In the May issue of the magazine, my article focuses on traction control systems and how you can make the most of their performance. Production systems and most (read: affordable) aftermarket systems are not at the level where you can let the traction control do all the work, and you must ride accordingly. While some systems are limited in their adjustment to the selection of one level from a limited number, many have more elaborate tuning parameters that can be changed.
When it comes to traction control, it definitely helps to have more than just rider feedback on which to base any adjustments. One of the biggest drawbacks to any TC system is that it can easily slow the bike down too much, even on the straights. It can be very difficult for a rider to determine if the system is not cutting enough power, is cutting the correct amount of power to maximize traction, or is simply slowing the bike down. This is where data acquisition with a channel that shows when the traction control system is active can be a big help.
Ideally, slip - the difference between front and rear wheel speeds - is compared to the traction control intervention channel, and changes made to the system accordingly. At the top levels, the data systems are accurate enough and the technicians that run them savvy enough that the rider may not even be involved when those changes are made. As I have discussed before, however, http://www.insidemotorcycles.com/blogs/item/308-measuring-slip.html">accurately measuring slip is a difficult proposition and some creativity may be necessary.
The example shown here is for a bike using the Bazzaz Z-Fi system, which works on a throttle position/RPM array to determine when and how much to cut power. It's clear from the chart that there are several instances where the motorcycle is on a straight (speed is rapidly increasing and the throttle is at 100 percent) and yet the TC is active and potentially slowing the bike down. Here, the symptom is clear and the remedy is fairly straightforward - reduce the amount if intervention at full throttle and high rpm. Because that combination of rpm and throttle position is rare in a corner, the reduction in intervention will not adversely affect performance in turns.
Also seen on the chart, some corner exits have a lot of TC intervention; in others there is very little. Here is where the slip channel and other channels can be used along with rider feedback to determine exactly what is happening on the track. The amount of slip can be correlated with how active the traction control system is, and changes made accordingly. Specific to the Bazzaz system, it's handy to have data channels for throttle position and rpm; with that information, the exact cells in the tuning array can be changed as necessary. This massaging of the traction control adjustments will likely be an ongoing effort, as different tracks and conditions can require subtle changes to the mapping.
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