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BBK Varitune Axle-Back Exhaust (15-17 GT)

Market Price $645.99 You Save 12% ($76.00)
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    Features, Video & Details

    • 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
    • Cut & Clamp Design
    • Fits 2015-2017 GT Mustangs

    Review & Installation Video

    Review & Install Video

    Hey, guys. Stephanie with with a quick review of the BBK Varitune Axle-Back Exhaust for 2015 and up GT Mustangs. This is an axle-back that's going to be a good option for someone who would like more of an old-school muscle car sound at a more budget-friendly price. Some axle-backs for the S550 GT are just plain loud. They have a ton of volume and noise. This axle-back isn't like that. BBK was focused on more of the quality of the sound in this case. They also worked in an option of going from a three-chambered muffler to a single chamber, which means you can change your exhaust note as you want. So, that means that this is a versatile, so it's something that can be quiet for those who want a nice, quiet upgrade or throaty for those who wants something a little bit more. So these mufflers have an internal adjustable valve and that's how they're going to change in sound. If the valve was closed, then the exhaust will be forced to all three chambers of the mufflers, which as you can imagine, is going to have a pretty mellow sound. When the valve is open, on the other hand, the exhaust can take the path of least resistance, which is through a single chamber. That's going to make the muffler a straight-through type of muffler, which is going to be much more throaty and have some more volume along with it. This means you can really personalize your exhaust system and choose which sound you like better, a calm upgrade over the factory mufflers or as much of volume as possible through the BBK system. This axle-back is deeper than stock for sure when the valve is closed and the exhaust is forced through all three chambers in the mufflers, but I will describe the system as very loud. It's louder than stock but pretty tame, in my opinion, but that's kind of what I expected here. Much like the Roush quad tip axle-back, I think the system with the valve closed sounds like a stock exhaust. It does get a little louder in the higher RPMs, and for that reason, I'm going to rate this axle-back as a one or two on the scale when the valve is closed. That rating is going to change when the valve is open, but I wouldn't say that there's going to be a huge difference when the valve is open. It's going to open up some more ground and some more rumble but you're not really looking at a night and day difference. I'm not saying that that's a bad thing, I'm just saying that you can expect along the same lines as far as sound just with a little more tone and growl. I noticed that with the valve open, it was a little deeper sounding and slightly more aggressive. You can hear that you have an aftermarket axle-back on the car from inside the cabin, but I wouldn't say there's any drone, so this could be a good option for daily drivers. Keep in mind that this is still with the factory resonator and even so, I'd rate this as a two or two and a half on the loudness scale. If you're looking for that aftermarket forceful sound, there are a ton of other axle-back options out there that won't leave you disappointed. And speaking of changing the internal valving, it's adjusted right here at this point on each muffler. Some of the other features that this system has is a full stainless steel construction and four-inch polished stainless steel tips. The tips are going to exit in the stock location, so you don't have to worry about modifying the rear bumper cover at all. When it comes to price, this is going to be one of the more affordable axle-back options that's currently available, especially when you start to consider some of the bigger players like Corsa, coming in at over a thousand bucks. You're looking at spending between $550 and $600 for the BKK's Varitune and that's going to come with your clamps as well as the system itself. You're going to be looking at the typical cut and clamp design with the install for this axle-back like all other axle-backs. I'm going to call this a two out of three wrenches on the scale but solely because of the cutting that's involved. It's nothing difficult, but I just recommend some eye protection and a fresh blade to make the cutting easier. Overall, you're looking at about two hours to get this all done. Wrapping this up, this BBK Varitune axle-back is the option of running a quieter three-chambered muffler or you can open up a valve from outside the car with a turn of a wrench and open up some more volume from a single-chamber straight-through type of muffler. This is a full stainless steel system that's easy to install, but it's like other axle-backs in the sense that it does require some cutting. I'm Stephanie and I'll see you next time right here at

    Adjustable Sound. Featuring patented tunable performance mufflers, this BBK Varitune Axle-Back Exhaust System allows you to customize your S550 Mustang's exhaust note to suit your own personal taste. The sound can be adjusted from mellow to throaty with just a twist of a wrench, for an 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.

    Durable BBK Construction. Constructed from high quality stainless steel for strength and durability, 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.

    Cut & Clamp Installation. The installation of this Axle-Back Exhaust will require cutting and removing the factory muffler assemblies and clamping the new muffler assemblies in place. Clamps and instructions are provided.

    Application. This BBK Varitune Axle-Back Exhaust is designed to fit all 2015-2017 GT Mustang models equipped with a DOHC 5.0L Coyote V8 engine.

    Fitment: 2015 2016 2017 Details

    MPN# 41115

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Passenger side muffler assembly
    • (1) Driver side muffler assembly
    • (1) Passenger side exhaust pipe
    • (1) Driver side exhaust pipe
    • (2) Exhaust Tips
    • (6) Band Clamps
    Installation Info
    Tech Specs
    Axle-Back Exhaust Specifications
    Piping Material: 304 Stainless Steel Tip Material : Polished 304 Stainless Steel
    Piping Size: 2.5" Tip Size: 4.0"
    Muffler Type: Straight-through Fitment: 2015-2017 GT
    Will it fit my Mustang?

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    Questions & Answers (2)

    2 Top Rated Questions

    I just want to be sure it fit on my mustang GT 2017 Convertible

    • The BBK Varitune Axle-Back Exhaust will fit the convertible without any issue.

    Helpful (0) Show 1 more answer

    My only question is does this exhaust system cause a drone in the cabin? I'm one that doesn't want to hear the exhaust inside the cabin at cruising speeds. Any help is appreciated, as this system does have the sound I'm looking for.

    • Exhaust tone can be difficult to determine as sound can be subjective. We would highly recommend listening to a few in-cabin sound clips to determine if this would be a suitable system for your application.

    Helpful (0)
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    Customer Reviews (7) Write a Review

    Overall Rating 4.9

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:0-$100

    • Loudness / Volume 4 4
    • Exhaust Note 4.714286 4.7
    • Fit & Finish 4.857143 4.9
    • Bang For Your Buck 4.857143 4.9

    • 5/5

      September 02, 2017

      Very pleased

      I am very happy with this system the sound is great I give it a 5 plus


      Year: 2015 Submodel: GT

      Helpful (5)

    • 5/5

      Installation Time: Less than 1 Hour

      August 07, 2017

      BBK Varitune Axle-Back Exhaust

      I had it installed at my dealership. Took the mechanic right at 40 minutes from start to finish. (So nice when you have a lift) He said all parts fit like a glove. We (he) ran it up on the lift a couple of times to adjust the exhaust note. Now it's at a nice rumble at idle, but not too loud when you take off, unless you floor it, which I don't do in my neighborhood. Overall opinion, it's a great system. Now if I could only get the GT 350 front scoops pre-painted, life would be good.


      Year: 2017 Submodel: GT

      Helpful (5)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      June 11, 2017

      Deep tone

      Not the loudest exhaust but for me its perfect. The VERY deep tone you get from 1000 to 3000 rpm is a great sound and never gets old hearing. I have the valves opened up all the way also to a 1 chamber. On the interstate it is still pretty quiet. It is not raspy like a lot of exhaust systems on mustangs. It fit well but I would recomend a shop install as the can heat the pipes and make everything fit perfect and center the tailpipes exactly in the middle . a couple welds also make sure everything stays in place.


      Year: 2017 Submodel: GT

      Helpful (5)

    • 4/5

      Installation Time: Afternoon

      January 18, 2017

      Nice Tone

      Installed the BBK on a 16 GT. I have an MRT H-Pipe, and found there to be excessive drone in the 1600-1900 rpm range. I spoke to BBK and they recommended opening one muffler's valve about a half inch further out from the other muffler to decrease drone. I believe it helped somewhat, but ultimately decided to reinstall my factory resonator. Very pleased with the factory resonator with the valves fully open. May try and X-pipe in the future.


      Year: 2016 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Afternoon

      May 24, 2016

      Sounds amazing

      I am very impressed with the sound of this bbk catback system. It took me about 2 hours to complete the install but it was my first time doing it. It was very simple and came with instructions. When I first started it up I had the vales closed and I was amazed at how great it sounded. than I opened up the vales and the beast was unleashed. It took me about 5-10 minutes to open and close the vales. After a day one of my bolts came off to hold the vales open or closed but it was my fault I guess and it can easily be replaced.


      Year: 2016 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Less than 1 Hour

      April 30, 2016

      Geeat sound!

      I was looking for the perfect sound from my mufflers, that late sixties deep rumble muscle car sound, and this product delivered. I combined it with the H pipe (resonator delete) and now have a great sounding car plus if I want to I can adjust it to make it louder, not that it is needed. With the H pipe and the new axle back there is a noticeable improvement in HP as well. Great product and a very easy install.


      Year: 2015 Submodel: GT

      Helpful (8)

    • 5/5

      Installation Time: Afternoon

      February 10, 2016

      Great Sound!

      I spent a long time looking and listening and to the various cat back and axle back systems and almost pulled the trigger on the Borla S-type. I'm glad I waited for the BBK axle back. The sound is just what I was looking for, and suprisingly louder and a deeper tone than I was expecting. My plan was to pair with the Hearthrob H-pipe, however, it was out of stock and I'm now thinking to skip as it could change the sound that's perfect for my taste. The kit was fairly easy to install and I find the machined finished tips look great.


      Year: 2015 Submodel: GT Richmond, TX

      Helpful (7)

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