As the electronics for sportbikes become increasingly sophisticated, most manufacturers' race-kit ECUs (Engine Control Units) are encompassing accordingly more functions. We had some experience with Yoshimura's EM Pro (Engine Management Professional) ECU for the GSX-R1000 in our June, '08 issue, and more recently had a chance to use Kawasaki's kit ECU for our ZX-10R. The company's list of performance parts for the ZX-10R is quite elaborate, and includes such goodies as pistons, connecting rods, close-ratio transmission parts, suspension internals and even a radiator. Almost the entire electrical system of the bike can be changed as well, with the kit including a wiring harness, lightweight generator, and the ECU. We were most interested in the latest ECU and software, and conveniently available is a short additional harness that allows the kit ECU to be used with the stock wiring harness. The kit ECU retails for $617.95, the sub-harness costs $114, and the PC to ECU interface cable is $601.95; all are available through Kawasaki dealers (although the Performance Parts catalog may not be readily accessible through normal dealer channels; your dealer may have to call the Accessories Division at Kawasaki Motors Corp USA to get the part numbers, etc.).
With the kit ECU you have direct access to all of the bike's electrical functions, including fuel injection, ignition timing and control of the bike's sub-throttle valves. Added features are a pit-road speed limiter, "rev spike control", the ability to add a quickshifter, and launch control. There are quite a few tables, graphs and parameters to keep track of, and the manual for the software is more than 50 pages thick. The software allows fuel injection to be mapped over an rpm/throttle-position array, much as a Power Commander or other fuel injection tool is adjusted. Alternatively, the mapping can be accomplished by dragging points on a graph higher or lower. You can go much deeper into the system than you can with an aftermarket tuning tool, however. For example, both the main and secondary injectors can be accessed. The injectors for cylinders 1 and 4 can be programmed differently than the injectors for cylinders 2 and 3. Fuel can be added or taken away under acceleration. The entire fuel map can be made richer or leaner with one simple adjustment. And finally, if you don't like the increments of rpm or throttle position the software utilizes, you can program your own. For example, if you want more control at partial throttle openings, you could change the array to reflect that desire.
The ZX-10R's fuel injection...
The ZX-10R's fuel injection and ignition timing can be adjusted using a table format (bottom portion) much like a Power Commander or a graph format (the top portion of the screen). This screen shows the fuel injection compensation map for cylinders 1 and 4. The various colored lines each represent a throttle position, with rpm on the x axis and the level of fuel compensation (in percent) on the y axis.
Just as the fuel injection can be modified over an rpm/throttle position array, the ignition timing can likewise be advanced or retarded, and the sub-throttle valve in the throttle bodies can be controlled. Some parameters can be changed depending on gear, and these also can be adjusted using a table or graph format. These include the kill time in each gear for the quickshifter, when the rev limiter cuts in (up to 1000 rpm higher than stock), and when the shift light on the dash illuminates. A separate list of operating parameters allows certain actions to be turned on or off, or set with a certain value. If the stock exhaust system is used, the butterfly valve's action can be modified. In the standard ECU, fuel to the injectors is cut when the throttle is closed in order to reduce emissions and protect the catalyzer in the stock exhaust system. The kit ECU allows fuel to be added at closed throttle, smoothing the off/on transition significantly.
The rev spike control, which we commonly refer to as traction control, has two options for settings. The sensitivity-how aggressive the system is at intervening-can be adjusted from 1 to 10, and the retard level-how much power is cut when the system does intervene-can also be adjusted from 1 to 10. Provisions in the sub-harness allow for the addition of a switch to turn the rev spike control on or off, but these settings cannot be changed while riding. A second switch can be added for the pit-lane speed limiter, which limits engine speed based on rpm in each gear. A program for launch control can be enabled, and this limits engine speed to a set level when the bike is in first gear and stopped. The shift light on the dash flashes to let the rider know the program is active, and control ends when the rider shifts into second gear.
Installation of the kit ECU using the sub-harness was simple, although room under the seat is tight for the additional wiring. This is definitely not a street-legal modification, as the ECU does not recognize the fan switch or sidestand switch. We added a toggle switch for the rev spike control, and mounted up an Akrapovic exhaust system so that we could sample the fuel-cut option without fear of damaging the stock exhaust system. The titanium Akrapovic Evolution header is made from hydroformed titanium with a carbon canister, is part of the kit for the ZX-10R, and retails for $2200 through Kawasaki dealers. The kit manual recommends a Battle Factory or Dynojet shift sensor for the quickshifter, and we wired in a Dynojet part we had from a previous project. One benefit of using a dedicated, standalone ECU as opposed to a piggyback tuning unit is that you don't have the added wiring and installation hassles associated with tapping into the ignition and injection wiring. Installation is considerably easier, and as much as a couple of pounds in weight can be saved.
The short harness (left) allows...
The short harness (left) allows the kit ECU to connect to the ZX-10R's stock wiring harness. The additional wiring meant things were a little crowded under the seat. The second harness shown here connects the ECU to a laptop for programming or viewing various parameters while the engine is running.
We used an Akrapovic Evolution...
We used an Akrapovic Evolution exhaust with the ECU that is listed as a Kawasaki accessory. The 4-into-2-into-1 pipe has hydroformed tapered header pipes, crossover pipes, and is offered with either a carbon fiber or titanium canister.
Using the sub-harness to connect...
Using the sub-harness to connect the ECU to the stock wiring harness forced us to slip the kit ECU under the passenger seat, as there wasn't enough room under the front seat for all the extra wires.
The ECU's software is mostly intuitive and easy to navigate, with simple and direct access to the various menus and tables. Actually programming the ECU requires first reading the changes into the program's memory and then writing that data to the ECU. This part is not so intuitive, but once familiar with the steps involved the process is straightforward. A second method of data transfer allows certain parameters to be quickly and temporarily changed for making adjustments on the dyno, but for permanent changes the read/write method of data exchange must be used.
We spent a couple of track days on the ZX-10R with the kit ECU and exhaust installed, and came away impressed. The bike gained power significantly in the midrange (unfortunately we don't have a dyno chart to show this) and had very nice throttle response. Even though the rev spike control has a limited number of settings, those settings are very well sorted to match the bike. The traction control was mostly transparent, intervening only when needed in corners and not at all on straights; changing the cut or sensitivity levels produced noticeable differences, however, making it easy and quick to find suitable settings for the conditions. -A.T.