Headers Are Worthless On Street Engines

[Hank70SS]

Originally Posted by English Power

Please explain to me how headers reduce back pressure when the cause of the back pressure (the restrictive exhaust pipes, mufflers, and tail pipes) is still there? Headers are only effective when they are run open or did you Americans forget that little detail? And then headers are only effective when the engine is being run at full power and high rpm; something street engines rarely (if ever) do.

Steel tubing exhaust manifolds do have their place in off road track racing events where mufflers aren't required but when used on street legal vehicles they offer no benefit at all. Just ornaments with a cool name and hefty price tag.

Pretty simple physics. The extremely hot exhaust gases leaving the cylinder create a lot of pressure in the manifolds or headers. As they cool and they cool down much faster in headers than in most stock manifolds, the pressure is reduced. Again, pretty simple, headers have much more exposed surface area to to cool the exhaust gases. Blow up a balloon with very hot air then cool it down to freezing and watch the balloon collapse.

Headers cool the exhaust gases faster, once they're cooled down they require less volume and the rest of the exhaust can handle it. Remember that everything that leaves the exhaust had to come in through the carburetor, which is as at ambient temperature. Know look at the ventures in your carburetor and compare the volume to that of the exhaust system. Simple, the sooner you cool the exhaust gases the easier it is for the rest of the exhaust system to handle it.

If you don't believe, fine. There are plenty of dyno runs available to prove it.