Why open pipes


Banned - Must pay $500
Can you state your reason on Why an Open pipe is better ?

Or make your statement on Tuned pipes.

ME. I get why people like an open pipe " Bbrapp " Bbrap. But does it really help ?

Tuned pipes create after burn, plus some pressure and you still get the bark. " Bbrapp " plus a bit of performance boost.

To me the tuned pipe is like a muffler without as much hold back .
Many Motorcycles run Tuned pipes.
Many Snowmobiles run Tuned pipes.

Its like some run open pipes on cars, some say its not good to do this.
They say some hold back helps make Power.

A header is always good, smoother flow is always a PLUS.

Is Hold Back needed when it comes to small engines ?

Header / Tuned Chamber / Silencer tip......

No Silencer tip, it would be called a Stinger

Last edited:
Hey Buddy, before the pulse width and scavange conversation starts: (reasons in bold)

All I run are flatheads. All of them work better with less restriction. Some of them have long exhausts, others have stock exhausts- all to keep things original. (vintage)

The bikes that do have modified exhaust were set up with ease of fabrication, installation, and maintenance as a priority. Not performance, not sound, either attenuation, or amplification.
Good answer

But does Open exhaust hinder or help a 4 cycle ?
It helps. Otherwise more restrictive systems would be used on 10,000 HP nitro motors. :laugh:

BUT: length of the pipe will determine the timing of any return pulse back up the pipe towards the exhaust valve at specific RPM. There are all kinds of physics comments out there on pressure waves.

In the end, it needs to be done on a dyno, not on a calculator.
A 2 cycle piston port motor does not have valves that open and close like a four stroke does. The piston itself works (kinda) like the valve. With a two stroke there is a lot of fresh charge ( fuel/air mix) that's lost out of the exhaust port before the spark plug fires, thus the expansion chamber / tuned pipe creates a wave of back pressure to "pack" some of the lost mix back into the cylinder before detonation. Not needed with a four stroke.


Banned - Must pay $500
All good info, Just wondered if there was a reason to run open pipe's.

Other than noise .

Its like ( why install a velocity stack on a carb ) ?

Just making conversation, people learn this way..