Subject: Muffler question
From: paul lamar
Date: 8/7/2017, 7:21 PM
To: A10-Me-Earthlink


Hi Paul,

I hope the  Oshkosh experience was very good.  The TTC project is  very impressive.

I’m gradually working through my radiator and oil cooler issues, and also building an exhaust header / tangential muffler.  I have a couple of questions on the latter.

Please see the attached, although very crude, drawing.  

I am using the Racing Beat SS header, with short 2.5”x 1.75” OD  .065 304 SS tubes welded in place.  These will slip into 0.65” 1.88” tubes that will in turn be welded into a 6” 304 SS .065 cylinder/muffler.  On the front, a 90 degree 1.88” tube is used to reduce the length of the 6” tube and significant weight.

Due to space and other constraints, I need to bring the 3” tailpipe (also .065” 304 SS) out of the rear of the muffler and up.  This gives me at least 3 options:  
1. A straight 3” pipe welded to the rear of the muffler.
2. Squeeze the 3” tailpipe into a fish mouth (your previous drawings showed an area about 1/2 of that of the tailpipe).  Or weld up a larger fish mouth.
3. Or, allow a short section of the 3” tailpipe to remain inside of the muffler, which could be  closed off and drilled with (e.g. 0.5”) holes to arrive at the same exit area as the fish mouth design.  I am wondering if this might be a more conventional muffler design and possibly allow better sound reduction?

The prior concerns regarding the longevity of any metal living “inside” the muffler have been noted. However, with a Renesis engine having exhaust ports coming through the iron housings, as well as a cooling tube, both giving lower exhaust temps, do you think this is a concern for .065" 304?  

Thanks for your input,

Scott Gettings

You are on the leading edge Scott. Nothing like this has been built yet.
The RX8 side port exhaust is  a little cooler so it should work all right. If it burns through opposite the exhaust ports
you can weld on doubler patches.


Paul Lamar

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