ENGINEERS FOR Hall give tips for 4x4 H3 mods

[h2co-pilot]

http://www.detnews.com/apps/pbcs.dll...706270330/1149


.... they took a standard Hummer H3 and did some modifications that can serve as a template for anyone interested in taking his or her H3 more toward the extreme of off-roading.

Two things the engineers needed were: increased ground clearance and clearance to mount a set of LT315/75R16 tires that are 35 inches in diameter. The standard H3 comes on 32-inch tires.

Going to 35-inch tires was vital to the work the engineers needed to do, said Todd Hubbard, H3 vehicle dynamics engineer.

Hubbard added that 35-inch tires also are something that serious off-roading H3 owners will want to consider. However, he suggested those owners not go to the extremes the engineering team did. Instead, he said all they really need to do is to do a one-inch body lift, which can be done with a dozen one-inch spacers and longer bolts.

He noted that the H3 brush guard can be adjusted to hide any resulting gap at the front of the vehicle and that the H3 fan shroud can be rotated to prevent the possibility of rubbing.

Hubbard said this setup is practical and maintains a lower center of gravity than the more extreme measures on the engineering truck, which features a four-inch Rancho front suspension lift (see www.gorancho.com).

After installing the kit, GM engineers and technicians at the Milford Proving Grounds modified the H3's rear suspension -- inverting some factory parts and fabricating others -- to raise the back end level with the front.

They also installed an electrically locking front differential, which is not yet available on the H3, and the wheel flares that are standard on the H3 in some overseas markets (those flares can be ordered through any Hummer dealership, Hubbard added).

Those flares were needed to fully cover the larger tires, which the engineers mounted on two-piece bead-lock wheels that were originally built for use by the Border Patrol. Off-roads often need to air-down their tires for enhanced traction and the bead lock setup means tires can be run at zero air pressure if needed. However, the wheels the engineers selected had to be modified to fit the H3 lug pattern and to provide the proper offset. Hubbard suggested that H3 owners should be able to find wheels for their 35-inch tires through standard off-road aftermarket suppliers.

The result with either with the simple one-inch lift or the more extreme Rancho package should be an H3 that takes its off-pavement capabilities to the extreme.

[marin8703]

nice tips

[stagger_lee]

I dont know about the front locker, but the pics look nice. I hate flares, but rims are saweet! I want beadies.

[usetosellhummer]

WTF shackles? naaa I keep it just the way she is thank you. I want those bigg a$$ fender flairs from Japan!

[Desert Dan]

What did they do with the rear suspension? A Spring over conversion?

I'll take the front locker, any part number out there?

[dochummer]

that should be how the alpha comes standard...

Nice mods that work. Even the fender flares are subtle. Too many lifted rigs are really setup to just look cool at the supermarket.

[HummBebe]

The first part of the article below...

Engineers make extreme Hummer:

Soup it up
Engineers make extreme Hummer
Larry Edsall / Special to The Detroit News

As part of their support of Rod Hall's off-road racing team, Hummer engineers needed a vehicle for testing components they were developing for Hall's Baja 1000 race vehicle.
So they took a standard Hummer H3 and did some modifications that can serve as a template for anyone interested in taking his or her H3 more toward the extreme of off-roading.

Here is a description of the mods on Rod Halls H3... http://www.entertainmentengineering....1/EE_v3i11.pdf

Article starts on page 9

As for the springs, the Team HUMMER H3 uses

higher-rate front torsion bars than production and the
rear leaf springs are stock components. The vehicle’s
factory 16-inch wheels provide a stock appearance, but
to accommodate the taller-than-stock 35-inch-tall tires,
the body was raised on the frame by one inch, using
solid body mounts.
The racing H3’s engine is based on the production
3.5-liter inline five-cylinder engine. Per the rules,
Team HUMMER made minor internal changes while
retaining the original cylinder block and head. A raised
compression ratio boosts horsepower to 248 and torque
to 238 lbs.-ft. The compression change enables the
engine to perform well on 100-octane racing gas. Also,
the engine-driven cooling fan was replaced with electric
fans freeing up some horsepower. The engine draws

air through a stock air cleaner mounted in the cab and

sends exhaust out a custom, low restriction exhaust
system.
The H3’s factory-installed Hydra-Matic 4L65 fourspeed
automatic transmission is used, with only slight
calibration adjustments. It sends torque to the stock
transfer case and axles, which use the factory 4.56:1
gear ratios. The stock oil and transmission coolers are
used, but an auxiliary trans cooler also is employed.
The most dramatically altered area of the racing H3 is
the purpose-built interior. It has been stripped of all its
upholstery, trim and convenience features and replaced
with only safety items and racing control items. The
trim panels, carpeting and other accoutrements are
removed in order to help offset the weight of a custom,
protective roll cage, which crisscrosses the interior.
Also included in the interior is a fire suppression system
routed to the engine, several fire extinguishers and a 44-
gallon fuel cell.
A pair of front racing seats replaces all of the H3’s
stock seats; one for the driver and the other for the codriver.
Racing five-point safety harnesses also replace
the factory safety belts (the air bags are deactivated
for racing). Air conditioning is eliminated, as it saved
valuable weight.
The H3’s instrument panel is stock and all the original
gauges are functional, but they are complemented by
a custom control panel and a PI Research data logging
system, which provides feedback on key powertrain
operations. A tracking system also provides real-time
positioning information that allows race officials and
anyone with an Internet connection the ability to track
the vehicle during a race. This is helpful in ensuring
the vehicle accurately followed the course and provides
location information in case of a crash.
“Performance in off-road racing isn’t just about speed,
it’s about strength” said Stump. To track the Team
HUMMER in the 39th SCORE Tecate Baja 1000 on
your computer, follow the link below on November 16

and 17.