BlueTahoe]

I don't want to be too critical until I see the actual city/highway numbers but I do agree that 20 hwy is lower than I would want it. They claim to have the lowest drag of any full-size suv and they have added DOD so I would hope that would gain more than 2mpg.

 

I am seeing 17.5-18 mpg highway out of my 03 tahoe with a 5.3. I have done a custom tune, air intake, and exhaust that should all help my mileage but I believe my oversized tires have basically made that a wash. I could get the same 17.5-18 mpg with the tahoe brand new with no mods. When I added tires I lost about 2-3 mpg. I would expect to see 20mpg out of my current tahoe if I went back to stock tire size.

 

I would hope that the general would have been able to get like a 22 hwy and 18 city out of these with the better drag and DOD. They also have things that they didn't use like Lean cruise mod and other things that they could improve in the computer programming. I don't think a hwy mpg rating over 20 is too much to ask. It seems very feesable with the current models if you do a few mods.

 

I hope the observed 20 is a hwy city mix. That would be right in line with my expectations. 20 hwy would be a let down for me but it is still an improvement. Remeber these things are still a big vehicle with lost of hp. Some cheap minivans are only getting 21-25 mpg averages in real world conditions. I would be happy with an 18+ average MPG out of a tahoe. I would pay the difference to not have to drive a minivan.

[Machine]

I want to remember that the 20mpg is a "combined" rating. Thus, the average of City and Highway. Which would put Highway well over 20.  I think thats a pretty good improvement.

 

You gotta think, an SUV no matter which way you shape it is going to have the aero of a brick, so to get over 20 without being a hybrid is good. I'm interested in what they can get with the hybrid system.

 

<{POST_SNAPBACK}>

 

 

 

 

A combined rating would be very acceptable. I didn't see that in the article but i hope that's the case. Thanks.

[gave20]

Early reports I read about DOD from motor trend and trailer life in 2004 was about 25% improvement.

[silverado3500]

I'm really hoping that those fuel mileage numbers are way low. The 01 tahoe 2wd (5.3) that we had consistently got 19/20 on the highway at 65, and made 16-17city. I was anticipating at least 24-25 on the highway with DOD. Maybe I'm way off, but at 25% improvement just from DOD would yield 3-4mpg, and the new 6L80-E and the more aerodynamic body should surely allow a gain of a mile or two.

[pacodiablo]

I'm interested in what they can get with the hybrid system.

 

<{POST_SNAPBACK}>

 

 

Considering how they did with the Silverado hybrid, I doubt it will be impressive.

 

Hybrids are not the godsend people think they are.

[vhato]

Eaton's Displacement on Demand Technology gives an average mileage increase of 8% on 5000 pound vehicles I read somewhere on their site last year. The lower drag will help some and the new 6th gear may give a 200-300 RPM decrease in engine speed. I say a 12-15% increase overall.

 

With my current tune I can get 15.6 MPG on a tank easily in the HD. I have since started to drive faster which puts me back at about 14.1 MPG which I don't mind. A 15% (combined) increase is 2.1 MPG putting me at 16.2 MPH whicle not changing my driving. Nothing substantial. Just DOD by itself would be good for 1.1 MPG on my truck.

[Elwood 2000]

Sorry to be a downer on DOD, but I feel it is not worth what GM paid for it. I have not even driven it yet, but the yeilds are not that much from what I am hearing. I feel that money better spent would be on a baby Duramax. Diesel is readily available in todays world, a tad bit cheaper than gasoline and the milage gains are HUGE compared to DOD. Just look a the Jeep Liberty with the diesel. They can't keep build them fast enough! Todays diesel technology keeps them quiet, they don't smoke like older ones, they are powerful, long lasting and get great fuel milage!

 

Want 25mpg out of your Suburban, better get a diesel in it! Until then, I think we are stuck with 15 mpg at best!

[Shawn T]

I will believe it when I see it. GM's Silverado Hybrid had very minimal gains. It was all the rave when it came to numbers, but when tested it's gains were so minimal the break even point on the cost difference would take hundreds of thousands of miles. And you know, the consumer will pay for the "engineering" of DOD on the sticker price. I am just curious is to how often it will be in four cylinder operation. An SUV on acceleration or slight incline will be firing on all 8, I'm sure.

[TonyMazz]

I have a 2004 Tahoe LS 4.8L, 4L60E 3.73 and I am getting a consistent 19.5 mpg with a stock setup....mostly highway, some city. My avg MPH is 41 mph and I am ok with that....great truck....

[Machine]

Autos Insider reported the following on 10/05:

 

The 2007 Yukon, debuting today along with the more richly-outfitted Yukon Denali, reveals why GM is so confident.

 

Compared with its predecessor, the new Yukon has a sleeker design, more upscale interior, expanded cargo space and additional safety features such as roof-mounted head curtain air bags. But the biggest improvement is in fuel economy.

 

Two of the V-8 engines offered shut down four cylinders at highway-cruising speeds. Some of the new SUVs also come with more efficient six-speed transmissions. The result is gas mileage that hovers around 27 mpg on the highway and slightly above 20 around town -- unheard of for a large SUV.

---------

 

 

Defining news. I'm back in the game if real world reports from 1st year owners validate this.

[Machine]

Nevermind the above post from Autos Insider - It's BS.

 

GMC.com posted specs for the new Yukon:

 

4.8L 15/19

5.3L 15/21 2WD, 15/20 4WD

6.2L 13/19 Denali option, only

 

Nothing great.

 

No doubt that the lager XL and Suburban will report less than what's listed above for the lighter / smaller Yukon.

 

My guess for the XL and the new 5.3L; 14/18, maybe 19.... Something i can almost touch with my current 5.3's. No thanks. Back to diesel I go after i'm done with what i have.

[16gaSxS]

Nevermind the above post from Autos Insider - It's BS.

 

GMC.com posted specs for the new Yukon:

 

4.8L  15/19

5.3L  15/21 2WD, 15/20 4WD

6.2L  13/19 Denali option, only

 

Nothing great.     

 

No doubt that the lager XL and Suburban will report less than what's listed above for the  lighter / smaller Yukon.

 

My guess for the XL and the new 5.3L;  14/18, maybe 19....  Something i can almost touch with my current 5.3's.  No thanks. Back to diesel I go after i'm done with what i have.

 

<{POST_SNAPBACK}>

 

 

 

So there we are GM fight to get back to where they aready have been!

won't the d**n bean counter CEO ever learn the FUTURE for large SUV MPG's is not in Hybryds or shutting down cylindars ala the great Cattlecar 4-6-8 engine they tried. IT"S DIESEL Europe know it. Heck guys with 6.5TD Tahoes are getting 22 hiway mpg's thats with 10+ year old trucks, I regular get with my C-2500 6.5TD from 24-19.5 hiway 75mph I get 19.5-19.8 mpg slow down and up it goes. a V-6 DuraBux in Tahoe or Yukon with the new 6 speed Auto I think they could get 25-28 MPG at 65 mph. But the bean counter CEO killed the V-6 Durabux project when Ford cancelled it's contract fro one with Navistar because of the 6.0 Power Joke problems. This guy should run a great major Corporation might help kill it .....hey wait he is. GM ......RIP!!!

[16gaSxS]

For the unbelievers:

 

"Both my Suburban and Yukon get about 16.5 mpg around town, but mileage goes way up when I hit the hwy. Back in June I towed my 18ft Bowrider to Lake Chelan. Essentially driving over steep mountain passes both ways. There were 5 people and all our gear crammed into my 2500 Suburban 6.5TD. To my utter amazement we averaged 20 MPG on that trip. I am still amazed by the fuel economy on that trip.

 

I know unloaded both my rigs average 22 MPG on the hwy easily, but 20 mpg with five people towing a boat? Wow!

__________________

1995 6.5TD Suburban LT

1994 6.5TD Yukon "