Frank van der Hulst wrote:

Paul wrote:

Frank, how are we going to get amplitude without a DB meter?

Do we need amplitude?

My thought was to analyse the spectrum, then design a muffler to
minimise the frequencies which have the most power. The absolute
amplitude value isn't important.

But then, I don't know a lot about muffler design.

Frank.

I now see where you are going Frank. Knowing you for as many years as I 
have I should have known you had something tricky up your sleeve :-)
That sounds like a good plan. We should have some before and after amplitude
measurements to see how well it worked however. 

Taking that idea a step further can you think of a way of making the 
resonators out of low temp low weight composites? 

I suspect a conventional metal tuned muffler will weigh as much and
be as large as a stock muffler. Therein lies the real problem.
Perhaps just copying an early stock RX4 or RX7 muffler (before catalyst) in thinner 
Inconel would work. Mazda probably spent big bucks tuning them to the rotary. 

The other thing to think about is how much is it engine exhaust noise
and how much is it prop noise.

Paul Lamar
 
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