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SLP Loudmouth Muffler Delete Axle-Back Exhaust (15-17 GT Fastback)

Market Price $434.95 You Save 8% ($34.96)
Our Price

$399.99

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  • Item 387058
  • MPN# 620054

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Features, Video & Details

  • Aggressive, Throaty Exhaust Note
  • Muffler Delete Design
  • Minimal Exhaust Flow Restrictions
  • 2.5" Mandrel-Bent 409 Stainless Steel Tubing
  • 4" Polished 304 Stainless Steel Tips
  • Cut & Clamp Installation
  • 29 lbs. Lighter Than the Stock Factory Axle-Back System
  • Emissions Legal in All 50 States
  • Fits 2015-2017 GT Fastback Mustangs

Review & Installation Video

Review & Install Video

Hey, guys. Stephanie with AmericanMuscle.com here with my review of the SLP Loudmouth Muffler Delete Axle-Back Exhaust for 2015 to 16 fastback GTs. Loud, that's the first thing that we're going to say about this system, even though it's just an axle-back, and for obvious reasons. We install this on the '15 that still has the factory resonator and cap, and you can hear the huge difference in the sound clips. What I like about this axle-back is that it gives a really throaty sound that has virtually no rasp. Personally, I'm thinking that this is going to sound mean as hell, even at idle, and it's going to turn heads for sure. So I'm going to rate it as a solid three on the loudness scale. I'm giving it this rating because while this system is loud, it is an axle-back. It could get even louder depending on if you change the rest of your exhaust setup. There's a lot of room to change the sound through different things like mid pipes, offered setups, or long tubes, and that's one of the nice things about an axle-back. You can see a big change in tone from a good quality brand without having to ditch your resonator or ditch to a catback, which could end up draining your bank account, and you always have the option of adding on later. Even with the stock resonator, the straight pipe set up does have a lot of drone, but that's kind of expected with an axle-back like this. If that's a feature that might bother you, then you might want to check out some other options. You are ditching some weight with the SLP here since there are no mufflers, so you're going to be about 29 pounds lighter than your stock setup. This keeps your two and a half inch tubing, but this axle-back is stainless steel and includes four-inch polished tips. Now, SLP says that this axle-back provides the most aggressive, free-flowing exhaust possible with the factory mid type in caps, and that's a point that's kind of hard to argue. Literally, there will be no more filtering of exhaust after it passes through the mid pipe section at all. All right now, price point. This system's going to come in with a price point that's lower than the normal axle-back, which is what I would expect, considering you are missing the heart of the material here with no mufflers. If you compare the SLP to other muffler delete axle-backs and even expand that to other rate series setups, we still see that the SLP here is less expensive and very budget friendly. Now, we all kind of know that if you're installing an axle-back, you're going to be doing some cutting, and this axle-back is no different. It's a standard cut-and-clamp design that we're used to seeing with other axle-backs, and for that reason I'm going to stick with what I've said in the past and call this a two out of three wrenches on the scale. Time-wise, it shouldn't really take too long to install, probably about an hour or so, but you do have to be careful when you're cutting. And remember that this system is not compatible with convertibles. I still just recommend a fresh Sawzall blade and some eye protection just to make sure everything goes smoothly. Wrapping things up here, the SLP is one of the inexpensive options in the axle-back scale when you compare it to the rest of the market, and it's an axle-back that's going to provide you with a ton of sound and the option to further change your exhaust down the road. As always, feel free to check out the full lineup of axle-back options here at AmericanMuscle.com.

Aggressive Exhaust Note. Add an aggressive throaty exhaust note your coyote powered S550 Mustang with a SLP Loudmouth axle-back exhaust system. This SLP muffler delete style axle-back provides the most aggressive, free-flowing exhaust possible with the factory Mid Pipe resonator and cats still in place - delivering more power you can both feel and hear.

Stainless Steel Construction. Manufactured from 2.5" diameter mandrel-bent stainless steel tubing for its excellent flow characteristics, this SLP Loud Mouth muffler delete axle-back exhaust system features a pair of highly polished 4" dual wall exhaust tips for intimidating muscle car looks.

Lightweight. This SLP Loudmouth exhaust system is 29 lbs. lighter than the stock Ford axle-back system, making it perfect for track and drag racers looking to shed unwanted weight in the pursuit of quicker times.

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

Application. This SLP Loudmouth Muffler Delete Axle-Back Exhaust system is specifically designed to fit 2015-2017 GT Fastback Mustangs. Cutting of factory exhaust is required for installation. Not compatible with convertibles.

Please Note. SLP Performance does not make any claims that their muffler-delete exhaust will meet any federal or local noise regulations or laws. Please check your local and state ordnances for installation and usage regulations.

Fitment: 2015 2016 2017 Details

What's in the Box
  • (2) Axle-Back Assemblies
  • (2) Polished Tips
  • (4) Clamps
Installation Info
Tech Specs
Axle-Back Exhaust Specifications
Piping Material: Stainless Steel Tip Material : Polished 304 Stainless Steel
Piping Size: 2.5" Tip Size: 4"
Muffler Type: Muffler Delete Fitment: 2015-2017 GT Fastback
Will it fit my Mustang?
  • GT - 15, 16, 17

Not compatible with Convertibles due to different bracing

Most Helpful Reviews

5/5
Perfect muscle car sound.

I listened to many of the sound reviews on this site and YouTube, and this was this only system that had a deep muscle car sound and no rasp. It sounds close to an old school car with flowmasters. The ...

Read More
Helpful (1)

5/5
Awesome Axleback

Always been a fan of SLP this axlebaxk sounds awesome, not too loud but still makes the car sound much more aggressive Highly recommend!

Helpful (1)

Overall Rating 4.6 out of 5 stars
Read All 14 Reviews

Customer Photos (1) Submit Your Photo

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2 Questions / 2 Answers

Ask a Question

I had the SLP Loudmouth Muffler Delete on my 2011 GT and was extremely satisfied with the product, price and fitment. Looking to modify my brand new 2017 GT now, I was considering the SLP Loudmouth again, but looking at your video, I absolutely dislike the fitment of the product. In the video, the exhaust does not appear to be centered well with the rear valance. Other muffler deletes in your video seem to be perfectly centered... Is that just an installation flaw, or does it have to do with the hangers on these for the 2017 model? Really hesitant to pull the trigger on these, and rather would go another route, if they can not be centered easily.

AndyR

  • This may have been due to an install error and or the kit was not adjusted properly for a perfect centered fit. As long as the axleback is installed correctly there should be no issues in offset of the axleback in relation to the rear valance.

    AMjordan

Helpful (0)

Hello, does this fit a Mustang v6 2017?

Jrlajara

  • This exhaust will not bolt on to the V6 models without custom fabrication due to the piping size differences.

    Ricky36

Helpful (0)

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Customer Reviews (14) Write a Review

Overall Rating 4.6

out of 5 stars

Installation Time:Afternoon

Installation Cost:0-$100

  • Loudness / Volume 4.583333 4.6
  • Exhaust Note 4.5 4.5
  • Fit & Finish 4.833333 4.8
  • Bang For Your Buck 4.666667 4.7



  • 5/5

    Installation Time: Afternoon

    May 25, 2017

    Perfect muscle car sound.

    I listened to many of the sound reviews on this site and YouTube, and this was this only system that had a deep muscle car sound and no rasp. It sounds close to an old school car with flowmasters. The driverside pipe that slipped over the existing pipe was a little tight but I made it work. The video from slp was great and I would highly recommend the system.

    Bill

    Year: 2016 Submodel: GT

    Helpful (1)

  • 4/5

    August 05, 2016

    Sounds Great

    Sounds great with factory resonator still in place so it could be even louder without the resonator. Good quality, price could be better for what it is.

    Cdukem

    Year: 2015 Submodel: GT

    Helpful (1)

  • 4/5

    Installation Time: Afternoon

    April 25, 2016

    Loud, Awesome sound

    This thing sounds absolutely fantastic on an otherwise stock exhaust at any rpm below 3.5k. Once you really start to step on it, the exhaust note does start to lose its refinement. I would highly suggest pairing this axleback with some form of midpipe (x-pipe or h-pipe) to sharpen the exhaust note higher in the rpm band. Gave it 4/5 simply because of the sound losing a bit of distinction as you dig into the gas, but there's no drone and this thing does turn heads.

    Cilio

    Year: 2016 Submodel: GT

    Helpful (1)

  • 4/5

    Installation Time: Less than 1 Hour

    April 20, 2016

    awesome first mod!

    So I just bought the 2016 gt and I wanted to get the best bang for buck with exhaust, and this slp definitely did it! Great sound and great product and would recommend it to anyone who wants a good sound but not crazy loud. Only thing I came across was I had to expand the end of slp exhaust where it connects to stock pipe to fit over but after that all smooth sailing.

    ghost

    Year: 2016 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    April 02, 2016

    Awesome Axleback

    Always been a fan of SLP this axlebaxk sounds awesome, not too loud but still makes the car sound much more aggressive Highly recommend!

    JohnnyS550

    Year: 2015 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    January 18, 2016

    SLP Delete

    I was a bit nervous about this system but once again SLP delivers sounds amazing paired with a resonator delete x pipe. Very easy to install. Everytime i fire this bad boy up everyone turns to look amazing product.

    Hotrod

    Year: 2016 Submodel: GT Virginia

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    December 18, 2015

    Great first mod

    Only had my 2015 Mustang GT for a month and it was so annoying how quiet it was. First mod were these Loudmouths. Sounds great just cruising and if you need to step on it watch out. I had a shop weld them on for $100.

    J

    Year: 2015 Submodel: GT Austin, TX

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    May 18, 2017

    SLP

    Great exhaust! Definitely sets the tone for the car...I luv it.

    Clem

    Year: 2016 Submodel: GT

    Helpful (0)

  • 2/5

    Installation Time: Less than 1 Hour

    May 03, 2017

    Way!!!!! To much!!!!!!

    Bought and installed, took off next day. Install easily with a sawzall in about 45mins. I have resonator delete h pipe and combined with the kit wasway too loud and way too much drone inside car.

    Will

    Year: 2016 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    October 26, 2016

    Amazing Sound! Sad they dont offer them anymore.

    I knew as soon as I purchased my mustang I would need to start getting some noise out of it. I went with this kit because slp is simply just one of the loudest muffler kits around. Can't beat the sound for the price and everyone turns their head when I com rolling by.

    Amatt

    Year: 2016 Submodel: GT

    Helpful (0)

  • 5/5

    August 05, 2016

    Just loud enough in throttle, perfect at idle

    It took me a bit to grow into liking this axleback, but three months in and I'm really happy with it. I wasn't looking at replacing much of my exhaust anytime soon, so I wanted something that was loud and aggressive when I get into it, but docile and not overly demanding of attention at idle--this SLP loudmouth 1 does the job incredibly well. At throttle, the car sounds like a screaming banshee with a thundering V8 as a soul and at idle, the car purrs with the demeanor of loin satisfied with its recent kill. For someone with a daily driver only looking to do an axleback, but still wants to hear the car when digging into the gas pedal, this is perfect. If you plan on doing headers, mid-pipe and axleback, this might be too load for a lot of folks--If I swap out the rest of the exhaust, I'll probably also replace this with something that has mufflers to balance out the increase in decibels.

    AndrewsggrH

    Year: 2016 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    June 17, 2016

    Sounds amazing

    This is a great quick replacement for the factory exhaust. My only wish is that it came with some kind of template for cutting the factory exhaust. But I would definitely recommend this for anyone wanting great sounding exhaust on their mustang.

    JT

    Year: 2016 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    February 15, 2016

    WOW!! We love it

    We recently traded our 2013 5.0 Mustang GT (which also had the Loudmouth exhaust) in for our new 2015 5.0 Mustang GT. Our course our first mod was adding this exhaust to the new car. We love it. It has a different sound than the 2013 but that may be that it's not "broken in" yet. Don't get me wrong; we love it. It has the deep throaty sound without very much "drone". LOVE, LOVE, LOVE IT! Gary/Lisa Hensley Virginia

    1BDBOSS

    Year: 2015 Submodel: GT Waterford, Virginia

    Helpful (0)

  • 5/5

    Installation Time: Afternoon

    October 16, 2015

    extremely loud

    I have a v6 I had this welded on rather than bolt on install requires impact gun to properly lock down exhaust easy install and it's very loud but you learn to pedal it on the highway so the drone isn't so bad

    kenney

    Year: 2015 Submodel: V6 new Jersey

    Helpful (0)

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