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Old 12-15-2012, 03:42 PM   #21
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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.
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Old 12-16-2012, 12:55 PM   #22
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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.
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Old 12-17-2012, 12:34 AM   #23
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Quote:
Originally Posted by Leafy View Post
Only 15.4, thats lighter than I was expecting that big of a magnaflow to be heavier than that.
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.
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Old 12-17-2012, 04:19 AM   #24
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Quote:
Originally Posted by Savington View Post
Magnaflow and Vibrant both make straight-through mufflers that are light and fairly cheap. You're going to have to do your own testing on the quiet part, though.
I have both. full 3.5" exhaust and..
With Magnaflow 5x11x22 ~90-92dB
Added Vibrant midpipe ~86dB
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Old 12-17-2012, 06:14 AM   #25
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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.

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Old 12-19-2012, 05:52 PM   #26
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Quote:
Originally Posted by curly View Post
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.



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".

Gives you a fairly good idea though, you really don't need much for a turbo race car.
Curly what size in that muffler? I like how it is angled and uses a center in/center out.
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Old 12-19-2012, 06:18 PM   #27
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2.0L N/A BP4W 182whp - MX-5 Miata Forum



Quote:
Originally Posted by naprotejay
what's the exhaust after the header?

love it, motor sounds great
Quote:
Originally Posted by emilio700
2.5" mandrel bent, resonator in mid section with giant Magnaflow behind the axle. It's built to meet T25 sound of 92db. The 180 bend into and 90 bend out of the huge muffler help sound but probably cost a few hp. The car is very quiet from outside.
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



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Originally Posted by TrackDayHookey
One plus - fireballs on shifts were then visible in the rear-facing camera

Last edited by EO2K; 12-19-2012 at 06:43 PM.
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Old 12-27-2012, 01:53 PM   #28
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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.
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