Lets see... the 2 inner runners that enter the plenum wall are
  1.25" in
diameter and the 2 outer runners entering the plenum wall are 1.5"
diameter. Add a radiused bellmouth to each of the 4 runners with the
bellmouth radius equal to 2D of the pipe. I come up with a plenum
wall that is 27.5" long. This may be ideal from an airflow
standpoint but it sure as hell doesnt fit my airplane.  :-)

  My intake is most definitely not ideal but I know it will make
  enough
power to get me flying. Sometime after that I'll probably revisit my
manifold and try to come up with something better. But I doubt it
will ever be large enough to conform to Lynn's ideal and still fit
on the airplane.

Mike Wills

You have a tandem seat RV4 and I have a side by side Kis Cruiser. My
cowl is wider than it is high and yours is higher than it is wide :-)
I gots plenty of room over there for a big intercooler/plenum combo.

Paul Lamar

Mike,
I share your PAIN.  There just isn't much room where you need it in a RV-4 cowl.
But we are really going to have neat airplanes when we get flying!!!!!!!!!

Ken P.

 
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