After swapping out the intake and exhaust for more free-flowing units on our project Street Bob, we sensed our already lean-running bike was now operating anorexically in the air/fuel mixture department. The addition to a free-flowing high-performance exhaust, such as the ThunderHeader, an ultra high-flow K&N intake can drastically change the airflow through the motor. This is due to reversion (pressure waves) during the valve overlap period that the stock motor and computer (ECM) is not set up for. This reversion affects the cylinder fill and air/fuel mixture based on RPM that the stock closed-loop ECM is set to. Yes folks, this can mean some loss of power at points throughout the powerband, but we were most worried about the adverse effects of an extremely lean running condition. 01. The MasterTune System Knowing the bike needed some sort of tuning software to make it run correctly, we went with TTS's MasterTune H-D ($425) setup. The system is a Windows-based ECM reprogramming tool specifically for use with '01-later Delphi-equipped Harley-Davidson motorcycles. The MasterTune is widely known as a thorough tuning software for our machines and it has a great reputation for first getting bikes to run properly, then building horsepower from a safe and proper baseline level. Though we are only tuning our bike using the basics, this system is vast and just about every aspect of the ECM management can be tuned to the given engine's need, no matter how big the motor is or what parts were used to build it. The MasterTune has many in-depth features such as saving and restoring the original factory calibration, changing of factory speedometer calibration, changing factory RPM limit, adjustment of front and rear cylinder spark advance, as well as each cylinder's volumetric efficiency. 02. When we strapped our bike to the dyno at Gene Thomason Racing in Torrance, California, we were not looking for magically big numbers on either horsepower or torque, we just wanted our bike to run safely and efficiently with the induction and exhaust changes we made. Added horsepower would just be a bonus. On hand for the tuning were both Steve Cole, the owner of TTS, and Gene Thomason, who is also a virtuoso of the MasterTune software. These guys combined have thousands of dyno tuning sessions under their belts, so it was safe to say this bike was going to get the help it needed.02. When we strapped our bike to the dyno at Gene Thomason Racing in Torrance, California 03. We first took a few dyno pulls to get some base information. Take into account that the stock readings of this bike without the upgraded pipe and air cleaner was 62.1 hp and 78.8 lb-ft and the first dyno pulls we had with the ThunderHeader and K&N filter were 66.3 hp and 92.8 lb-ft. The findings also showed us that our Dyna was running fairly lean. There were also a few issues with timing, fuel, and spark throughout the curve of our dyno chart that we had to address as well.03. We first took a few dyno pulls to get some base information. Take into account that t 04. Once the MasterTune software was loaded into the laptop and plugged into our bike's data port, a marriage of sorts happened where the TTS system electronically mated itself to our Dyna. From there a mirror image of the stock calibration the ECM was running was made and saved into the MasterTune software. This was done in case any mistakes happened during the tuning process or if the bike ever needs to be returned to its stock configuration.04. Once the MasterTune software was loaded into the laptop and plugged into our bike's d 1 | 2 | » | View Full Article By Jeff G. Holt Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
