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Old 12-31-2011, 11:04 AM   #21
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I'm surprised they won't fix that under warranty. I guess I'll take care of it myself then. Thanks for the info.
Cause they are silly.
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Old 12-31-2011, 02:58 PM   #22
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Thats pretty interesting! Cant you do basically the same thing with an electric cutout?
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Old 12-31-2011, 03:40 PM   #23
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Thats pretty interesting! Cant you do basically the same thing with an electric cutout?
I'd assume if u put a hole in the butterfly so its not a completely closed thing it should work.
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Old 12-31-2011, 04:13 PM   #24
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yes but all other cutouts I found (mech, elec) were pricier than the entire VT mufler.
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Old 12-31-2011, 05:00 PM   #25
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I've been wanting to build my own muffler with one of these flaps in it, I think i am going to use a resonator though and put the flap inside it. That way when the flap is closed it causes the gas to go through the packing in the resonator, instead of just blocking most of the flow.
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Old 12-31-2011, 06:11 PM   #26
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If you're willing to go that far why not just run a cutout before the muffler?
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Old 12-31-2011, 06:59 PM   #27
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Because a cutout has to seal 100% and that would be too hard for me to build. That and i'm really cheap, even the cable style cutouts (which don't seal well) are nearly 60 dollars. For a few pieces of metal and cutting and welding the resonator I already own i can make my own... why not?
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Old 01-01-2012, 04:29 PM   #28
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Get a 10 bucks throttle body from an old civic or something. The mount is easy to make if u have a welder.
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Old 01-01-2012, 08:12 PM   #29
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Not sure an aluminum throttle body would hold up at the end of the downpipe. Not to mention it still probably would not seal 100% although it would be really close.
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Old 01-01-2012, 10:07 PM   #30
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Remember that these restrictors work best at quieting the drone/thrum when installed at the end of the exhaust. This way the exhaust pulses have the entire volume of the exhaust to pressurize/de-pressurize.
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Old 01-01-2012, 10:13 PM   #31
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EVOs, F430s, and E46 BMW afaik have them.

EVO muffler cutaway: Flapper is in the upper left. The arrows show the flow while flapper is closed. When it opens it bypasses the circuitous route.

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My 3" custom exhaust with spring loaded flapper valve-03-06-evo-viii-ix-including-rs-mr.jpg  
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Old 02-15-2012, 01:10 AM   #32
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The popular quiet 3" muffler seems to be the 22x5x11 Magnaflow, but I like the flapper idea. All the Dynomax VT Mufflers are of the smaller variety except for the 17963:


If a Dynomax 17963 were to be installed on a miata I would envision that the dual 2.5" outlets would have gradual 90 turndowns, rotated 45 to the rear. The flapper may not last a long time, but these mufflers are relatively cheap if they need replacement in a few years.

Pro's?
Con's?
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Old 02-15-2012, 03:51 AM   #33
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Don't use turndown tips that point to the ground. The noise gets reflected from the ground up to the car. Ask me how I know...
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Old 02-15-2012, 11:15 PM   #34
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So are you guys figuring out how to get the brown note out of the exhaust, cause road trips kinda suck with a brown note! just saying.
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Old 02-15-2012, 11:32 PM   #35
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Don't use turndown tips that point to the ground. The noise gets reflected from the ground up to the car. Ask me how I know...
How do you know?
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Old 02-16-2012, 12:51 AM   #36
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LOL I'll bite whether you're joking or not... what else, I tried it when I upgraded my old 2.5" muffler to a larger one, was aghast at the noise ... complained bitterly to Magnaflow, then realized it was the temporar turn down...(was waiting for a proper tip to come in)
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Old 02-16-2012, 02:34 AM   #37
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I am so pissed off that they dont sell something like this seperately from the muffler, for say, 50-60. I mean its simple as hell, and obviously effective, why hasn't someone already started mass producing these thingamabobs?
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Old 02-16-2012, 02:02 PM   #38
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I am so pissed off that they dont sell something like this seperately from the muffler, for say, 50-60. I mean its simple as hell, and obviously effective, why hasn't someone already started mass producing these thingamabobs?
Then you wouldn't have to buy their muffler...
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Old 02-16-2012, 02:04 PM   #39
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Duh...
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Old 02-16-2012, 02:07 PM   #40
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My research on these VT mufflers hasn't shown much promise. Apparently they are really bad for boxer engines (boo for my Forester) and cars with cams. Apparently the flapper and rattle at idle and other situations. Also, it seems the flapper starts to wear over time and loses some performance, for the Evo guys it was after ~ 1 year.

Honestly, I wish somebody would run with this idea but do a better job engineering it. The Dynomax VT muffler is pretty affordable but it seems to have some serious flaws. Personally I would rather pay $200 for the muffler if it worked 100% as advertised. Versus paying ~$100 for a muffler that sort of works but also rattles like hell at idle...
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