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

Market Price $419.95 You Save 5% ($20.00)
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$399.95

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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?

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    4 Questions / 3 Answers

    Ask a Question

    I recently purchased the Ford Racing Cat back system by Borla. If I purchaed the SLP Loudmouth Muffler Delete AxleBack, would they fit with the new X pipe from the Ford Racing?

    JustinF

    Can I switch between this and the SLP Loudmouth 2 axlebacks without making any additional modifications (in other words, are the overall dimensions the same as the SLP Loudmouth 2 axlebacks)?

    Arthur

    • The SLP Loudmouth Muffler Delete Axle-Back Exhaust can be switched out for the SLP Loudmouth 2 with no problems yes.

      AMRickyD

    Helpful (0)

    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)

    Customer Reviews (21) Write a Review

    Overall Rating 4.7

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:0-$100

    • Loudness / Volume 4.368421 4.4
    • Exhaust Note 4.631579 4.6
    • Fit & Finish 4.789474 4.8
    • Bang For Your Buck 4.68421 4.7



    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      May 04, 2018

      Awesome sound

      I had these on my 2008 GT.. loved them on that car .. sounds even better on the 5.0.. recommend these any day..

      sniemeyer81

      Year: 2017 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Afternoon

      April 04, 2018

      Great purchase!

      The SLP Loudmouth gives a nice aggressive sound. Fit and finish is 4 stars because you really need to take your time to measure precisely where to cut and clamp.

      MathewH

      Year: 2017 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Less than 1 Hour

      January 16, 2018

      Awesome sound!

      Very impressed with install and sound! Good product. Not crazy inside cab on a otherwise stock exhaust.

      CodyC

      Year: 2017 Submodel: GT

      Helpful (1)

    • 5/5

      October 18, 2017

      All around great product!!

      Cut and installed in my garage on rear wheel ramps which wasn't too hard. Install wasn't more than a couple hours Just because it was hard to get the saw under the car on ramps. The tips look great with the rear bumper and fill in most of the gap. Completely changes the sound of the car and with stock mid pipe, you can be quiet for the neighbors but pretty loud if you're getting on it!

      HarrisonF

      Year: 2015 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Less than 1 Hour

      September 29, 2017

      Great Axle-Back

      So this axle back is much louder than i thought, but it's not terribly loud. My neighbors don't like me as much but thats okay. Install was easy and it sounds soooooo nice. I can't stop smiling when i turn my car on :D

      LincolnT

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      September 05, 2017

      Hear me roar!

      Love the slp, definitely made my 16 GT Roar! I have received alot of compliments about my exhaust. Buyer be aware it is very loud. Not alot of drone at highway speeds.

      JoseM

      Year: 2016 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Less than 1 Hour

      August 30, 2017

      Exhaust note I was looking for.

      I was looking for a louder exhaust but also wanted a deeper, throaty sound and this product delivered.

      JustinS

      Year: 2015 Submodel: GT

      Helpful (3)

    • 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 (2)

    • 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 (1)

    • 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 (2)

    • 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 (1)

    • 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 (2)

    • 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 (3)

    • 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 (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 (2)

    • 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 (3)

    • 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 (2)

    • 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 (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 (2)

    • 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 (3)

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