hey, i know what powerband does, you go faster at, but what makes it do it, and how does it work, any help would be appreciated.

 

Powerband is usually described with two strokes, in mind. Four strokes have a realtivly flat torque curve, and theres no power hit, like on a properly tuned two stroke.The power band usually extends from slightly below the engine's torque peak to slightly above its power peak.

powerband
This article does a pretty good job of explaining, why.

 

thanks man, that site is awesome

 

most of the time 2-strokes are associated with having a very "narrow" powerband, meaning that you have to keep the rpms within a specific range to maintain power. most 4-strokes tend to have a broader powerband, where they make more power throughout a larger rpm range.

 

"Powerband" is the HP/torque curves of any engine. The sudden hit of a 2-stroke that people refer to as "hitting the powerband" or "coming on the pipe" happens when the engine hits its sweet spot. 2-strokes rely on the frequency of waves. Notice how the exhaust of a 2-stroke is shaped. The length of the pipe from the cylinder to where it goes small again after the expansion chamber affects where the power peaks at. The angle of the cone where it goes smaller is also one of the MANY factors to a 2-stroke pipe. The piston going up and down creates a "pulse" of exhaust gas. Everytime the exhaust port opens another "pulse" of exhaust gas is released into the pipe. 2-strokes actually also pull raw, unburnt fuel into the exhaust along with the burnt fuel (one reason they can't pass emissions). The sound waves caused by each pulse will follow through the pipe and bounce off of the cone at the rear. They then follow back forward and shove the fuel back into the cylinder. When the engine starts hitting the perfect RPM where the piston is travelling up and down creating a pulse that is in time with the sound waves in the pipe is the RPM where you start to feel that sudden hit.

 

thanks for the awesome explanation, i get it now, im not exactly stupid all thought it may sound it because of this question, but i just needed a lil explainin on what exactly happened to give the boost in "powerband". Thanks again guys!!!

 

I never thought you were stupid. 95% of the people that ride have no idea how their engine works. I would rather 100 people ask a question and have it answered than to hear another person say "I had a powerband put in my banshee" or say "my banshee has reeds, FMF pipes, and a powerband". As a joke, a local shop had a bucket of rubberbands sitting on the sales counter marked "powerbands". Each color had a type of 2-stroke bike written on it. YZ250, banshee, CR125, etc. You would be surprised at the guys that had been riding for years that wanted one for their bike.