jetting apps

Back before the EVO iteration of the Rotax Max, jetting was not easy. Clouds could come in while you were on grid and you could find yourself off a jet. Fortunately the EVO changed all that. Between the new carb and new timing curves in the ecu, jetting is much easier. There are really only two jets that work in any of the configurations. I try to explain that to people, but some folks either want to make tuning more difficult, or, more often, are looking for speed in a jetting change that really should be a chassis or driving change. Other people just want to depend on a phone app rather than testing at the track. I've played around with them all, and I have to say, I find them pretty useless. They all seem to want to jet way too rich. The one app that is closest is the one offered by Rotax itself. The only thing with this app, and it's a big thing, is that it is designed for use with the latest generation of cylinders (2017+ for Junior and 2018+ for Senior). The latest cylinders flow much better than older cylinders and require more fuel. If you are tuning off of the Rotax app with an older cylinder, you will be running one to two jets too rich, and probably a pin height too high.