Boosting an engine is the way to get major power from an otherwise mundane powerplant. I love boost. You still have some problems to work out. I'm always interested in the solutions people come up with.
A slide carb isn't my first choice because once you are able to get the turbo under a load and the boost is raging, the differential pressure on the slide will stick it in its bore and hold the throttle open. A small butterfly carb will be the answer or maybe a double cable carb to physically pull the slide down.
You have probably already thought about how to get fuel to the carb under boost. Since the float bowl will be pressurized the fuel will not be able to flow from the tank into the pressurized float bowl. The obvious solution is to pressurize the tank. But this leads to another problem. When the throttle is closed after a boost, the tank will have pressure that does not drop as fast as the float bowl. Gas under pressure will overcome the needle and seat and flood the carb.
I've heard of floats that collaspe under boost pressure but this was with cars. Motorcycle carb floats may be smaller and therefore stronger.
Detonation is a killer. Not only is the combustion pressure high but the mixture heat is much higher. Common solutions are high octane (pump is only 93), severe retarded timing (kills power), pig rich mixtures (cools somewhat but drowns the power), intercooler (difficult to position) and water injection (rarely used). My solution has always been water injection. I run a super simple WI on my roots system.
Now get that system in a good handling bike for us to drool over!
Tom Graham
