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DiabloSport InTune 3 Hand Held Unlock and Tune Kit GM Silverado | Sierra 6.6L 8T 2020-2023

$778.00 SALE: $699.95


Model #8266-R

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This product is for Racing Competition only and is not legal for use in highway or street vehicles or other non-racing competition off-road vehicles.

Purchasing this product requires you to sign our Vehicle Compliance Waiver here.

The 2020-2023 6.6 L8T GM gas trucks have been locked down since their introduction. Owners of these trucks have been waiting patiently for a tuning solution, and DiabloSport has delivered in a big way! The new 8266-R kit includes our inTune 3 handheld tuner, along with our industry exclusive locksmith device and harnesses required to unlock the ECM in your truck. Once unlocked, the inTune 3 offers up tunes for 87, 91 and 93 octane fuels, as well as 2 transmission tunes to choose from. Beyond the preloaded tunes, we offer a host of user adjustable parameters, like throttle response, speed limit, tire size, and more. We've even added some new features for drivers of these newer trucks, like the ability to recall your last mode setting!

Get power you can feel, with DiabloSport!


  • ECM unlock included!
  • Unlock and Tune, at home!
  • Preloaded tunes for multiple octane levels
  • Support for 6.6L L8T applications with 6 speed Transmission
  • Throttle Boost setting for adjustable throttle feel
  • Adjust speedometer for larger tires (26"-38")
  • Calibrate speedometer for gear change (3.42-5.13)
  • Remove speed limiter for increased top speed
  • Adjust engine rev limiter for increased RPM range (+/- 400 RPM)
  • Adjust engine idle speed in Park/Neutral and Drive
  • 'Keep Drive Mode Setting' allows you to select a drive mode and it will remember that mode next time you start the truck!
  • Adjust fueling at WOT in multiple RPM ranges
  • Calibrate spark timing at WOT across multiple RPM ranges
  • Front/Rear TPMS threshold adjustment
  • Air Filter Monitor system control
  • Transmissions adaptive relearn
Install Instructions:Fitment:
  • Chevrolet Colorado Silverado 2500 HD 401/6.6L V8 2020-2023
  • Chevrolet Colorado Silverado 3500 HD 401/6.6L V8 2020-2023
  • GMC Sierra 2500 HD 401/6.6L V8 2020-2023
  • GMC Sierra 3500 HD 401/6.6L V8 2020-2023
  • 7 - This part is legal under the provisions of EPA?s Tampering Policy dated November 23rd, 2020. The company has reasonable basis (test results) to verify that this product allows the vehicle to operate within legal emissions standards and is therefore legal to be sold for on-street use in all states that accept the legal provisions of the Clean Air Act and the EPA Tampering Policy. This product is NOT LEGAL FOR SALE OR USE IN THE STATE OF CALIFORNIA. Testing with the California Air Resources Board, in order to achieve 50-state compliance, is pending with CARB. Once testing is complete with California, and an E.O. number is issued, this product will be updated to 50-state legal status.

Proposition 65

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Vehicle Engine Notes
Chevrolet Silverado 2500 HD

Chevrolet Silverado 3500 HD

GMC Sierra

What Makes DiabloSport Special?

DiabloSport is an industry-leading manufacturer of automotive performance programmers based in Sanford, Florida. They focus on making the maximum power, drivability, and fuel economy gain on late model fuel injected vehicles. Whether gas or diesel powered, our products optimize a vehicle?s performance by programming its factory computer or plugging it into its factory engine harness. Since 2001, DiabloSport offers industry-leading performance programmers that stay ahead of the technology curves. Today, they are the only company to offer color touch screen hand-held programmers in all of their OBD-II flash devices. Their goal is to continue offering innovative electronics that are loaded with industry-leading ?tune? files that create better power, economy, and drivability on late model cars and trucks

Quality and Performance You Can Trust

DiabloSport is made up of a team of people who are horsepower junkies by trade- making the biggest possible power gain is why they go to work every day. They use an in-ground SuperFlow Chassis dyno to make and develop their performance tunes, and then they take the cars out on the Florida streets to see what they have. DiabloSport will not settle for anything but the maximum horsepower and torque gains over stock. DiabloSport is a manufacturer of high-performance automotive electronics that re-program a vehicle?s factory computer. They are an industry leader in vehicle calibration, which is performed by ?flashing? or re-programming vehicles through the OBD-II port (Diagnostics port).

Why You Should Purchase DiabloSport at Vivid Racing

Regardless of what styles or sizes you're interested in, the one thing you can depend on to come up with every product order is the best buying experience in the business. From fitment help from our in-house wheel experts to shipping packages, we'll take care of you and your order every step of the way. We know how much of a financial investment you're making in buying these products, and in return, we'll deliver service and product that is second to none

At Vivid Racing, we simply love cars. Cars are our vice in life. We love the automotive community and love our customers who think like us. Vivid Racing ensures that they meet the customer?s expectations in terms of quality, size, and strength

Buy online or give one of our world-class professionals a call at 1-480-966-3040

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