Project Greenspeed
Understanding COBB Project Green Speed and Your Pro Tune
Thank you for considering a custom COBB Pro Tune. We want every customer to get the best possible results—smooth, safe, and optimized performance—while understanding the current realities of COBB’s tuning platform.
What is Project Green Speed?
Project Green Speed is COBB Tuning’s emissions-compliance initiative. In 2022, COBB updated its Accesstuner software (the tool used for custom/Pro tunes) so that calibrations cannot disable or bypass certain factory emissions-related systems and diagnostic functions. This change aligns with EPA and CARB expectations and helps keep COBB products and calibrations on the right side of regulations.
The update removed the ability to suppress or modify diagnostic trouble codes and related controls tied to emissions systems. The goal is to ensure tunes maintain the vehicle’s designed emissions functionality rather than create “delete” calibrations.
Why This Matters for a COBB Pro Tune
A Pro Tune is a custom calibration written specifically for your vehicle’s combination of parts, fuel, and goals. For the tune to reach its full potential—and for the car to operate as intended—the factory emissions hardware that the ECU expects must still be present and functional.
If key systems are removed or rendered non-functional, the ECU continues to monitor them. Because Green Speed-compliant software no longer allows those related codes to be turned off, the result can include persistent check-engine lights, reduced functionality (such as disabled cruise control on many models), timing pull, boost control limitations, or other protective behaviors. In short, the calibration cannot be optimized the same way, and the overall driving experience suffers.
Systems That Must Remain in Place
For the best results with a current COBB Pro Tune, the following need to be installed and operating correctly:
• Tumble Generator Valves (TGVs) — These are no longer deletable in software. Cars with TGV deletes cannot have those codes suppressed. Keeping the OEM TGVs (or properly functioning replacements) allows the tune to work with the ECU’s expected airflow and combustion characteristics.
• EGR (Exhaust Gas Recirculation) — EGR deletes are no longer supported. The system must be present and functional.
• Secondary Air Injection (air pumps) — These systems help with cold-start catalyst light-off. Deletes or missing components can trigger codes and related issues that cannot be disabled.
• Catalytic converters — The ECU monitors catalyst efficiency. Catless or poorly designed downpipes/j-pipes that prevent proper monitoring will trigger codes that cannot be suppressed under current software. High-quality, properly located high-flow catalysts (such as those using proven GESI cores placed correctly between the oxygen sensors) give the best chance of clean operation while still supporting performance goals.
Careless or non-compliant downpipes (catless pipes, incorrect catalyst placement, or units that consistently fail efficiency monitoring) create the same problem: the ECU sees a fault it can no longer be told to ignore. This limits how thoroughly the tune can be refined and can leave the car with warning lights or protective strategies active.
Power and Drivability Reality
Many experienced tuners have found that properly functioning TGVs, EGR, and air-injection systems do not meaningfully hold back power on modern calibrations when the rest of the car is built and tuned correctly. In many cases the difference is minimal or negligible, while reliability, cold-start behavior, and everyday drivability improve. Keeping the systems intact simply allows the Pro Tune to do its job without fighting the ECU’s protective logic.
Preparing Your Vehicle
Before scheduling a Pro Tune, please confirm that TGVs, EGR, secondary air injection (where equipped), and functional catalytic converters are in place and working. If previous deletes were performed, restoring the OEM (or equivalent functional) components is the path to the cleanest, most effective custom calibration.
We are happy to discuss your specific vehicle, modification list, and goals so we can set clear expectations and help you prepare. A well-prepared car with intact emissions hardware gives us the best foundation to deliver a smooth, powerful, and reliable Pro Tune.
Feel free to reach out with questions about your setup. We’re here to help you get the most out of your vehicle under the current COBB platform.
Thank you for understanding and for choosing a careful, professional approach to tuning.