The question is not how much soot the car blows, but at what rpm does the car blow soot?
If it's blowing soot through the entire rpm range, then it is overfueled for the air charge at the given rpm and boost level.
However, soot at high rpms (approaching or exceeding stock goverened speed) implies that the amount of fuel injected cannot be burned within the combustion window - which in terms of degrees of crankshaft rotation is the same size, however in terms of real time, occurs in half the time at 6000 rpm as it does at 3000 rpm. At this point soot will occur regardless of intake charge - even with a boost pressure of 60 psi the engine will smoke, because the fuel doesn't have enough time to burn completely before it is expelled via the exhaust valves.
Running fuel with a higher cetane level decreases smoke because the fuel will ignite earlier in the compression stroke, meaning more of it will be burnt. - I believe I read Dr Diesel has shaved pintles as well to advance the start of injection?
Although the concept of the (really) high speed diesel seems to me to be wasteful, and in the long term, detrimental to the engine (and the environment...
) It's still pretty damned cool though, having said that, and I would love to see it in action.
Drew