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Discussion Starter · #1 ·
Hi Everyone! I've done a lot of reading through the site, and I can't find if anyone has looked into this idea yet and I need advice...

I'd like to get the community's input on this "Moxman/stock hybrid" idea- having a custom exhaust installed by a good local muffler shop, consisting of:
CVF 3" in catted downpipe
Magnaflow "12278 muffler (3 inch single inlet to dual 2.25 inch outlets) in place of the stock resonator
Stock pipes from the new center muffler back, including stock mufflers
Optional - adding a 3 inch Ultra-quiet resonator (either 1794 or 1795, depending on fit) in front of the center muffler, and shortening the muffler to model 12198.)

Here's why: I'm thinking of this:
I just acquired (July 2021) a 2016 Ecoboost Premium convertible (automatic trans), and a Cobb AP. I am running Cobb OTS Stage 1 right now, and I have a CVFab street intercooler on order so Cobb OTS stage 2 will follow soon.

After that, for increased power at WOT, I'm pretty sure I want to upgrade to a catted 3" downpipe and run either Cobb OTS stage 3 (which my Cobb still has on it) or get a pro-lifetime tune, TBD later. I also want to get rid of the stock resonator because I don't want the restriction down to a single 2.25in inlet or the restrictions within the resonator... The catch is, I see folks say this tends to make the system even louder and I do NOT want to go any louder than I absolutely have to for this - I don't like "fart-can" raspy exhausts - plus I'm in/out early and late with neighbors in a quiet neighborhood - and my wife is adamant she doesn't like "loud" exhausts.

I have been interested in the "Moxman" setup from after reading about it (center muffler in place of resonator, straight pipes out) since it can maintain a 3 inch pipe until it splits but may be quieter than a regular Y-pipe. So, my questions are:
  1. Would combining the center muffler approach with the stock mufflers would yield an ever quieter setup than straight pipes axle back?
  2. Would this hamper flow in some way or have other adverse effects (vs the straight pipes axle back)?
    • If so, would a 2.5" muffler axle-back solve flow issues but still be quieter than straight pipes axle-back?
  3. Would adding a resonator in front of the center muffler make it quieter still?

Again, my goal is 3" catted DP and 3" pipe all the way to wear the flow splits (inside the center muffler), but to also be AS QUIET AS POSSIBLE for this diameter... PLEASE chime in and tell me - what do you think?

Thanks in advance, all!
Jonathan
 

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And...
If you do decide to go with the center inlet, your need to modify your downpipe and also the OEM exhaust support
 

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Discussion Starter · #4 ·
Thank you for pointing that out - I just learned the resonator had an offset inlet... I am sure I could swap in an offset inlet muffler to do the same job.

Any thoughts out there on the sound level /flow quality?
 
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Hi Everyone! I've done a lot of reading through the site, and I can't find if anyone has looked into this idea yet and I need advice...

I'd like to get the community's input on this "Moxman/stock hybrid" idea- having a custom exhaust installed by a good local muffler shop, consisting of:
CVF 3" in catted downpipe
Magnaflow "12278 muffler (3 inch single inlet to dual 2.25 inch outlets) in place of the stock resonator
Stock pipes from the new center muffler back, including stock mufflers
Optional - adding a 3 inch Ultra-quiet resonator (either 1794 or 1795, depending on fit) in front of the center muffler, and shortening the muffler to model 12198.)

Here's why: I'm thinking of this:
I just acquired (July 2021) a 2016 Ecoboost Premium convertible (automatic trans), and a Cobb AP. I am running Cobb OTS Stage 1 right now, and I have a CVFab street intercooler on order so Cobb OTS stage 2 will follow soon.

After that, for increased power at WOT, I'm pretty sure I want to upgrade to a catted 3" downpipe and run either Cobb OTS stage 3 (which my Cobb still has on it) or get a pro-lifetime tune, TBD later. I also want to get rid of the stock resonator because I don't want the restriction down to a single 2.25in inlet or the restrictions within the resonator... The catch is, I see folks say this tends to make the system even louder and I do NOT want to go any louder than I absolutely have to for this - I don't like "fart-can" raspy exhausts - plus I'm in/out early and late with neighbors in a quiet neighborhood - and my wife is adamant she doesn't like "loud" exhausts.

I have been interested in the "Moxman" setup from after reading about it (center muffler in place of resonator, straight pipes out) since it can maintain a 3 inch pipe until it splits but may be quieter than a regular Y-pipe. So, my questions are:
  1. Would combining the center muffler approach with the stock mufflers would yield an ever quieter setup than straight pipes axle back?
  2. Would this hamper flow in some way or have other adverse effects (vs the straight pipes axle back)?
    • If so, would a 2.5" muffler axle-back solve flow issues but still be quieter than straight pipes axle-back?
  3. Would adding a resonator in front of the center muffler make it quieter still?

Again, my goal is 3" catted DP and 3" pipe all the way to wear the flow splits (inside the center muffler), but to also be AS QUIET AS POSSIBLE for this diameter... PLEASE chime in and tell me - what do you think?

Thanks in advance, all!
Jonathan
Hello Jonathan,

Here's what I would recommend. If you're going to use a 3" downpipe, then the Magnaflow muffler is the right call. All you need to do to connect it to the downpipe is make a little "S" pipe out of 3" tubing. We use what are called "U-bends." They're mandrel bent and can be cut and welded to make the perfect bend. You do NOT want to run stock tubing from the muffler back. It's 2 1/4" and defeats the purpose of a custom exhaust. You want 2 1/2" tubing. Then, before you put tips on the tailpipes, start the engine and see if you like the sound??? If you do, then finish the job with the tips of your choice. We use double-wall stainless, with a 4" diameter and they fill the rear valence to perfection! If you think the sound is too loud, you can easily add short resonators, where the stock mufflers used to live. Additionally, if sound is important to you, you probably want to rule out the shorter version of the Magnaflow muffler. We've done a few cars with them and I didn't care for the sound. The customers did, of course, but I much prefer the sound of the longer muffler. I hope this helps.

Best regards,

Steve
 

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Discussion Starter · #6 ·
Steve,

First, thanks for taking the time to share your expertise!

I'm curious - why use resonators at the back end of the setup instead of additional mufflers (2.5 single in & out)?

Interesting about the muffler length - how would you describe the sound difference between the shorter vs longer mufflers? How long of a muffler do you like the sound of?

Also, what did you think of the idea of using a center resonator before the center muffler (vs a longer muffler)?

Last, would it avoid the extra u-bends to use this offset muffler instead of a center to dual one?

Thanks again!
Jonathan
 

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Steve,

First, thanks for taking the time to share your expertise!

I'm curious - why use resonators at the back end of the setup instead of additional mufflers (2.5 single in & out)?

Interesting about the muffler length - how would you describe the sound difference between the shorter vs longer mufflers? How long of a muffler do you like the sound of?

Also, what did you think of the idea of using a center resonator before the center muffler (vs a longer muffler)?

Last, would it avoid the extra u-bends to use this offset muffler instead of a center to dual one?

Thanks again!
Jonathan
Hello again,

To answer your question(s), most of what is involved in the exhaust system is a "packaging" or fitment issue. If you need resonators, the rear location, where the mufflers used to be, is ideal. They fit! The concept of using a center resonator on the Mustang Ecoboost is just not workable. There's just not enough room for a muffler and resonator in that space.

With regard to muffler length, the 24" muffler has a much deeper, rich tone. The shorter one is too raspy for my taste. It also drones a little bit.

Also, I wouldn't bother with an offset muffler. I promise you that it won't fit on the downpipe and you'll have to make some sort of intermediate pipe to make it fit. So why not just use a center inlet muffler and make sure that the exhaust heat is in the center of the transmission tunnel? Ford actually had a recall on early cars, to add heat shields around the resonator, because they were building up so much heat. By ditching the factory resonator, you also lower the heat factor and lose about 20 pounds of unnecessary weight.

This should be enough to make some good decisions about your exhaust. It's not a complicated system, so there's no need to overthink it, or over-engineer it.

Best,

Steve
 
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Discussion Starter · #8 ·
Hello again,

To answer your question(s), most of what is involved in the exhaust system is a "packaging" or fitment issue. If you need resonators, the rear location, where the mufflers used to be, is ideal. They fit! The concept of using a center resonator on the Mustang Ecoboost is just not workable. There's just not enough room for a muffler and resonator in that space.

With regard to muffler length, the 24" muffler has a much deeper, rich tone. The shorter one is too raspy for my taste. It also drones a little bit.

Also, I wouldn't bother with an offset muffler. I promise you that it won't fit on the downpipe and you'll have to make some sort of intermediate pipe to make it fit. So why not just use a center inlet muffler and make sure that the exhaust heat is in the center of the transmission tunnel? Ford actually had a recall on early cars, to add heat shields around the resonator, because they were building up so much heat. By ditching the factory resonator, you also lower the heat factor and lose about 20 pounds of unnecessary weight.

This should be enough to make some good decisions about your exhaust. It's not a complicated system, so there's no need to overthink it, or over-engineer it.

Best,

Steve
Hi Steve,

One follow up question - when you started using this setup, did you disable the artificial engine sounds our cars pipe through the radio, or did you leave it active?

Thanks,
Jonathan
 

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I don't really understand why Moxman wants to replace the 2 1/4" pipes with 2 1/2" pipes.
Two 2 1/4" pipes will flow more than one 3" pipe. It's simple math, pie times the radius squared. It seems to me that the 2 1/2" pipes just add more weight and expense. I like his basic design though. It's generally the lightest and cheapest way to go, even if you pay someone else to do it for you.
 

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I don't really understand why Moxman wants to replace the 2 1/4" pipes with 2 1/2" pipes.
Two 2 1/4" pipes will flow more than one 3" pipe. It's simple math, pie times the radius squared. It seems to me that the 2 1/2" pipes just add more weight and expense. I like his basic design though. It's generally the lightest and cheapest way to go, even if you pay someone else to do it for you.
I've heard the same statement about the 2.25 inch pipes! But, what I haven't heard about is the OEM resonator stock mufflers being restrictive? Any ideas??
PS: I think the GT pipes are 2.5 inches, that may be a more affordable modification!??
 

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I've heard the same statement about the 2.25 inch pipes! But, what I haven't heard about is the OEM resonator stock mufflers being restrictive? Any ideas??
PS: I think the GT pipes are 2.5 inches, that may be a more affordable modification!??
Well, they're more restrictive than the single straight through muffler that Moxman recommends. Plus, those 3 are certainly heavier than the single magnaflow, and I could probably get it done for $400, at most,
if I retained the 2 1/4" pipes, and I wouldn't have to crawl under the car and do it myself.
DIY exhaust work sucks.
 

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I don't really understand why Moxman wants to replace the 2 1/4" pipes with 2 1/2" pipes.
I think it's partially due to the 2-1/4" pipe is kind of an oddity, whereas 2-1/2" is much more common and easy to aquire.
 
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