Posted by rickyracer (IP: 209.244.229.100) on September 21, 2000 at 19:01:14:
In Reply to: So you make the runners and exhaust longer...? posted by Mavman on September 21, 2000 at 12:27:24:
nope, they make the gases speed up. As the exhaust gases leave the chamber they expend and that slows them down, the ports keeps the gas speed up so as not to expand. When they expand it causes a back pressure against the gases trying to get out and slowing down the flow and making the piston work harder to push them out. It's the same idea as the insulation on headers to slow down exhaust gases from expanding. Intake side to big will slow down the flow into the cylinder because of the big pipes. Think of it as water and you want the most speed for your size.
: : port plates are made to bolt on either on the intak or exhaust manifolds to raise the floor of the port. the exhaust plates are supposed to help the exhaust flow out musch better and increase your low end torque. they're around $75 .