Announcing The Turbo Kit 80mm GEN3 2014-18 Mazda 3 Cat Back Exhaust

 SkyActiv Mazda 3 Cat Back Turbo Exhaust Kit

Around 3 years ago the 80mm Cat Back Exhaust was released for the 3rd Gen Mazda 3. During this time many have enjoyed the increased sound, performance and looks that it offers. As we have been developing the Turbo Kit for the 2.5L 3rd Gen Mazda 3, we have also had a chance to refine and tune the 80mm Cat Back Exhaust to further improve the tone and sound of the exhaust while reducing drone for 3’s equipped with the Turbo Kit. That is why we are excited to release the Turbo Kit specific 80mm Cat Back Exhaust to those of you who have or are looking to pick up the Turbo Kit for your 2014-2018 2.5L Mazda 3.

2014-2018 Mazda SkyActiv Turbo Exhaust

With the original 80mm CBE installed on our Turbo Kit equipped Mazda 3, we found that while the sound was good, the drone it created in the cabin was too aggressive for our liking. To combat this we tested multiple different combinations of midpipes and axle backs with different resonator configurations to find the best solution. From this testing we found that the combo that worked best was to keep the same midpipe setup, but to modify the axle back so that no resonators were used. This resulted in a substantial reduction in drone while adding in a more aggressive tone at higher RPM’s. With that being said if you are upgrading from a stock or 60.5mm exhaust it will be a large increase in NVH (Noise, Vibration, and Harshness) but this is offset in our opinion by the tons of fun noises it offers. Since the axle back is the only component that has been changed for the Turbo Kit specific exhaust, if you already have an 80mm CBE and want to upgrade, all you have to get is the non-resonated axle back to take advantage of the reduced drone and improved sound. To get a good idea of how the 80mm CBE will sound during different driving conditions, check out the video below.

Aftermarket Turbo Back Exhaust Mazda3 2014-2018

The Turbo Kit 80mm CBE also provides the same great appearance of the original 80mm CBE. Both the sedan and hatchback exhausts feature 100mm or ~4” tips. On the hatchback this helps fill out the bumper cutouts and the slant cut design helps them match the flow of the bumper profile. The sedan on the other hand, features a single wall design so that water and other debris don’t get caught in the tip since they are hidden behind the bumper and angled down. No matter which model you have, these features help the rear of the car stand out and provide an aftermarket look that is subtle and classy as it should have been from the factory.  

Performance Turbo 2014-2018 Mazda3 Exhaust

The great build quality and material are also carried over from the original 80mm Cat Back Exhaust with the use of T-304 stainless steel that is polished to a mirror like finish. This helps keep the CBE looking new and protects against corrosion for a long time to come. All joints are TIG welded to ensure durability along with a nice appearance. The resonators use a flow-thru design so exhaust flow remains uninterrupted while drone is kept down. Check out the product page for more pictures and details on the Turbo Kit 80mm CBE

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GET THE 80mm Non-Resonated Cat Back

The 80mm Non-resonated Cat Back is the perfect sound for the 2.5L 3rd Gen Mazda 3 Turbo Kit

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2018+ Mazda6 Performance Exhaust for the 2018-up 2.5T

Mazda did a great job bringing a turbocharged engine back to the Mazda 6 (Mazda 3 next please?), but may have done too good of a job of keeping it quiet. Say hello to the CorkSport 80mm Cat Back Exhaust and Axle Back Exhaust for 2018+ Mazda 6 equipped with the turbocharged 2.5L engine. If you’re interested in waking up your SkyActiv-T in both excitement and power, read on as we breakdown the newest CS exhaust.

As with all CorkSport exhausts, the goal of the Mazda 6 2.5T exhaust is to improve power and sound by improving the flow of the OEM exhaust. We started by increasing the size of the piping from 60mm to 80mm. That is an increase of over three-quarters of an inch to really help your turbocharger breathe better. In addition, the CS exhaust system eliminates the crushed areas present in the OEM exhaust and replaces the restrictive muffler sections with pass-through resonators. These resonators control volume and drone without affecting power output.

All that extra flow does mean a power increase. In our in-house dyno testing, we saw an increase in 5-6WHP just by bolting on the CorkSport  Cat Back Exhaust. Check out the dyno sheet down below to see. This increase came with no tuning changes, no check engine lights, and the only other mod being the CorkSport Short Ram Intake, which was installed for both tests. With the 80mm piping size, this exhaust is ready to support future modifications and would likely show more power gains with proper tuning.

The CorkSport MZ6T exhaust is more than just function. We went through multiple iterations and designs to ensure the best-sounding exhaust for your Mazda 6. The finished product ups the volume without being annoying to daily drive yet still sounds great when in hard acceleration. We strongly recommend you watch the video below to hear what to expect from this exhaust.

If you feel the video below gives you too much volume for the daily, then check out the Axle Back Only Exhaust.  Recently added to the CorkSport line-up, the Axle Back alone adds a mellower, but still noticeable tone to the exhaust.  This is a great middle ground between the CorkSport Cat Back and the stock exhaust.

To give a great-looking, long-lasting finish to each exhaust, they are manufactured from fully polished 304 stainless steel. To ensure a high-quality fitment, all components are precision TIG welded together on jigs made from OEM exhaust components. Lastly, as a finishing touch, we use 100mm dual wall exhaust tips. They fill out the bumper cutouts and are extended slightly to give a classy look and enhance the new Mazda 6’s styling.

The CS Mazda 6 Turbo Exhaust comes with all the hardware and gaskets you need for installation, high quality instructions, and CorkSport support for any questions you may have. Pick up a CorkSport MZ6 2.5T Exhaust today and liven up that daily commute.

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Mazdaspeed 3 Exhaust Manifold Break Down

Today we want to break down the OEM exhaust manifold for the Mazdaspeed platform so that you can better understand how and why the CorkSport Manifold makes power.  

If you haven’t heard, CorkSport has been developing a performance cast exhaust manifold for the Mazdaspeed platform.  We’ve tested and validated samples on Mazdaspeeds ranging from 350whp to 684whp. We’ve done dyno testing on the OEM exhaust manifold vs the CS manifold, as well as on the XS Power V3 manifold vs the CS manifold with the man, Will Dawson of Purple Drank Tuning, setting the calibrations. Both tests showed good gains from just the CorkSport Exhaust Manifold alone.   However, we can get into those details later.  

Mazda Exhaust Manifold Design

Mazdaspeed Exhaust Manifold Flange
OEM Exhaust Manifold Flange

This is the OEM (original equipment manufacturer) exhaust manifold found on the 2007-2013 Mazdaspeed 3 and 2006-2007 Mazdaspeed 6.  Manufactured from cast iron and very compact in design, the OEM design leaves A LOT on the table in the performance department.   

In the image, we’ve labeled each cylinder since that will be important for later discussion.  

OEM Manifold Exhaust Flow

So now let’s talk flow.  Fluids (or exhaust gases in this situation), will always take the path of least resistance.  When the flow path is not clearly defined for the exhaust gas, such as a merge between different cylinders, turbulence is created which reduces the efficiency of the exhaust manifold. 

A prime example of turbulence is shown in the image above with the orange arrows at the merge for cylinder 1 and cylinder 2.  Cylinder 2 comes to a “T” and therefore could flow left or right.  This creates turbulence which causes a loss in potential power.  

Next is the yellow arrow.  This is identifying the inner diameter of the runners in the OEM exhaust manifold.  To our surprise, the inner diameter of the OEM exhaust manifold is actually pretty decent at ~1.48 inches.  This diameter partially defines the power a manifold can support efficiently. Bigger is better in this situation, but small changes here will make big differences in the final performance. 

Surprisingly, there are “performance” exhaust manifolds on the market for the Mazdaspeed platform that have smaller inner diameter runners… 

Mazdaspeed Exhaust Manifold Gasket
OEM Exhaust Manifold Gasket

We also wanted to point out an unusual but important aspect of the Mazdaspeed exhaust manifold and gasket.  Have you ever noticed the seemingly useless extend flange off of cylinder 4? This extended flange acts as part of the passage for the exhaust gas recirculation port.  

You can more clearly see this port path in the gasket.  

OEM  Exhaust Manifold
OEM Exhaust Manifold

Designing For Efficiency

In this image, we want to direct your attention to a very unique and troubling design feature of the OEM exhaust manifold.  There is a right way and wrong way to pair cylinders on an exhaust manifold for a 4 cylinder engine… and this is the wrong way. 

Referencing our cylinder callouts in the first image above; you can see that the OEM design pair cylinder 1 & 2 together and cylinder 3 & 4 together.  This design physically works, but it is not ideal from a performance standpoint. In a divided manifold you should pair cylinders 1 & 4 together and cylinders 2 & 3 together for optimal cylinder exhaust gas scavenging. To learn more about exhaust scavenging you can check out a blog on that here, or watch the video below!

Exhaust Gas Scavenging. See the difference between the CS and OEM Manifolds.

Before we wrap here we do have one good thing to say about the OEM exhaust manifold.  It does sound really good and gives the Mazdaspeed platform a unique exhaust note, but don’t worry you don’t lose your unique rumble with the CorkSport design.   

Thanks for checking in with CorkSport Mazda Performance.  Stay tuned for more info about the CorkSport Performance Exhaust Manifold.  

-Barett @ CS

OEM Part Breakdown: 2.5L Skyactiv-G Exhaust Header

Analyzing an OEM part is usually our first step in creating a new performance part. We’ve been looking at the Mazda 2.5l SkyActiv-G Exhaust Header, and I wanted to bring you all along for the ride. It’s surprisingly complex for an OEM manifold/header and some serious engineering went into it.

If you’ve been paying attention to the CorkSport channels, you may have seen rumors here and there of a race header for the GEN3 Mazda 3 and Mazda 6 2.5L. While I can’t say too much on that just yet, but I can give you a breakdown of the OEM exhaust header that’s hiding in the back of your engine bay.

The OEM Exhaust Header

Stock Gen 3 Mazda 3 Exhaust Header
Stock Gen 3 Mazda 3 Exhaust Header

Excuse the dirty part, as this OEM header has had a hard life! I imagine many of you have not seen the stock header as it’s in the back of your engine bay surrounded by heat shields. Taking the heat shields off gives us a glimpse of the craziness that is the stock header. Mazda has gone with a true 4-2-1 design (also known as tri-y) with an integrated catalytic converter and what appears to be equal length runners. Stay with me, I’ll explain what all that means.

SkyActiv-G Exhaust Manifold Flow Path
Exhaust Flow Path

The image above hopefully helps you visualize the 4-2-1 design. Starting at the engine, there are four exhaust ports from the head. Each exhaust port gets its own pipe, known as a “primary”. The primaries then pair together to form two “secondaries”. Finally, the two secondaries combine into one collector pipe, in this case heading directly into the catalytic converter. The three unions or “y’s” are where the tri-y name comes from. The 4-2-1 design was chosen by Mazda for a very specific reason. Check out the image below and Mazda’s explanation HERE.

Mazda SkyActiv-G Exhaust Chart
Residual gas reduction by 4-2-1 exhaust system – From Mazda.com

Essentially, using a very high compression ratio causes very high exhaust gas temperatures. If too much of this exhaust gas is leftover in the cylinders for the next combustion cycle, knocking can occur. In addition, if you have a short 4-1 header or a log-style manifold you can suck exhaust gas into a cylinder before combustion as one cylinder can be on an intake stroke while another is on an exhaust stroke (see the upper image in Mazda’s diagram).

OEM Design Efficiency

The 4-2-1 has two benefits to fight this. First, the long length means the exhaust gas takes longer to traverse the pipes, so one cylinder sucking in another’s exhaust is drastically reduced. Second, the cylinders are paired correctly to one another (1 with 4 and 2 with 3). Since the firing order is 1-3-4-2, each secondary is receiving an exhaust pulse at a regular interval. If you paired 1 with 3 for example, you would receive two pulses quickly, and then a large gap as the other two cylinders fired. This helps with exhaust scavenging as the pulse from one cylinder helps “pull” the leftover exhaust from the cylinder it’s paired with. These benefits can also be present on a long tube 4-1 if designed well but, there is a good reason why Mazda did not choose this option.


2.5L Skyactiv-G
2.5L Skyactiv-G

Typically a well-designed 4-2-1 will make more power and torque in the midrange while a well-designed 4-1 will make more power way up at the top of the RPM range. Since normal driving does not involve being at the top of the RPM range all the time, it makes sense that Mazda went with the 4-2-1. We will likely do the same as we want to retain the low knock characteristics of the 4-2-1, high midrange power & torque, and because the SkyActive 2.5L is a fairly low revving engine.

OEM Exhaust Header 4-2-1 Design
OEM Exhaust Header 4-2-1 Design

It appears that Mazda also went with close to equal length runners. This means that each primary section is the same length and each secondary section is the same length. Having equal length runners ensures the exhaust pulses are arriving at the collector (or Y) at uniform intervals.

The easiest way to explain why this is a good thing is by visualizing the entrance ramp to a highway.  When cars entering the highway follow the “zipper” method for merging, the cars currently on the highway do not need to slow down. The highway and entrance ramp merge and flow in a smooth and consistent rate. However, if a surge of cars come down the entrance ramp to merge onto the highway you will get a back-up of cars on the entrance ramp and will disrupt the flow of cars on the highway.  If the cars are exhaust gases and the highway is the exhaust pipe, you can understand why equal length can help. Again, we will adopt this strategy with the CorkSport Race Header.

So far so good then, as Mazda has put a lot of thought into making a high-quality stock header. However, as usual, there are a few areas we can improve on. That’s coming in a later blog though so you’ll have to stay tuned for more details! Let us know if you have any questions or thoughts down below.

-Daniel @ CorkSport

80mm Gen3 Mazda3 Cat-Back Exhaust

CorkSport 80mm Exhaust Installed
CorkSport 80mm Exhaust Installed

4 years ago, we released the 60.5mm Exhaust kit for the 3rd Gen Mazda 3 (both in axle back and full cat back flavors). It’s certainly been a hit, but there have been a few of you longing for more noise. Today we are proud to announce the 80mm variant of our cat back exhaust for the 2014-2018 Mazda 3 Hatchback and Sedan! At this time, just the hatchback version is available, but we will have the Sedan version ready in just a few short months.

The Dirty Details

CorkSport 80mm Cat Back Exhaust Exhaust
CorkSport 80mm Exhaust Installed

Now I know what you’re thinking, an 80mm exhaust for Mazda 3 seems excessively large for a naturally aspirated car making less than 200whp. But, hear me out because I think you’ll like what’s coming.

80mm piping allows for some unique & louder tones its smaller little brother can’t offer, but it wasn’t as easy as just using the old design and making the pipes larger. We had to do quite a bit of resonator experimentation and NVH analysis to get to the finished result with as little drone as possible. I’ll be upfront with you guys though, this is loud. It’s a good loud with tons of fun noises, but if you’re looking for something subtler, then our 60.5mm cat back or axle back may be a better fit. We do a good job of capturing the audio for you though so you have a good understanding of what you’re getting. Be sure to check out the product video to hear it.

Listen Now!

The Beauty of the Design

For those wanting this more aggressive exhaust note, sound isn’t the only bonus. We thought about the appearance, and how we could take advantage of this time to tinker with the design. The 80mm does a nice job of not only filling the exhaust tunnel under the car, but the axle back portion is a bit more prominent when you catch a glance.

On the Hatchbacks, the exhaust tips got a nice size increase up to 100mm and they are slant cut to help follow the profile of the bumper. Sedans have also been upsized to 100mm tips, which were lowered slightly to ensure your bumper doesn’t melt with the large piping. This has the added bonus of making the tips a little more visible from the rear and side of the car. In both cases, the way the upsized exhaust accents the rear of the car provides an aftermarket look, that’s classy and somehow the way it always should have been from the factory.  

CorkSport 80mm Mazda 3 Cat Back Exhaust Installed on Hatchback
CorkSport 80mm Exhaust Installed

CorkSport Quality

As with every CorkSport exhaust, this new 80mm Mazda 3 Cat Back Exhaust variant is made from fully polished T-304 stainless steel for long-lasting corrosion resistance. All flanges, hangers, and resonators are precision TIG welded in place while all of the piping is made with smooth mandrel bends. Each resonator uses a direct flow-thru design to keep the drone down and the volume up without sacrificing power.

CorkSport 80mm Mazda 3 Exhaust Hanger
CorkSport 80mm Exhaust Hanger

Power Levels

Speaking of power, check out the dyno graph below. The upsize to 80mm showed similar power gains as the 60.5mm variant, so the extra size isn’t really needed at similar to stock power levels (aside from the great noise of course!). The only change in parts or tune between the two graphs was the exhaust. OEM exhaust (red) vs. CorkSport Mazda 3 80mm Exhaust (green).

CorkSport 80mm Exhaust Power Gains
+6.6HP!

We also believe it’s also very important to be prepared. Future proofing your car for mods down the road is always a great idea, and you’ve probably heard that we have a turbo kit (yes it’s still happening!) and race header in the works. More on those projects later, but I’ll let you put 2 & 2 together…

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