"The WB" (thewb)
09/05/2013 at 19:40 • Filed to: None
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"The WB" (thewb)
09/05/2013 at 19:40 • Filed to: None | 5
| 15 |
My brother added a 12" magnaflow glasspack to his exhaust system. It's a Mazda MX-6, and he built a full 2.5" exhaust to match his headers, but the 3-chamber Magnaflow was quite loud and had the raspiest sound under hard accel. He was tired of everyone trying to race him, as well as the undue attention from the law after it turned out to be a bit loud.
Rasp usually means broadband or high frequency noise. Just to be sure, and to show him some acoustical science, we hooked up a mic to the computer with !!!error: Indecipherable SUB-paragraph formatting!!! and took it for a spin, which pretty clearly showed broadband noise across the whole spectrum.
The most effective silencer for broadband and high frequency noise is a perforated packed muffler (i.e. glasspack.) In theory it was supposed to cut out all the rasp and mostly preserve the harmonics of the existing system.
It turned out to work quite well. He spent the day with the MIG and it took all of the ricer 'tin' out of the exhaust and smoothed it out. In his words, it sounds like a pillow, if a pillow had 6 cylinders. No harsh notes, just the strongest harmonics from the engine.
So, if you're interested in that "tuned" yet not too loud chambered sound without the rasp of a large exhaust on a low displacement motor, I recommend a short glasspack in line with your chambered muffler of choice. Just be sure it's perforated and no elements are in the flow stream, as protuberances tend to add turbulence and thus high frequency noise (some have little scoops instead of perforations.)
I'll try to get some comparison sound clips as well as the spectrograms.
Brian, The Life of
> The WB
09/05/2013 at 19:43 |
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Which motor does he have?
Nighthawkwill7, Hoon Depot Manager
> The WB
09/05/2013 at 19:45 |
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The WB
> Brian, The Life of
09/05/2013 at 19:47 |
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2.5L KLDE V6 Auto. He's either going to put in custom grind or KLZE cams and intake when he puts in the manual transmission. At that point he'll do a full motor rebuild as well.
As it sits it's stock except for the headers and exhaust. Oh, and the slightly-better-than-OEM struts.
GTRZILLAR32-Now saving for Godzilla and a condo
> The WB
09/05/2013 at 19:53 |
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Been debating on whether or not to glass pack my exhaust system. Currently it is stock and along the piping there are 3 resonators then the muffler, it sounds good but I want it a bit louder.
Sparf
> The WB
09/05/2013 at 19:57 |
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That sounds really interesting! I read up a lot on the K series V6 when I was looking on info on swappping it into a Miata. The MX-6 is pretty damn cool as well, even if it's FWD. Is your brother planning on installing an LSD as well to handle the 200-ish horses? From what I read about putting a KL-ZE in the 323F (Lantis) a while back , it's pretty difficult (but still entirely possible) to source a LSD 5-speed from Japan (where there apparently was a model with it, although I've forgotten if it was for the Lantis Type R or the MX-6).
!!! UNKNOWN CONTENT TYPE !!!
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The WB
> GTRZILLAR32-Now saving for Godzilla and a condo
09/05/2013 at 19:57 |
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That sounds like a way to do it. In your case I'm not sure, since moving the resonators may change the main harmonics, but it's always something you can put back together.
What kind of car?
SteyrTMP
> The WB
09/05/2013 at 20:01 |
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14" long downpipe leading to 2.5" side exhaust. I rest my case.
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The WB
> Sparf
09/05/2013 at 20:01 |
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Yeah, he wants to, but it comes down to finding one like you said. He isn't thrilled it's FWD either, but the car is very well balanced and the V6 is a lot of fun to drive and sounds great.
He's also tossed around the idea of a low-pressure turbo, but we'll see if he manages that.
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Sparf
> The WB
09/05/2013 at 20:05 |
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My dad's hot rod has been running a glasspack muffler for the last few years, and we've burned through it at least three times and had to replace the fiberglass. This might have something to do with the fact that it's got pretty short sidepipes and a mid-60s 350+ horsepower 327 SBC that can't run on unleaded low octane and needs at least 98 to run properly (which I reckon means that it runs pretty hot), but I thought I'd still warn you.
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The WB
> Sparf
09/05/2013 at 20:12 |
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Yeah, given you're running 98 octane, I bet it has 12:1 compression and just blasts the crap out of the packing. :D His poor little V6, at half the displacement, is not going to be nearly as hellish on it, especially since it has 5 feet of pipe before exhaust hits it.
I'll tell him to keep an eye on it though, thanks for the warning.
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The WB
> SteyrTMP
09/05/2013 at 20:13 |
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Haha, that's one way to annoy the neighbors.
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SteyrTMP
> The WB
09/05/2013 at 20:47 |
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Guilty as charged... The beast is very rev happy... I love to downshift too. It's actually pretty quiet, as long as I'm off the boost, or not downshifting. If I want to be (i.e. cops), I can cruise along quieter than a Civic with a fart can... but if I'm downshifting... Mmmm..... loud, with a wicked burble at the end. I like idling to a stop in second gear, the really low rpm burble sounds like a British sports car of yore.
Thankfully, most of my neighbors are also car savvy... one family has two really nice Magnums, (hers is nicer than his, in my opinion), and the guy across the road has an 8-second tube chassis Camaro. So loud cars is normal here.
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The WB
> SteyrTMP
09/05/2013 at 21:36 |
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That's the best kind of neighborhood. They're getting harder to find these days.
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GTRZILLAR32-Now saving for Godzilla and a condo
> The WB
09/06/2013 at 09:25 |
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2001 dodge stratus r/t coupe, it has the 3.0L V-6.
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The WB
> GTRZILLAR32-Now saving for Godzilla and a condo
09/06/2013 at 10:42 |
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You couild always go piece by piece, replace the muffler first, then if that's too loud, replace the resonators with packed ones.