PONTIAC, MICH. -
GM's Duramax 6600 6.6L turbo-diesel V-8 engine
will provide higher power and torque ratings and major emission improvements
beginning in January 2004.
Silverado and Sierra 2500HD and 3500 Series
trucks with the Duramax 6600 and the Allison automatic transmission will
receive a new version of the engine with 310 hp @ 3100 rpm, 10 more
horsepower than before. The engine also features a higher torque rating of
590 lb-ft @ 1600 rpm, a 70 lb-ft increase over its previous maximum high. At
the same time, Duramax 6600 NOx emissions have been reduced almost by half.
"Since its introduction in 2001, the Duramax
6600 has re-established GM in the full-size diesel powered truck market by
increasing our share of the segment to nearly 30 percent," said Charlie
Freese, executive director, diesel engineering for GM Powertrain.
Silverado and Sierra models with the Duramax
6600 and a standard ZF S6-650 six-speed manual transmission receive the same
emissions improvements as those with the Allison 1000, with carryover power
"Over 90 percent of our three-quarter and
one-ton customers order their Duramax 6600 with the Allison 1000 five-speed
automatic transmission - prompting us to focus on power, torque and
emissions improvements, where they provide greatest benefits for the largest
number of customers," Freese said.
Both the new version of the Duramax 6600
turbo diesel with the Allison automatic transmission and the version with
the standard ZF six-speed manual feature improved hardware. The new version
also has additional software calibration changes to help provide its higher
Primary hardware changes include a variable
nozzle turbocharger, new electronic control module, next-generation fuel
injectors, electronically controlled cooled exhaust gas recirculation (EGR),
50 state catalytic converter usage, improved charge air-cooling and a closed
crankcase ventilation system:
The common rail fuel system also uses
smaller, more precisely machined and positioned next-generation fuel
injectors to inject its fuel pulses into the cylinders. The injectors are
now fully accessible, allowing service technicians to access them without
having to take the cylinder head cover off. Servicing is typically required
only every 100,000 miles or more.
The new variable nozzle turbocharger
features vanes that are now hydraulically controlled to precisely adjust the
level of boost generated by the turbocharger.
A more powerful, 32-bit, next-generation
engine control module provides the capabilities for integrated control of
the additional engine hardware. The new engine controller provides faster
microprocessor speeds, increased throughput and more memory than the
previous generation controller.
The EGR system in conjunction with catalytic
converter usage reduces NOx emissions in all 50 states to approximately 2
grams per brake horsepower hour from a previous 4 grams in 49 states and 3.5
grams in California.
Charge-air cooling is used to provide cool
dense air to the cylinders to help generate the new engine's increased
power, torque and improved emissions.
The closed-crankcase ventilation system,
although not required to meet 2004 emissions regulations, anticipates
upcoming 2006-model emissions requirements by incorporating a closed
crankcase ventilation system in which harmful vapors are vented internally
and burned as part of the combustion process, rather than being vented to
the outside atmosphere.
"The engine's high torque across the power
band helps Duramax 6600-equipped GM trucks excel in off-the-line
performance, acceleration and heavy-duty trailering and hauling," Freese
New versions of the Duramax 6600 will be
produced at GM's Moraine, Ohio facility. The engine was developed through a
GM and Isuzu Motors joint ventures (DMAX Ltd. and GMIDEL).
GM Powertrain is a global producer of
engines, transmissions, castings and components for GM vehicles and other
automotive, marine, and industrial OEMs. Headquartered in Pontiac, GM
Powertrain has operating and coordinating responsibility for General Motors
powertrain manufacturing plants and engineering centers in North America,
South America, Europe, and the Asia-Pacific region.
General Motors Corp. (NYSE: GM), the world's
largest vehicle manufacturer, employs 342,000 people globally in its core
automotive business and subsidiaries. Founded in 1908, GM has been the
global automotive sales leader since 1931. GM today has manufacturing
operations in 32 countries