2010 GMC Terrain: 32 MPG or Bust

That's pretty much what I get on the highway in my ALL wheel drive Outback which has an EPA rating of 27-- driving at 72 mph.

This is the second port I've seen recently regarding fuel economy with this vehicle and I'm wondering how much of a difference (if any) the "eco" button makes . . .

With the fuel-sipper smackdown results and the lifetime logbook mileage it's obvious GM has gamed the EPA test to achieve the 32 highway figure. Wasn't "Old GM" the company that would over promise and under deliver? What's the point of advertising 32 mpg if consumers can't reasonably achieve it?

Hey, 29 mpg isn't bad for a fairly unaerodynamic 3800 pound SUV. Still, kinda disappointing that you can't match the EPA numbers.

bimmmerjay,
This car runs the same fuel economy / emission cycles that every other car runs that's sold in the US. They are just reporting the results from that cycle as per EPA requirements. You make it sound like a big conspiracy :) Like they cheated or something. The EPA verifies the results on their own so I think this is not possible.

All companies optimize their cars for fuel economy and emissions around the mandated cycles because if they don't meet the minimum requirements, they pay a fine.

Mike,
Can you or someone from Insideline do an article on what testing the EPA mandates (specific cycles) for both city # and hwy #. I think it's a combination of 5 cycles (LA4, HWFET, FTP75... what else).

Just saying my close to 5000lb All Wheel Drive Tribeca with a 6 cylinder engine going 65-70 with side view mirrors as aerodynamic as a brick can get in the high 23's and pull 24 if I'm lucky.

@vtirocz,

I realize the EPA runs a standardized test regimen and the manufacturers are obviously well aware of the protocols. A car can be set up to maximize efficiency specifically under the conditions and cycles the EPA uses. This may not translate into the real world, as seems to be the case with the Terrain. A manufacturer can choose how to set their car up to perform - do you do whatever you can to get the best numbers or do you strike a balance such that the consumer will be more likely to achieve/exceed the test numbers? From a customer satisfaction standpoint, if people are buying a car based on an advertised number they're going to be pretty pissed if they can't come anywhere near it.

"turn off the A/C"

Windows down?

I beat your numbers with an AWD model with the A/C on.....

"You make it sound like a big conspiracy :) Like they cheated or something. The EPA verifies the results on their own so I think this is not possible."

They put in a powertrain designed for the highest possible score on EPA's treadmill test instead of real world responsiveness. It's not cheating the EPA but it's sure cheating the buyer.

The long term Rav 4 - with a 270 horse V6 and a 27 mpg window sticker - also got 29-30 mpg tanks when they babied it. Because it was built to drive well and not to game an indoor dynamometer.

That's the same reason the "18/25" C300 they had a while back got the same mileage as the other V6 sedans in the fleet with 3-4 mpg better stickers.

Guys, the EPA only tests a small number of the cars and trucks. The EPA lets the manufacturer publish the numbers based on faith. However, the EPA's numbers and the manufacture's numbers are usually very close. The EPA mostly tests models with new gas saving tech in them or cars close to the gas guzzler tax.

Our ratings for the Terrain are 6.1 L/100km or 38.5 mpg (US). A local magazine drove one from Montreal to Toronto. Despite sticking to the speed limit, windows up and A/C off they averaged 8.2 l/100km (28.6 MPG US).

It requires carefully driving to beat the Canadian numbers normally but anyone can beat the EPA numbers.

I was impressed when GM came out with the Terrain and it's clones with their great mileage numbers. Maybe that's why it's bugs me so much that I was hosed.

Did one of the editors clean the interface with sandpaper?

Note how Mike's Los Angeles to San Francisco trip and firstwagon's mention of a similar Montreal to Toronto Terrain tour resulted in near identical mileage. (29 mpg)

Also I would like to mention I still love the Terrain's jaunty mug just as much now as when I first saw it.

"New" 2008 EPA rules include A/C on

"Wasn't "Old GM" the company that would over promise and under deliver? What's the point of advertising 32 mpg if consumers can't reasonably achieve it?"

what planet do you live on? EVERY automaker is doing this. HAve you not noticed the new Edge which weighs 4600lbs is rated at 27mpg highway? Did you miss the reports about the Sonata turbo with 274hp getting 34mpg? Or the 305hp Mustang that supposedly gets 31mpg?

This is not a "GM" problem, this is something that is going on industry wide in a race to have the highest advertised fuel economy.

" From a customer satisfaction standpoint, if people are buying a car based on an advertised number they're going to be pretty pissed if they can't come anywhere near it."

Go to carspace and read the comments in the Equinox mileage forum. NUMEROUS owners reported getting over 30mpg on highway trips. The variation between the trip computer and Mike's calculations seems hard to believe. How many gallons of gas did he put in? What is tank size?

"They put in a powertrain designed for the highest possible score on EPA's treadmill test instead of real world responsiveness. It's not cheating the EPA but it's sure cheating the buyer."

and what is everyone else doing? Honda just announced mileage on the 2011 Accord has magically jumped by 3mpg on the highway with no major technical changes. Sound like gaming the system to you? Tall gearing and low resistance tires are the name of the game these days. automakers are trying to increase EPA ratings as cheaply as possible.

"Maybe that's why it's bugs me so much that I was hosed."

LOL very Canadian......"hosed" that made me chuckle this morning.

"Or the 305hp Mustang that supposedly gets 31mpg?"

Remember the test that Ford ran a few months ago where the Mustang far exceeded its EPA highway MPG? Now that was of course very carefully controlled but it still did it. It would be interesting to see other car makers do the same thing to prove its cars in fact perform like advertised.

I was thinking they used a brillo pad for cleaning, but maybe sandpaper was closer at hand. :)

I'll add that I see no big deal just because this one driver couldn't get the car to the rated HWY milage. Could have been the driver, could have been the conditions, could have been the gas, could have been a clogged filter...fact is, it was one driver on one day.

"Remember the test that Ford ran a few months ago where the Mustang far exceeded its EPA highway MPG? "

No I dont and tests of the Mustang V6 have come FAR short of the EPA combined numbers. Check the comaparos for yourself. I believe in MT the Mustang did worse than the Camaro which has inferior EPA ratings.

I've heard of trip computers being off a little bit, but not by over 10%. That makes me wonder how the real number was calculated. I assume he filled up when he left and then was able to put 8.1 gallons in the tank at fill up.

ptcdawg says:

06:51 AM, 09/17/10
"...fact is, it was one driver on one day. "

Fact is; it was two drivers on two days running two different routes that both got 29mpg (rounded). That clearly shows that the 32mpg advertised number is a hoax. That I can live with, because as mentioned its a game everyone is playing these days in order to meet the stupid CAFE requirements.

However, the issue I have with the Terrain is the on board computer overstating actual fuel economy by almost 15%. That large a discrepancy isn't tolerable and only adds to the idea that GM is outright lying about their fuel efficiency to consumers.

That, in my opinion will quickly come back to bite them. How upset would you be if you buy a new car or truck with a window sticker showing 22/32mpg which, when taken home actually averaged 20.5mpg??? To add to it, the GMC Terrain's website slots the trucks' fuel economy as its #1 selling point, above safety.

30% lower fuel economy than (heavily) advertised will have me shopping around next time if I had bought into the hype they created.

http://blogs.insideline.com/roadtests/2010/09/big-list-of-fuel-economy-august-2010.html
http://www.gmc.com/terrain/terrain/index.jsp?pvideo=false&seo=goo_|_2008_GMC_Retention_|_IMG_GMC_Terrain_|_Terrain_GMC_Terrain_|_gmc_terrain

@stoppre75,

Exactly. The overly optimistic trip computer only adds insult to injury.

I would argue that 2 drivers on 2 different days is not much better than 1. Oh well, maybe it is all a HO AX.

I know my Wife can consistently beat my MPG by 20% or more.

This of course is not even close to real-world driving...

"It's definitely not a speed record, but the 2011 Ford Mustang with V6 engine has set a record on the racetrack nonetheless. The Mustang with the new 3.7-liter, 305-horsepower DOHC V6 and six-speed transmission averaged a very impressive 48.5 mpg over 1,457 laps of the Bristol Motor Speedway at an average 43.9 mph. The entire run used up one tank of gasoline."

http://www.insideline.com/ford/mustang/2011/2011-ford-mustang-v6-sets-hp-mpg-record.html

I've had my GL350 BlueTec for 4 weeks. The sticker says 17/21. Last week I drove up to the mountains on Interstates 95, 26 and 40, cruise set on 74, a/c on but the rear a/c off. Halfway through the trip the trip computer was telling us we were getting 26.5 mpg and I thought there was no way. So pulled over, filled up and did simple calculations. I came up with 26.2. Hmmmmmm. When we made it to North Carolina, it had gone down to 25.2 (climbing the steeper grades?) and again, the fill-up confirmed it as almost accurate. The trip home I turned into some kinda Prius driver, trying to eke out the mpg. Cruise set at 70mph, after 274 miles the computer said 28.4 mpg. After filling up with diesel and figuring out the mileage at the station in Georgia right off of I-95, my simple calculations showed 28.1 mpg. So I guess my question is, what in the world is Mercedes doing that, in my estimation, grossly underestimates the mileage?

"Exactly. The overly optimistic trip computer only adds insult to injury."

And yet the same could be said for any of the models that have optimistic EPA ratings. Thats the point you keep missing. This isnt a Terrain only issue.

And I don't believe for a second that a normal driver would average 20mpg in this vehicle. Nothing I've seen in the way of owner comments supports anything that low. That is about what IL averaged with the Aura which was rated 17/26 and weighed over 3600lbs.

"And yet the same could be said for any of the models that have optimistic EPA ratings. Thats the point you keep missing. This isnt a Terrain only issue."

Alright, so which other cars in the LT fleet are missing their combined EPA figures by 21% or more? Perhaps you missed this:

"You've seen our monthly fuel economy logs, and recently we've starting comparing our test vehicle's observed average mpg to their EPA Combined rating.

Most of the time we come within 1 mpg of this figure. Our driver rotation and the varied nature of everyone's commute and weekend activities means that, after several thousand miles, things get nicely randomized. No single commute or driving style dominates the average. The exception here is the high-horsepower machines where the temptation to "leg it" is simply too great.

But the GMC Terrain does not fit the pattern. It's a glaring exception and its observed MPG is way off. In our most recent tally, the Terrain's average fuel consumption over 13,000 miles was 20.5 mpg, a full 5.5 mpg (21%) below its EPA Combined rating. It's best-ever tank of 28.7 mpg trails 3.3 mpg (10%) behind the EPA Highway figure."

http://blogs.insideline.com/roadtests/2010/09/2010-gmc-terrain-underwhelming-mpg.html

Or maybe you missed the 'Fuel-Sipper Smackdown 3':

"Despite the GMC Terrain coming in 2nd place among the SUVs, it was the first vehicle in our three Fuel-Sipper Smackdowns (14 cars total) not to meet or beat its highway fuel economy number in this testing portion. In fact, the Terrain didn't even come close to its 32-mpg estimate despite this 368-mile test route's lower highway speeds. Our guess is that its tall gearing, which is ideal for the EPA test, wasn't well suited for the steep hills of this driving portion. Of course, the GMC had to descend those hills as well, and all the other underpowered fuel-sippers that have tackled this same terrain didn't suffer like the Terrain."

and

"As we've mentioned already, the GMC Terrain failed to meet its EPA mileage estimates in a test
where ALL OTHER VEHICLES HAVE HISTORICALLY MET OR EXCEEDED THEM." [emphasis added]

http://www.edmunds.com/advice/fueleconomy/articles/162566/article.html

There is simply no excuse for GM's misleading advertising of the Terrain's fuel economy.

GM cheated on the EPA test, it's just so common nowadays

My '10 Mazda 3 is the first car I have owned with a trip computer and it does have me driving more conservatively, however after 2500 miles I take its numbers with a grain of salt.

#1 - Range. It will constantly tell me I can run ~400 miles on a tank, but never fail my gas light is blinking on around 315-330 miles with no change in driving habits over the entire tank.

#2 - Avg MPG. Funny enough it sometimes reads high and sometimes reads low. It tends to report lower MPG when there is more idling time and higher MPG the more in gear 99.9 MPG instantaneous readout coasting.

Nonetheless it is still within .8-1 MPG from my average. I am averaging ~26 MPG on a 50/50 commute which falls into line with the 22/29 EPA estimates.

4mpg error? Did you guys reset the computer before the trip?

We routinely get 1.3-1.5mi overstated mpg from the computer compared to what I calculate with the trip odo/fuel pump reading. I've never seen a 4mpg error with our Equinox's computer. I don't get it. 29 isn't hard with the vehicle on the freeway with the AC on. Turn it off and we get 30-31mpg. I don't think the ECO button really matters much.

We routinely get the above EPA city mileage around town without effort. I don't know why you guys are getting such poor results. That's not our experience. Could the odometer be off in your vehicle?

Okay, I haven't traveled to the left coast, so I don't know if California requires ethanol in the gas or not. But when I run E0 gas in my Chevy HHR, 2.4L, I average 29 MPG. When I run E10 gas, my gas mileage drops to 26-27.

Now, the ag industry is lobbying the EPA to increase the ethanol blend to 15%. On EPA's web site, fueleconomy.gov, they compare E85 to E0. Miles per gallon decreases using E85 and amazingly, annual fuel costs increase with E85!

Ethanol blended gas is hygroscopic. It attracks water into the fuel system. Ethenol blended gas destroys two cycle engines used in lawn and garden equipment and also outboard marine engines.

EPA Docket: EPA-HQ-OAR-2009-0211