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Odd harmonics from expansion chamber.

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Old Feb 7, 2008 | 06:14 AM
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Odd harmonics from expansion chamber.

Has anyone else experienced odd harmonics or non sync sounds from a expansion chamber?

Very weird, the harmonics stop around 6200 rpm and become a odd whoosh sound.

Just wondering.
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Old Feb 7, 2008 | 11:15 AM
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Expansion chambers?
Name:  wankelpipes02.jpg
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Or do you mean your regular old mufflers that could be burnt out and buzzing?
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Old Feb 7, 2008 | 11:26 AM
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Thats a funky looking header.
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Old Feb 7, 2008 | 03:27 PM
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Trying to apply 2 stroke exhaust technology to a 4 stroke engine I see. Yes the rotary is a 4 stroke and the exhaust does not in any way behave like a 2 stroke regardless of what anyone claims. That setup would never work. The whole point of a 2 stroke exhaust's design isn't only to help pull gasses from the engine but also to push some back in. You do not want this on a 4 stroke engine. This is why the inlet to the 2 stroke muffler is much larger than the stinger (outlet).
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Old Feb 7, 2008 | 05:04 PM
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I know it would never work, which is why I never built these pipes in the first place. I found these pics of these pipes a long time ago and thought it was funny. The reference to expansion chambers only reminded me of them. I bet they would sound really strange though.
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Old Feb 7, 2008 | 11:49 PM
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Thank god! I thought you were crazy!
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Old Feb 8, 2008 | 12:05 AM
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A small expansion chamber after the collect can knock the sound down pretty good, or change the tone of it.

This is or was a feature on some of paul yaw's headers.
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Old Feb 8, 2008 | 06:09 AM
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The large single expansion chamber I have on, if alot larger than that and smoother. The car went about.7 seconds faster in the Quarter Mile.

Paul Yaw is the man. I have been following his progress since 93, after I met Cameron Worth, the owner of Pettit Racing. We managed to bring his first TKT he ever built, down to him, in 93. This is when he was starting to make the Banzai, the 3 rotor swap..

All the race cars had some sort of chamber on them..it must work for them.

Thanks for the help..
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Old Feb 13, 2008 | 08:47 AM
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What kind of header is that?

The pre-expansion chamber section of that looks just like this "mystery header" I have that came with my latest car. Have no idea who made it.



Sorry for the 'jack
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Old Mar 1, 2008 | 11:48 AM
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That is a Mindtrain header. The company is no longer around.
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Old Mar 1, 2008 | 06:04 PM
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Sweet! Thanks for the info.

I had suspected that it was a Mind-Train but without being able to see pics of their products, I was unsure.

That header was modified to fit a 13B, and I'm still using it. I only needed to grind out of the outsides of the tubes inside the flange, and barely into the flange itself. That was a lot easier than ovalling the bolt holes!
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Old Mar 3, 2008 | 11:58 AM
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From: https://www2.mazda.com/en/100th/
Originally Posted by slo
A small expansion chamber after the collect can knock the sound down pretty good, or change the tone of it.

This is or was a feature on some of paul yaw's headers.
isc had something like that too.
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