TPS wrote:Mad Buffalo,
I have the other mains on order at the moment, i will post my progress as i fiddle with it for you and anyone who may be interested.
Yes please do. I'd like to see how similar or different your settings end up being than mine to find out if, yes, all bikes are a little different or, no, that's just something pipe makers say for legal reasons. Should be a good test given that we both have virtually stock bikes other than the chambers.
Was also wondering if the Bromlech system generates power in a different way than Higgspeeds. 3-3 chambers use sound reverberation to recycle unused gas but could the Bromlech system be more of a power valve approach? Modern two strokes have power valves that change the exhaust output depending on rpm and maybe the Bromlech system is just letting more exhaust through which is what you want at a high rpm. Then at low rpm more exhaust is still getting through which explains the power loss there. Or maybe I've just been at work too long today and my brain is fried. Anyway it's just a thought. Feel free to agree or attack as you see fit.
Josh, "recycle unused gas" - you have to explain that one to me sometime
Two strokes use pressure waves to "suck" burned gases out of the combustion chamber and they also "suck" some fresh mixture out. At the tight revs, some of that is 'shoved back in" just before the exhaust port closes.
3 into 1 does the same thing at low speed but typically the waves arrive at the wrong time for the other cylinders at higher revs. Some 3 into 1 systems get around that by making resonant lengths very long or very short so that the exhaust is in time at revs that are very different to normal peaks. That should stretch the powerband up or down slightly. Strader used very long pipes, Bromlech used fairly short pipes.
Sled 3 into 1 or 2 into 1 systems ted to use really short headers and large volume chambers and they work remarkably well. Not as effectively as separate chambers for each cylinder but much better than one might expect.
tz375 wrote:some of that is 'shoved back in" just before the exhaust port closes.
Thanks for the clarification. That's more or less what I meant by "recycling unused gas", although my choice of words may have been odd? Anyway, that was the reason for the post - to hopefully be corrected and learn something.
Expansion chambers are shaped to pull in mixture into the cylinder, that's why the pipe expands in shape. A good pipe can pull fresh mixture 12" into the pipe. The reverse (baffle cone) takes the sound wave, reverses it and pushes that fresh mixture back into the cylinder. Depending on the pipe length, heat, and cone length, determine the timing of the return sound wave and the strength.
When a 2 stroke "comes on the pipe", or hits the "power band", what is happening is that the engine circuits are in phase and working together.
At lower rpm the circuits are not quite in phase so the returning sound waves in the pipes are not arriving at the right time and fuel is lost out the pipe. A 3 into 1 is sending back 3 (weaker) sound waves which help at lower rpm, as 3 sound waves will have more of a chance of getting the fresh mixture in the pipe pushed back in the cylinder. So low rpm torque is better. BUT, when in the "powerband" range of rpm The 3 weaker return sound waves now counter act the process, and the mixture doesn't fully get pushed in the cylinder. That's why most 3 into 1's have the power dying off right where the powerband is supposed to "hit".
They can be designed to work their best at different rpm "sections", as on snow mobiles, as they stay in a small range of rpm.
Well, the Bromlech 3-1 i have does not 'Die off' at high RPM. It's quite the opposite. I like it better than the standard system.
At any rate, it's off the bike now and the Higgspeed chambers are my new favorite. Im still waiting for the jets i ordered so i have no further updates yet.
