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Rented Tahoe Last Week, Very Interesting Mpg


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I currently own a 2010 Silverado Ext Cab w/ 6 spd and 3.08 axle, truxedo bed cover. I have about 6k on it and have achieved 20.3 and 20.1mpg on a couple tanks, other tanks have yielded 18-19 mpg. I am a on road rep so I am constantly on the interstates in Texas.

 

So, we go on vacation to Colorado and rent a Tahoe. This Tahoe was a 2010 with about 13k on it. 5.3 and 4wd. I am not sure what axle but pretty sure it was 6 speed. We drove all over the state (over 800 miles), up and down mountains, some off road as well. Flooring it and passing other vehicles going up mountains in the passing lanes, etc. Yes there was some coasting going down the other sides, but I could not believe we ended up getting over 20mpg over the entire trip in this Tahoe!

 

Had I been driving the Tahoe as I do my truck, easing it off the line, very rarely speeding or passing, no off road, I am sure I would have been very well over 20, like 24ish.

 

How is it that this 4x4 Tahoe gets so much better mileage than my truck? I thought the truck would be better on fuel as it is a lighter vehicle, no 4wd and 3.08 axle.

 

Is it the leaner mixture up in the higher elevation out west? Lower octane fuel out west?

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  • 2 weeks later...

Yup lower to the ground, more aerodynamic, and fuel does burn differently up here at altitude, which is why we can get away with running 85 Octane instead of 87 or 87 instead of 91. That being said though, I would think you would get better gas millage in Texas rather than up here with all the hills and mountains.

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So as a general rule, could we say that the Tahoe will always get significantly better mileage than it's truck counterpart (silverado/sierra)???

 

Probably so depending on what is considered significant. The Tahoe has a pretty decent drag coefficient for it's size compared to other full size SUV's and I would think even better when compared to a truck. You can read about it here. http://gmauthority.com/blog/2010/06/fyi-ta...ient/#more-5825

 

Click on the term "Kammback Design" in the article to see why a SUV would do better then a truck even if the front ends were the same.

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no they say u loss 2% per 100lbs so i doubt that! like i said u got 3.42s vs 3.08s. 3.42's make it easier to get the truck moving and used less gas. Also altitude plays a major roll. if u go to dealer the window sticker will show them 1-3mpg less

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no they say u loss 2% per 100lbs so i doubt that! like i said u got 3.42s vs 3.08s. 3.42's make it easier to get the truck moving and used less gas. Also altitude plays a major roll. if u go to dealer the window sticker will show them 1-3mpg less

 

Interesting indeed. I know higher altitude=less air=less fuel which = better mpg. But that being said, this Tahoe is heavier and 4x4 vs the silverado. Add the fact that I was continually driving with the throttle pinned going up mountains! Both are rated at 15city and 21hwy.

 

By significantly better fuel economy, I mean 10-15% the Tahoe was better than the silverado. Maybe the answer to my finding better MPG for my Silverado is to move out West at altitude. HA!

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He posted it had a cover. The gearing is just a not a friendly on the truck. Like i said b4. With 3.08 gears u have you push the gas more to get it going using more gas. Look at the guys with lifted truck with big tires. 35+" The have 3.42s and go up to 4.56 or 4.88s and get better mpg with the bigger tires then they did with 3.42s.

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He posted it had a cover. The gearing is just a not a friendly on the truck. Like i said b4. With 3.08 gears u have you push the gas more to get it going using more gas. Look at the guys with lifted truck with big tires. 35+" The have 3.42s and go up to 4.56 or 4.88s and get better mpg with the bigger tires then they did with 3.42s.

 

Not disputing in any way, BUT, supposedly the new 6 spd transmission makes up for the 3.08 rear ratio by having a lower gear ratio in 1st for take off and providing a higher gear ratio in 6th for interstate cruising. So are there different transmissions coupled with the different rear end ratios? Or is there just 1 six speed transmission that is fitted to all tahoes/silverados?

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