High-port vs. Low-port...pros & cons

[Bruce_Hearn@cd-tech.com]

Theoretically, the high-port head should flow better than the low-port.  The
better the injection shot at the back of the valve head, the better the fuel
atomises with commensurate power and mileage increases.  Also, straight pipes
flow better than curved pipes.  That said, I posit that the high-port head won't
out-perform the low-port until at least 8,000 rpm.   Ponder this: the SR20DE has
been rated at 140 hp and 132 ft-lb torque since its introduction to the North
American market. With the switch to low-port heads for '94, pollution gear was
reduced, cams were milder, yet the same output was maintained. 1995 and later
low-port engines made that power at lower rpm. For street use, SR20 head design
isn't the limiting factor, that's for sure.

Bruce in Houston