This is another “trim value” which you can use to tweak the main fuel map based on an additional parameter. In this case that’s speed.
The logic behind this is that at lower speeds you may want to keep the AFR a little leaner – maybe in the 13.7 range for a nice responsive ride, but when you’re hitting higher speeds you probably want power over responsiveness, so can richen the mixture accordingly.
I’ve gone for very little adjustment here with only a little richening at higher speeds. As you’ve probably seen by now there’s a number of things that influence the final fuel value, and it’s possible to get lost in too much data.
The PCV had the basis for something similar to this in that it had “per-gear-mapping” (i.e. 6 separate maps which could be optimised individually) but it required an additional speed sensor fitting to the back wheel and despite my efforts I never quite got to the point of making that work, nor do I know of anyone else who got it to work. Dynojet were quite surprised when I even asked them about implementing it.
Bear in mind this seems to work in KMH – as in it seems like it uses KMH even if you’ve set the display units to MPH.
It will also depend on the speedo (“Meter Calibration”) being set correctly.
