Edmunds Rides the H3 Alpha

[Flybrian]

Assaulting Paved Terrain With a New V8

By Ed Hellwig, Senior Editor Email | Date posted: 07-12-2007 | Link to Original Article @ Edmunds

In order to create the new, more powerful 2008 Hummer H3 Alpha, the engineers at GM's off-road brand had to take a couple steps backward.

The standard H3's inline five-cylinder might be technologically unique and suitably tractable for off-roading, but it's hopelessly overmatched by the H3's weight, especially on the road. So, sure enough, the Hummer engineers adopted an idea that's been around at GM for half a century — V8 power.

With the 2008 Hummer H3 Alpha, GM hopes this addition to the H3 model range will broaden this SUV's appeal beyond the hard-core rock-crawling crowd. It's a logical move and it's long overdue.

Not a Plug-and-Play Proposition

When we grilled the Hummer engineers about the H3's overdue adaptation of V8 power, they offered up a number of explanations.

For one, the H3 shares its frame with the Chevrolet Colorado/GMC Canyon pickup, which was never designed to accommodate a V8 engine. Since the space between the frame rails was sized only for the narrow inline-5, adding a V8 hasn't been a simple plug-and-play option.

The engineers also note that Hummer has addressed the output of the five-cylinder by increasing its displacement from 3.5 to 3.7 liters. The H3's standard five-cylinder now produces 242 horsepower and 242 pound-feet of torque.

But we must note that the engineers also shrugged their shoulders plenty of times, so it's clear that there's plenty of corporate acknowledgement of the I5's deficiencies.

Add Some Aluminum, Then Some Iron, Too

Sourcing a V8 for the H3 Alpha wasn't a problem, as Hummer settled on the same aluminum-block 5.3-liter V8 found in the latest Chevrolet Silverado/GMC Sierra pickup. In the H3 Alpha, this V8 is rated at 300 hp and 320 lb-ft of torque. These numbers are slightly below those produced by the engine in its pickup truck application because the H3 uses more extensive emissions hardware. Yes, the Hummer H3 Alpha emits fewer pollutants than its truck counterparts, so it's as green as it can be.

Getting the wider V8 to fit into the H3 required several small modifications. Both the firewall and the frame rails had to be reshaped and new motor mounts added. A revised oil pan maintains the engine's oil pressure during off-roading across extreme terrain. Meanwhile, every 2008 H3, regardless of engine configuration, gets a revised rack-and-pinion steering system to improve road feel on the highway.

Once the H3 had been altered to fit the V8, a few other specifications had to change for the Alpha model. Among other things, the lightweight aluminum differential has been replaced by an older but stronger cast-iron unit. "We had to make the switch to handle the extra torque of the V8," says Daryl Ehrlich, the H3's powertrain engineer. "Using cast iron adds a little weight, but it's very tough, so it's good for serious off-roading."

And off-roading matters with the H3 Alpha. More than a third of H3 owners take their rigs off-road, the Hummer people tell us, and that's probably why the tractable inline-5 hasn't aroused more complaints, despite its anemic performance on the highway.

A set of 4.10:1 axle gears comes standard with the H3 Alpha in place of the standard model's 4.56:1 ring-and-pinions, yet even with the taller gears the Alpha's maximum tow rating is up 1,500 pounds to 6,000 pounds. GM's fuel mileage estimates for the Alpha V8 are 13 mpg city/16 highway, not far off the standard inline-5's 2008 numbers of 14 mpg city/18 highway.

Transformed It's Not

Although GM's 5.3-liter engine is a hearty motor, we're driving in Durango, Colorado, and the air is a little thin at 6,500 feet. Since horsepower declines about 3 percent per 1,000 feet of altitude, we expect the H3 Alpha will feel a little soft. Less oxygen doesn't keep it from sounding better, as the low, muscular hum from the V8's exhaust is just about right for a butch SUV like the H3. Compared to the raspy sound of the standard inline-5, the Alpha sounds like Bigfoot.

As we head through town, the V8 doesn't make much of an impression. The throttle response is a little better and 1st gear has some real push to it, but it's not a transformation. After all, the H3 Alpha still weighs 4,854 pounds — 100 pounds more from the V8 and an additional 60 pounds from the cast-iron differential.

It's not until we merge onto the highway that the added 58 hp and 78 lb-ft of torque produced by the V8 become a little more evident. While the inline-5 runs out of steam after 4,000 rpm, the V8 pulls hard through each gearchange. Not that there are very many of these, as a four-speed automatic is the only transmission choice for the Alpha.

The Alpha actually has the power to pass slower vehicles, but you still need a good run to do it safely. There's also an added sense of refinement, as the V8 never sounds as labored as its five-cylinder counterpart.

Hummer estimates acceleration to 60 mph in 8.0 seconds flat for the H3 Alpha. Given that we tested a V8-powered Toyota 4Runner four years ago that did it in 7.6 seconds, the H3 Alpha isn't exactly breaking new ground here.

Even Better Off-Road

Once we get to the Hummer's natural habitat of boulders and sand washes, the H3 Alpha finally feels at home. At these speeds, the big V8 is less of an advantage, as the inline-5 had little trouble powering the big truck at 2-3 mph.

It's still nice to have the V8's torque, instead of relying solely on the gears to do the work. Hummer has tuned the V8's throttle response specifically for off-road tractability, so even in the low range of the transmission's transfer case it's easy to roll on the power without spinning the wheels. A revision to the traction control system for 2008 also allows us to use left-foot braking without overriding the system, so it's even easier than before to pick our way over massive boulders.

Once you add the Hummer off-road package with its locking differential, larger tires and 4:1 transfer-case gears, the H3 Alpha is one of the most seriously capable SUVs you can buy short of a Jeep Wrangler.

Competing in a New Price Category

The 2008 Hummer H3 Alpha naturally has its own exclusive interior trim and options list, and it adds up to a base price of $38,645, roughly $4,000 more than the base model with the same options.

It looks like big money for an engine upgrade, but it's no more than you would pay for a V8-powered Toyota 4Runner or Jeep Grand Cherokee. And far less than a Volkswagen Touareg or Land Rover LR3.

A V8 engine still doesn't make the 2008 Hummer H3 Alpha powerful enough to deliver carlike performance on the road, but it does give an added dimension of useful highway capability to what remains a hard-core off-road machine. If you're serious about the dirt, an H3 Alpha is what you want. The V8 just makes it possible to live through the time until you can get it dirty again.

[FUTURE_OF_GM]

Not bad... But the Transformer pun and the Toyota reference pissed me off.

(Trying to kill the GM-Transformer buzz and comparing GM to it's arch enemy to make the GM model look way outdated)

[BuddyP]

What's up with the worthless milage numbers??? 16 hwy?? Doesn't a new heavier Tahoe get 16 city?