Here is my take on the induction for our Legacy.  This is the largest K&N Filter I could fit without blocking the inlet.  If K&N is to be believed, and according to Vangrunsen’s RV tests they can, the reduced turbulence increases flow by an inch plus of MP.  I do not have comparison figures yet but my reasoning is the Lancair Ram Tube is vented to the cowl upper plenum when the butterfly valve is open to Ram so any additional ram pressure would be lost, right? 

The downside is I don’t have alternate air with the current configuration but the radiant heat from the cylinder (and the 20 degree temp rise I did not know about, thanks Fred) may keep enough of the filter ice free until I can execute the instant U turn and or decent when icing occurs.   Or maybe these factors will offset any anticipated gains.  I will test with temp probes and without the Filter and Tube to get some numbers.

Steve Colwell  15SC FLYING!