Benza - 12/10/2003 2:23 PM
Tim - 12/10/2003 9:33 AM
The H2 is a "show off" SUV built on a Chevy Tahoe platform.
The H2 chassis is a three-piece, fully welded, boxed ladder-type frame with hydroformed components in a number of locations to maximize strength while limiting weight.
Though the H2 began life using more of a Suburban frame, the final frame assembly is made up of 3 sections. The front uses a modified GM 2500-Series utility frame. The mid-section is ALL NEW
and is completely boxed. The rear section uses a modifed GM 1500-Series frame which is upgraded for 8000 pound gross vehicle weight. Front and rear receiver mounts with 9000 pound winch capability are integrated into the frame. The rear hitch has an estimated 7000 pound capacity.
"We share chassis and steering components with the heavy-duty 2500-Series Suburban and the 1500 Suburban," says Charlie Martin, the vehicle systems engineer for the Hummer H2 chassis and drivetrain. "But most of those shared parts have been heavily modified
All new components include the H2's center frame as well as the flat crossmembers that are used around the transmission mounting area.
A unique design of the H2 is all of the drivetrain components are mounted flush with or above the frame rails. This design allows the H2 to actually slide over obstacles that would otherwise hang up other trucks or SUVs.
In addition, the H2 incorporates special underbody protection. The forward most is a thick aluminum shield the runs from below the front bumper back to the transmission. That overlaps a 1-inch thick tubular, ladder-type shield that protects the transmission and catalytic converters-and the tubular skid plate can actually support the weight of the H2 for brief periods of time as it slides over obstacles.
The H2 can safely charge into six inches of water at 40 mph, for example, or travel through streams more than 20 inches deep at a leisurely 5-mph pace. It can also comfortably and confidently climb 16-inch steps and rocks, without getting hung up or jarring its passengers. And it can paddle through deep sand or run over sandy surfaces in high-speed desert conditions with remarkable ease.
Where fording streams is concerned, the H2 is good for 20-plus inches of water. Those numbers are still better compared to the gamut of factory sport-utility 4x4s on the market.
As for the Drive system the sophisticated
four-wheel-drive system and transfer case are versatile and driver-selectable. The integrated Borg-Warner two-speed electrically controlled full-time 4WD system is capable of further reducing the vehicle's gear ratios by 2.64:1 when necessary, for highly controlled obstacle climbing. It provides a 40/60 percent front-to-rear torque split in "High Open" mode or when the differentials are unlocked and a 50/50 percent front-to-rear power split when the transfer case differential is locked. A specially designed low-range throttle progression allows the driver to precisely control engine speed (and as a result, the vehicle) during very rough terrain driving, and is automatically engaged when the transfer case is in "4 LO."The transfer case controls provide five mode selections, four of which can be accessed by dash-mounted button selectors. The fifth mode, neutral, is available by simultaneously pressing two of the button selectors. Selections include:1) A high-range open or "4 HI Open" for normal, everyday driving on dry road surfaces at any speeds.2) A high-range lock or "4 HI Locked" for semi-slippery surfaces like snow, light sand or wet areas, such as those around a boat launch; this selection locks the front and rear output shafts together, so their wheels rotate at exactly the same speed.3) A low-range lock or "4 LO Locked" for severe off-pavement use, such as crawling over large rocks or logs. In addition to locking the two propshafts together, it provides a 2.64:1 gear reduction in the planetary gearset. By lowering the ratios of each of the gears, it adds the equivalent of another, extremely deep-ratio first gear and provides a great deal more torque for slow-speed climbing. Low Lock also activates a new, more measured throttle progression curve, which greatly enhances off-road driving comfort and control. High and Low Lock also allow a driver to select a different set of calibrations for the traction control system, using a separate "TC2" button. This provides additional wheel slip for select operating conditions and road surfaces, such as paddling through deep sand.4) An Eaton electronic rear differential lock or "4 LO Locked + Rear Diff Locked," available only when the transfer case is in Low Lock position. It permits locking up the rear differential for optimum slow-speed capability in climbing over large rocks or up long, steep grades. It locks the two rear axle shafts together so they rotate at exactly the same speed-and does so electronically. (Since this mode can only be accessed when the transfer case is in Low Lock, the front and rear propshafts are already locked.)5) "Neutral," obtained by simultaneously pressing the "4 LO Locked" and "4 HI Open" buttons and holding them down for 10 seconds. It permits flat-towing the H2 behind another vehicle.
The Single Wheel traction control system provides additional capability under certain operating conditions. The system detects a slipping wheel and applies brake pressure to it to slow it down, transferring torque across the differential to provide traction for the wheel on the opposite side. The system senses any slipping wheels and applies the brakes to them individually, while the driveline and differentials transfer torque to the wheel with the high traction for added traction. A driver could have as many as three wheels on a slippery surface with virtually no traction and still get enough torque out of the fourth wheel to propel the truck up a 10 percent grade.
With three transfer case selections, two rear axle differential selections and two modes provided by the TCS mode switch, the driver actually has total of seven driving mode selections, providing unprecedented versatility to tailor H2 performance to match driving conditions.
Because of H2's full-time 4WD system, GM engineers also took great care to minimize the NVH transmitted by the front axle to the frame, devising a special three-point mounting system to isolate it. Two forward mounts vertically connect the axle to the frame, while the rear mount attaches it to a crossmember that fits between the two lower control arm brackets in the frame.The front frame section incorporates a GM-first standard winch receiver. It is designed to handle an impressive 9,000-pound capacity winch for freeing a vehicle that's helplessly grounded. An extension for the receiver could also be used for adding such accessories as a bicycle rack. The receiver itself has the same diameter as the standard integrated rear trailer hitch receiver. Therefore, the front receiver could also be fitted with a hitch that would allow pushing a boat into the water, for example. The winch platform, including the receiver and a bracket, is built right into a thick front crossmember as an integral part of the vehicle's design. Paired tow loops up front complement the distinctive HUMMER-style rear pivoting tow loops.The mid-frame has a stamped-steel box section design, with common inner and outer sections and a clamshell-welded configuration. Its strength and stiffness help minimize ride and body vibrations, contributing to a smooth ride on-road and providing the strength and stiffness required to handle severe bumps and jolts. As in other GM SUVs, the composite fuel tank (with large, 33-gallon capacity) is mounted inside the left frame rail, ahead of the rear axle, for maximum protection.The hydroformed, short rear-frame section helps create a high departure angle. It is heavily reinforced in key areas for H2's 8,600-pound GVWR capacity. The rear section incorporates a standard, integral trailer hitch receiver. Unlike with most SUVs (whose hitch receiver is added on), the H2's is built right into the last crossmember of the frame rail and developed into the bumper. A Class 3 trailer hitch is standard
Let me assure you that this is no Tahoe or Suburban!
Have you ever seen a Tahoe like this?