aytona Sensors’ new Twin Scan II Plus System (sold by Daytona Twin Tec) takes away all the guesswork and time consuming dyno time when the job’s a performance tune on a new Harley. It’s the smart way to work. The Twin Scan II Plus System combines a Twin Scan II scan tool with the WEGO IIID dual channel wide-band exhaust gas oxygen sensor interface and two Bosch LSU 4.2 wide-band sensors. All of this used in conjunction with Harley’s own Screamin’ Eagle Race Tuner (SERT) makes the tuning easy. And on the newest ‘08 touring bikes with their electronic throttle actuator this is about the only viable solution currently available to make those tuning changes.
     A quick hook-up puts the system in tuning mode with the Twin Scan II data logging the RPM, throttle position and air/fuel ratio (AFR) commands from the Harley’s data bus. With those wide-band Bosch sensors temporarily replacing the OE narrow-band sensors you’re also data logging the actual AFR for both the front and rear cylinders.      The Twin Scan II’s software then analyzes all of that to generate easy-to-read tables of correction factors all sorted into RPM and throttle position (TPS) cells neatly arranged to match the rows and columns Harley uses in its SERT software. From there it’s a simple matter of plugging in the new values. Enter the corrected changes in the various cells as required and you’re done. The beauty of all this is that the Twin Scan II Plus logs several data sets under varying conditions, everything from hard acceleration to steady cruising. It can all be added together during the analysis and re-programming. It’s a fast and straightforward process, especially when compared to the old way of doing multiple runs and then having to manually calculate the required corrections for dozens and dozens of cells.
     The Twin Scan II Plus System will be especially welcome when a 2008 touring model Harley with its electronic throttle actuator comes into the shop. Not only does the Twin Scan II read the actual throttle position and integrate that data with the SERT, right now the SERT is about the only viable solution if you want to make tuning changes to these bikes. The SERT is made and supported by Harley-Davidson so there won’t be any compatibility or liability issues if the electronic throttle control malfunctioned.
     The Twin Scan II Plus System can be used over and over again to tune as many bikes as you want. It’s a great diagnostic tool, too, and it’s available through Drag Specialties.