greenmonster wrote on 05/09/12 at 12:24:13:I hate reading technical posts when I'm sick, stuff that should make sense just doesn't.
Vers, you open up your exhaust and you "allow more unburnt gasses to pass through" does that mean that we should be putting leaner jets into the carb when we put a free flowing exhaust system on?
No, think 2 stroke reverse cone exhaust.
with a 2 stroke, the exhaust open 1st and most of the exhaust runs down the pipe, then the intake opens sucking it a fresh charge.
And quite a bit of the fresh charge gets into the exhaust, yet both intake and exhaust are still open.
This pressure wave finally hits the reverse cone and reflects back to the piston. This pushes the fresh charge in the exhaust pipe back to the piston. This creates a super charge effect in the compression chamber.
A similar effect happens with the 4 stroke, just not a severe.
So no, leaning out the jets won't stop gas getting into the exhaust. But it will reduce the power produced.
This is why open exhausts don't work as well.