The Hummer H2 is a brilliantly-marketed sort of baby huey version of a Chevrolet Tahoe. General Motors (GM) owns AM General, which makes the Hummer SUV, which is in turn just a civilian model of the military HMMWV vehicle. The Hummer/HMMWV has a stunning feature set, although it is definitely not meant for rock climbing as the commercials might suggest; It has 16" of ground clearance for the majority of the width of the undercarriage, provided by a drop-down fully independent suspension, and the ability to operate submerged when fitted with a snorkel device, as well as an independent on-the-fly tire inflation/deflation system. It's really meant for rapidly crossing mixed terrain including desert, grassland, and scrub.
The H2 is offered with two body styles. The first is a basic SUV shape, and the other is a truncated SUV with a short pickup bed known as the "H2 SUT", for sport utility truck. The two models have basically identical mileage and weight.
The H2 comes with a 6.0 liter Vortec 6000 V8 coupled with a 4L65-E electronically controlled four speed automatic transmission providing 325 hp at 5200 rpm and 365 ft-lb of torque at 4000 rpm. It uses a "full-time 4WD" system (also known as all wheel drive) and has four-wheel, four-channel ABS disc brakes, which it uses to provide electronic traction control. And, that's about it. Oh sure, you can get a winch, or a wrap-around bumper, or a navigation system, but it's utterly, completely useless as an off-road vehicle in much the same way the Chevy Tahoe (a sort of shrunken Suburban) is, except for one feature; It comes with electrically-actuated locking differentials in the transfer case and both axles. Meanwhile, the 4L60-E transmission is simply an updated, electronically controlled version of the ancient 700R4 transmission, which GM has been using since the early eighties. The 700R4 is technically a three speed automatic trans, with automatic overdrive.
Compare this to the Tahoe: It's offered with either the Vortec 4800 (4.8l V8) or 5300 (5.3l V8) rather than the 6000. Either way, it uses the same 4L60-E transmission. The 4800 provides 285 hp and 295 ft-lb while the 5300 outputs 295 hp and 335 ft-lb. Note that this is only 40 hp and 30 ft-lb less than the 6 liter. The 4800 delivers 16 mpg city and 20 mpg highway, while the 5300 is 15 and 20 respectively (19 mpg highway with the 4WD model.) Meanwhile, the H2 gets about 10 mpg on the street, and maybe 12 mpg on the freeway. A decrease of 5 mpg city and 7 mpg highway is really, REALLY amazingly pathetic for a vehicle with only nine percent more horsepower and nine percent more torque.
Of course, unlike the H1 (the new name for the original Hummer, when AM General branched out and made more than one kind) the H2 has a live axle rear suspension. This is a big mistake for a number of reasons. The first, and probably most significant in an "off-road" vehicle, is ground clearance. A Hummer has a 16" ground clearance while the H2 only has 10". For reference, the average passenger car has five or six inches. Having twice the ground clearance of a passenger car is not much of a selling point for a SUV carrying the Hummer marque. The tahoe comes in at 8.4 inches; even if you were to buy a two inch lift as an aftermarket upgrade (which means buying all the parts over again) you would expect to pay no more than two thousand dollars, and possibly considerably less depending on the parts involved.
Now, let's talk turkey. The 2005 H2 has a $52,430 base price tag. The 2005 Tahoe is $42,200 with the 5300 engine. There is no extra charge for the version of the 5300 that can run on E85 fuel, which is 85% methanol.
My conclusion is that the H2 is some kind of joke put over on people dumb enough to purchase cars as status symbols. There's not $10,000 worth of addons on a base H2 that make it worth more than a Tahoe.
In October of 2004, GM produced a hydrogen-powered concept version of the H2 SUT (sport utility truck) called the "H2H". It uses the same six-liter Vortec engine as the ordinary H2, but also utilizes a supercharger to get compression up to the point where you can burn hydrogen. The vehicle was delivered to Arnold Schwarzenegger, Governor of California on October 22, 2004. There are no plans to sell the Hummer H2H. Hydrogen-burning vehicles have nearly no emissions; aside from burning lubricants (all four-stroke internal combustion engines burn someoil) the emissions from burning hydrogen are only heat, and water.
The H2 is in turn being followed by a H3 which is smaller and lighter, using a Vortec engine just a bit over three liters in displacement. One of its design goals was for it to be able to navigate the Rubicon Trail. Unfortunately, it too has a live axle rear suspension, which does no one's ground clearance any good. Even Ford has figured out this independent rear suspension (IRS) thing, and its Explorer SUV reflects that. When Ford is leaving you behind technically, it's usually a sign that you need to be a little more innovative.
- Wickell, Dale. HUMMER H2H Hydrogen Powered Experimental Vehicle. About.com, October 22, 2004. (http://trucks.about.com/od/hybridcar/a/hummer_h2h.htm)