On Dec 30, 2004, at 1:05 PM, Rob Logan wrote:

3psi = 6 in. Hg... this means at sea
level std day, we shouldn't use more than 24 MAP?

No, that's not what it means.  It means that the pressure under the cowl is adequate to give you a pressure differential--even at WOT at sea level.  In a static condition, the WOT manifold pressure is not equal to the ambient pressure under the cowl.  It's *about 1" lower.  That 1" differential is enough to improve the atomization of the fuel.  (that's what the screen on the injector is for... to let in the higher pressure air.)  The reason turbo-charged engines enjoy a very good atomization and better vaporization of the fuel is that they can keep the pressure differential higher then their NA cousins.

Walter