2007+ 6.6L Duramax

The LMM debuted part way through 2007 and ended production with the start of the 2011 calendar year and is mated to the 6-speed Allison transmission. The LMM was the only Duramax offered for model years 2008-2010.

The 6.6L RPO LML is the latest version (2011–present) of the Isuzu/GM Duramax V8 diesel engine and actually a further advanced version of the LMM engine with the majority of the changes addressing a required drastic reduction in engine emissions. Some mechanical aspects of the engine, such as piston oil flow design for improved temperature control and oil pump design, were also improved to enhance durability even further.

The LML engine was significantly updated for 2011 to provide improved exhaust emissions that comply with the new federal emission standards for diesel engines, provide better engine rigidity and further noise reduction. New 29,000 PSI piezo injectors, a complete fuel system-hardening to tolerate up to 20% biodiesel mixtures and urea injection (to reduce Nitrogen oxides) with a 5.3 gallon urea tank are updating the fuel and emissions systems. This engine has a fuel injector in the exhaust tract, to allow raw fuel injection during the particulate filter recycling routine. The RPO LML engine is rated at 397 horsepower (296 kW) at 3000 rpm and 765 lb·ft (1,037 N·m) of torque at 1600 rpm.

DPF Delete (GM)

A Diesel Particulate Filter, sometimes called a DPF, is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine. Wall-flow diesel particulate filters usually remove 85% or more of the soot, and can at times (heavily loaded condition) attain soot removal efficiencies of close to 100%. A diesel-powered vehicle equipped with functioning filter will emit no visible smoke from its exhaust pipe.

The DPF can hinder performance, mileage and reliability. The DPF filter installed on the latest generation of diesels reduces power by reducing exhaust flow, reduces fuel economy by using diesel to burn accumulated particulate and reduces engine life by allowing uncombusted fuel to seep into and dilute engine oil. Deleting the DPF system has become an extremely popular modification.

Key Benefits

  • Prevent oil dilution
  • Greatly improve engine longevity
  • Add over 100 horsepower and 200 lb/ft of torque
  • Fuel savings of 3-8 MPG depending on application
  • No longer need to add diesel exhaust fluid

Although these kits are extremely popular, they are considered off-road/race only and will void your original manufacturers warranty. Liability waiver must be signed in order to purchase any DPF Delete products.

EGR Valve/Cooler Delete (GM)

In a diesel, the primary function of the EGR system is to lower the amount of nitrous oxides (NOx) produced by the combustion of the diesel fuel.. A portion of the engines exhaust gas is recirculated into the enine and combusted again. The problems with the EGR system arrise when the particulate being reintroduced into the engine, begins to clog the intake and EGR valve. Deleting the EGR is a popular modification that will increase the engines reliability. Tuner required.

Key Benefits

  • Eliminates soot build up and clogged EGR Valves
  • Coolant tempatures run cooler because they are not running thru EGR Cooler
  • Hot exhaust gasses are not being re-routed back into the motor


H&S Performance Mini Maxx DPF Delete Race Tuner

The Mini Maxx race tuner is part of the next generation of diesel downloaders from H&S that offer everything a diesel owner could want, all in one high-tech unit. Exclusive to H&S Performance, the Mini Maxx offers the flexibility of shift-on-the-fly tuning, as well as giving you the ability to monitor vital engine and transmission statistics at a glance.

The Mini Maxx comes loaded with 4 power levels that can be changed at any time, on the fly, and is sure to leave the competition in the dust. When you are ready to step up to the next level of performance, step up to the Mini Maxx!

Standard Features

These are generic features that come on all Mini Maxx Tuners.

  • Comes preloaded with DPF Present and DPF Removed capable tuning
  • Allows removal of the DPF system and ALL related sensors
  • Reads/Clears Diagnostic Trouble Code
  • Internet Update-able with included SD Memory Card & USB adapter
  • Automatic safety backdown. adjustable by EGT, Boost, Trans. Temp, and Coolant Temp
  • Mini Maxx can only be installed on one vehicle at a time!

DYNO RESULTS – Duramax LMM (Shift-on-the-fly)

  • Stock HP
  • Mild: 60 HP
  • Wild: 120 HP
  • Hot: 175 HP

DYNO RESULTS – Duramax LML (Not Shift-on-the-fly)

  • Stock HP
  • Mild: 50 HP
  • Wild: 100 HP
  • Hot: 150 HP