Top 10 6.6L Duramax Tech Articles

The third diesel engine in our tech article recap is GM's 6.6L Duramax, which came on the scene in 2001. The powerlant, code-named LB7, was the first modern-era oil-burner to feature common-rail fueling (Cummins didn't enter that arena in 2003), and it put out 300 hp and 520 lb-ft of torque.

In subsequent years, LLY (2004.5-2005), LBZ (2005-2006), LMM (2007-2010), LML (2011-2016) and, L5P (2017-present) engines were produced, with power and torque increasing for each one.

"Which Duramax is best?" is a question we're frequently asked. Because there are so many variants and they all have virtues, it's hard to declare one powerplant superior. For example, LB7s and LLYs do not have much emissions hardware and the desired quality for those who wish to modify. However, Duramax LBZ engines are extremely popular, because their performance—310 hp/605 lb-ft—can easily be increased because they also are void of much restrictive smog equipment. Later DMax engines "make more" power, but that typically happens after emissions equipment is bypassed.

Our Duramax-tech content is similar to the work we've done with 5.9L Cummins and 7.3L Ford Power Stroke engines. Here are 10 articles that focus primarily on the power side of modifying, because making gains in that space is really where it's at with Duramax engines.