Magnaflow 12578/12579 - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 05-30-2015, 12:48 PM   #41
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

Quote:
Originally Posted by lvw View Post
Dag, I meant the 12579.
I suspect it is minimal.



This image is interesting. You can see where the inside edge of the perforated internal tube "disrupts" the flow into the side tubes. On my 1x579 muffler there was one end that looked like the above pic, and the other end was actually much better. It may just be manufacturing tolerance (or lack thereof) or simply luck of the draw. My muffler is oriented so that the "better" side is the "inlet" side. I'd like to think that'll help.

I considered getting in there with some sort of tool and cutting down those edges but its all stainless. It looked like it was going to be a bitch to do so I moved on to other things.
Attached Thumbnails
Magnaflow 12578/12579-50095d1343148904-bros-op-muff-12579.jpg  
EO2K is offline   Reply With Quote
Old 05-30-2015, 12:48 PM   #42
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

Quote:
Originally Posted by lvw View Post
Anyone have any idea how much horsepowers are lost with the 12578? My wife and I just took a trip to the Mitty in the Miata, Va. to Ga. We could'nt hear the radio, so we cut it off. The drone gave me a headache after a while. Would lie to fix that without loosing my horsee's.
Not sure on the 12579, but the 12578 is minimal. I used to run one as a Laguna exhaust on Theseus (normally ran that car straight-piped, no mufflers/resonators). There was no significant difference in the power with or without the muffler, and it took ~13dB off the exhaust note.
Savington is offline   Reply With Quote
Old 06-01-2015, 12:23 PM   #43
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Quote:
Originally Posted by Savington View Post
??? indeed, dude. I literally posted a link to Magnaflow's product page for the exact muffler you're talking about.
More precisely, I meant there was no cutaway view nor a detailed description nor the text "dual flow" on Magnaflow's website, according to google.

Quote:
Originally Posted by EO2K View Post
In fact, it looks almost exactly like this thing inside the muffler:

http://www.summitracing.com/parts/mpe-10778

And that's funny, because not only is it also made by Magnaflow, I also own that part as well, its part of the exhaust on my truck
Now I get it. The above 'Y' has a flat surface between the dual tubes which is visible in 18psi's actual muff pic. What threw me off was the 'V' transition between the dual tubes in EO2k's sketch.

While much better than a simple expansion chamber, the flat instead of a 'V' will introduce some turbulence. It would be interesting to measure the actual muffler pressure loss. I measured mine some time ago, (3" straight through), and it was on the order of 1 psi including the bends before and after the muff, when the whole system including cat and downpipe was dropping ~4.

Last edited by JasonC SBB; 06-01-2015 at 03:06 PM.
JasonC SBB is offline   Reply With Quote
Old 06-01-2015, 12:42 PM   #44
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default



If I can figure out some way to measure and log it, I'll try to do so. I know Ian asked as well over in his build thread.
EO2K is offline   Reply With Quote
Old 06-01-2015, 01:29 PM   #45
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,181
Total Cats: 2,581
Default

That was my concern in the muff thread too, and then brainesack berated me for it, and since I'm too lazy to test this sorta stuff I just kinda didn't care.

In theory the noise redux should be significant, no idea about turbulence because it's likely not as significant as the sweet sweet quietness
18psi is offline   Reply With Quote
Old 06-01-2015, 01:54 PM   #46
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

I would speculate that it might effect the very top end, but under 5k worth of flow its probably negligible.

Priorities for me are sound reduction, then flow. In that order.
EO2K is offline   Reply With Quote
Old 06-01-2015, 02:15 PM   #47
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Quote:
Originally Posted by EO2K View Post


If I can figure out some way to measure and log it, I'll try to do so. I know Ian asked as well over in his build thread.
Measuring is easy if you have holes in the right places. I have the bits to instrument it if you want to bring it up to San Jose sometime.

--Ian
codrus is offline   Reply With Quote
Old 06-01-2015, 02:19 PM   #48
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

Once its up and running we can definitely make that happen. I know we have the same MS3-Basic so adding that stuff should be easy, now that you've figure out how to do it of course
EO2K is offline   Reply With Quote
Old 06-01-2015, 02:23 PM   #49
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,181
Total Cats: 2,581
Default

Make sure to lube your probe before you stick it in his hole
18psi is offline   Reply With Quote
Old 06-01-2015, 03:03 PM   #50
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Quote:
Originally Posted by EO2K View Post
Priorities for me are sound reduction, then flow. In that order.
I said the same thing about the stupid louvered resonator I had before which had a shocking amount of pressure loss. I don't assume "it's probably all right" anymore.
JasonC SBB is offline   Reply With Quote
Old 06-01-2015, 03:10 PM   #51
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

Well don't get me wrong, flow is still super important. If I didn't care about flow at all there would be a louvered resonator in there along with a chambered muffler. I see the 1x579 series as a very minor compromise in the flow vs sound debate. It was a minor compromise I was willing to make, and I'm glad to provide data once its up and running.

In fact, if someone is willing to loan us a 1x578 or 1x589 series muffler, or if I can convince Gesso to buy one for his project, we can splice it into my exhaust and do some legitimate "all things being equal" back-to-back testing with Cordus' sensor setup. That'll really give us solid data.
EO2K is offline   Reply With Quote
Old 06-01-2015, 03:21 PM   #52
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Quote:
Originally Posted by EO2K View Post
In fact, if someone is willing to loan us a 1x578 or 1x589 series muffler, or if I can convince Gesso to buy one for his project, we can splice it into my exhaust and do some legitimate "all things being equal" back-to-back testing with Cordus' sensor setup. That'll really give us solid data.
You might want to consider welding in O2 sensor bungs in strategic location while it's easy to get to. My FM exhaust is designed to be usable with a stock ECU, so it's got three or four bungs in it (2 before the cat, and one or two after as well). I have an O2 sensor plug that I drilled and tapped for 1/8 NPT, so I can put the copper tubing for the probe into that.

--Ian
codrus is offline   Reply With Quote
Old 06-01-2015, 04:11 PM   #53
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

I like this plan. I'll add some mild bungs to my shopping list, and maybe an additional stainless one for the downpipe.

Out of curiosity, where would you recommend putting them/where exactly are the ones located in your FM?
EO2K is offline   Reply With Quote
Old 06-01-2015, 05:40 PM   #54
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Quote:
Originally Posted by EO2K View Post
I like this plan. I'll add some mild bungs to my shopping list, and maybe an additional stainless one for the downpipe.

Out of curiosity, where would you recommend putting them/where exactly are the ones located in your FM?
The FM exhaust has one in the down pipe right where you can see it through the driver's side wheel well, which is actually really convenient to get to. The one for the wideband is right before the cat, located on top. There's also one right after the cat (actually in the cat pipe itself), and I think there's one midway down the mid pipe (where the stock 49-state second O2 sensor goes).



Actually, now that I look at the photo, I'm not sure there *is* one in the midpipe after all. The downpipe ones are obvious in the photo, and the post-cat one is right under the exhaust hangar for the midpipe in the photo.

For pressure sensing between the cat and the muffler, I don't really think it matters all that much, the pressure should be pretty constant all the way along the pipe. If you're trying to measure turbine performance, I think it's better to have them right before and after the turbine itself.

--Ian
codrus is offline   Reply With Quote
Old 06-01-2015, 05:56 PM   #55
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

Pre-turbine is going to be a problem for me. There really is no convenient place to put on in my manifold, plus its coated, or I could drill and tap a hole in the EFRs turbine housing. I'm not sure I'm crazy about either TBH. Someplace in the downpipe is do-able as is before the first resonator. We'll figure something out.
EO2K is offline   Reply With Quote
Old 11-27-2015, 05:53 PM   #56
Senior Member
iTrader: (3)
 
Join Date: Sep 2011
Location: Plano TX
Posts: 595
Total Cats: 2
Default

Any reports back on which is quietest and still good power/spool.
About to pull trigger

12578 or 12579 or 12589?

I want quietest without much power spool sacrifice ( That not to much to ask for right LOL)
90 Turbo is offline   Reply With Quote
Old 11-27-2015, 06:01 PM   #57
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,181
Total Cats: 2,581
Default

yes
18psi is offline   Reply With Quote
Old 11-28-2015, 01:54 AM   #58
lvw
Junior Member
 
Join Date: Jun 2008
Location: Hanover,Va
Posts: 91
Total Cats: 0
Default

I ended up with the 12589 because my installer requested it. More room to make the bend past the differential.I am completely satisfied with the sound level though, we made another trip to MATG. No headache and still feels like I have my power.Nice roar when I get on it too.
lvw is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Turbo 1995 Miata Low mileage Clean Tekel Cars for sale/trade 29 02-05-2016 05:16 PM
Megasquirt 2 or 3 ? TheNomad Engine Performance 3 09-21-2015 11:20 PM
Can my stock ECU handle one more mod? TheNomad Engine Performance 30 09-19-2015 08:00 PM
Magnaflow Muffler Opinions patsmx5 General Miata Chat 23 06-10-2008 06:48 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:10 PM.