A lot happened between the last post and this one - we've had to make some hard decisions which really affect the rest of the season.
Because of budget reasons, this will likely be my last year in karting - college rapidly approaches, and as a family we really cannot continue funding racing. I'm sure I'll go into much more detail, but suffice it say that with our available budget not being even a fraction of that of everyone else on the grid with me, we have to be very smart and think long-term.
With that in mind, we looked at this engine situation, and since the plan so far is to sell everything at the end of the season, we decided that our Birel kart will sell better as an X-30 package than as a Rotax package. This is the main reason why we took advantage of IAME's trade-in offer and switched from Rotax to X-30.
From what we've seen so far, there really isn't a performance difference between the two engines, but the X-30 is a different animal than the Rotax, requiring much more attention from driver and tuner. The power band is also different, which requires a different driving technique.
I've driven a Leopard before at NJMP and in Florida, so I'm not completely lost with the engine switch. But I know it will take some getting used to. An advantage of the X-30 is being able to change carburation much more easily than with the Rotax, with which you had to take the carburetor apart and change the jetting manually. With the X-30 there are two levers that control the high and low end carburation respectively. The engine can be made to behave differently at high and low RPMs.
We also had to invest in a Mycron 5 module, which gives us the ability to monitor the exhaust gas temperature as well as the water temperature. This is important, as you want the exhaust temps to be within a certain range, which requires adjustments in carburation (which you can now make on the fly).
Another reason to make the trade-in was the fact that the remaining races on the calendar - Canaan Motor Club in New Hampshire and NJMP - are very high speed tracks in which the Rotax is generally considered to be at a severe disadvantage to the X-30. However, once Rotax runners figure it out, we may see this not be the case. Time will tell.