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Old 05-27-2015, 08:29 AM   #1
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Default Magnaflow 12578/12579

Hi,

Does anyone know if the "super quiet" 12578/12579 Magnaflow muffler comes in a center/offset configuration? Or do I have to go to the louder 12589 for that?

Is the 12579 a pain to route back to the midpipe on an NB?

Cheers
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Old 05-27-2015, 10:01 AM   #2
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EO2K and Gesso just did exactly that, see his build thread for extensive pics.
The dual chamber muffler can't be offset for obvious reasons. The other one can.

I don't think the difference would be drastic, but it's all theories because so far only 1 other (documented) person used the dual chamber design and you really can't judge sound from videos.
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Old 05-27-2015, 07:37 PM   #3
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Thanks Vlad.

The 12578 (offset/offset) version of the dual chamber lead me to believe it would be possible to have a center/offset version.

I want this thing to be as quiet as possible, I was almost tempted to go 2.5" but I think that would be sacrilege with an EFR!

Cheers
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Old 05-27-2015, 07:39 PM   #4
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NP. I think EO's setup is about as quiet as it will get. Maybe add a cat to it since those really help too
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Old 05-28-2015, 02:01 AM   #5
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NP. I think EO's setup is about as quiet as it will get. Maybe add a cat to it since those really help too
I haven't seen his setup, but I can tell you mine is quieter. And doesn't flow as well either. And my previous setup was quieter still, though almost 30 lbs heavier.

Timk, I don't know if you're serious about the "as quiet as possible" part, but if you REALLY are serious about the exhaust being quiet, a straight-thru muffler is Not the quietest muffler you can buy. In fact, it's going to be the loudest. But they of course flow the best. Anyone that says their exhaust is "quiet" with no cat and a straight-thru muffler is full of crap.
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Old 05-28-2015, 02:11 AM   #6
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I haven't seen his setup, but I can tell you mine is quieter. And doesn't flow as well either. And my previous setup was quieter still, though almost 30 lbs heavier.

Timk, I don't know if you're serious about the "as quiet as possible" part, but if you REALLY are serious about the exhaust being quiet, a straight-thru muffler is Not the quietest muffler you can buy. In fact, it's going to be the loudest. But they of course flow the best. Anyone that says their exhaust is "quiet" with no cat and a straight-thru muffler is full of crap.
lol.
You are wrong. I'm not even gonna try to prove why, it's pointless until you actually experience/test what we're talking about.
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Old 05-28-2015, 02:23 AM   #7
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Hey Pat,

I should have said as quiet as possible using a straight through muffler.

My previous NB had an Eaton M45 supercharger with JR headers, 2.5" 200 CPI cat, 2.5" midpipe going to a straight through Magnaflow 5x11x22" with 2.5" inlet/outlet. It was tolerable, but I would have preferred quieter.

I am currently running a 3" dump pipe, 2.5" 200 CPI cat, 2.5" pipe to the stock MSM resonator and rear muffler. It's barely any louder than a stock MSM (maybe a bit deeper note if anything).

I expect I probably can't match these sound levels with a 3" system, but if I can get close, then that'd be awesome. The car is still very much a street car, I like the option of being able to take hands free phone calls in it and easily talk to my kids riding shotgun when we do mountain passes.

I guess even replacing the MSM muffler with the straight through 2.5" Magnaflow would increase flow considerably?

Cheers
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Old 05-28-2015, 02:24 AM   #8
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lol.
You are wrong. I'm not even gonna try to prove why, it's pointless until you actually experience/test what we're talking about.
I have literally run one of these muffler on my miata. Magnaflow straight thru muffler. So I do have actual experience with this muffler on MY miata with a turbo.

EDIT: In 2008. https://www.miataturbo.net/general-m...pinions-21993/

EDIT2: Unless the new ones are wayy better than the older ones? Have they changed a lot? I tried one before and wasn't impressed. Are new ones a lot better?
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Old 05-28-2015, 02:31 AM   #9
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lol.
You are wrong. I'm not even gonna try to prove why, it's pointless until you actually experience/test what we're talking about.
My stock 05 Outback is "quiet" as I can't hear the exhaust.

My C63 is reasonable, it's loud when cold but with the windows up, it's pretty quit. From the outside it's loud if you get on it though.

My miata is damn loud. But I have a header, (no turbo..... which do muffle a lot) then a 300 cell cat and a dynomax baffled muffler. It's loud enough that I can leave the car idling, go inside my house, and still hear the exhaust. If you can hear your car at IDLE from inside your house, it's not quiet.
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Old 05-28-2015, 02:37 AM   #10
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Originally Posted by timk View Post
Hey Pat,

I should have said as quiet as possible using a straight through muffler.

My previous NB had an Eaton M45 supercharger with JR headers, 2.5" 200 CPI cat, 2.5" midpipe going to a straight through Magnaflow 5x11x22" with 2.5" inlet/outlet. It was tolerable, but I would have preferred quieter.

I am currently running a 3" dump pipe, 2.5" 200 CPI cat, 2.5" pipe to the stock MSM resonator and rear muffler. It's barely any louder than a stock MSM (maybe a bit deeper note if anything).

I expect I probably can't match these sound levels with a 3" system, but if I can get close, then that'd be awesome. The car is still very much a street car, I like the option of being able to take hands free phone calls in it and easily talk to my kids riding shotgun when we do mountain passes.

I guess even replacing the MSM muffler with the straight through 2.5" Magnaflow would increase flow considerably?

Cheers
I ran a turbo, 3 glasspacks, and a magnaflow muffler. Pretty much 5 mufflers total including the turbo. It was wayyy louder than stock. You're not going to build a 3" system that's as quiet as stock. Then I put a real muffler on the car, that's baffled, and it was much quieter than the magnaflow, but still it's not as quiet as stock. So yeah, you're not going to build a "quiet" 3" exhaust unless you put 6 or 7 mufflers in there, and there is literally no room for them.

If you ran a turbo, a 300+ cell cat, then a couple glasspacks, and then a real baffled muffler, it would still be considerably louder than stock. Stock is quiet.

I also ran a turbo, 3 glasspacks, and a stock 99' muffler. That was in fact as quiet at stock. But it killed the HP big time. I don't recommend that unless you are okay with less than 220whp.
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Old 05-28-2015, 03:23 AM   #11
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Pat, for ***** sakes, the rest of the people here have a secondary muffler known as a 'turbo'.

Relax.
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Old 05-28-2015, 03:29 AM   #12
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No ****, I drove a turbo miata for years, I know what it's like. And 3" straight through exhaust is not "quiet" even with a turbo. When the car gives you a headache on long trips, it's not quiet.
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Old 05-28-2015, 03:42 AM   #13
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MagnaFlow Exhaust Products - For Trucks, Suv's, American Muscle, Diesel, & Sport Compact Vehicles

I have this, it is quiet, it is super duper quiet and straight thru. All I have, no cat, just 2.5 to 3" before the trans output.

I don't have a stock to compare to, but I'm freaking close.
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Old 05-28-2015, 10:14 AM   #14
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Quote:
Originally Posted by patsmx5 View Post
I have literally run one of these muffler on my miata. Magnaflow straight thru muffler. So I do have actual experience with this muffler on MY miata with a turbo.

EDIT: In 2008. https://www.miataturbo.net/general-m...pinions-21993/

EDIT2: Unless the new ones are wayy better than the older ones? Have they changed a lot? I tried one before and wasn't impressed. Are new ones a lot better?
That's not even close to the one we're talking about. The one you ran I also ran back in like 09, it's like half the size and way louder.

Quote:
Originally Posted by patsmx5 View Post
My stock 05 Outback is "quiet" as I can't hear the exhaust.

My C63 is reasonable, it's loud when cold but with the windows up, it's pretty quit. From the outside it's loud if you get on it though.

My miata is damn loud. But I have a header, (no turbo..... which do muffle a lot) then a 300 cell cat and a dynomax baffled muffler. It's loud enough that I can leave the car idling, go inside my house, and still hear the exhaust. If you can hear your car at IDLE from inside your house, it's not quiet.
Yeah, that's LOUD! Mine isn't even half that loud. You can't even hear it more than 20' away.
Quote:
Originally Posted by patsmx5 View Post
I ran a turbo, 3 glasspacks, and a magnaflow muffler. Pretty much 5 mufflers total including the turbo. It was wayyy louder than stock. You're not going to build a 3" system that's as quiet as stock. Then I put a real muffler on the car, that's baffled, and it was much quieter than the magnaflow, but still it's not as quiet as stock. So yeah, you're not going to build a "quiet" 3" exhaust unless you put 6 or 7 mufflers in there, and there is literally no room for them.

If you ran a turbo, a 300+ cell cat, then a couple glasspacks, and then a real baffled muffler, it would still be considerably louder than stock. Stock is quiet.

I also ran a turbo, 3 glasspacks, and a stock 99' muffler. That was in fact as quiet at stock. But it killed the HP big time. I don't recommend that unless you are okay with less than 220whp.
glasspacks suck. They really are not "mufflers" becuase they don't actually muffle anything. they simply take away the rasp. they are resonators
I have tried them, they don't do nearly anything. the key is not length of resonator, but girth (that's what she said? lol). You can have the whole exhaust out of glasspacks, and it still won't be nearly as quiet as one of these HUGE magna's with offset angles or dual chambered (not in the "typical" way either, look up it's construction).

Seriously though, if you haven't ran the exact models we're talking about, you simply don't know what we're talking about.

I've ran one of these big boys in 2.5 and 3 configuations, both were significantly quieter than even a RS3 exhaust mated to a OEM header+OEM ginormous CAT on an NB.

I am crazy about quietness. Trust me when I say: if there was a quieter setup that was as good flowing as this, I'd already have tried it. So far the only way to make this 3" setup quieter is with a spring loaded flapper valve like TurboTim and I think JasonCSBB run. Everything else is louder

Last edited by 18psi; 05-28-2015 at 10:50 AM.
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Old 05-28-2015, 04:04 PM   #15
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Ok so I bought a Magnaflow muffler for my new exhaust system. It's a 3" in/out center in/out. Part number 12249. Muffler case measures 5x8x18 oval 24" overall. Looks high quality and is all stainless steel.
Magnaflow 12578:
5x11x22 oval overall 28"

My car running a magnaflow 12578 with a cat is downright quiet and mellow. You hear the engine at idle more than you hear the exhaust.
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Old 05-28-2015, 04:18 PM   #16
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That's not even close to the one we're talking about. The one you ran I also ran back in like 09, it's like half the size and way louder.



Yeah, that's LOUD! Mine isn't even half that loud. You can't even hear it more than 20' away.

glasspacks suck. They really are not "mufflers" becuase they don't actually muffle anything. they simply take away the rasp. they are resonators
I have tried them, they don't do nearly anything. the key is not length of resonator, but girth (that's what she said? lol). You can have the whole exhaust out of glasspacks, and it still won't be nearly as quiet as one of these HUGE magna's with offset angles or dual chambered (not in the "typical" way either, look up it's construction).

Seriously though, if you haven't ran the exact models we're talking about, you simply don't know what we're talking about.

I've ran one of these big boys in 2.5 and 3 configuations, both were significantly quieter than even a RS3 exhaust mated to a OEM header+OEM ginormous CAT on an NB.

I am crazy about quietness. Trust me when I say: if there was a quieter setup that was as good flowing as this, I'd already have tried it. So far the only way to make this 3" setup quieter is with a spring loaded flapper valve like TurboTim and I think JasonCSBB run. Everything else is louder
Well sounds like the new ones are different. Sweet, when I get some spare $$$ I'll have to try one for myself.

Also funny you mentioned spring loaded flapper valves, I'm thinking about installing one on my car actually.
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Old 05-28-2015, 04:30 PM   #17
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Well sounds like the new ones are different. Sweet, when I get some spare $$$ I'll have to try one for myself.

Also funny you mentioned spring loaded flapper valves, I'm thinking about installing one on my car actually.
The cheapest place to get Magnaflow mufflers is from advanceauto.com. Use one of their 30+% off coupons and they ship for free. If I am not lazy tonight I might go start up my turbo car and get a quick clip of how the exhaust sounds when idling.
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Old 05-28-2015, 10:09 PM   #18
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What's a Magnaflow "dual chamber"?
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Old 05-28-2015, 10:24 PM   #19
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<p>Hey Jason, speaking of quite mufflers, how did your dynomax vt flapper valve hold up? &nbsp;I was reading through some old threads and saw you and others were worried about the spring going and/or it making noise flapping closed.</p>
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Old 05-28-2015, 10:51 PM   #20
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What's a Magnaflow "dual chamber"?
Magnaflow 12578
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