I am really curious to see how you are going to get a speed density system to work with ITB's as you point out there is little or no manifold pressure to work with.
Speed density by defitnition requires a good manifold pressure signal.
My guess is that the system is going to go full rich as soon as you tickle the throttle. This may be fine for a drag race application which may be what you have in mind. For street usage though its not ideal.
The only way that I can see a ITB system working is to run alpha-N, but this has some drawbacks.
I'd be interested in following your progress in getting this running.
