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WTF? MBRP axle back- mufflers are different inside

4712 Views 16 Replies 6 Participants Last post by  ultramax
Has anyone else ever run into something like this? Got my MBRP axle back this afternoon and the mufflers are quite different has bigger louvers than the other. Couldn't take the best pic with them side by side but I'd say you can see the difference here:

Any ideas as to why?
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that's your pair of new mufflers side by side i assume? thats pretty interesting to say the least
The only thing

I was thinking either a part was not installed during fabrication.
The design maybe that if the internals are different then each muffler has a different acoustical signature and minimizing or cancelling the posibility of drone or unwanted tones or just the opsite to produce the tone or note you desire.
If you stagger say resinators or say the old Glass Packs. 1 futher upstream and 1 further down stream you can minimize the effect of drone. Just a thought.

T Wayne in Iraq
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Well that's kinda what I was thinking too...I dunno, just looks like the one muffler didn't get the louvers fully punched or something.
Could be different production runs, or manufacturing tolerances, or on purpose.

Probably would give a better rumble and less drone.

Put them on and hear how they sound!
The funny thing is, I found a picture on google (prior to even buying these) that someone took of the inside of their mufflers on an MBRP axle back, and theirs had straight rows of louvers instead of spiraled ones.

I did get it on last night, BTW- sounds good, I like it! I'm surprised how mild the volume is for being such a straight-through design with downstream-facing louvers. It sounds like there's probably some resonance right below 2000 RPM, but at 70 on the highway my car is at 2200 and I didn't notice anything at all really.
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If they sound good.

Well if nothing is rattiling around inside and they are solid and the sound is good sounds like a winner. I always wondered how that brand fit and finish stood up to other brands.

T Wayne in Iraq
Well I can give you the lowdown on that (I had difficulty finding some of that stuff out myself, I guess these aren't real popular):

Finish is nice, all polished 304SS...there was some weld splatter in one or two spots and one of the tips had a small nick in the outside edge (looked like an errant grind mark) but otherwise they are some real purdy mufflers, shame they're all hid up under the car. I also believe these things are made in Canada, from what I've read (I'm trying to avoid the Chinese stuff as much as possible). Admittedly a good part of the reason I bought these was for the nice double wall tips and I am not disappointed, they look very nice.

Fit & installation was a breeze...these went in REALLY easy, can't tell 100% if the tips are straight or not because since the bumper is curved I can't tell if it's playing a visual trick on me or not :shigrin The driver's side tip appears to be sticking out just a tad further than the passenger side, may see if I can do anything to adjust that or not. Otherwise it just took light finagling to keep everything lined up right and it went together very well.

BTW I found these via google for $330 shipped to my door, you can't beat that.
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Do you mind my asking where you found these for $330 shipped? I'm seriously considering these and the best I can find is $360. Also, now that you've had them awhile, how do you like them? Still drone free? Are they loud enough compared to stock that it's obvious they aren't stock? Heard good things, but that they may be a little on the quiet side compared to FRPP stingers, etc. If they are drone free, it'd be worth it though.
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Yep got em right here:

Best price I found anywhere, had to search the actual item number on google to find it.

I stll like them a lot...they look great from the back, and sound great too. My car has 3.55's so I don't really think I'm in the "drone zone" much on the 70 mph I'm turning roughly 2200 RPM and I notice very mild drone at best. If I speed up to 75 mph it all but goes away.

You will notice some from about 1500-2000 RPM when you're just driving around town with the windows closed, but I don't really think it's annoying.

As for sound...I think it's pretty obvious they aren't stock. Different tone and more volume. I shot a real short vid and put it on youtube if you want an idea:
‪2005 Mustang GT MBRP axle back‬‏ - YouTube
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It's hard to gauge the volume, but it sounds great! Thanks for the clip. Nice low rumble.

I think I saw the place you linked and a couple others that had the same exact web design and was a bit scared to try them. No problems with delivery or billing though?

Thanks for the input!
Forgot to ask - did you ever find out why the left and right look different inside? I'm wondering if that is indeed how they reduce droning.
Yeah my camera doesn't always pick up sound really great on video, but they sound great. I was just driving around this evening admiring how good they sound :bigthumbsup

I was a little hesitant of those websites too, but I had no issues whatsoever- I ordered, they sent me a tracking number within a couple days, and I got it. Mind you, for some reason it doesn't come in an original MBRP box but everything was there.

And nope, no idea why they're different...perhaps it's a small manufacturing defect, maybe that's why that guy is selling them so cheap? Couldn't tell you.
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Sounds like you made out well. Thanks for all the info and help!
Not bad

Sounds good on all accounts. Glad everything worked out.

T Wayne in Iraq
I hate to bump up an old thread, but this particular thread continued to be at the top of the search list a couple of weeks ago when I was deciding if the MBRP axle-backs like the OP bought were right for me.

I want to confirm that the left and right silencers are different on mine also, with the left being "straight" louvered, and the right being "spiraled." This must be engineered in for some purpose, as was suggested already in this thread.
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