GM hybrid SUVs' fuel rating rivals Camry's

[NINETY_EIGHT_REGENCY]

GM hybrid SUVs' fuel rating rivals Camry's
Richard Truett
and Leslie J. Allen
Automotive News
September 26, 2007 - 3:11 pm EST



The hybrid versions of the full-sized 2008 Chevrolet Tahoe and GMC Yukon SUVs will deliver fuel economy gains of 50 percent in the city over the standard, non-hybrid models.

Tomorrow at the Texas State Fair, General Motors will announce the EPA fuel economy estimates of 21 mpg city and 22 mpg highway for the two-wheel drive versions of the Tahoe and Yukon hybrids.

Those fuel economy ratings are expected to give GM best-in-class fuel economy for large SUVs. The ratings also rival those of many midsize and large cars. For example, the 2WD Tahoe and Yukon match the four-cylinder Toyota Camry's 21 mpg city rating and beat the V-6 Camry's city rating by 2 mpg.

GM expects to sell 10,000 units per year, combined, of the hybrid SUVs. Prices won't be announced until closer to launch, but are expected to start in the low- to mid-$40,000 range.

The Tahoe and Yukon hybrids are the first vehicles to use the innovative Two Mode hybrid transmission GM developed with DaimlerChrysler and BMW. GM will also use the hybrid system in pickup trucks.

The EPA fuel economy figures are lower than some expected, but that's due to the agency's changing its test procedures to more accurately reflect real-world driving conditions.

The official EPA figures for both vehicles are 21 city/22 highway for 2WD models and 20 mpg city/20 mpg highway for 4WD models.

The Yukon and Tahoe hybrids are equipped with GM's cylinder deactivation system, which cuts off four of the V-8's cylinders when the vehicle reaches highway cruising speeds. They have lightweight body panels and wind-cheating bumper covers.

Two Mode Specifications
The 2008 Chevrolet Tahoe Hybrid and GMC Yukon Hybrid tow like SUVs, but are no more thirsty than a midsized car.
Price: Low-to-mid $40,000 range
City/Highway EPA Ratings: 21/22 (two-wheel drive); 20/20 (four-wheel drive)
Engine: 6.0-liter, V-8
Horsepower: 332 hp
Torque: 367 pounds-feet
Transmission: Two Mode hybrid/four speed automatic
Batteries: 300-volt nickel-metal hydride for hybrid system; 12 volt for accessories
Towing capacity: 6,200 pounds (2WD); 6,000 pounds (4WD)
Curb weight: 5,541 (2WD); 5,787 (4WD)
Source: General Motors


The 2008 Yukon Hybrid goes on sale in early November.
The two-mode hybrid is a full hybrid, meaning the Tahoe and Yukon can drive entirely on electricity. GM's two-mode hybrids can go up to 32 miles per hour using just electricity. At higher speeds, the two-mode system uses either all gasoline or a combination of fuel and electric propulsion.

GM, DaimlerChrysler and BMW invested $1 billion in the Two Mode system.

"This is something that really changes the game," said Gary White, GM vice president and vehicle line executive for full-sized vehicle development team.

Tahoe and Yukon hybrids are by far the most fuel-efficient large SUVs on the market. By comparison, the two-wheel drive 2008 Nissan Armada and Infiniti QX56 and the two-wheel drive Ford Expedition all get EPA ratings of 12 city and 18 highway. The EPA has not released figures for the 2008 Toyota Sequoia.

The Nissan and Infiniti ratings are for the 5.6-liter V-8 and the Expedition rating is for the 5.4-liter V-8. GM's Two Mode hybrid SUVs have a 6.0-liter V-8 engine.

GM is also planning to use the Two Mode system in its Silverado and Sierra pickups. The Dodge Durango will use the Two Mode system next year, and Mercedes-Benz and BMW will use their versions in the ML 450 and X6 SUVs.

Jamie LaReau contributed to this report.

[Buick61]

So all this "Dual Mode" talk about how the second mode increases Highway Fuel Economy unlike other [Toyota-esque] systems is really just bogus.

The standard 2wd (5.3L) Tahoe gets 20mpg highway. This thing gets 22. I doubt many will be impressed. Sure you get more power (due to the bigger 6.0L), but is more power why someone would be interested in this over the 5.3L Tahoe in the first place? No, I think they'd want more MPGs than HPs. Chevy pulled a Lexus.

[SkiD666]

Cylinder deactivation nets an increase of 3% or so.
Cylinder deactivation + more horsepower + hybrid assist nets an increase of 10%.
Is it really worth the extra cost for a 1 or 2 MPG increase, probably not, but it is available, so why not use it.

[Tiger]

Originally Posted by Buick61

So all this "Dual Mode" talk about how the second mode increases Highway Fuel Economy unlike other [Toyota-esque] systems is really just bogus.

The standard 2wd (5.3L) Tahoe gets 20mpg highway. This thing gets 22. I doubt many will be impressed. Sure you get more power (due to the bigger 6.0L), but is more power why someone would be interested in this over the 5.3L Tahoe in the first place? No, I think they'd want more MPGs than HPs. Chevy pulled a Lexus.

Apples to apples B61...my 2004 GM 5.3L truck got 14 City 18 Hwy - under the OLD EPA method!!!

The new Hybrid models in 2008 under the NEW EPA testing method are 20 City and 22 Hwy. The new method dropped those old ratings...the 2 cannot be compared. So, the increase is actually greater than it appears!

Ex: 14mpg City (pre 2007 number) moving to 20mpg City (2008+ number) is actually effectively greater than the 6mpg window sticker increase!

Given the harshness of the 2008 EPA ratings (A Prius dropped by 12 mpg) I am pleasantly surprised to see these number remain at 20 or above.

[Geotpf]

Change title to say "city fuel rating". The Camry 4 cylinder gets 31 MPG highway, a whole heck of a lot of difference from 22. Hybrids tend to boost city MPG more than the highway numbers.

[Buick61]

Originally Posted by Tiger

Apples to apples B61...my 2004 GM 5.3L truck got 14 City 18 Hwy - under the OLD EPA method!!!

The new Hybrid models in 2008 under the NEW EPA testing method are 20 City and 22 Hwy. The new method dropped those old ratings...the 2 cannot be compared. So, the increase is actually greater than it appears!

Ex: 14mpg City (pre 2007 number) moving to 20mpg City (2008+ number) is actually effectively greater than the 6mpg window sticker increase!

Given the harshness of the 2008 EPA ratings (A Prius dropped by 12 mpg) I am pleasantly surprised to see these number remain at 20 or above.

The 2008 5.3L Tahoe 2wd is rated 20mpg highway. It's not apples to oranges: they were both tested under the same NEW methodology.

[Tiger]

Originally Posted by Buick61

The 2008 5.3L Tahoe 2wd is rated 20mpg highway. It's not apples to oranges: they were both tested under the same NEW methodology.

There have been changes made to the 5.3L over the past few years...most likely it was also tuned for the 2008 EPA regs as well. Manufacturers can't sit still thanks to the EPA.

[mrfunji]

I had one of these to drive (2-mode) and I was getting about 35 mpg cruising down the street at about 40 mph in Hybrid mode. These trucks are awesome - totally seamless operation.

[Chaz_23]

So we're talking about 16-19 real life MPG, huh?

[ericmvest]

Originally Posted by Buick61

The 2008 5.3L Tahoe 2wd is rated 20mpg highway. It's not apples to oranges: they were both tested under the same NEW methodology.

The focus of hybrids is increasing city milage, not highway. That the dual mode hybrid gets 10% better highway mileage is impressive and is icing on the cake. Also, a 10% improvement in highway fuel economy is a lot. If we could get a 10% improvement fleetwide, it would save a tremendous amount of oil.

[blaksabb]

Originally Posted by Buick61

So all this "Dual Mode" talk about how the second mode increases Highway Fuel Economy unlike other [Toyota-esque] systems is really just bogus.

The standard 2wd (5.3L) Tahoe gets 20mpg highway. This thing gets 22. I doubt many will be impressed. Sure you get more power (due to the bigger 6.0L), but is more power why someone would be interested in this over the 5.3L Tahoe in the first place? No, I think they'd want more MPGs than HPs. Chevy pulled a Lexus.

I don't recall 2-mode as ever being billed as a method to boost highway mileage more so than competing full-hybrids. Rather, dual-mode allows a full-size, large curb weight vehicle to still have an impressive GCWR (ie, tow capability) by intergrating the electric motor into the transmission and run full electric, full engine or combination (which I think Toyota's Synergy Drive does as well).

[uboys]

Does anyone know how the performance numbers will change when the lithium-ion batteries come on board?

Will the top electric speed go up from 32 mph to 50mph? Is that feasible?

What about the mileage? What would be reasonable to expect (given other Two-Mode revisions by then)?
25 city/25 highway? 27/25? 30-something?

[Buick61]

Originally Posted by blaksabb

I don't recall 2-mode as ever being billed as a method to boost highway mileage more so than competing full-hybrids. Rather, dual-mode allows a full-size, large curb weight vehicle to still have an impressive GCWR (ie, tow capability) by intergrating the electric motor into the transmission and run full electric, full engine or combination (which I think Toyota's Synergy Drive does as well).

2 Mode has nothing to do with allowing fullsize vehicles to have impressive tow capablities. If that's a side effect, than good. But 2 Mode is not just intended for large vehicles:

Originally Posted by GM Media

Because the architecture can be scaled to fit multiple vehicles and adapted to gasoline or diesel engines, the 2-Mode full hybrid can be applied globally. In Europe, for example, where diesel engines are common in passenger vehicles, it can provide a significant reduction in fuel consumption, which would help automakers meet the region’s ever-stringent carbon dioxide emissions standard.

And to answer the first part of your post, the whole reason for the second mode is so that highway fuel economy is also aided by the hybrid system.

From Chevrolet.com:

The second mode is used primarily at highway speeds to optimize fuel economy...The addition of a second mode to the drive system improves efficiency and reduces the need for large electric motors, which are used in today's single-mode systems

And beyond the Hybrid complexity that they added, let's not forget what else went into that 2-mpg increase:

To maximize efficiency, the front of the Chevrolet Tahoe Hybrid is lowered 10 mm compared, which provides additional aerodynamic benefits as well as a smoother and sleeker appearance. The hood and liftgate are made of aluminum to trim weight, and the leading edges of the hood have been streamlined.

The Tahoe Hybrid retains Chevy’s trademark dual-port grille with Chevy bowtie, but with a larger intake to accommodate the hybrid powertrain’s higher airflow requirement for cooling. The fascias are tuned at the corners and air dam, and the running boards are flared in front in an effort to guide airflow around the wheel openings. Hybrid badging appears on the C-pillar, on the rear liftgate and on the hitch cover.

Other aerodynamic refinements include sharpening of the D-pillar rearward, including the taillamps, a CHMSL appliqué detail spoiler over the rear hatch and a closeout panel under the back of the vehicle to facilitate airflow.

Lightweight, aero-efficient wheels with the lowest rolling-resistance tires available for full-size trucks further trim fuel use, and are complemented with a tuned ride to provide the ride and handling performance and attention to detail that customers expect from a totally integrated vehicle.

It's lowered, reshaped, weight-reduced, and hard-compound rubber tired. All the tricks that the Prius employs (with little mention).

So if you're a highway driver, this hybrid will have the same dubious benefits that every single other hybrid "offers." I expected more from the hype, I guess.

[coaster.n3rd]

Originally Posted by blaksabb

I don't recall 2-mode as ever being billed as a method to boost highway mileage more so than competing full-hybrids.

Same here. I think people are missing the big picture, this thing gets 21mpg in the city. That is very impressive for something the size of B1 bomber hurtling down the road in stop & go traffic. For the people that really need a vehicle that size, this will be a good thing for them, their wallets and the environment.

I am a little perturbed that they will only sell 10K. I hope the demand is a little higher for it.

The article was not calling out the Camry, just showing that it can get the same mpgs in the city as a much lighter & smaller fuel efficient sedan.

Originally Posted by [B

Chaz_23[/b]]So we're talking about 16-19 real life MPG, huh?

Depends on how you drive it. Studies have shown that people will drive as efficiently as possible when they have the ability to view their fuel economy as they drive. The Prius has proved this and luckily GM saw fit to include a visual monitor on the nav screen in these vehicles.

[uboys]

So, 30+ mpg is possible even now? I hope they are understating the mileage.

An EPA rated 30mpg full-sized SUV would be a candidate to bring back the heady days of mass SUV-buying; with Gm at the front.