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BBK Varitune Axle-Back Exhaust; Stainless Steel (11-14 GT)

Item 56241
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      Review & Installation Video

      Hey Justin with and I'm here with one of the most exciting new products to come along in sometime. I'm talking about BBK's Vari-tune fully tunable axle back exhaust system fitting all 2011 and newer Mustangs. Alright, before we start breaking down the Varitune this would be a great time to tell you to subscribe to our YouTube channel, just by clicking on the link below or on the AM logo up in the corner there. That's so you can stay up to date with the latest products, like these Varitunes, for your Mustang. Alright, getting into the Varitunes themselves, as the name suggests, this is a fully tunable muffler, so basically by adjusting this screw on the end of the muffler you can essentially change from a 3 chamber muffler to a single chamber muffler in a matter of minutes. Of course this gives you the best of both worlds by offering an exhaust that can be both loud or quiet depending on your mood. With the power valve fully closed like it is now, the exhaust tone will take on the characteristics of a 3 chambered muffler - it's going to be relatively soft and relatively quiet. But by opening the power valve all the way you are bypassing those first two chambers and it's at that point the muffler takes on the characteristics of a single chambered muffler. It's going to get a lot louder, and you're also going to get those rough around the edges sounds coming off the revs, all those pops and subtle backfires. Of course you can experiment with the valve being half open to see what kind of tone that will give you as well. So with the Varitones bolted up to our 14 GT, we were interested to see if they would make any power with the valves fully open as opposed to fully closed, well after a few Dyno pulls we actually put down about 8 more horsepower at the rear wheels with that power valve fully open. So now that you know what the Varitune does why would you want something like this? Well we as car people have the tendency to change our minds over time. So even though having the loudest exhaust possible when you first pick up your Mustang is the only way to roll for most Mustang owners out there, over the years you might change your mind a little bit, and you'll probably want to tone it down a little bit. That's where the Varitune comes into play. The Varitune gives you the luxury of having a loud and a tame muffler in one package and allows you to change your tone easily as your preferences change. Getting into the actual construction of the Varitune, BBK offers this exhaust in aluminized steel and full-stainless, with a slight difference in price between the two. In addition we're looking at 3" mandrel bent tubing, and these brightly polished 4" tips, with an optional black tip available from the drop down menu just in case you wanted to switch up the look a little bit. If you're not watching this on our site already, go ahead and click the link below to head back to our site to see a wide variety of BBK products available for your Mustang. Installing the Varitune is just like installing any other axle back for your Mustang and can easily be done in about an hour using basic hand tools. Adjusting your sound is even easier and only requires a 7/16th wrench and socket and a minute or two of your time. Now if you should run into any problems you can always call our customer service reps at 1-855-422-7439 or feel free to shoot them an email at Now let's hear how the Varitune sounds on our 2014 with the valve fully closed first, and then fully open.

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • BBK Varitune Axle-Back with "Adjustable Power Valve"
      • Change from a Three to One Chamber Exhaust for More Power and Sound
      • 8-10 Decibel Range Difference
      • Stainless Steel Construction
      • 4" Polished 304 Stainless Steel Tips
      • Direct Bolt-On, No Cutting or Welding Required
      • Fits 2011-2014 GT Mustangs


      Adjustable Sound. This BBK Mustang Axle-Back Exhaust system features BBK's patented tunable Varitune performance mufflers that allow you to change from a mellow three chamber exhaust sound to a rich throaty straight-through exhaust note with just a twist of a wrench, for a 8 to 10 decibel sound level difference!

      How It Works. BBK Varitune performance mufflers utilize an internal "Adjustable Power Valve." When in the closed position the valve blocks the exhaust flow, forcing it through all three chambers of the muffler for a classic mellow sound. When in the open position, the valve "uncorks" the exhaust flow, allowing it to take the path of least resistance, acting more like a straight-through muffler for a rich throaty exhaust note. This unique design is perfect for personalizing the power and sound levels of your Mustang to suit your own specific needs.

      Stainless Steel Construction.
      Constructed from highest quality Stainless Steel available, this BBK Performance Axle-Back exhaust system features Varitune chambered mufflers that end with 4" polished 304 stainless tips for impressive looks and sound. The tips exit in the stock locations so no modifications are required to the rear bumper cover.

      Application. This BBK Varitune Axle-Back Exhaust is designed as a direct fit bolt-on upgrade for the 2011-2014 GT Mustangs equipped with the 5.0L 32V DOHC V8 coyote Engine.

      Fitment: 2011 2012 2013 2014 Details

      MPN# 41015

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (13)

      Write a Review

      Ratings Summary

      4.4 out of 5 overall rating from 13 customers

      Installation Time: Afternoon

      Installation Cost: 0-$100

      • November 14, 2019

        5 2014 GT - RobertB Installation Time: Less than 1 Hour



        Helpful (0)
      • September 29, 2016

        4 2011 GT - MKPony Installation Time: Afternoon

        Nice Units, Easy Install... Mostly

        Took me about 2 hours to install. But, I have my own lift. The clamps that came with were a bit oversized, so I had to use my impact wrench to torque them VERY tight to get a good seal. Alignment was a bit tricky, but worked out in the end, best done as a 2 person job. Mine is a 2011 GT, and getting the old mufflers out was the biggest issue. Best to have a sawz-all, or oxy-acet handy to cut off the one rear hanger. It has a flare on it that makes pulling it out rearward virtually impossible. I sawed it off, and went through 2 blades to do it! I give it a 4 because of the odd clamps, and the instructions failing to mention the old unit removal issue. I have mine cranked wide open, sound great, little drone, and seem to have upped performance! They also hide up under the valence very nicely so they look better than stock too. I fully approve and recommend!

        Helpful (8)
      • January 01, 2016

        4 2014 GT - Scotsman Installation Time: Less than 1 Hour

        Varitune Review

        Choosing an exhaust system is not an easy task. Computer videos are of some help, but unless you can hear it in person its just an educated guess, and every engine will make it sound different. Installation was a breeze, i helped my mechanic as the gofer and it took maybe 35 minutes. i have spent about three hours tuning the exhaust and have found an adjustment i like for the time being. The loudness is not that major diff from closed to open, but the tone, pitch, rumble, back pops all change. There is some droning at 2000 but you can adjust it to what you like. i happen to like some drone but if necessary, u can turn in full closed for hardly any. I now have it at the halfway point on drivers side and about 1/3 out from closed on passenger side. Will experiment with the tip length in the future as they can also change the sound. I get lots of comments on how the car sounds and am really enjoying them. Thinking doing the TrackCal Package and the lobe idle should be awesome.

        Helpful (8)
      • September 19, 2015

        5 2011 GT - Ghosts Installation Time: Less than 1 Hour

        It was worth it and wanna thank you for your support and it is great doing business you I recommended you guys to a friend how has a 2015 mustang

        It make a difference in the performance and sound.

        Helpful (8)
      • June 05, 2015

        4 2014 GT - WolfMan Installation Time: Afternoon


        The installation was about 2 1/2 hours, it was relativity easy but required some adjustments to make the exhaust fit correctly and centered other then that was easy, the sound is deep and throaty, it is just fine no to laud all the way open, in overall is a good exhaust I recommend it if you do not like your car to be to loud.

        Helpful (8)
      • May 14, 2015

        4 2013 GT - Bira Installation Time: Afternoon

        Great V8 sound finally unleashed!

        Bought this to unleash the V8 rumble in my '13 GT and it has not disappointed in that arena. Love the fact that I can tone it down for a long trip if the volume becomes tiring but so far it has stayed fully open. Got the stainless version which looks great and hopefully last forever. Took me about 2 hours to install, including ripping old mufflers out first, on jack stands in my garage. Not difficult at all but took a little manipulation to get tips aligned properly. There is a slight drone at around 2000 rpm, but not unbearable with them wide open. I don't find that I'm often right at 2000 rpm anyway.

        Helpful (8)
      • December 19, 2014

        3 2014 GT - Terry5357 Installation Time: Shop Install Installation Cost: 0-$100

        Was kind of disappointed

        The mechanic that Installed them said it was a piece of cake, I had informed him about removing the exhaust pipe that had the resonator in them and then swapping out mufflers. I couldn't tell any difference with adjusting plug all the way in or all the way out. The sound is really low pitched and soft. When coasting down to a stop the sound reminds me of how an 18 wheeler sounds when it's coasting to a stop. Not the raspy sound I heard on the video at all. Varitune muffles are SS and very well built. Mechanic told me the hangers were unequal lengths and he had to bend so one side didn't hang low. As far as quality they are worth the over $550 I paid for them, as far as sound, I think the Varitune is a gimmick more than a good sounding muffler. Also the drone is pretty bad at 2000 rpm. Will replace them as soon as I can afford it. Also tips are single wall chrome pipe NOT what I would expect for the money I paid. Hopefully BBK will put these on a stock 2014 hear them and realize their mistake. All in all I give them a 10 on build quality and a 2 on sound. That is just my opinion. Thank you BBK for being an American company and allowing me to voice my opinion.

        Helpful (8)
      • December 02, 2014

        5 2014 GT - rickdelprado Installation Time: Shop Install Installation Cost: $100-$250

        Wow, I am amazed

        Ladies and Gents, the sound clips and video don't do this exhaust justice. I was a bit concerned with the low number of reviews and very little info online about the BBK Varitune. I had the shop install it with the valve open and the car sounds beastly! I love the deep throaty roar and the tone of an old school muscle car. I have no other mods so I can safely say the sound coming out of my car is 100% due to this exhaust. With the valve open to the fullest at low rpms you can really hear it inside the car but it isn't annoying in any way because the sound is deep and beautiful. I wish the exhaust was slightly cheaper at 499 I highly considered others with far more reviews, but I took a chance and it payed off. I really liked the idea of having the valve and being able to control the noise factor. Some day I may want to tone it down a bit, but until then, open all the way and full speed ahead!

        Helpful (8)
      • June 23, 2014

        5 2014 GT - Koppe06 Installation Time: Shop Install Installation Cost: 0-$100


        Bought this system just because I was able to adjust the loudness. Had it installed by my local mechanic. Best thing I've ever done. Seems everything was off by a little - plus it would help to have an extra pair of hands. Once they were on I couldn't be happier. Nice deep rumble but not overbearing. The big nut on the adjustment screw is 15/16 and it seems that a 12 m.m. wrench works best for the end of the adjustment screw. I would recommend this product.

        Helpful (8)
      • March 22, 2014

        4 2012 GT - Fyrman00 Installation Time: Less than 1 Hour

        Great sound on stock pipes

        The installation was not that hard even on the floor with two jack stands. Pipes took a little "fine tuning" to fit together but over all not the hardest part I've installed. Sound is great even on stock pipes, it's mellow closed and open still sounds great with some rough edges. Great product !

        Helpful (9)

      Questions & Answers (5 answers)

      5 Top Rated Questions

      What's the size of inlet for tips?

      Could it be fitted on a 2016 Eco-Boost Mustang?

      • Unfortunately, the BBK Varitune Axle-Back Exhaust is only designed for the 11-14 GT. It will not fit a 2016 Ecoboost Mustang.

      Helpful (0)

      How much do these axle-backs weigh? Wanted to know how much these weigh compared to stock. Thanks!

      • After carrying the box with the bbk varitune and then carrying each stock muffler I can safely say that they are about half as light as the stock, if not very close to it. For sure they are lighter and its apparent as soon as you try to carry them. The exact numbers I am not sure.

      Helpful (0)

      Is there any drone? Is there any drone when running these mufflers?

      • With the valve fully open there is slight drone at low rpms. That can easily be remedied by closing a valve and playing with it till you find the sweet spot. Honestly with the valve open I am perfectly happy. It isn't enough to upset me and I love the sound of the exhaust so much that I wouldn't have it any other way.

      Helpful (0) Show 1 more answer

      Loud Is this exhaust louder with the valve closed compared to the stock pipes?

      • Yes it is louder than the stock with the valve closed.

      Helpful (0) Show 1 more answer
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      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Passenger side muffler assembly
      • (1) Driver side muffler assembly

      Tech Specs

      Will It Fit My Mustang

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