Flowmaster Axle-Back Exhaust Kit Outlaw Stainless Steel 3" With 4" Black Quad Exhaust Tips Without Active Exhaust Option GT 2018-2023

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Flowmaster 3" Stainless Steel Outlaw Axle-Back Exhaust Kit with 4" Black Quad Exhaust Tips for 2018, 2019, 2020, 2021, 2022, and 2023 GT Mustangs without the Active Exhaust Option.

Are you looking for a way to give your 2018-2023 GT Mustang a louder and more head-turning exhaust note? And you want an exhaust that’s easy to install? Then be sure to pick up this Flowmaster 3" Stainless Steel Outlaw Axle-Back Exhaust Kit with 4" Black Quad Exhaust Tips that’s now available at CJ Pony Parts! 

Features & Benefits:
- Fits All 2018-2023 GT Mustangs without the Active Exhaust Option (Convertible and Fastback)
- Dyno-Tested to Achieve Maximum Performance
- Provides Aggressive, Race-Inspired Exhaust Sound
- Made of 409 Stainless Steel Mandrel-Bent 3" Tubing
- Includes Two (2) Black Powder-Coated Outlaw Mufflers
- Includes Premium-Quality Black 4" Double Wall Angle-Cut Quad Exhaust Tips
- Easy Bolt-On Installation with Included Mounting Hardware
- Made in the USA 

This Flowmaster (817806) 3" Stainless Steel Outlaw Axle-Back Exhaust Kit comes with 4" black quad exhaust tips and two Outlaw mufflers! This kit has been dyno-tested to achieve maximum performance and provides an aggressive, race-inspired note. It’s made in the USA out of 409 stainless steel with mandrel-bent tubing, and it’s easy to install with the included mounting hardware. 

Vehicle Fitment:
- 2018-2022 GT Mustangs without the Active Exhaust Option
*For 2018+ models only. This exhaust will NOT fit 2015-2017 models regardless of the installed valance.

Please Note: This system is only designed for use with models that are NOT equipped with the Active Exhaust Option from the factory. 

Tech Tip: Installation requires cutting of the factory exhaust piping. Once the modifications have been made to the factory exhaust system, installation is a simple bolt-in procedure. 

California Residents: Proposition 65 Warning

Installation Difficulty


Intermediate skill is required for this installation.

Installation Videos

Video Transcript

We're going to turn our 2018 Mustang GT into an Outlaw, with help from Flowmaster.

This is the Flowmaster Outlaw axle back, and CJ Pony Parts is one of the only places that's going to offer this for the 2018 Mustang. Now, when I spoke to Flowmaster and asked what their plans were when they designed this system, the one-word answer I got, loud. It was designed to be a loud, aggressive exhaust for your 2018 Mustang GT. It features the Flowmaster Outlaw muffler with 4/9 stainless steel pipes, and then your choice of either a black or a four inch chrome tip.

For this installation you'll need a lift of a jack and jack stand, 3/8 ratchet, 13 millimeter socket, 15 millimeter socket, a small pry bar or flathead screwdriver, measuring tape, marker, sawzall, file, and safety glasses.

The Flowmaster Outlaw system is an axle back, but unlike a lot of other axle backs, it actually cuts it further forward in front of the differential. The first thing you have to do on your 2018 Mustang, you've got multiple heat shields. The two rearward heat shields, you have to cut the strap and then bend them and snap the weld to remove them. To get this off, you're going to cut this strap. Now, I came in with a sawzall, if you do it with a cutting wheel, it will be easier, but if you're using a sawzall to cut the pipe itself, you can actually use it for this as well. We'll pull this strap off, and this will actually move. A small pry bar or screwdriver will make it easier. Basically push it up, and you'll feel the weld kind of snap, and then remove it.

Once you remove the heat shield, we're ready to cut. Where you're going to cut, you see the heat shield further forward here. You're going to follow this until you see this curve. Get underneath, and right where this curve starts going straight, you're going to make a mark. We'll grab a tape measure, we're going to go five inches further back from that mark. Make another mark, and that's where we're going to cut. Okay, with the pipe cut to remove it, we're going to remove this bolt here for the hanger. Pop this off, and slide it forward.

We're ready to install the Flowmaster exhaust, but before you do so, though, grab a file, just clean up the edges here, make sure there's no extra metal. Now grab your Flowmaster Outlaw axle back, put a clamp on that end, grab your original hanger, we're going to slide it on here, and starting with the muffler end, put it up into place. You'll want to reinstall the bolt we removed for the hanger. Now we're going to adjust the pipe and tighten the clamp. Once you have it adjusted, tighten it down, and we'll want to repeat the process on the other side, and your installation's finished.

Flowmaster promises loud, let's hear how it sounds. Now, right off the bat, at idle, it's loud, and it's actually deep. It's a very, almost boomy sound at idle. Yeah, that's what I expected, a loud sound, yes, aggressive sound. It crackles, it pops, it's exactly what you'd expect an Outlaw to sound like.

I've got to admit, I was a little bit worried when Flowmaster told us they were giving us an Outlaw axle back. I haven't heard the Outlaws before. Sometimes the Outlaw does get borderline, to me, obnoxious. I've heard it on some other cars, especially when people go like, cat-less, they just get loud. There's two louds to me, there's loud that sounds good, and there's loud for the sake of being loud. A lot of times, like when I heard the Outlaw ... Like I said, the older style Outlaw, especially with people with off road pipes and stuff like that, it seemed like it was more along the lines of loud for the sake of loud. It was just pure volume. It was almost too much. I'm going to say I'm pleasantly surprised the way this sounds. It is loud, don't get me wrong. This is a louder exhaust, especially for an axle back only, but it has a good sound to it. It's got a good growl to it, even at idle here. You can hear almost a slight lope to the exhaust. When you rev it up and stuff, it sounds good.

As it goes through the gears, it has a nice deep tone to it. More RPM gives you more of like that growl kind of sound, but it has a deep sound across the board. We'll give it some highway speeds here in a minute and see what the drone's like. There we are, we're cruising 2000 RPM, 10th gear, highways speeds, and yeah, you can still hear it, but it doesn't have that reverberating tone to it that a lot of these get, that's just really, really annoying as far as the amount of resonance you get. This isn't doing that. You can hear its, sounds good on the highway, but it doesn't have that painful drone. Yeah, when you get on it, though ... It really changes pitches, it's pretty cool. You go from that, just that nice deep cruising sound to a really ... I mean, it gets loud and it growls, the best way I can describe it. It sounds good all the way to red line, too.

So, the Flowmaster Outlaw is exactly as advertised. We've heard Outlaws on previous models, we know what to expect. Flowmaster didn't let us down. It's a loud, aggressive exhaust for the 2018 Mustang. Keep in mind with these sound clips, this still has the factory resonator. Add a resonator elite, and it's only going to get a lot louder. As far as installation, like any axle back, pretty straight forward, probably about an hour or so, and you'll be back on the road in no time.

Vehicle Fitment

This product will fit the following Mustang years:

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