Wasn’t planning on turning this into a car blog but I have to mention one more company using Hayabusa engines since they seem to have quite a business building street legal cars and kits. The comany is Z Cars over in England and they have some of the coolest conversions, putting bike engines into a Mini, a Lotus and some other cars, most notably, the Ultima, where they use two Hayabusa engines to drive all 4 wheels. Sign me up. Personally, the one with the highest “need one now” factor is the Mini, a Yamaha R1 engine in the back and a very high grin quotient.
The more I dig into this, the more I find companies using the Hayabusa engine to power things other than motorcycles (It’s quite the engine), which starts a whole new line of thinking. The Hayabusa is immensely powerful and with turbocharging easily capable of well over 300hp and in some cases over 400hp. Think about that. That’s well into automotive high performance territory and with the power to weight ratio of a motorcycle you get the extreme speeds the big Busa is capable of. But cars are using the engines now and starting to show the same performance even with their higher weight because traction favors the car as does aerodynamics at higher speeds, no matter how closely you tuck, a bike isn’t the most aerodynamic vehicle around. Now, the tradeoffs begin.
A couple years ago, Chrysler produced the 
Tomahawk for the show circuit. A Viper V10 wrapped in just enough drivetrain to make something a person could conceivably ride. I got a kick out of reading journalists who would just repeat what they were told and say the Tomahawk had a top speed of 300mph or 400mph. Not likely. Besides finding someone crazy enough to check it out, the other problem is air resistance. That thing must have drag numbers like a Mack truck. Pure horsepower won’t do it and I wonder how much faster motorcycles can go and still look like a motorcycle. We may be reaching limits there already. Anyway, it’s neat to see all of this engineering going on and I can’t wait to see what the next guy comes up with.
See also Motorcycle engine powered cars