I wanna buy the SBP Expansion chamber for my bike. My friend said that expansion chambers on 2 strokes make the gas mileage go down alot. Is this true? Ill just get a 36 tooth sprocket if the gas mileage goes down with a pipe.
Gas mileage with expansion chamber?
- Thread starter socialdistortionkid
- Start date
Expect to do a re-tune on the carburetor after installing the expansion chamber exhaust.
The gas mileage can go up quite a bit if you stay in the RPM range where the pipe is most effective.
The pipe works by reflecting the pulses of high pressure created when the exhaust port opens back into the cylinder. It does not reflect back the exhaust gasses mind you, only the pressure wave. This effectively pushes the fresh incoming intake charge that would normally escape out the exhaust port and get wasted back into the cylinder, increasing both power output and fuel economy.
If you ride it like a bat out of **** after installing the expansion chamber, then yes, expect a loss in fuel economy. If you ride it within the means of the pipe and the engine is well tuned, enjoy the little extra benefit of better fuel economy.
Here's a link with a good animation of a pipe and explanation of how it works.
The green is the fresh intake charge.
Two stroke - scoot.net
The gas mileage can go up quite a bit if you stay in the RPM range where the pipe is most effective.
The pipe works by reflecting the pulses of high pressure created when the exhaust port opens back into the cylinder. It does not reflect back the exhaust gasses mind you, only the pressure wave. This effectively pushes the fresh incoming intake charge that would normally escape out the exhaust port and get wasted back into the cylinder, increasing both power output and fuel economy.
If you ride it like a bat out of **** after installing the expansion chamber, then yes, expect a loss in fuel economy. If you ride it within the means of the pipe and the engine is well tuned, enjoy the little extra benefit of better fuel economy.
Here's a link with a good animation of a pipe and explanation of how it works.
The green is the fresh intake charge.
Two stroke - scoot.net
Thanks for the explanation but yeah im aware of how an expansion chamber works being around 2 strokes all my life ive used them on dirtbikes, gopeds etc. and love the extra power. Expansion chambers are the single biggest power upgrade you can do and it shows the potential your engine has.
Yah.. what he said.
an exp chamber makes a bike 'pipey'.
It will run better... stronger, faster, more efficiently in the rpm band the pipe is built for, and the engine is tuned for.
SO, with all that, you will get more out of your fuel at that rpm.
it's gonna bog, more or less, at all other rpm ranges.
THAT will deliver less beneficial use of your fuel.
Everything is a trade-off.
After reading through as many of the posts as I can, and still doing so, you'll find the best to do for economy, power, and reliability, is to take the engine apart, replace nuts and bolts, clean up mating surfaces, and remove excess of poor quality castings and alignment.
lol
I put the WRONG pipe on a dirtbike once.
Turned it into a real screamer at top rpm.
precisely what I did NOT want!
Best
rc
an exp chamber makes a bike 'pipey'.
It will run better... stronger, faster, more efficiently in the rpm band the pipe is built for, and the engine is tuned for.
SO, with all that, you will get more out of your fuel at that rpm.
it's gonna bog, more or less, at all other rpm ranges.
THAT will deliver less beneficial use of your fuel.
Everything is a trade-off.
After reading through as many of the posts as I can, and still doing so, you'll find the best to do for economy, power, and reliability, is to take the engine apart, replace nuts and bolts, clean up mating surfaces, and remove excess of poor quality castings and alignment.
lol
I put the WRONG pipe on a dirtbike once.
Turned it into a real screamer at top rpm.
precisely what I did NOT want!
Best
rc