Have you driven a Hummer H1 lately? We have, and from a diesel perspective, things have gotten a lot better since Hummer finally defected from the technologically ancient 6.5L turbodiesel engine. The inclusion of the remarkable Duramax 6.6L turbodiesel for 2006 has such a positive impact on the H1's performance it's staggering. We'll get to that in a minute. First, we have to briefly dissect the H1 for those of you whose knowledge of said vehicle is limited to viewing it in rap videos or seeing it valet-parked at your local Four Seasons.
If you were to cast a quick glance at our Diamond Metallic '06 H1 Alpha, you would probably only notice the new Alpha badging. The reality, though, is that the Alpha's body is positioned 2 inches higher than the previous 6.5L-powered H1. This body modification was needed to facilitate fitment of the Duramax diesel engine and Allison 1000 transmission. Other new exterior changes for the '06 include a redesigned brushguard and brighter finish aluminum wheels.
With the rear swing-open cargo doors in their full open position, accessing the cargo area was easy. This Hummer offers 58.3 cubic feet of space, and it's lined with easy-to-clean carpet.
The H1 is a direct descendent of the military's M998 Series High Mobility Multi-Purpose Wheeled Vehicle (HMMWV), more commonly known as the Humvee. The H1, a civilianized version of said vehicle, was introduced in 1992. Over the years, it has undergone a few changes-arguably the most notable being the addition of a turbocharger to the 6.5L diesel in 1996 and an interior restyle in 2004. It's very important to realize that the H1 is based on a vehicle originally designed for the military, because then you'll understand why it's designed the way it is and why it has certain traits not found in mass-produced SUVs. First and foremost, the H1 is an off-highway vehicle that harbors spectacular capabilities. It sports breathtaking approach and departure angles of 72 and 37.5 degrees, respectively; a righteous minimum ground clearance of 16 inches; a puckering side slope capability of 22 degrees; and a fish-viewing water fording depth of 30 inches. No, you won't use or appreciate these numbers on the interstate or at the country club, but you'll fall madly in love with 'em on a gnarly trail.
The Duramax engine didn't just jump into the H1. As a matter of fact, a number of significant modifications had to be made to the H1 in a variety of areas. Engineers had to redesign the Duramax oil pan to ensure that it didn't protrude past the H1's framerails and screw up the smooth, protected underbody. The oil pick-up and baffles inside of the pan were also changed to prevent oil starvation at the extreme angles the H1 was designed to operate. They also had to design a new cooling package. The performance improvements were well worth the trouble. The Duramax 6600 spits out an impressive 46 percent more horsepower than the previous 6.5L Optimizer Turbo Diesel. Further, the Duramax produces a welcome 18 percent more torque. These numbers translate to power you can feel under your right foot. We were awed by the vastly improved power, and we found that it helped propel the 7,558-pound rig from zero to 60 mph in less than 14 seconds, which is about 3 seconds faster than the non-Duramax '05 model. We found it interesting that the Duramax was far more vocal at idle and speed than the Duramax found in the GM pickup trucks. This is due to a shorter length, larger-diameter exhaust. As in the GM light trucks, the Duramax is mated to the awesome Allison 1000 five-speed automatic transmission, and as expected, this proven combination works exceptionally well in the H1. Not all H1s get the Duramax, however. Fleet vehicles and Humvees still get the 6.5L turbodiesel.
As has always been the case, the H1 uses a beefy four-wheel independent suspension consisting of coil springs and double A-arms. The front suspension also includes a 27mm stabilizer bar. New for 2006, the inboard-mounted brakes have been enhanced with 12-inch-diameter rotors (1.3 inches larger than the '05 model). To handle the increased output of the Duramax engine, the half-shafts and steering gear have been bolstered, and the geared hubs have been redesigned with a helical-cut gearset that improves gear engagement and reduces both the noise and rocking motion during deceleration and stopping maneuvers.