Maximum Torque and Exhaust Velocity

[cudabob496]

Interesting discussion here. Max torque is obtained by exhaust valve size, size of primary header tubes, and size of collector.
This discussion says that after the collector, zero back pressure is preferred for max power. Meaning, I assume, that no exhaust system
after the collectors will give max power, but, the noise will get ya! So, perhaps having a smaller diameter exhaust pipe all the way back is not
necessary for maximum torque.

Valuable info: primary header pipe size for different engine sizes, at different rpms, for max torque.

http://www.hotrodders.com/forum/exhaust-diameter-formula-49188.html

[73EStroker]

I hear ya on that one. My 451 revs like a Formula 1 car and just about bends the tach needle with open headers. Hook up those Cherry Bomb Turbos and not nearly the same throttle response. Suspect, because I bought cheap junk mufflers, that there is too much back pressure. So yesterday I bought 2 new stainless Magnaflows that look like the stock Challenger resonators. Will advise after they are installed next weekend.

[cudabob496]

I hear ya on that one. My 451 revs like a Formula 1 car and just about bends the tach needle with open headers. Hook up those Cherry Bomb Turbos and not nearly the same throttle response. Suspect, because I bought cheap junk mufflers, that there is too much back pressure. So yesterday I bought 2 new stainless Magnaflows that look like the stock Challenger resonators. Will advise after they are installed next weekend.

I really like the straight through 3 inch Magnaflow on my LS1 Trans Am.

[cudabob496]

I suppose a lot of this info on torque and stuff is behind the
concept for developing step headers, that increase in diameter
a few inches from the head.