With the ECU, harness and pipe installed and the U4.2 in the tank, Reeves saw a four-horsepower increase on a Dynojet dyno compared with his previous setup, which was a full exhaust system (from a different manufacturer), Power Commander and U4.2. Midrange power was much improved, while bottom-end power was slightly down from the original setup. Reeves reports that with the modifications his GSX-R feels noticeably stronger throughout the rev range, with clean but crisp throttle response from the standard map. Peak power was down a bit with the map intended for AMA Superstock use, but driveability improved somewhat.
On a Dynojet dyno the results...
On a Dynojet dyno the results of adding the ECU and Yoshimura pipe are evident. The baseline run is with a race pipe (not the Yoshimura piece), Power Commander and U4.2 race fuel, and the final run is with the EM Pro, Yoshimura pipe and U4.2.
The $635 Yoshimura kit harness...
The $635 Yoshimura kit harness unleashes the full potential of the EM Pro by changing the functions of the left clip-on's switch cluster to manage the ECU. Additionally, the S-DMS mode switch now activates three levels of traction control. Eliminating much of the street-oriented wiring saves almost three pounds of copper and plastic.
The aluminum bracket, part...
The aluminum bracket, part of the Yoshimura kit, mounts the sidestand switch to the water-pump cover. A second bracket attaches to the shift shaft, activating the sidestand switch when the shift lever is moved. This elegant solution for a quickshifter switch is doubly so when you consider that the shift pattern can be reversed without affecting the switch's function. The brackets are part of the Yoshimura kit and retail for $85.
The kit quickshifter took some time to dial in, as it's very sensitive to the position of the pawl on the shift shaft. Once set, however, full-throttle shifts were seamless and smooth. An added benefit of the Yoshimura system is that the switch operates directly on the shaft rather than in the linkage, meaning that swapping from standard shift to GP shift doesn't require a different switch. Engine braking is reduced from stock, taking some work away from the bike's slipper clutch, and the settings provided with the standard map make for easy entries into corners with no drama.
Experimenting with the mode switch revealed some interesting characteristics. In B mode the GSX-R was definitely easier to ride, with most slides caught and controlled by the ECU before they could get out of hand. C mode exerted too much control over the power, and lap times were noticeably slower as a result. For most track days and races Reeves used B mode. Interestingly, tire wear is much reduced with the system activated, and perhaps this is the biggest boon traction control offers to the average trackday rider or club racer. Tire performance was more consistent over the course of a race, and rear-tire mileage was markedly better at track days. Our only complaint with the safety mode is that the settings-off, soft and hard-are too coarse, and the ability to fine-tune or further program them would be a big improvement.
As a tuning tool the EM Pro allows almost unrestricted access to the GSX-R's fuel and ignition parameters; this is the main attraction for serious racers. Anyone, however, can benefit from the well-sorted rider aids-the quickshifter, adjustable engine braking and traction control-and the improved tire wear. At $4500 the setup is not cheap, but its functionality and performance are unmatched. Consider a cheaper tire bill and the safety aspects of traction control, and the EM Pro starts to look like a bargain.