Last Updated: 22.07.2021

The Best Diesel Tuners for 6.6 Duramax – Review and Buyer’s Guide

The 6.6 GM Duramax is a powerful engine produced by General Motors and Isuzu and has been a great choice for pickups, vans, and medium-duty trucks because of its performance. Although it does perform well, you might have notice that you’re limited in several ways, not because of the mechanical factors, but in how the engine control unit (ECU) is calibrated by the truck manufacturer. But there’s a way around this! You can maximize its capabilities and improve its drivability and fuel efficiency through truck tuning methods using our recommended best diesel tuners for 6.6 GM Duramax below.

The 4 Best Diesel Tuners for 6.6 Duramax:

  1. BULLY DOG 40420 GT PLATINUM PERFORMANCE TUNER – the best diesel tuner for 6.6 Duramax
  2. DIABLOSPORT PREDATOR P2 PERFORMANCE TUNER – the best budget diesel tuner for 6.6 Duramax
  3. EDGE 85400 CTS2 DIESEL EVOLUTION PROGRAMMER – a sleek looking Duramax tuner
  4. HYPERTECH 2100 MAX ENERGY 2.0 POWER PROGRAMMER – Duramax programmer

Our Recommendations

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All the information and opinions you find on come from a team of automotive journalists and an independent mechanic, Steve “Whip” Whipple with 11 years of auto industry experience. We look at the latest market research, talk to experts, and draw from our own practical experience to bring you reviews and guides that reflect what you’ll encounter in your garage. For more information about the team, see here.

1. BULLY DOG 40420 GT PLATINUM PERFORMANCE TUNER the best Duramax tuner

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The Bully Dog 40420 GT Platinum Performance Tuner has impressive and unique software features, which is why it has made it on top of our best diesel tuners for 6.6 Duramax. Even though it’s pricey, you get an all-in-one performance booster that not only increases the horsepower and torque of your truck, but it also serves as a monitor to help you see your driving style based on data and solve potential errors that could mess up any trip. The Bully Dog is compatible with all the GM Duramax 6.6 trucks from 2001 to 2015. The brand is currently working on a diesel tuner update to match the newer models.

Small yet Powerful with Pre-loaded Tunes

When you purchase the Bully Dog 40420 GT Platinum Performance Diesel Tuner, the package comes with everything you need to install the device: the GT head unit, a suction mount, an OBDII Adapter Plug, a DC power cable, an HDMI cord, a Mini USB cable, a MicroSD card and a MicroSD card reader.

The screen size of this diesel tuner from Bully Dog is 2.4” – just a bit bigger than your dashcam. Most buyers initially think that it’s a touch screen. Unfortunately, it’s not. However, navigating is still very easy because of the 7 capacitive touch buttons around the main screen. Since these are very sensitive, you hardly have to push the buttons for it to respond.

Before you start tuning, don’t forget to update your device first. But here’s a tip: Update it during business hours so in case you get an error, you can immediately call Bully Dog’s customer support.

It’s also pre-loaded with four tunes. Once you’ve connected it to your OBDII port, the suggested tunes will show on the screen. You can calibrate the parameters based on your preferred performance.

Teach Yourself Better Driving Habits with the Driving Coach

The Bully Dog 40420 is known for its Driving Coach. It is an exclusive feature you can take advantage of if you get this highly recommended tuner for your 6.6 Duramax truck. This was designed by Bully Dog to help you adjust your driving to improve your fuel mileage and just conserving energy. It coaches the driver to build better driving habits by providing real-time visual and audio feedback. Remember, regardless of how well you have calibrated the parameters of your vehicle, if you have poor driving habits, you won’t be able to fully take advantage of the expected performance.

Protect Your Engine with the Safety Defueling Feature

Another reason why the Bully Dog 40420 is on top of our list of the best diesel tuners for 6.6 GM Duramax is its safety defueling feature. After you’ve downloaded the preferred tune on your truck, you need to understand that a problem may arise if you fail to responsibly drive it. Adding too much power on a drivetrain that is designed to withstand a certain limit could potentially damage your engine.

In order to prevent that from happening, the Bully Dog 40420 has a safety defueling feature that will automatically decrease your power level and will notify you that you have a temperature issue on the screen. The defueling feature is triggered by the boost level or the temperature of your pyrometer, coolant, oil, and transmission. You can calibrate all these so that your Bully Dog performance tuner will know when to go back to its stock tune. Unfortunately, this feature is not available on LML Duramax.

Why should you get it?

The Bully Dog 40420 is loaded with tons of features that will get you to see how well your truck can really drive. From the pre-loaded tunes that will get you started immediately to the Driving Coach feature that will make any tune (including stock) a better, more fuel mileage, and fuel economy. Your truck will see lots of better driving days. The safety defueling feature is there too, to protect you in case all of the extra power you’re finding in your truck is going to your head.



  • Driving Coach
  • Safety Defueling
  • Includes complete installation kit


  • Safety Defueling not available for LML Duramax
  • Pricey

2. DIABLOSPORT PREDATOR P2 PERFORMANCE TUNER the best budget diesel tuner for 6.6 Duramax

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If you’re on a budget yet but still want one of the best tuners for the diesel 6.6 Duramax, check out the DiabloSport 7203 Predator P2 Performance Tuner. This is packed with features in spite of being among the most affordable among the list. It’s specifically created for 2001-2015 Sierra or Silverado HD trucks with 6.6 Duramax engines. It can boost the horsepower by 100 and increase your miles per gallon by 2-4mph, which is an extraordinary improvement if you’re a long-haul driver. After the tune-up, you will experience better fuel economy and additional towing power.

Economy, Towing, Performance or Extreme Tuning

After you install the DiabloSport Predator P2, it will automatically show the quick options where you can change specific parameters related to your factory settings. One example is the tire size. If you’ve changed your tire to a bigger one, it will also adjust the speedometer limit according to what matches it. As you start tuning, you can choose whether you want the economy tune for better drivability, the towing tune for stronger towing power, the performance tune for harder daily driving, or the extreme tune for a big performance boost. You can customize each tune with adjustable parameters, but this specific Predator model does not accept custom tunes.

The device will save the stock tune before it overwrites the data. It’s a great feature so that you won’t have to visit your car manufacturer for an expensive reflash back to stock.

Simple Installation and Keeps DTC Codes Away

The DiabloSport Predator P2 installation is super quick, basically just plug-and-play after you make sure that the software is up-to-date. It also clears the Diagnostic Trouble Codes to fix occasional warnings.

However, note that since you can’t mount it on your dashboard, you won’t be able to monitor your driving performance. This is a hand-held device that solely calibrates your tune, and should be disconnected after the procedure.

Why should you get it?

Aside from its affordability, the installation and tuning process on the DiabloSport 7203 is quick and easy. Typically, your truck is ready to go with a new tune within just 10 minutes. You get four impressive tunes that will probably cover most driving situations. Plus, you can still customize some of the details like the tire size so you get the most efficient tune for your 6.6 Duramax. And if you run into warning lights along the way, the device can help you figure out if it’s something that you can fix or if it’s time to go to the mechanic.



  • Budget-friendly
  • Clears DTCs
  • Speedometer automatically adjusts with tire size


  • Can’t be mounted
  • No custom tunes

3. EDGE 85400 CTS2 DIESEL EVOLUTION PROGRAMMER a sleek looking Duramax tuner 

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If you want something with a more modern look, the Edge 85400 CTS2 Duramax Diesel Evolution Programmer is a great choice. It compliments almost all 2001-2015 6.6L Duramax trucks, from the 2500 chassis to the 5500. (The only exception is the Chevy Silverado 4500 and 5500, it only covers the 2001-2013 models with 6.6L Duramax engines.) Compatible in all 50 states, the CTS2’s full color, high-resolution 5″ screen touchscreen is where you get to control all the magic. It can also act as the monitor for your Edge products back-up camera, sold separately.

Monitors up to 9 Parameters at One Time

You can mount the Edge 85400 CTS2 Duramax Diesel Evolution Programmer on your windshield with the included suction mount. All you need to do to install is connect it to your OBDII port with the included HDMI cable. The box comes with zip ties so you can secure and hide the cords around your dashboard.

At a glance, this tuner can display 9 parameters at one time. These can be manually be set depending on what you want to easily monitor while driving. It can also be used as a display for your Edge products backup camera, which you can separately purchase.

Comes with Four Tunes Out of the Box

The Edge 85400 CTS2 Duramax Diesel Evolution Programmer has 4 pre-set tunes (plus the stock tune it will save automatically):

  • Economy: The lowest power level specifically tuned to achieve the maximum fuel economy.
  • Towing: Typically used to give you more power if you need to tow heavy loads.
  • Performance: The fuel injection and timing are semi-aggressively calibrated to extract power gains.
  • Extreme: The highest power level where the fuel injection and timing are aggressively calibrated.

You’ll immediately have tunes that will boost your truck’s performance right out of the box. If you’re unsure, Edge’s Performance Test will help you figure out which level should work for you. You can find it on the right side of the menu and will help you compare the stock and the chosen level seamlessly. And don’t forget to set the right weight of your truck before the Performance Test so you’ll get accurate data.

Why should you get it?

The Edge 85400 CTS2 Diesel Evolution Programmer has a lot of features that will satisfy any serious truck owner. With the big, colorful touchscreen display showing off the parameters, gauges, and tune options, you’ll keep finding new ways to improve your truck. The Performance Tests will help you find your way if you’re a beginner. It also has the ability to work with accessories like the Edge products back-up camera.



  • Lets you assess the different tuning levels through the Performance Test
  • Full color and high definition touchscreen
  • Monitors up to 9 parameters on display


  • Available back-up camera screen function needs another purchase to work


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The Hypertech 2100 Max Energy 2.0 Power Programmer is specifically designed for towing purposes and works in all 50-states. So, if you use your truck to tow, this is exactly what you should have. It comes with tunes for most applications and specifically for all 6.6L GM Duramax engine types.

Doesn’t Let Your Teen Speed

The Hypertech 2100 2.0 Power Programmer has a very basic display – no color nor fancy graphics unlike the first three tuners on the list. However, because of the interface, it’s just all straight business with this device.

This device will load parameters based on the calibrations allowed for your vehicle. Therefore, just like the others, you are guaranteed that whatever you change will not ruin your truck. You can increase or decrease your RPM with an interval of 100. If you have a teenager who would like to borrow your truck, you can even make sure that he won’t go beyond 70 MPH just by adjusting the top speed.

Set Your Own Tunes

If you really know how to tune your truck, the Hypertech 2100 Max Energy 2.0 Power Programmer is a great tool since it allows you to set and save your own tunes instead of having to load a pre-calibrated one. This will save you more time instead of waiting for the tune to load and then start changing the necessary parameters.

In case you need to bring your truck to the manufacturer’s shop, you can go back to your stock settings and once you are done, you can flash the saved pre-set tune that you have set. You don’t need to do the manual calibration all over again.

Why should you have it?

The Hypertech 2100 Max Energy 2.0 Power Programmer is perfect for those heavy towers that know what’s going on under the hood. If you’re that kind of person, then the device will give you a ton of power and performance to get the results you want.



  • Saves your pre-set tunes
  • Lets you control your speed limit
  • Powerful towing improvements


  • Basic display

Final Thoughts on the Best Diesel Tuner for 6.6 Duramax Review

These diesel tuners for the 6.6 GM Duramax will guarantee that you can increase the performance of your truck. We can’t deny the fact that the 6.6 GM Duramax is one of the best trucks GM has ever made. However, the opportunity to increase its capabilities shouldn’t be ignored, especially if you use it on a regular basis.

Our top pick was the Bully Dog 40420 GT Platinum, incredibly packed with features and will help you become a more efficient and fuel-saving driver, if you want. The DiabloSport 7203 Predator P2 has only four included tunes will probably cover most situations but it’s comes at a great price. If you’re willing to make the investment, the Edge 85400 CTS2 Diesel Evolution Programmer is the splurge pick. With its 5″ color touchscreen you’ll easily get to see all the many available gauges and parameters that you can play with. And finally, for those that make towing their job, the Hypertech 2100 Max Energy 2.0 Power Programmer is the device for you. It’s screen might be simple, but the towing performance boosts you’ll get will be amazing.


What is the best diesel tuner for a Duramax?
Among the choices that we have on this page, the two clear favorites are the Bully Dog GT and the Edge Diesel Evolution. If you’re looking for a feature-rich choice in a small form factor, it’s hard to go wrong with the Bully Dog GT. But if you don’t mind mounting a larger monitor in the cabin that gives you a plethora of info, including real-time updates, the Edge Diesel Evolution is a clear winner. You can even use the screen as a monitor for your truck’s reverse camera.

Best Diesel Tuner for 6.6 Duramax by Year 2005, 2013, 2015, 2017, 2018, 2019

What’s the best programmer for the 2005 Duramax?
There are quite a few choices available for the 6.6 Duramax. For the 2005 Duramax, you can check out the Diablosport Predator. It’s a handheld tuner, perfect for the truck since you aren’t obligated to mount it in the cabin. Not only does it enable you to clear DTCs, but you can also access the inbuilt tunes and choose depending on the use, and most importantly, it won’t cause a big hole in your pocket.
What’s the best programmer for the 2013 Duramax?
If you’re after a tuner that not just offers a fairly long list of features but also monitors vital information at the same time, the Bully Dog GT is one of the best options out there. It has a 2.4-inch screen (not touchscreen), that’s easy to read and the device doesn’t take too much space in the cabin either. It also comes with a nifty ‘Driving Coach’ feature that helps you improve your driving abilities.
What’s the best programmer for the 2015 Duramax?
If you use your 6.6 Duramax truck for towing, you’ll appreciate the Hypertech 2000 Max Energy tuner. It comes with towing-focused tunes inbuilt with the device. That’s backed by the ability to go back to the stock tune — which is as easy as pressing just a few buttons on the device. Having said that, it does miss out on a feature-rich screen, though.
What’s the best tuner for the 2017 Duramax?
The thing about the newer trucks with the 6.6 Duramax is that you might find it difficult to lay your hands on a good tuner — at least not as easily as the earlier models. But thankfully, a few manufacturers do offer tuners for the 2017 Duramax. The Pulsar in-line tuner is a nice choice. It needs to be accompanied by an in-cabin monitor but offers everything from power adjustments, the ability to adjust TPMS, axle ratio, RPM, throttle sensitivity control, etc. You can even program the Cruise Control buttons to work as toggle switches for power modes.
What’s the best tuner for the 2018 Duramax?
The 2018 Duramax can benefit from a device like the Edge Pulsar for all the tuning needs. It offers everything from increased power and torque (up to 90 hp and 156 lb-ft), the much-appreciated ability to control throttle sensitivity and other parameters, get the transmission to relearn new power modes, etc. It also offers various modifications to give you better control of what your truck is doing. It needs to be bought with an in-cabin monitor to access and display these features though.
What’s the best tuner for the 2019 Duramax?
For the 2019 Duramax, if you’re looking at monitoring how well your truck is performing, there’s nothing better than the Edge Insight CTS3. The high-resolution screen can work either as a display for a tuner or a standalone monitor to display what the truck is doing in real-time. It’s got a responsive and high-quality touchscreen, has various performance meters, can be updated using the internet, and depending on your truck, it can even read and clear DTC codes.