Who is useing Header extensions?
Unfortunately, the only true way to know what, if any benefit there is or could be to header extensions is to dyno the engine or the whole vehicle to test various length extensions.
Once the actual length is found to make best power, you need to put on a box and then construct the rest of the exhaust. This box is mimicking an open exhaust to produce the cancellation wave back to the exhaust port to help draw in more of the intake charge.
Unfortunately, the only true way to know what, if any benefit there is or could be to header extensions is to dyno the engine or the whole vehicle to test various length extensions.
Once the actual length is found to make best power, you need to put on a box and then construct the rest of the exhaust. This box is mimicking an open exhaust to produce the cancellation wave back to the exhaust port to help draw in more of the intake charge.
