Diesel Tuners for 6.6 Duramax – Buyer’s Guide!

The 6.6L Duramax is a GM DMAX engine, which is a joint venture between GM and Isuzu. The Duramax is produced in the Moraine, Ohio plant, and in 2007 they reached their first million engines produced since 2001. This diesel engine is a V8 model that comes in 8 variants, these are:


Each engine variant is completely different from the other, and some models come with multiple variants for different applications:

CodeYearsPower@rpmTorque@rpmRedline (rpm)
LBZ2006–2007360 bhp (270 kW) @3200650 lb-ft (881 Nm) @16003450
LLY2004–2005300 bhp (220 kW) @3000520 lb-ft (705 Nm) @16003200
LLY2006–2007250 bhp (190 kW) @3200460 lb-ft (624 Nm) @16003450
LML2011–2016397 bhp (296 kW) @3000765 lb-ft (1,037 Nm) @16003450
LMM2007–2010365 bhp (272 kW) @3200660 lb-ft (895 Nm) @16003450
LMM2007–2010250 bhp (190 kW) @3200460 lb-ft (624 Nm) @16003450
LMM2011–2016260 bhp (190 kW) @3100525 lb-ft (712 Nm) @16003450

There are quite several variants for the same V8 engine, ranging from 250bhp to 397bhp, and from 460TQ to 765TQ, essentially, the same engine design but the output is completely different.

Now it’s time to look at the 5 best diesel tuner for 6.6 Duramax.

List of Top-Rated Diesel Tuners for 6.6 Duramax Comparison Table:

1. Bully Dog - 40420 - GT Platinum Diesel Diagnostic and Performance Tuner for 6.6 DuramaxBully Dog 404202 pounds6.8” x 6.2” x 4.1”View on Amazon
2. Hypertech 2100 Max Energy 2.0 Tuner for 6.6 DuramaxHypertech 21001 pounds8.7” x 5.2” x 2.4”View on Amazon
3. DiabloSport 7203 Predator P2 Performance Tuner for 6.6 DuramaxDiabloSport 720311.5 ounces6.3” x 5.5” x 2.2”View on Amazon
4. Edge Products 85400 CTS2 Diesel Evolution Programmer Tuner for 6.6 DuramaxEdge Products 854001.75 pounds9.5” x 6.5” x 3.7”View on Amazon
5. Edge Products 21502 Juice with Attitude Engine Computer Tuner for 6.6 DuramaxEdge Products 215024.4 pounds18” x 10” x 4.1”View on Amazon

The Diesel Tuners for 6.6 Duramax Reviews & Buyer’s Guide:

1. Bully Dog – 40420 – GT Platinum Diesel Diagnostic and Performance Tuner for 6.6 Duramax

The Bully Dog GT Diesel is an exceptional shift-on-the-fly tuner with customizable gauges and 10 custom tunes stored in the device.


This is a Dyno Proven Performance tuner that delivers increased HP and torque with every tune.

What you also get with this model is a boost gauge, current coolant temperature status, a pyrometer and all the standard options that a modern comprehensive tuner provides. Including the speed calibration, tire size and axle ratio changes and a load of on the fly changeable tunes.


  • Accessory Delay
  • Daytime Running Light
  • Mobile Desoot
  • Diesel Particulate Filter Burn-Off enable.
  • Optical Flash on Lock
  • Pyro 1 and Pyro 2
  • Shift on Fly
  • Transmission Adaptive Learning


This is an advanced model and is perfect for the heavy duty and long road, long haul, driver.

2. Hypertech 2100 Max Energy 2.0 Tuner for 6.6 Duramax

The Max Energy 2.0 Power Programmer is specially designed to tune for towing and is emissions Certified 50-State Legal device.


When it comes to comprehensive, and a load of canned tunes ready to pop your engine’s performance, nothing comes close to the Max Energy 2.0. What you get here is a wide array of speedometer calibration, TPMS threshold adjustments, top speed and RPM limiter adjustments, and a plethora of Automatic Transmission Adjustments that includes: Shift Firmness Tunes, Shift Response and shift point tunes, as well as torque converter clutch (TCC) tunes too.

There are several Throttle Adjustments and Throttle Response Tunes that include 0-60 Throttle Restriction calibration.

This device delivers the standard read and clears DTC’s as well as manage temperatures. You also get the return to the stock feature, and all the tunes are updateable via the internet.


  • Tuning for Popular Air Intakes
  • Emissions Certified 50-State Legal
  • Speedometer Calibrator, TPMS Threshold, Top-Speed Limiter
  • Automatic Transmission Adjustments; Shift Firmness Tunes, Shift Response, TCC Slip Tunes, Shift Points
  • Fuel Management Systems “V4/V8 mode.”
  • Throttle Adjustment, 0-60 Throttle Restriction, Throttle Response Tunes, RPM “Rev” Limiter
  • Cooling Fan “On/Off” Temperatures
  • Read & Clear Diagnostic Trouble Codes(DTCs)
  • Return to Stock or Change Option Settings
  • Internet Updateable


Hypertech is a classic universal device that comes with specific tunes for most applications, especially for all 6.6L Duramax engine types.

3. DiabloSport 7203 Predator P2 Performance Tuner for 6.6 Duramax

The DiabloSport 7203 Predator P2 Performance Tuner model 7203 is specifically prepared for all Sierra or Silverado HD trucks and will add to your Duramax 6.6L engine an additional 100HP.


When it comes to preset tunes (canned and Dyno proven) its hard to be the popular market DiabloSport, and their Predator models are giving the pack a strong lead in performance.

The 7203 comes with specific canned tunes for specific applications; these include tunes for towing, and tunes for, fuel economy, and high performance. When applied correctly, you will not only increase the HP with an additional 100 but improve your MPG by 2 to 4, which is sensational saving for the long haul driver.

This model will boost your towing performance, will calibrate for tire size changes, and will read and clear all your DTC’s; you will also get up to an additional 200TQ.


  • User adjustable options
  • High-speed OBD-II Data Logging
  • Reads and Clears Diagnostic Codes
  • USB for updates and downloads
  • Save stock and custom tunes
  • 50-State Legal applications


The DiabloSport is a well-balanced tuner for the efficient driver that seeks a quick solution without too much hassle. If you just want to improve your performance without having to press too many buttons, this is the model to get.

4. Edge Products 85400 CTS2 Diesel Evolution Programmer Tuner for 6.6 Duramax

The Edge Evolution CTS2 is a cross-platform, a versatile model that delivers one of the markets most comprehensive tuning capabilities.


The Evolution CTS2 increases horsepower and torque and monitors your engine’s performance as you drive. It integrates beautifully with your dash, and you get the most comprehensive and easy to use touch screen operational models to date.

This model is a classic Edge device; it is highly-priced since it comes with more features and design specifications than most of its competition. A such you get a system that is Compatible with Expandable Accessory System (EAS). It connects into your dash for a seamless look and provides you with In-Cab Monitoring with a True Speed Display on a fully customizable 5” color screen.

This model just starts with the standard read and clear DTC’s, from there, you get capable video performance with an auto dim feature that comes with auto-testing and is internet updateable.

This device will give you over 40 different parameters to view and change, however with such versatility I suggest you just use canned tunes and don’t take the genie out of the lamp without a professional to control the unlimited power to create or destroy your 6.6L Duramax engine.


  • 5” full color, high-resolution, swipe screen
  • HDMI style plug for power and linking EAS accessories
  • Custom color mixer for gauge arcs, needles, and backgrounds
  • Fully customizable backgrounds
  • One-touch easy menu navigation
  • Notification center
  • Comprehensive digital multi-gauge display
  • Light sensitivity meter to dim screen as ambient light decreases
  • Internet Updatable


One of the ultimate devices to use, it goes beyond comprehension and delivers you with a game like addiction to tuning. Watch the road! If you are distracted by up to date information, don’t buy this.

5. Edge Products 21502 Juice with Attitude Engine Computer Tuner for 6.6 Duramax

This is the Edge 21502 Juice with Attitude Engine Computer, yup; I left the best for last.


Lest start off with the price, it indicates perfection of performance and not just name brand cost. The price is high because the device is the ultimate tuner for 6.6 Duramax engines. You do not get better than this, but you need deep pockets to own one.

The Attitude CTS2 is an in-cabin controller; you get to view and monitor the data as well as adjust it on the fly.
This model comes with a full range of options and canned tunes that delivers perfect performance for different application requirements including mileage, towing, daily driving, and performance.

Naturally, this device is compatible with Expandable Accessory System (EAS).


  • Slim, sleek case design
  • 5” full color, high-resolution, swipe screen
  • Custom color mixer for gauge arcs, needles, and backgrounds
  • Multiple gauge screen layouts
  • Fully customizable backgrounds
  • HDMI style plug for power and linking EAS accessories
  • One-touch easy menu navigation
  • Notification center
  • 6 on-the-fly adjustable power levels
  • Get up to an additional 180HP and 440 ft-lb TQ
  • Dynamic safety features
  • Improves low-end response
  • Light sensitivity meter to dim screen as ambient light decreases
  • Internet Updateable


Too much to write, too good to be true, but it is true, and honestly, I think this came from the future, I decided to get one, and now I sleep with it too!

6.6L Diesel Duramax FAQ


The LB7’s applications are the Chevrolet Silverado HD, GMC Sierra HD, medium-duty GMC Topkick, and the medium-duty Chevrolet Kodiak. The main issues with the LB7 were injector failure, which was frequent.


During 2004, the LLY phased out the LB7 and continued production until 2006. The LLY featured in the Chevrolet Silverado HD, GMC Sierra HD, Hummer H1, Chevrolet Kodiak, and GMC TopKick models. This was the first emissions controlled Duramax which was integrated with the Allison 1000 5 Speed or the ZF 6 speed manual transmission.


The 6.6L Duramax LBZ’s replaced the LLY but lasted for a very short time. The LBZ is found in the Chevrolet Silverado HD, GMC Sierra, HD, Chevrolet Kodiak, and GMC Topkick. The LBZ is the aftermarket “hot rod,” and is the last model produced without a diesel particulate filter.


The LMM arrived mid-2007 model year, phasing out the LBZ. This model came with a new diesel particulate system requirement that provided “active regeneration” to regularly clean the DPF by literally burning the collected material.


In 2011, the LML Duramax was released. This latest version of the 6.6L Duramax comes with advanced emissions equipment, which uses diesel exhaust fluid injection to reduce nitrogen oxide emission levels by 63% over the previous LMM powered trucks. It is said that the LML uses 60% newly designed components. Including an upgraded engine block casting, oil pump, high strength pistons, and connecting rods, main bearing design, and re-routed oil passage circuit.


This is the latest model, introduced in 2017. The LP5 delivers 445 horsepower and 910 lb-ft of torque. The Duramax L5P replaced the LML for the 2017 model year Chevrolet Silverado and GMC Sierra HD pickups. This model delivers 48 horsepower and 145 lb-ft of torque more than the LML. Its stand out feature also includes electronically actuated solenoid injectors replacing the standard piezoelectric injectors that were used in all models starting in 2001.

Tire Size

Between 2001-2010 GM trucks left the factory with lightweight 16-inch wheels and 30-inch highway tires. As such, a large percentage of truck powers upgrade their tire size with aftermarket options, these were usually larger than 35”. A change in the tire size means you need to change the engine tune to accommodate the new set of wheels.

What can be tuned?

Most modern tuners will let you calibrate every engine part and all electronic components for performance and comfort. This includes Camshafts, Cold air intakes, Cylinder heads, Fuel injectors, Full exhaust systems and headers, Intake manifolds, Nitrous systems, Rear gear changes, Superchargers/Turbochargers, and Throttle bodies. As well windows, locks, alarms, etc.,

Custom, Canned and Dyno

There are three types of tunes available, these are:

  • Canned: A generic preset tune that comes with the device.
  • Custom: A specially written tune, either prepared by a company or made by a professional.
  • Dyno: A shop prepared tune, where the tuner dials it in real-time.

I always suggest that you never buy a tune from an unknown source, and never tune by yourself. Custom tuning is for professionals that understand the nature of the entire operation; one change can destroy your performance, let alone an entire range of changes.

Tuning Variants

There are two variants for tuning; one is the use of chips, which come with preset tunes that you can employ at the flick of a switch. These are closed circuits, which means you cannot make custom adjustments. The second variant is Tuners, which come with open circuits that allow you to make custom changes to specific options.

Is the 6.6L Duramax reliable?

Duramax 6.6L is known to provide durable and reliable performance for 19 years. Many owners consider it to be the best engine in the world. However, some owners claim that air may get stuck in the fuel lines or fuel starvation may take place.

What is the horsepower of a 6.6L Duramax?

The peak horsepower of a 6.6L Duramax engine (2011-2016) is 397 HP at 3,000 RPM. The latest GM 6.6L L5P V-8 model produces 445 HP.

What is the fuel mileage for a 6.6L Duramax diesel?

It mostly depends on your driving habits and gearing. The fuel economy of Duramax 6.6L (when running empty) ranges from 15 to 20 mpg.

Is the LB7 the best Duramax?

The LB7 proved to be one of the most reliable diesel engines ever produced. It was introduced in 2001 and replaced by LLY in mid-2004. It featured high-pressure common-rail direct injection and a unique design cylinder head. Moreover, the LB7 has proved to deliver more torque, be more durable and efficient in terms of fuel economy. However, a few common issues with this model took place. Namely, injector failures, blown head gaskets, overheating, and oil dilution problems.

What is so special about the LBZ Duramax?

The LBZ was introduced in 2006 and was the first Duramax to achieve up to 350 hp at 3,200 rpm and 650 lb-ft of torque at 1,600 rpm. The LBZ had a huge performance potential and support abundance. It was the last model that was produced without a diesel particulate filter. The LBZ featured more aggressive engine tuning, a higher-pressure fuel injection system, a more durable engine block design, increased piston pin diameter, a thicker (than its predecessors) connecting rod section, a variable geometry turbocharger, yielding a substantial increase in horsepower and torque over LLY (the previous model). It was available for only two model years (2006-2007). Then it was replaced by LMM, which was more efficient in terms of emission regulations.

Is the 6.6L Duramax a “big block”?

Not really. More like neither “small” no “big.”

Who owns Duramax?

General Motors. The 6.6L Duramax is produced by DMAX (GM and Isuzu joint venture (since 1998) which is located in Moraine, Ohio).

What’s better: Duramax, Power Stroke, or Cummins?

These 3 diesel engines share the same fuel requirements and systems. Both the 6.6L Duramax and Ford 6.7L Power Stroke are V8 engines when the 6.7L Cummins is I6 (inline-six-cylinder diesel engine). The Cummins has a better torque (1000 lb.-ft.) and is the oldest (since 1919) diesel engine. Ram trucks are known for the Cummins engine, Chevy has the Duramax, and Ford trucks run with the Power Stroke. In terms of fuel economy, Duramax is the leader.

  • In terms of horsepower: Cummins (400 HP), Duramax (445 HP), Power Stroke (450 HP)
  • In terms of torque: Cummins (1000 lb.-ft.), Duramax (910 lb.-ft.), Power Stroke (935 lb.-ft.)
  • In terms of towing power: Duramax (23.300 pounds), Cummins (31.210 pounds), Power Stroke (34.000 pounds)

How can you tell if you have the LBZ Duramax?

The 8th digit of the engine’s VIN number is “2” in LLY and the LBZ is “D.” Besides, the badges on the LBZ are typically blue, LLY has the red ones.

What year Duramax has the best fuel mileage?

The efficiency, in this matter, depends on factors like speed, driving habits, weight, towing, etc. So results may vary. But the stock LB7 2001-2004 engines are considered to be the most fuel-efficient (around 20 mpg on cruise control). However, a few modifications will provide the same mileage, no matter the engine’s year.

What does the LBZ Duramax mean?

LBZ is one of the RPO (Regular Production Option) numbers for Duramax engines. There was also the LMK, developed by GM for full-size half-ton trucks, but this engine was never brought to life.

Does the LLY Duramax have Injector Problems?

This was the case with the LB7. To avoid the same issues with the LLY, GM changed the valve covers for easy injector replacement. However, watch out for blown head gaskets.

How many miles can you get on the LBZ Duramax?

You should get around 350,000-500,000 miles on a stock truck without major engine repair. But keep in mind that modifying parts lowers the number.

How many miles does a Duramax last?

It depends on how treated and maintained. It is supposed to last as long as you are ready to spend the money to keep it running. Unless there’s a good reason to change it when something irreparable happens. Many drivers have over 700.000 miles on their trucks.

How many miles can you get out of an LLY Duramax?

The same case as with LBZ (or any other) – it all depends on how you treat it. Many owners have over 300.000 miles on their LLYs since 2005, without any major repairs.

What Allison Transmission is in the Duramax diesel?

Allison 1000 transmission which is the standard automatic transmission for the Duramax diesel since 2001.

How often do you change the oil filter on Duramax?

Every 10.000 miles or when you see the message “change engine oil” (as stated by the manufacturer). Some manufacturers recommend changing oil between 5000-7000 miles.

Are Duramax engines made in America?

Yes. All engines are produced by DMAX in Moraine, Ohio.

What Duramax is in 2019?

The GM 6.6L L5P Duramax that was introduced in 2017.

What problems does LBZ Duramax have?

As some drivers claim, the most common troubles may be due to weak cast-aluminum pistons and wrist pin issues.

Are all 2006 Duramax LBZ?

No, there is also the LLY (engine code “2). In mechanical terms, both the LBZ (engine code “D”) and LLY engines are actually the same, with different tunes.

What oil does a 6.6 Duramax take?

Amsoil, Mobil 1, Delvac, Rotella (T6 full synthetic), Conoco Phillips (semi-synthetic) 5W-40 or 15W-40 engine oils also fit.

What years are LBZ Duramax?

The LBZ was introduced in 2006. Then, in mid-2007, came the release of the LMM.

Does 2002 Duramax have Allison Transmission?

Yes. Allison 5-speed automatic transmission.

What oil does GM recommend for Duramax?

The manufacturer strongly recommends Amsoil Heavy Duty 15W-40 full synthetic engine oil for all Duramax diesel engines, or Amsoil Heavy Duty 5W-40 full synthetic engine oil for cold weather.

What vehicles have Duramax engines?

Chevrolet and GMC trucks mainly. LLY is also used on Hummer H1 Alpha.

  • LB7 (2001-2004): Chevrolet Kodiak/GMC Topkick, Chevrolet Silverado/GMC Sierra HD
  • LLY (2004-2005): Hummer H1 Alpha, Chevrolet Silverado HD/GMC Sierra HD
  • LLY/LBZ (2006-2007): Chevrolet Silverado HD/Kodiak/Express; GMC Sierra/TopKick/Savanna
  • LMM (2007-2010): Chevrolet Silverado HD/Kodiak/Express; GMC Sierra HD/Topkick/Savanna
  • LGH (2010-2017): Chevrolet Silverado HD/Express; GMC Sierra HD/Savanna
  • LML (2011-2016): Chevrolet Silverado HD; GMC Sierra HD
  • L5P (2017): Chevrolet Silverado HD; GMC Sierra HD

What is the horsepower of a 2018 Duramax?

445 hp at 2,800 pm.

What year Duramax have injector problems?

The 2001 to 2004 model year Duramax LB7.

Is the Duramax diesel a turbo?


What size Duramax is in Colorado?

GM-exclusive Duramax 2.8L Turbo-Diesel engine (LWN). The dimensions are 25.4″(L) x 25.8″(W) x 34.1″(H). 2.5L 1-4 and 3.6L V6 options are also available.

What year Duramax have DEF?

GM has introduced the Diesel Exhaust Fluid injection system for Duramax in 2011.

How much HP does an LBZ Duramax have?

The LBZ produced 360 HP.

How much horsepower does the 2020 Duramax have?

445 HP.

How much HP does an LLY Duramax have?

310 HP.

What is EFI Live Duramax?

EFILive is a special tuning device/tool/software that is used to alternate computer parameters in the stock ECU and TCM in ’01-to-current Chevys and GMCs. This is how you access and adjust the data.

How much weight can a 2500 Duramax diesel pull?

That depends on distance, speed, and frequency. Initially the 2500HD tows around 14.500-15.400 pounds. But you can pull from 20.000 to 24.000 pounds if you upgrade the trailer hitch.

Does the new Duramax have glow plugs?

Yes. But will only come on when it needs to.

How much horsepower does a 2018 Chevy Duramax have?

2018 Chevy Duramax has 445 HP @ 2,800 rpm.

Did Chevrolet build a Duramax-powered Suburban?


How much torque does the new Duramax have?

910 lb-ft. at 1,600 rpm (2018 Duramax)

How big is the fuel tank on a 2017 Duramax?

The fuel tank capacity for 2017 trucks is 21.0 gallons for (mid-size) and 26.0-36.0 gallons (full-sized).

How much does a 6.6 Duramax weigh?

All 6.6L Duramax engines weigh approximately 835 lbs.

How does a Duramax diesel work?

Diesel engines operate much like a gasoline engine. Inside the engine, controlled combustion in a cylinder chamber causes pistons to move up and down, which forces a crankshaft to rotate. However, the combustion process is different when it comes to a diesel engine, due to the fact that diesel fuel is different than gasoline. We are talking about spark-ignition (gasoline engines) vs compression-ignition engines (diesel) here. Diesel fuel gets into the combustion chamber at high pressure when the air inside this cylinder is compressed to a high-pressure level. There’s no need for a spark/spark plug to ignite the diesel fuel since the air inside the cylinder grows hot enough to do that.

Which Duramax gets the best mpg?

The first 2001-2004 models with the LB7 engine RPO marking have the best mileage.

When was the first Duramax diesel made?

Duramax has replaced the 440 lb-ft Detroit diesel with the 500 lb-ft LB7 in 2001.

Does Duramax have aluminum heads?

Yes. Always had. But that’s the last thing to worry about.

How many valves does a 6.6 Duramax have?

Four valves per cylinder.

How much oil does a Duramax 6.6 hold?

10 quarts (with filter).

What is LMM Duramax?

The LMM is an RPO for the Duramax engine produced in 2007, which famous for its emission-friendliness (up to 90% cut emissions compared to previous generations). The engine met strict EPA regulations for 2007. The engine featured the Allison 1000 six-speed automatic transmission, 365 HP @ 3.100 rpm, and 660 lb-ft @ 1,800 rpm. The dimensions of the LMM are 30″(L)x30″(W)x32″(H). It was replaced by the LGH in 2010.

What engine is in a 2002 Duramax?


What year did Duramax get EGR?

2004. The LB7 trucks did not have an EGR system (except for a California emission vehicle).
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About the author

Jim Malkovich

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