Quoted from a thread relating to CD...

) Can it be too high causing something to sonic choke at the SSR? Yes it can choke but NO it cant Sonic choke. There is no such thing as Sonic choking in an intake tract. They operate at a maximum of about.5 to .55 mach 600+ft/sec, which is far below Mach. If the mean velocity in the intake tract where to exceed mach .55 the power would drop off dramatically. Sonic only occurs on the exhaust side and usually at lower lifts in super charged engines.

Darin Morgan