Power gains of up to 85whp and 120wtq to the wheels on a stock truck without the risks of flashing!

This plug and play tuner attaches to two easy to access sensors in your GMC Sierra engine bay and works with your factory ECU tuning to remap your boost, timing, and fueling for optimal performance and reduced turbo lag.

Installation is very discrete and unlike flash remaps which are quick to install but can never be fully removed with a JB4 the vehicle is never aware it’s making more than the factory boost or power levels. Fuel economy during normal driving is unchanged and it’s compatible with all driving modes including towing.

Unlike other less advanced systems, the JB4 includes CANbus functionality allowing it to take in critical engine data directly from the ECU for real-time tuning. The data includes pedal position, throttle position, timing advance, fuel trims, air/fuel ratio, engine knock, fuel trims, gear, and much more. Other tuners without CANbus are not able to even monitor this critical engine data no less incorporate it real-time into their tuning algorithms. CANbus allows the JB4 to provide huge power increases with unparalleled power delivery.

The JB4 includes multiple maps including those for 91 octane, 93 octane, factory tuning, VALET mode, E85 mixtures, and unleaded race gas. In addition, it offers boost by gear settings to improve launches, the ability to read and delete fault codes, and much more. The JB4 is made in the USA and includes a 5-year warranty.

Wirelessly connect the JB4 for the 2019+ GMC Sierra 1500 2.7L to your Bluetooth 4.0 compatible iOS and Android device via the JB4 Mobile connect kit, or to your Windows laptop with the BMS data cable. Both options allow you to record and analyze vehicle and tuning data, change JB4 performance maps, and update JB4 firmware as we release free newer versions with updates, more powerful maps, and new features under development. A separate JB4 Mobile app purchase is also required.

JB4 Power Gains, Features, & Benefits

• Power gains of up to 85whp and 120wtq to the wheels on a stock vehicle
• Improves 0-60 times and 1/4 mile times
• Preloaded with custom JB4 GMC Sierra tuning software and up to 8 maps for various fuel and modification levels
• Ethanol (E85) compatible tuning maps
• Able to read/delete fault codes
• View and record up to 40 different gauges/engine parameters in real-time with the JB4 app.
• Boost by gear in 1st, 2nd, and 3rd can be controlled via the JB4 app for a perfect launch
• Exhaust flap operation can be controlled in most JB4 applications
• Compatible with JB4 Mobile for smartphone logging, tuning changes, and adjustment
• The JB4 offers a lot more performance, functionality, and safety than your average performance chip
• Quick Plug & Play Installation
• CANbus OBDII integration offering unrivaled tuning features and performance
• Improved performance over non-integrated chip tunes
• Runs as smoothly as stock. This is how your vehicle should have come from the factory
• Compatible with all driving modes
• Fuel economy unchanged during normal driving
• 91 octane fuel or better required for performance gains
• Not VIN locked and can be removed without a trace and resold down the road
• Includes the rugged JB4 billet aluminum enclosure for protection
• Made in the USA
• Free USA Shipping
• 5-year warranty

Vehicle fitment

GMC
• 2019+ GMC Sierra 1500 2.7L Turbo

What is a JB4?

The JB4 is a plug & play tune available for turbocharged vehicles. The JB4 tuner installs between your car’s sensors and its DME/ECU (computer) and manipulates vehicle performance through these connections making your vehicle much faster. While it’s not the only tuning system that operates this way the JB4 separates itself from the competition with much more advanced connection points and processing including CANbus, fuel & spark control, Bluetooth to your smartphone, and a variety of innovative and advanced features not possible with any other system. BMS regularly publishes free mapping and firmware updates adding performance and features as ongoing development allows. In addition, the JB4 system is not VIN-locked to your vehicle and can quickly be removed and swapped between cars or resold at a later time. Often imitated but never duplicated the JB4 has been the gold standard in plug and play turbocharged performance tuning for over a decade.

Dyno Results

Stock vs. JB4 Tuned (Same engine as the 2019+ GMC Sierra 1500 2.7L Turbo)