Duramax V8 6.6L Diesel LB7

The LB7 (8th digit of VIN is a “1”) Duramax was introduced in 2001 and continued into 2004. It features a 32 valve design with a Bosch high pressure direct injected common rail fuel system and aluminum heads. One of the initial issues with the LB7 motor is injector failure. GMC responded by upping the warranty to 7 yr/200,000 mile warranty coverage and the motor made the 10 Best Engines List in 2001-2002. The LB7 Duramax motor features 300HP and 520 ft. lbs. of torque. Diesel Tunes Performance Chips for the LB7 adds up to 100HP and 180 ft. lbs. of torque to this model of engine. Special care was taken in the design of this performance module in consideration of the injector failure that was prevalent in the early years of production. A self adjusting pressure logarithm is programmed into the Diesel Tunes Power Module so that pressure adjustments are very gradual in order not to interfere with temperamental injector performance.

Duramax V8 6.6L Diesel LLY

The LLY (8th digit of VIN is a “2”) is a turbocharged engine which was produced from 2004.5-2005. It shares the 32 valve motor and Bosch high pressure common rail fuel system with the LB7 model and was GM’s initial try at introducing emissions requirements on trucks. They added a variable vane turbocharger and an EGR valve to assist in emissions reduction. GM also learned from the injector issues with the LB7 and adjusted the valve covers to allow injector access without actually having to remove the covers which saved a lot of money in labor if the injectors needed to be replaced. There were initial issues with overheating and blown head gaskets with the LLY motor. Diesel Tunes Performance Chips were programmed exclusively for the LLY model with special emphasis on reducing overheating by micro adjustments in the fuel plume which resulted in a faster and more complete burn of fuel. This avoided excess fuel burning in the manifold and turbo which causes increased Exhaust Gas Temperatures (EGT’s). Many Diesel Tunes customers noticed an immediate decrease in engine temperatures because of this revolutionary performance module design. The stock LLY motor features 310HP and 590 ft. lbs. of torque with the Diesel Tunes Chip adding up to 100HP and 180 ft. lbs. of torque for a formidable combination of fuel economy and sheer power.

Duramax V8 6.6L Diesel LBZ

The LBZ motor (8th digit of VIN is a “D”) was produced in 2006 and was used into the 2007 model year. It is loaded with a more substantial power tune in the software which gives it up to 360HP before adding a Diesel Tunes Chip which brings HP output to an impressive 460HP. The Diesel Tunes chip was specially designed to work in conjunction with the enhanced power tune that was programmed at the factory into the LBZ motor.

Duramax V8 6.6L LMM & LML

The LMM motor (8th digit of VIN is a “6”) was offered in 2007-2010 GMC Duramax trucks while the LML (eight digit of VIN is an “8”) was introduced in the 2011 model year. Each of these designs is an improvement over the previous engines in terms of emissions reduction and improved performance and durability. Diesel Tunes Performance Modules are available for the LMM Duramax and helps optimize combustion especially during the regeneration process/ particulate filter recycling. Very specific and detailed programming was created in order to optimize performance for the LMM motor. Diesel Tunes is currently working on a performance module for the LML motor which will be introduced in the near future. Diesel Tunes has manufactured performance modules for the Duramax since 2001 and is actively involved in providing feedback to GM in regards to performance improvement.