Heavy-duty GM trucks have been equipped with diesel engines since 1982. Despite the fact that diesels back then were kind of horrible, they’ve been doing it for a long time.
With the help of Isuzu, they developed the new 6.6 Duramax in 2001. It has been modified numerous times since then to meet the current needs.
We’ll take a look at the 6.2 Detroit Diesel first before I tell you everything you need to know about the 6.6 D-Max.
Diesel engine 6.2
One of the most interesting things is how many people absolutely adore the 6.2 Detroit engine. The car only produces 160 horsepower and 285 lb-ft of torque. In terms of horsepower and torque, it doesn’t even compare to a gasoline engine.
In GM’s case, this was a good thing since they marketed it as an environmentally friendly alternative to their gasoline engines.
6.2 Detroits were used in AM General HMMWVs (Humvees) and on CUCVs. It may be because of its military history that the 6.2 Detroit is so popular.
The 6.2 Detroit was so popular with M General that they now operate the turbocharged 6.5L.
Engine Basics for the Duramax 6.6
Since 2001, the 6.6 Duramax engine has been available. Its architect has remained largely unchanged, despite its drastic changes. With every passing year, emissions regulations get stricter, forcing GM to make major modifications to the 6.6 Duramax.
Here are some photos of the D-Max through the years:
Duramax 6.6: LB7
From 2001 to mid-2004, the LB7 was in use. With high-pressure direct injection and 32 valves, the LB7 was equipped with a common-rail design. Overheating and fuel injector failures are some of the most memorable things about the LB7.
These issues are now covered by GM, but the LB7 will always be called that.
Power: 300 horsepower at 3,100 revolutions per minute
The torque is 520 pounds-feet at 1,800 revolutions per minute.
Duramax 6.6: LLY
LLY was first produced in 2004 and lasted until 2005. Several of the components were the same as on the LB7, but it had some improvements. Fuel injectors were repaired easier and cheaper with modified valve covers.
A few new emissions components were included in the LLY, which diesel enthusiasts did not like.
310 horsepower at 3,000 rpm
At 1,600 revolutions per minute, torque is 520 lb-ft
LBZ 6.6 Duramax
Aside from their tunes, the LLY and LBZ in 2006 are identical. The power produced was less than intended because of slight detuning to
. Tuned in mid-2005, the car now has more horsepower than before.
Engine: 310 hp @ 3,000 rpm
600 lb-ft of torque at 1,600 revolutions per minute
Duramax 6.6: LMM
GM introduced a new pickup truck body style in 2007. The LMM engine came along with it. In contrast to the LBZ engine, the LMM has more advanced emissions controls.
Several upgrades resulted in a torque increase to 660 lb-ft on the LMM.
365 horsepower at 3,200 rpm
Torque: 660 pounds-feet at 1,600 revolutions per minute
Duramax 6.6: LML
Further improvements are made to the LMM with the LML. A few mechanical changes are included, but most of the changes concern the emissions system.
Unlike the LMM, the LML does not allow you to easily plug in a tuner and crank up the power.
