Honda Spree and Elite 50 Forums

So I've been doing some research on expansion chamber design. I came across an article that was very informative about designing pipes with software and then micro breaking individual cones and so on. Anyway the author of the article wrote that there is a more efficient way to build the pipes with high pressure water. So I started to research hydroforming and it seems to be the easiest way to build tuned exhausts. Was just wondering if anyone on here has any experience with hydroforming or building custom expansion chambers in general. Would like to try building a few this summer so any tips or advice would be greatly appreciated!

Here are some of the articles I found if anyone is interested:

http://www.instructables.com/id/Build-a ... -2-stroke/

http://www.eurospares.com/frame8.htm

I have never but I know there were some kids on moped army hydroforming pipes a few years back.

There are also step by step videos on the youtubes.

Apparently the main attraction is that they are easier to mass produce and are lighter.

Once you sort out what pattern ends up working (which takes much trial and error apparently) you can crank them out a lot quicker than welding up cone sections.

You need to be able to put down a really solid consistent weld too and the whole thing seems kind of dangerous, especially if your weld failed up near where it mates to the pressure washer.

Seems like you would have a torpedo if it failed.

I have read up on this a bit and am very interested in attempting it. The most attractive pump I would use is call a test pump. http://www.ebay.com/itm/261166179018?_t ... EBIDX%3AIT here is one

The water pump is expensive, and requires more trial and error to get the shape. Not a bad way to go for mass production where you can take those costs and cut them up over many parts.

Water is incompressible, so there's no torpedo... if it broke off the end the water would just drain out. If you were doing this with air, which is compressible... yes, that would be very dangerous.

noiseguy wrote:The water pump is expensive, and requires more trial and error to get the shape. Not a bad way to go for mass production where you can take those costs and cut them up over many parts.

Water is incompressible, so there's no torpedo... if it broke off the end the water would just drain out. If you were doing this with air, which is compressible... yes, that would be very dangerous.

Yeah I was thinking for some reason there was air in there before the water, but of course there isn't.

IIRC you have to have a valve at one end of the pipe to get the air out, so water can fill the chamber. Once the air's out you shut the valve and the water pressure blows out the pipe.