[Joshinator99]

Originally Posted by airtroop01

Ordered them from Summit and they just came. With any luck I’ll get them on tomorrow. I’m thinking they will work great!

Incidentally, if I knew just how much Magnaflow pinched off the inside of that muffler, I never would have bought it. And now that I know what inside looks like I certainly wouldn’t recommend it. As an engineer, I’m disposed to be a math guy. So let’s look at the math: Area = pi * (diameter /2) ^2

So stock 2.5” pipe is 4.9 square inches of area * 2 = 9.8 square inches
Then you upgrade to 3” pipe for better flow which is 7.06 square inches * 2 = 14.12

And then, with this muffler in-line, Magnaflow takes 14.12 square inches of inlet flow and necks it down to 7.06 square inches (less than the flow of your stock exhaust system if you had left it alone…) and then opens it up to 14.12 afterwards. But the damage/restriction is already done. Still shaking my head on who would design such a thing. If they did a 4.25” ovalled center section that would be 14.19 square inches of area and would have worked.

Anyway, cutting that thing out like a cancer tomorrow.
@cw3sf - thanks again for the tip

Doesn’t look like that calculation is correct for this muffler looking at the internal muffler pics…

[Z OH 6]

Originally Posted by Joshinator99

Agreed. And I feel like the boost number would be higher than it should vs the amount of WHP put down.

I understand people want to use math and maybe math would determine if there's an actual loss IF you knew all the variables which I doubt most people do. I think the very tiny area in the X section is so small that the exhaust really isn't as choked as people think. Let's not forget our cars come with crushed exhaust pipes from the factory that look unsightly to many people and MUST be restrictive according to some yet I don't think anyone has confirmed that they're a restriction. I've heard one person say around 800whp, cant recall if thats confirmed, and that's dual crushed 2 3/4" pipes which by all exhaust calculators says it should be a restriction around 550hp. The biggest restriction in exhaust is always closest to the engine, that means the headers are most restrictive and then followed by the cats, after that, the catback exhaust just don't seem to matter as much as long as you aren't installing a 1" garden hose size pipe. This stands to reason as we go UP in catback exhaust size from the factory exhaust, we typically gain nothing.

[Z OH 6]

Originally Posted by Joshinator99

Doesn’t look like that calculation is correct for this muffler looking at the internal muffler pics…

I seem to recall there some discussion on this muffler last year and if I recall, early versions of this muffler (or maybe the PN was slightly different) did actually combine into a single 3" section but later versions were proven to be an actual X pipe internally and not a single 3" section. Maybe that's where some of the confusion is coming from. I eyeballed mine very well before installing it and mine was a true X internally, there was no single 3" pipe section.

[Joshinator99]

Originally Posted by Z OH 6

I seem to recall there some discussion on this muffler last year and if I recall, early versios of this muffler did actually combine into a single 3" section but later versions were proven to be an actual X pipe internally and not a single 3" section. Maybe that's where some of the confusion is coming from. I eyeballed mine very well before I stalling it and mine was a true X internally, there was no single 3" pipe section.

That would definitely make a big difference if that’s the case and might explain why airtroop had issues but I didn’t.

[Bangkok_ZL1]

Originally Posted by Sakudog

(Scroll to the bottom for pics)

You're tracking with a MM Wild. They don't recommend that. I have one also. Do you find any issues with that, or did you make any adjustment to the canister?

[Camaro1973]

Originally Posted by Z OH 6

I seem to recall there some discussion on this muffler last year and if I recall, early versions of this muffler (or maybe the PN was slightly different) did actually combine into a single 3" section but later versions were proven to be an actual X pipe internally and not a single 3" section. Maybe that's where some of the confusion is coming from. I eyeballed mine very well before installing it and mine was a true X internally, there was no single 3" pipe section.

12469 was the original part number and the muffler everyone was using. I’m
Not sure what 12599 is, maybe they replaced the design with a true x design or it’s a new part itself.

However 12469 still exists for sale from numerous places.

Actually I just double checked. 12599 is a completely different part #/muffler.

[Z OH 6]

Originally Posted by Camaro1973

12469 was the original part number and the muffler everyone was using. I’m
Not sure what 12599 is, maybe they replaced the design with a true x design or it’s a new part itself.

However 12469 still exists for sale from numerous places.

Actually I just double checked. 12599 is a completely different part #/muffler.

I have the 12469 muffler and its a true X internally. I'm thinking there were earlier versions that may not have been a true X muffler and had a single 3" section but later revisions were true X internally. I wouldn't have installed it on mine if it was a single 3" pipe internally, I visually looked through mine and it was a true X internally. Its possible if they have the same PN that some retailers might still have the older version in their warehouse and some might still be receiving those when ordering. I'm half tempted to order one from Amazon just to take some internal pics and then return it to put this issue to bed.

[Camaro1973]

Originally Posted by Z OH 6

I have the 12469 muffler and its a true X internally. I'm thinking there were earlier versions that may not have been a true X muffler and had a single 3" section but later revisions were true X internally. I wouldn't have installed it on mine if it was a single 3" pipe internally, I visually looked through mine and it was a true X internally. Its possible if they have the same PN that some retailers might still have the older version in their warehouse and some might still be receiving those when ordering. I'm half tempted to order one from Amazon just to take some internal pics and then return it to put this issue to bed.

I bought mine like what 9 months ago and it’s a Y design. The diagram on magnaflows website still shows it being a Y design.

12599 however is a true X pipe.

[6spdhyperblue]

This has become quite the conundrum

[Joshinator99]

Originally Posted by Z OH 6

I have the 12469 muffler and its a true X internally. I'm thinking there were earlier versions that may not have been a true X muffler and had a single 3" section but later revisions were true X internally. I wouldn't have installed it on mine if it was a single 3" pipe internally, I visually looked through mine and it was a true X internally. Its possible if they have the same PN that some retailers might still have the older version in their warehouse and some might still be receiving those when ordering. I'm half tempted to order one from Amazon just to take some internal pics and then return it to put this issue to bed.

Originally Posted by Camaro1973

I bought mine like what 9 months ago and it’s a Y design. The diagram on magnaflows website still shows it being a Y design.

12599 however is a true X pipe.

This is all I can find about 12469 on Magnaflow’s website. While their little video clip portrays an X design, they don’t give a look at the mufflers internals. Also, I apologize for screwing everyone up with the 12599 pics, as I indeed have the 12469 as well.

[Z OH 6]

Originally Posted by Joshinator99

This is all I can find about 12469 on Magnaflow’s website. While their little video clip portrays an X design, they don’t give a look at the mufflers internals. Also, I apologize for screwing everyone up with the 12599 pics, as I indeed have the 12469 as well.

Just take it off and you'll make another 80whp.

[airtroop01]

Originally Posted by Joshinator99

This is all I can find about 12469 on Magnaflow’s website. While their little video clip portrays an X design, they don’t give a look at the mufflers internals. Also, I apologize for screwing everyone up with the 12599 pics, as I indeed have the 12469 as well.

Part number 12469 - I had talked to the engineers at Magnaflow and requested the internal schematic of the muffler. They confirmed that although the website shows an X is is indeed a Y

If you look at the attached schematic, lower right corner is #12469

They mentioned they have other mufflers that indeed have an internal X
But this form that fits in the tunnel with a 5x8” and variable length doesn’t exist with them with an X. They are typically wider.

Again passing what info I got from the tech.
I really wanted it to work out for me but it is what it is.

As an aside, I installed the 3” in out MBRP resonators and while the sound is louder/more aggressive… I was able to go full WOT, full power and breathed a sigh of relief. Still need to figure out a quieter solution for certain tracks but if I am cruising around and don’t jump on the throttle it’s quiet enough and quite reasonable.

[Z OH 6]

Originally Posted by airtroop01

Part number 12469 - I had talked to the engineers at Magnaflow and requested the internal schematic of the muffler. They confirmed that although the website shows an X is is indeed a Y

If you look at the attached schematic, lower right corner is #12469

They mentioned they have other mufflers that indeed have an internal X
But this form that fits in the tunnel with a 5x8” and variable length doesn’t exist with them with an X. They are typically wider.

Again passing what info I got from the tech.
I really wanted it to work out for me but it is what it is.

As an aside, I installed the 3” in out MBRP resonators and while the sound is louder/more aggressive… I was able to go full WOT, full power and breathed a sigh of relief. Still need to figure out a quieter solution for certain tracks but if I am cruising around and don’t jump on the throttle it’s quiet enough and quite reasonable.

So you're telling me that with the Magnflow muffler in place, you couldn't go WOT, full power? Joshinator isn't experiencing that nor am I or anyone else that installed this muffler in this thread. That's very strange.

[airtroop01]

Originally Posted by Z OH 6

So you're telling me that with the Magnflow muffler in place, you couldn't go WOT, full power? Joshinator isn't experiencing that nor am I or anyone else that installed this muffler in this thread. That's very strange.

Clarifying my statement:

I did two events besides street/highway driving:
(1) Car rally that was about 280mi and 5 checkpoints
(2) SCCA autocross event.

Initial observations:
Quieter, really nice sound. Minimal and medium load situations are fine. With the 2650 and a ton of torque, you can get around most cases using only 10-30% of the throttle and the setup was perfectly fine.

Further observations (40% throttle - 100% throttle):
1. Mid throttle, high load situations
I was getting some bucking as the boost went to about 15psi - something I did not experience before and I'm not experiencing it right now as I pulled the muffler out yesterday.
I data logged some of this with the PDR: coming out of a turn 20mph, 1.1g, accelerating to 60mph. Tried in 2nd gear and 3rd gear. More pronounced in 3rd gear and a bit better in 2nd gear.

2. WOT scenarios
- i.e. coming out of a turn (low speed 30mph about 1.15g according to PDR) to about 125mph. Visible jagged edges on longitudinal acceleration throughout RPM band.
- also noticed this on many highway pulls 40/50/60 roll to 120+ speeds. The car would just sit back instead of propelling itself (if that makes sense at all)

Had both myself and some instructors/passengers who came for a ride with me and driven the car note that it felt choked off because the power comes on wanting to go and you can literally feel it in the pedal rolling back on you.

Keep in mind, if you're happy with it... keep running it.
Just trying to share my experience and maybe it will help some of you.
Without the muffler, WOT - the car took off with the pedal mashed to the floorboard while trying to break traction on the freeway.