The Myth of SOTF Truck Tuning
Tuning a diesel engine with switch-on-the-fly (SOTF) tuning is a longstanding trend that has been going on for many years in the industry. With plenty of after-market parts and options to choose from, it has historically been rather easy to change up the power potential of your truck, allowing for more or less torque and horsepower depending on the job at hand.
So what is SOTF tuning? Up until 2011, Duramax powered diesel trucks could have an upgrade installed called a DSP5 (Duramax Switchable Position 5). This upgrade began with an update to the electronic files in the Engine Control Module, using a custom EFI LIVE operating system, and was accompanied by a dial wired into the dash that allowed the driver to choose between five different settings (as pictured on this page). As this dial was turned, the ECM would change tune files in the operating system, changing the fuel pressure maps, throttle maps, etc. to match the setting and give more or less power to the engine.