After some thought, this is the plan I'm going with. Currently trying to find an NZ supplier of centrifugal fans like this..
otherwise I'll get one from the US. Will flow soemthing like 200cfm which should easily be enough. Will mount it either low down in the engine bay or with a pick up that is low down and then run a 'hose' to a 'diffuser' which will aim the airflow between the WAI core and the cam cover. I'll also look at an additional heat shield above the cam cover - stainless or ally - and blow the air between that and the WAI unit. I anticipate having it running full time and rigging up some form of timer so it can run after the ignition is off - say for 10 minutes.
It'll almost be like the set-up the old MG Montego and Maestro turbos used. They had a similar set-up to blow cold air over the SU carb when the ignition was switched off to prevent the fuel in the carb evapourating (the carb was directly over the exhaust manifold!).
Gary
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1994 Toyota Celica ST205 GT-Four Group A WRC - running in rebuilt engine....