Is back pressure necessary for a modern superbike (ZX10R) exhaust system?

Answer 1

You DO need some length of pipe.
ie; the bike cannot be run without a header.

The amount of back pressure required depends on the tuning of the motor. meaning you cannot take a stock bike and just run it with straight pipes. this can be done if the bike is tuned properly, (jetting, fuel map mod, whatever). It would take more than a simple response to answer this correctly....



For the purpose of this question, yes you need back pressure.

Answer 2

I'm not sure but I believe back pressure is necessary in todays bikes. If you put on headers, with a huge tube size, on the bike and you dont have the exhaust area to match, the gas speed would slow down and would tend to hurt bottom-end performance. It may not help the top end either. Exhaust gas must accelerate to high velocity to duck under the exhaust valve and get through the port throat. If the header tube is too big, the gas than has to slow down again.

Todays sport bikes unlike yesterdays bikes have very technical pipes that are tuned to provide power throughout the power band. So unless your bike came from the factory with straight pipes, my guess is that yes, back pressure is still needed.

Modern race bikes in all classes except maybe drag racing have some type of exhaust cansiter on them. In the AMA, WSB, and Moto GP all of the bikes have canisters on them therefore providing proof that back pressure is necessary. They're out to win so they would have straight pipes if it would improve there performance but they don't. I would guess that even with fuel injection you still need back pressure.

Answer 3

Most modern bike exhaust systems use the exhaust from one cylinder to help "pull" the exhaust from the other. Some custom motorcycle engines are designed to be used with straight pipes, but usually these are not found on production bikes. If your bike has a crossover pipe in the exhaust system, changing to straight pipes can cause damage to your engine. Check with the head tech at your dealer to see what modifications can be safely made.