SR Volumetric Efficiency vs. Boost and RPM

[jspaeth]

I am trying to work on my fuel maps......the higher RPMs are difficult to do without a steady-state dyno...


Anyway....technical question for the EXPERTS out there.


V.E. vs. RPM......does it change with manifold pressure?

Example....if I want constant 12.0:1 AFR at 10 psi in all RPMs, I would need to steadily add fuel up to where I achieve peak torque, and then after that, the V.E. drops off, and I could actually use less fuel to get same AFR, right?


Okay, assuming that I got that right, is there any reason to expect that the V.E. (or relative amounts of fuel at different RPMs at fixed manifold pressure) should be different at 0 psi compared to 10 psi compared to 20 psi?


I have a really good fuel map that allows me to achieve desired AFRs in the vacuum portion of my map, and I am seeing clear trends in where I need more fuel vs. RPM at fixed manifold pressure.....I am hoping I can apply these trends to the lower half (positive manifold pressure) of my map.....

Anyone have any insights?