Description
Overview
The Flowmaster Flow FX Axle-Back Exhaust System is a complete, ready-to-install upgrade engineered for the 2011-2014 Ford Mustang equipped with the 3.7-liter V6 engine. Built around Flowmaster’s Flow FX series muffler, this axle-back system is designed to deliver a noticeable improvement in exhaust flow, sound, and street presence without the complexity of a full exhaust replacement. If you want a factory-easy bolt-on that wakes up your Mustang’s tone and adds a custom look out back, this Flow FX system checks every box.
Performance and Sound
At the heart of the system is the Flow FX muffler, tuned for a moderate to mild sound level that adds character and depth without droning or becoming obnoxious on the daily commute. It’s the ideal balance for drivers who want their Mustang to sound more aggressive while remaining comfortable inside the cabin. On the dyno, this axle-back setup produced max gains of 7 horsepower and 6 lb-ft of torque at the rear wheels over the stock exhaust, thanks to freer-flowing mandrel-bent tubing.
Mandrel-bent 2.5-inch 409 stainless steel tubing keeps exhaust gases moving efficiently while standing up to heat, corrosion, and the demands of daily driving. The system finishes with larger 4.00-inch black ceramic-coated stainless steel tips featuring an embossed logo, giving the rear of your Mustang a bold, purposeful, custom appearance. The dual tailpipe layout and center inlet/center outlet muffler design (2.50-inch outlet, 27.25-inch overall length) make for a clean, factory-style fit.
Easy, Bolt-On Installation
This is a true axle-back system that uses your Mustang’s factory hanger and mounting locations, so there’s no need to modify or cut. All necessary hardware is included, making installation straightforward for a confident DIYer with basic tools. Because it replaces only the axle-back portion, you keep the fit and function of the factory system upstream while transforming the sound and look at the rear.
Highlights
- Flow FX series stainless steel axle-back system for the 2011-2014 Ford Mustang 3.7L
- Mandrel-bent 2.5-inch 409 stainless steel tubing for maximum flow and durability
- Flow FX muffler tuned for a moderate/mild sound level
- Max dyno gains of 7 hp and 6 lb-ft at the rear wheels over stock
- Larger 4.00-inch black ceramic-coated stainless tips with embossed logo
- Dual tailpipes, factory hanger fitment, and all hardware included
Fitment and Compliance
Designed specifically for the 2011-2014 Ford Mustang with the 3.7-liter engine, this system is CARB (California) compliant with an emission code of 5. It is backed by Flowmaster’s Lifetime Limited Warranty. Please note the California Proposition 65 warning applies. Upgrade your Mustang’s performance, tone, and appearance with a bolt-on system engineered by one of the most trusted names in exhaust.















