Lynn,
it is a P-Port, which certainly adds to the MAP issue. I am
seeing that on the single rotor when the MAP connection is right at the rotor
housing, even with a 40thou hole. All I do is showing it on a boost gauge, it
is unredable below 1500RPM.
Fortunately, it is not an issue with a carb.
FWIW.
Richard Sohn
N2071U