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Kennedy Custom Tuning for Duramax LB7, LLY, LBZ, LMM, and LML
Kennedy Custom tuning is developed in house by yours truly John Kennedy using EFI Live tuning software. It is my preferred way to improve power, economy, and drivability on the Duramax. There is no added hardware to fail, no tune downloading to lock up the ECM, and if you keep the stock ECM you can revert back to stock in a matter of minutes without so much as a trace of evidence showing that the vehicle has been altered. I have personally run and tested just about every aftermarket tuning device available for the Duramax diesel trucks including extensive street, towing and Superflow dyno time. I own three Duramax equipped trucks (02 LB7, 05 LLY (sold after 100,000 miles of use), 07 LBZ and 12 LML) and have tuned as well as set up many of the most successful Duramax truck pullers and drag racers. I also do a lot of tuning for the Average Joe who tows or is simply looking for an economy boost. The diesel business is more than just a hobby for me, it's my life. Kennedy Diesel also offers a very complete line of service parts in addition to our performance line of products.

Tuning options:
Tuning is designed to cover three basic categories covering a wide range of driving conditions: Economy/Tow, Performance, and Race. Many people have no desire to race or compete with their trucks but want enhanced performance. Some want the best economy, some want improved towing performance and others want to be able to dust the guy in the other lane at a stoplight. We can accommodate all of those aspects with Kennedy Custom tuning. The Economy/Tow tunes are typically more laid back in their nature providing improved response without being overly aggressive. Performance tunes are generally more aggressive, and geared towards those with performance built transmissions, but can also help with economy if one can exercise restraint when driving. Response is quite lively, yet smoke is generally kept to a minimum. Race tuning is the most aggressive and can produce a fair amount of black smoke. I typically try to tune to the "clean" side except for cases where maximum Race performance is the objective. Generally my Race tuning is smooth and progressive enough to drive daily. The Race tune can also perform tow duties provided the driver respects the rest of the drive train and uses common sense when driving. Fuel economy can also be just as good as my Economy tuning if the driver can exercise restraint. Many of our customers tow large travel trailers to the track, unhook, and proceed to race with the same tuning.

Switchable tuning:
With Kennedy Custom switchable tuning you can have multiple tunes available controlled by a simple switch. These tunes can range from basically stock tuning all the way up to the Race tuning covering multiple steps along the way depending on the user's needs and vehicle configuration. Switching can be done on the fly and is available for the 01-05 Duramax LB7 and LLY models only.

Application of tuning:
At present Kennedy Custom tuning is loaded in-house to your ECM, or to a Kennedy Diesel supplied core ECM. Once loaded, the ECM is locked to provide copy protection and to prevent the accidental loss or overwrite of tuning. Many people purchase a Kennedy Diesel core ECM so that they can keep their original ECM in case of emergency or for warranty service.

Ordering Tuning:
In order to develop a custom tune for your vehicle Kennedy Diesel needs as much information as you can provide. The complete VIN number, the tire size (see below) for speedometer calibration, the intended vehicle use and any other modifications such as turbo, injectors or transmission upgrades will be required. These notes can be sent in via email or added to the Customer Comments-Shipping Instructions blank at the time of order placement, or sent in an email to me. I prefer to have all pertinent details in a single email document so that I can easily access it if a question arises during production.

Tire size/speedometer calibration
Every tire manufacturer specs out their tires in revolutions per mile. This spec is what I use for speedometer calibration. While on the surface one would thing that the P metric number (265-75-16 etc) would suffice, there can be a large variance in actual dimensions between manufacturers and even among same size tires of different models. Using the revolutions per mile spec we are about as accurate as one can get. An example of this spec can be found here:
Use this only as an example. You will need to identify YOUR tire Make and Model along with size and use the data provided by the manufacturer. Tire calculators will not give accurate results. Michelin for example, has 3 different LTX 265-75-16E tires all with different revs per mile specs.