I know it probably doesn't help your mid-mount, full-race setup, I had my exhaust off the car, and just weighed the muffler unit (with three hangers, 3" tip, and 3" connector pipe with a v-band) at 15.4lbs.

The one in this picture:


It's a magnaflow piece, and is fairly tame around town, but has some anger in it when you go WOT. I'd definitely be able to DD. And that's with no cat.

When I was talking to Abe about my exhaust build, he gave me the options of loud, louder, and loudest. He said this one was apparently "louder".

You might want to talk to him about mufflers, he has a lot of first hand experience.

Fast forward to 1:05:



Gives you a fairly good idea though, you really don't need much for a turbo race car.

 

Only 15.4, thats lighter than I was expecting that big of a magnaflow to be heavier than that.

In the name of science I whipped up spreadsheet that calculates the frequency of exhaust noises from the firing cycle, it doesnt account for mechanical noise because I have no ******* idea of to calculate it. But this math wasnt that bad. Since I'm pretty set on going with a round glasspack at this point I really just need to pick the right length to cancel out the most sound at the frequencies I care about. From the spreadsheet I would actually want a body. The one piece of info its missing is an accurate estimate of the exhaust gas temp where the muffler would be, and it makes a huge difference.

 

Considering the hangers and inlet/outlet pipes, I'd say it's around 10 or 11lbs. It's really not enough weight in a turbo race car to worry too much about it's weight. Just get the one that fits and meets your sound requirements, and spend your R&D time in more beneficial areas of the car. A muffler is in the complete back of the car, damn near the lowest point it can go. Concentrate on higher items, or items that are spinning.

 

I have both. full 3.5" exhaust and..
With Magnaflow 5x11x22 ~90-92dB
Added Vibrant midpipe ~86dB

 

Im about to do a POSSIBLY 3.5" system, if not 3" for a car with a 2560 and Use only a single hotdog, and shoot the exhaust straight out the US drivers side, Ill post results in this thread weight and volume wise.

Dann

 

Curly what size in that muffler? I like how it is angled and uses a center in/center out.

 

2.0L N/A BP4W 182whp - MX-5 Miata Forum



I'm pretty sure Brain had your number with the Magnaflow 5x11x22. You can ask Emilio for details, but "giant Magnaflow" is generally code for the 5x11x22. I can confirm that the exhaust Crusher was running for the T25 this year was disturbingly quiet for a racecar, but I have no idea if the parts Emilio described back in March in the above m.net thread are the same parts that were on the car in Dec for the T25. He may or may not be willing to share details.

You could always do this: MX-5 Miata Forum - View Single Post - [NA] DIY Rotrex Miata Challenge Build

 

Yup I think it's the 5x11x22 Magnaflow. We eventually blew all the stuffing out of it and melted the interior partitions. So John at Hytech cut it open, repaired and stuffed with a bunch of new non-steel fiber packing. It weighs about 20lbs now but should last a full season. Resonator is a straight through, perforated core with packing around the outside. Last year we melted several of those and had to go to thicker gauge material in the resonators. 3 hrs @ 1100° destroys even 304 SS mufflers unless they're pretty burly. Our enduro exhaust are not light. I gave up trying to make light race exhausts a few years ago. Now the focus is on making them last a full season and being quieter that a street exhaust.