Scott:

**That's interesting,  3 psi is 6.1" Hg. - not possible for me no matter how fast I go.  The best I can hope for is 0 psi at WOT or by flying with a greatly reduced throttle setting. But, at least it is not negative psi.  Does this mean that turbo/super charged systems maintain such a differential?  If only I could use the 12-port electronic injectors supplied with my motorcycle and, they don't need no stink'nr to help with atomization.  **

If there is no differential pressure, there is no atomization. The fuel comes out in a stream, not a fog. Having a slight differential pressure is very helpful. I must not understand your setup. Is it NA or TC'd? If it is NA, then the upper deck pressure under the cowl is higher than MP and that is the source of the differential pressure for the injector. If it's TC'd, the upper deck pressure comes through the controller off of the turbo and is forced through the injector under a 3psi differential (above current MP), otherwise, the fuel wouldn't go into the port without a very high fuel pressure. I have some pics of this difference in fuel stream out of injectors if you'd like to see them.

Walter