Torque Peak vs. Flow Passage Size Essentially, this is a subject
almost unto itself. However, since we're discussing port size
fundamentals and their relative effect on engine performance
(torque output), a brief but general discussion seems
appropriate. Here's the deal. Even though intake and exhaust
flow is considered "unsteady" and "bi-directional" (at times),
it is possible to determine what we'll call "mean flow velocity"
(m.f.v.) at a given time (rpm). Simply stated, there is a mean
flow velocity that's measurable at any rpm point, specifically
at peak torque. Further, it turns out this m.f.v. is virtually
the same for any engine at its peak torque rpm. It's a
combination of conditions involving fluid dynamics and
acoustics. From a parts selection or component design
standpoint, peak torque rpm can be influenced (sometimes
significantly) by passage size or cross-sectional area. If you
subscribe to the concept that a common m.f.v. will exist among
engines at their peak torque rpm, then increasing passage