A competitor had previously performed a custom dyno tune on this completely stock 2016 ATS-V A8 and claimed 492 whp. We took a look at the tune and found four major issues. First, the competitor has desensitized the knock sensor settings so the ECM could no longer protect the engine in case lower octane fuel was ever put in the fuel tank. Second, the competitor has disabled fuel trim learning, taking away the ECM’s ability to correct air/fuel ratio based on feedback from the factory oxygen sensors. Third, they didn’t understand how to properly command boost at higher engine speeds, resulting in boost, torque and horsepower curves looking like a roller coaster. And fourth, actual horsepower was only 435 whp, which was only about 10 whp more than stock and 57 whp less than claimed. After doing a baseline run, we loaded a Tapout tune in the car and made some minor adjustments. Competitive tune (blue lines) is overlaid with Tapout tune (red lines) in the above dyno chart. This car is much more powerful and quite a bit safer now with the new Tapout tune in place.