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Ford Focus RS Exhaust Upgrade Guide

Austin Parsons

Meet Austin

Austin holds a technical writing degree and has 5 years of experience working as a Technical Product Specialist at BMW. He is an avid car enthusiast who is constantly watching F1, consuming automotive content, racing on his simulator, and working on his Toyota’s and BMW’s. Austin’s technical writing skills, extensive automotive knowledge, and hands-on experience make him an excellent resource for our readers.

While the RS might not be wielding a high-displacement V8 behemoth under the hood, the 2.3L Ecoboost is very responsive to aftermarket additions. The MK3 Focus RS is unquestionably an exciting car from the factory. But, as with most things, it can be more exciting. One of the standout modifications that can introduce a little more verve to your RS driving experience is an upgraded exhaust system.

Since the 2.3L Ecoboost is a turbocharged engine, there is quite a bit to be gained from fitting a less restrictive exhaust. In addition to performance gains, an upgraded Focus RS exhaust can introduce some additional sound into the equation for those that want to make a grand entrance.

Types of Ford Focus RS Exhausts

In addition to thinking about the considerations listed above, you’ll also have to consider what type of aftermarket Focus RS exhaust will be the best option for you. There are two main types of commonly fitted exhausts to 2016-2018 Focus RSs. These include turbo-back and cat-back exhausts. 

Turbo-Back Exhaust

A Ford Focus RS Turbo-back exhaust system is the most intensive type of exhaust that you can install. Unlike cat-back exhausts, a turbo-back exhaust replaces nearly every component of your factory exhaust. That includes your downpipe and catalytic converter. This allows you to be able to enlarge the diameter of the entire system, allowing a larger volume of exhaust gas to escape. Turbo-back exhausts provide the most significant performance gains due to this. Since a Focus RS header-back exhaust replaces everything, they are generally the most expensive kind of exhaust that you can buy. In addition, they are also the most difficult type of exhaust to install of the two. 

Cat-Back Exhaust

A system commonly fitted to lightly modified Focus RSs is a cat-back exhaust. Cat-back exhausts are exactly what they sound like. They replace all of the factory exhaust components from the catalytic converter to the exhaust tip. This type of exhaust is generally made of stainless steel and is made to improve exhaust gas flow out of the engine, resulting in a bit more power and a lot more noise. Aftermarket Focus RS cat-back exhaust systems can vary a good amount in terms of their pipe diameter, tip diameter, and how they exit the vehicle. 


Factory Focus RS Exhaust System

For a stock exhaust system, the MK3 Focus RS actually has some pretty solid equipment. The factory RS exhaust has a pretty familiar layout to most other turbocharged sports cars. It features a catalytic converter almost immediately after the turbo in the downpipe. From there, a 2.75”-diameter cat-back system takes over which doesn’t have too many notable or significant restrictions. In a lot of other cars similar to the RS, there will be an additional cat further down the system. Apparently, the RS doesn’t need any additional exhaust cleanup from an emissions perspective. I guess that speaks to the 2.3L Ecoboost’s efficiency.

The factory Focus RS exhaust is a pretty optimized system. In terms of its actual design, it has good factory flow figures from the catalytic converter to the exhaust tips. For that reason, you won’t see a very dramatic gain in performance from an aftermarket Focus RS cat-back exhaust. With a turbo-back system, the gains will be more noticeable. That is because turbo-back exhausts replace the factory cat with a higher flowing one that removes a main source of restriction. It is safe to assume that a cat-back exhaust will garner an extra 5-10 horsepower, while turbo-back gains will be in the ballpark of around 20 horsepower. 

How Does the Exhaust Valve Work?

A significant feature of the factory Focus RS exhaust system is its valved design. While valved exhausts aren’t a new concept, there is some general confusion in the Ford Focus community about how the RS valved exhaust actually works. In simple terms, the factory RS exhaust has a valve built into the left-hand muffler outlet pipe. The RS’s PCM controls the valve electronically and actuates it to two positions, either open or closed. 

During a cold start, the PCM is programmed to open the valve to either piss off your neighbors or impress your friends, whichever applies. After the cold start routine, the valve will close. It will then open and close depending on engine load, engine rpm, and vehicle speed. The Focus RS’s PCM consistently takes readings of all of these factors and adjusts in real-time.

While there isn’t a big performance difference between the two valve positions, there is certainly a notable difference in sound. The owner manual states that with the valve open, exhaust restrictions are at a minimum. It also claims that the engine produces an enhanced “sporty” sound with the valve open. They could have probably been a tad bit more descriptive than that, but so be it. With the valve closed, the factory Focus RS exhaust is slightly more restricted and produces much less noise.

One of the biggest letdowns surrounding the factory Focus RS valved exhaust system is the fact that there is no manual control for the valve. That unfortunate caveat is a big reason that there are so many aftermarket valved exhausts available.

Best Ford Focus RS Exhaust Systems

With the background info out of the way, it’s time to jump in and discuss some of the best Focus RS exhaust upgrades:

  • AWE Switchpath
  • Mountune V2X
  • COBB Tuning Turboback
  • Milltek Exhaust Catback

This isn’t an exhaustive list as there are tons of great exhaust systems available. Of course, a lot is also opinionated and depends on your preference for exhaust and engine sounds. That said, these are some of our favorite exhaust setups for their balance of performance, quality, and sounds.

1) AWE Switchpath Exhaust 

Price: $2,595.00

Compatible with 2016-2018 Models

If you are looking for a performance Focus RS Catback solution that retains the valved functionality of the factory exhaust but provides a bit more control, look no further than the AWE Switchpath. AWE is a brand that has carved out a notable space in a number of aftermarket communities. They provide quality exhausts for everything from McLarens to Volkswagens. Their Ford exhausts are especially well known and favorably reviewed. The AWE Switchpath is a favorite in the Focus RS community for providing a good middle ground between aftermarket performance and stock features. 

Like the factory Focus RS exhaust, the AWE Switchpath features a valved design. Unlike the stock RS exhaust, the AWE allows you to switch the valve mode at the press of a button. The Switchpath comes with a wireless remote that overrides the RS PCM valve control system to give you ultimate control. 

Beyond just the fun valve party trick, the AWE Switchpath is a very solid exhaust from a performance standpoint. It is constructed entirely from T304L stainless steel and has larger diameter piping than the factory exhaust. The Switchpath’s 3.0” diameter allows for better gas flow out of the 2.3L Ecoboost engine, ultimately resulting in more power. The AWE exhaust is available either with or without resonators. They recommend ordering it with resonators if minimal exhaust drone is your goal. Otherwise, the non-resonated version is the one to go with if you are looking for a bit more sound and power.

While the AWE Switchpath is the most expensive Focus RS exhaust option on this list, it truly is the best from both a versatility and performance perspective. 

2) Mountune V2X Exhaust

Price: $1,287.99

Compatible with 2016-2018 Ford Focus RS

Generally speaking, there’s usually an aftermarket manufacturer that stands above the rest when it comes to a specific manufacturer or car. In the case of the MK3 Focus RS, that manufacturer is Mountune. They unquestionably have the most tuning experience with the RS and have the largest selection of Focus RS performance parts of anyone. The Mountune V2X is pretty much universally loved in the RS community and it’s easy to see why. 

In terms of its actual construction, the Montune V2X doesn’t fiddle with the original formula too much. The most significant change is the increase in exhaust pipping to 3.0,” which, once again, allows exhaust gasses to escape a tinge easier. It features a high-flow silencer that removes exhaust drone from the equation entirely. All of the joints are connected by either V-band or custom double-slip joints ensuring the best seals possible. The V2X is available in either valved or non-valved form, depending on your preference. The non-valved V2X is undoubtedly the louder option. 

The primary reason that the Montune Focus RS exhaust is so highly praised is the sound that it produces. Most 2.3L Ecoboost Ford RS owners claim that the factory exhaust noise is underwhelming, to say the least. The Mountune V2X remedies that issue by allowing the 2.3L Ecoboost engine’s character to shine through a bit better under heavy acceleration. Owners of the V2X say that the exhaust really releases the crackles and pops that most RS owners are searching for.

3) COBB Tuning Turboback Exhuast System

Price: $1,425.00

Compatible with 2016-2018 Ford Focus RS

If you are looking to unleash the maximum amount of power and performance from your exhaust system, you’ll need to spring for a full turbo-back system. While cat-back systems can unquestionably help with exhaust flow, the factory catalytic converter in the downpipe is really the true restriction. The COBB Tuning MK3 Focus RS turbo-back system replaces the stock catalytic converter with a 4.5” high flow GESi cat to reduce backpressure significantly. 

Like many of the other options on this list, the COBB exhaust is also a 3.0” system that features a custom straight-through muffler and resonator, which provides a perfect balance between sound and flow. The COBB Focus RS Turboback is a valved system that makes use of an OEM valve that is provided with the kit itself. Owners of the COBB Turboback claim that it unleashes the perfect amount of raspiness when on throttle and softens out substantially during highway driving. 

In terms of performance, the COBB Focus RS Turboback is the cream of the crop, especially when paired with a performance tune. COBB is a tuning company at heart and builds their performance parts with tuning in mind. When paired with a tune, the Turboback can yield double-digit horsepower and torque gains. COBB even claims that their Ford Focus RS exhaust is so unrestrictive that it flows far beyond the capabilities of the factory turbo. If big power is in your future, buy the COBB Turboback and never worry about your exhaust again.

Focus RS Milltek Exhaust Sport Cat-Back

Price: $1,599.00

Compatible with 2016-2018 Ford Focus RS

Milltek is far from new to the exhaust game. In fact, they’ve been creating high-quality exhaust components for a variety of manufacturers for over three decades. As a result, they know what they are doing. That applies to their 2016-2018 Ford Focus RS Sport Cat-back system as well. Build materials are a strong point for the Milltek exhaust, which is constructed from anti-magnetic 304 aircraft-grade stainless steel. The quality steel is extremely durable and less susceptible to discoloration over time. Milltek takes pride in their state-of-the-art CNC mandrel tube benders which provide the buttery smooth bends that aid in exhaust gas flow. 

The Focus RS Milltek exhaust is available in both resonated and non-resonated forms. The former provides slightly better exhaust flow characteristics. To make things a bit more interesting from an aesthetic perspective, the Sport exhaust is available with four different 4.5” exhaust tips to choose from. These include polished stainless tips, brushed titanium tips, ceramic black tips, and burnt titanium tips. The Focus RS Milltek exhaust retains mounting hardware for the factory valve components. While it doesn’t allow for manual valve control, at least the factory valve option is still there. 

Focus RS Exhaust Upgrade Guide Summary

The Ford Focus RS is a modern hot hatch that carries a proven racing pedigree. The 2.3L Ecoboost engine that powers it is a fantastic powerhouse that has a ton of untapped potential that can be released with some choice modifications. One of those modifications is an upgraded exhaust system. The benefits of a Focus RS exhaust upgrade are primarily twofold. They increase power marginally and give your RS a new and improved sound guaranteed to put a smile on your face. The factory-valved Focus RS exhaust system leaves quite a bit to be desired in the sound department. With a larger diameter system that has a better-designed resonator (or a resonator delete), you’ll hear your RS a lot more inside and outside of the cabin.

If you are in the market for a Focus RS cat-back exhaust system, don’t expect to see any genuinely significant power gains. Since the factory RS exhaust design is efficient after the catalytic converter, the gains really only come from swapping to a high-flow cat. For that reason, a turbo-back system is your best bet if you are aiming for more performance. There are some very big names in the Focus RS exhaust game, from AWE to Milltek. All of the exhausts on this list are guaranteed to be quality and add an extra element to your driving experience.

Also, check out our other guides including common 2.3 EcoBoost engine problems and the 2.0L vs 2.3L EB engines.

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