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How to Install an Exhaust System on a 2011-2014 Coyote-Powered Mustang

By: Wes Duenkel | 12/15/2020 < Back to Motor Life Home
001-mustang-coyote-flowmaster-flowtech-exhaust.jpg

Turning up the exhaust volume and performance on Coyote V8-equipped Mustangs is a simple process with an abundance of available aftermarket products.


The factory exhaust on 2011-14 models measures 2.75 inches, except in the section from the catalytic converters and the H-pipe where the tubing necks down to 2.25 inches. Flowmaster's Scavenger Series X-Pipe (P/N 81106) replaces the restrictive factory H-pipe with 3" mandrel-bent, stainless steel tubing and an X-pipe junction to increase exhaust flow and scavenging.


The Flowtech Non-Muffled Axle-Back System (P/N 12137RFLT) completes the transformation by replacing the rear mufflers with straight, 2-1/2" 304 stainless steel tubing and polished, double-wall exhaust tips.


Wait...no mufflers? Yes, eliminating the mufflers isn't as extreme as that may sound (pun intended). Even with the mufflers chucked aside, the stock exhaust is still attenuated by the factory catalytic converters and two resonators. So, while the Flowtech axle-back deletes the mufflers, the exhaust overall is still muffled.


Installing both the Flowmaster Scavenger Series X-Pipe and the Flowtech Non-Muffled Axle-Back System can be completed in a couple of hours on jack stands or ramps. While the exhaust is notably louder than stock, the tone is "bassier" and smooth. Interior resonance around 2,000 RPM is present but not objectionable. We even have little exhaust pops and burbles between shifts.


Besides adding a meatier exhaust tone, the Flowtech Non-Muffled Axle-Back shed 32 pounds from the rear of this 2012 Mustang GT. Not bad for an afternoon's work.


2012 Mustang exhaust kit flowmaster flowtech

Here's how we're going to turn up the volume (both sound and exhaust flow) on a 2012 Mustang GT: Flowtech's Non-Muffled Axle-Back System (left) and Flowmaster's Scavenger Series X-Pipe (right).

Flowmaster 81106

Flowmaster's Scavenger Series X-Pipe (P/N 81106) replaces the restrictive factory H-pipe with 3" mandrel-bent, stainless steel tubing and an X-pipe junction to increase exhaust flow and scavenging.

Flowmaster 81106

Flowmaster's Scavenger Series X-Pipe consists of 3" tubing and connects to the factory catalytic converters with this female socket joint.

Flowmaster 81106

The Flowmaster Scavenger Series X-Pipe includes this merge section and connects to the factory exhaust system.

 Flowtech 12137RFLT

The Flowtech Non-Muffled Axle-Back System (P/N 12137RFLT) replaces the rear mufflers with straight, 2-1/2" 304 stainless steel tubing and polished, double-wall exhaust tips

Flowtech 12137RFLT

Flowtech's Non-Muffled Axle-Back System connects to the factory exhaust system, utilizes the stock muffler hangers, and features polished tubing and TIG welds.

2012 Mustang H-pipe removal

We began by loosening the exhaust clamps connecting the catalytic converters to the factory H-pipe.

2012 Mustang H-pipes

Then, we loosened the slip clamps behind the H-pipe.

With the clamps loose, we slid the factory H-pipe off the exhaust system.

The Flowmaster Scavenger Series X-Pipe reuses the factory clamps, so we used a screwdriver to release the retaining tab and slide the clamps off the H-pipe.

H-pipe modification

We used a cut-off wheel to cut the tab retaining the ball-and-socket clamp to the factory H-pipe.

X pipe comparison

The Flowmaster Scavenger Series X-Pipe's 3" mandrel-bent tubing (right) doesn't restrict flow like the factory 2-1/4" tubing of the factory H-pipe (left)

Seating X-pipe

After transferring the clamps to the Flowmaster Scavenger Series X-Pipe, we slid it over the factory exhaust tubing and seated the ball-and-socket joints.

Tightening clamps

We tightened the clamps at the front and rear incrementally and made sure everything was properly seated before fully tightening the clamps.

Removing exhaust clamps

Moving to the rear, we loosened the clamps securing the axle-back system to the exhaust pipes.

Removing factory axle-back

After removing the screws attaching the muffler vibration isolator brackets to the chassis, we removed the factory axle-back system.

Axle-Back Comparison

Not only is the visual difference between the factory mufflers (left) and the Flowtech Non-Muffled Axle-Back (right) striking, so is the weight: the factory mufflers weigh 22 pounds, while the Flowtech setup weighs only 6 pounds. That's a 32-pound total weight saving!

Removing exhaust isolators

We resumed installation by transferring the exhaust isolators from the factory muffler to the Flowtech setup.

Removing muffler clamps

The muffler clamps are also attached to the factory tubing, so we freed them with a cut-off wheel.

Flowtech axle-back

With the factory ball-and-socket clamp slid over the Flowtech Non-Muffled Axle-Back System, we hung the rear isolator bracket and loosely tightened the clamp.

Aligning Mustang exhaust

We reinstalled the isolator bracket screws, checked the alignment of the tubing, and tightened the clamps.


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