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Not all porsches! (if you consider 928s porsches ) the early 928s (pre 80) had vented rotors with no curved vains , so there were no left or right rotors, just one.
Originally Posted by Van
All Porsche rotors that have curved vanes have a left and right set.
Obviously, if the the vanes are straight, then there is no left and right, along with 928s, it's the same with 944s, non-S 944 turbos, "vintage 911s", and all rear brakes.
Of course, the old 914 solid, non-vented rotors have no left and right either.
As always van you are spot on! Many people simple forget that the air is being scooped from the inside & pushed out... Why else would we be putting all that duct work in there... :-)
To be more precise with this type of impeller the air is not being “scooped” it is being drawn in by a partial vacuum. As the air inside the vane is spun its weight causes it to move outward from center just as a ball on a string would. Air pressure at the leading edge zone is negative. If this were not the case straight vane impellers would not work. With curved vane impellers the curves help with acceleration of the substance being impelled. Too high of an acceleration rate can cause cavitation, fluid/ gas stalling and other nasty things that reduce efficiency and impeller life. Among other things the curves increase the path lenght.
Screwdriver trick is the one I teach. Simple to teach, do and remember.
09-10-2010, 10:55 AM
) the early 928s (pre 80) had vented rotors with no curved vains , so there were no left or right rotors, just one.
