Can someone please explain to me the difference in performance between a 4-1 header and 4-2-1 header? I would like to know the reason behind the difference (get technical). Also I have no clue on how the traction bar works, does it only help on a straight line or it is good for track use also?. Please explain

 

You need to understand how a header works.. As exhaust waves come out of the cylinder and passes by where another cylinders runner is they create a low pressure area which when the other cylinder's exhaust valve opens it sucks the exhaust out..

As the engines rpms increase the wave moves faster so its further down in the runners when the next cylinders valve opens, so a 4-2-1 header will give you more low-mid power and a 4-1 header will give you more mid-topend power..

 

What about the traction bar?

 

here is some good reading on Header-Exhaust Design Effects on Engine Power for you!

 

Thank you

That is exactly what I was looking for.

 

Anybody else with a similar article about traction bars?