SR Test: Yoshimura EM Pro ECU And Exhaust;VP U4.2 Fuel For GSX-R1000

Traction Control. To some it's the holy grail of rider aids that lets you do no wrong, while to others it's nothing more than a Band-Aid for sloppy riding. In either case, traction control is now available in production form and via the aftermarket, and when we got word that Yoshimura's kit ECU for the GSX-R1000 included a form of the electronic aid, we just had to order a unit up to see for ourselves what all the fuss is about.

The EM Pro (Engine Management Professional) is a replacement black box available for Suzuki GSX-R models that can be used in conjunction with the stock wiring harness or a kit harness that opens up more options. In the GSX-R1000's case, using the kit harness changes the bike's S-DMS function to three degrees of traction control: none (A), soft (B) and hard (C). The system is not true TC in that front-wheel speed is not compared with rear-wheel speed to detect a loss of traction, but rather rpm is monitored and limited should a sudden spike occur (indicating a loss of traction at the rear wheel). Yoshimura's instruction manual calls it a safety mode-others refer to it as rate-of-change traction control-and this was the main feature of the box we were interested in.

The EM Pro allows other adjustments as well. The software provides direct access to the fuel and ignition curves, and two maps for each can be programmed and individually selected for each gear. The harness converts the hazard switch to a map selector, allowing the rider to change between the two settings on the fly. The EM Pro takes control of the stock bike's fast-idle circuit but for another purpose-holding the throttle open on deceleration for less engine braking. This also can be programmed for one of three levels in each gear. The stock rev limit can be raised by 500 rpm. A pit-lane speed limiter can be turned on with the left turn-signal switch. And finally, a quickshifter function is built in and can be given a set delay time for each gear. Surprisingly, the kit setup uses the stock sidestand switch, relocated, for the quickshifter function, which activates the switch with a pawl bolted to the shift shaft.

To test the EM Pro we handed everything to John Reeves, a local club racer and trackday rider. Installation of the ECU and harness is relatively straightforward but time-consuming, as everything electrical on the bike must be unplugged from the stock harness and plugged into the kit harness. Aside from the benefits of activating the various control functions, the kit harness has shed almost three pounds from the GSX-R with the elimination of most of the street paraphernalia. The software and instruction manual for the EM Pro is quite expansive, but base maps are provided and once everything was installed we were up and running in relatively little time.

The kit includes "compensation maps" for various setups; we used a standard map that called for a Yoshimura full exhaust system and unleaded fuel with an octane of 100 or greater. The software also includes maps for Superbike and AMA Superstock setups. We ordered up a Yoshimura titanium header with a carbon TRC canister as per the specification. The $2250 single-canister system installed easily enough with typical Yoshimura quality, fit and finish, and scaled in at approximately nine pounds total-18 pounds less than the stock twin piper. To handle the fuel requirements we turned to VP and its U4.2. This fuel is an advancement of the company's U4 and U4.1 that does not clog injectors when left in the bike for extended periods of time and that has a less pungent odor. The oxygenated fuel is listed at a motor octane of 102, perfect for our requirements.

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.

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.