Banana Expansion chamber help?

[JohnnyDash]

Okay now I know that everyone says that these "banana" expansion chambers dont work properly because it doesnt have the correct header distance and this cause the back to... well a lot of mathematical information that I dont really understand...but what they dont say is how much distance does it need to work correctly, I have to tools and know how to make the changes I just need to know the distance from the header should be, can anyone help me?

 

[Theon]

Depends on the revs your after/ where you want the 'band'
Trial and error seem the way.
Maybee start at 8"?

 

[Greg58]

For low end power 16 inches of pipe before the muffler or chamber worked best for me, most people that build a lot of pipes say go longer for low end shorter for higher rpm. Funny mine with a 16 inch pipe helped all the way through the rpm range.

 

[massdrive]

I have reconfigured my pipe 3 times in the last 2 months. Everyone says, "longer for low end torque, shorter for high end..." I found that just the opposite is true. I shortened my pipe a total of 6 1/2" since I first installed it and created a significant increase in low end and mid range power with no noticeable decrease in the high end.
My "j" pipe now curves down and wraps around the frame than sweeps back up and gracefully arcs into the chamber that is mounted high on the right side. I've got about 12" of pipe between the header and the expansion chamber. Experiment until you find the sweet spot that makes you happy. Unless you have a pipe bender I've found the most convenient material to use is old handlebars. Just cut them up and weld them back together. Make your curves smooth and graceful, not abrupt. Most important of all; have fun...

 

[maniac57]

I have reconfigured my pipe 3 times in the last 2 months. Everyone says, "longer for low end torque, shorter for high end..." I found that just the opposite is true. I shortened my pipe a total of 6 1/2" since I first installed it and created a significant increase in low end and mid range power with no noticeable decrease in the high end.
My "j" pipe now curves down and wraps around the frame than sweeps back up and gracefully arcs into the chamber that is mounted high on the right side. I've got about 12" of pipe between the header and the expansion chamber. Experiment until you find the sweet spot that makes you happy. Unless you have a pipe bender I've found the most convenient material to use is old handlebars. Just cut them up and weld them back together. Make your curves smooth and graceful, not abrupt. Most important of all; have fun...

Every pipe and engine is different. You are 100% right in ignoring opinion and doing whatever YOUR engine likes. Just like extended intakes...not every engine will respond the same.

 

[Tyler6357]

If you set it short you will get more high end torque. As you move it back, you will get more low end torque. Find the power band that you like. I have mine set back 17". That is, 17 inches of pipe from the exahust manifold until the chamber starts to expand. At this length I get more low end torque to help me make it up some pretty steep hills in my area. I hit the power band at about 1/4 throttle and can hold it almost to WOT. I could get more top end if I moved it closer but I like having the extra acceleration on the bottom end. I don't have a welder but I ran mine around the front part of the frame on my mountain bike (see pic). Awesome upgrade, a very noticable improvement!!