Power gains of up to 100whp peak and 220whp under the curve!

JB4 is finally here for your C8 ZR1 Corvette! Featuring our latest JB4PRO hardware this system attaches to easy to reach connections in the engine bay, as well as your OBDII port, to retune the LT7 for higher power and torque levels. By intercepting and altering specific sensor signals dynamically the JB4 can safely reshape your boost, timing, and AFR profiles without having to unlock the ECU or rewrite any ECU tables.

The JB4 includes several maps including a map for pump gas, race gas mix, straight race gas, up to 30% E85 mixtures, and a bypass/factory map. Using the free JB4PRO app you can change maps on the fly and make various tuning adjustments including boost limiting by gear for improved traction in lower gears, setting maximum boost safety levels, and even reshape your desired boost/torque curve manually.  The JB4PRO app also includes data logging, tuning insights, performance estimates, code management, and much more, giving you full control over your tuning experience. 
 

Includes the JB4PRO app! Wirelessly connect the JB4 to your iOS or Android device 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.

The JB4PRO app features an intuitive easy-to-use interface, help buttons, and advanced log analysis tools that can estimate the performance of your car and help identify any tuning concerns. More information on the JB4PRO app is available here.

JB4 Features & Benefits

• Power gains of up to 220whp under the curve on a stock vehicle with high octane
• Improves 0-60 times and 1/4 mile times
• Preloaded with maps for pump gas, race gas, and ethanol mixtures up to E30.
• Ethanol (E85) compatible tuning maps up to E30
• Able to read/delete fault codes
• View and record up to 20 different gauges/engine parameters in real-time with the JB4PRO app.
• Boost by gear in 1st, 2nd, and 3rd can be controlled via the JB4PRO app for a perfect launch
• Compatible with the FREE JB4PRO app 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
• Designed and Assembled in the USA
• 5 year warranty

Vehicle Fitment

• 2025+ Chevrolet Corvette C8 ZR1

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 it's 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 and is sold in over 67 countries worldwide.

Is the JB4 a real tune?

Yes the JB4 is a real tune. By tapping into specific sensors and CANbus for real time vehicle data the JB4 is able to alter your boost, timing, AFR, and/or fuel trims, to a similar degree an ECU reflash would, but without the vehicle ever knowing its been tuned. The result is safe, smooth, and significant power and torque gains while retaining your factory safety systems and without having to unlock/flag your ECU.