A Better Design for the Mazda 3 Turbo Upgrade – Housing Design

2024 looks to be freaking fantastic for the Mazda 3 Turbo performance enthusiast, and here’s why.  CorkSport has been diligently developing a Drop-in Performance Turbo Upgrade for the SkyActiv-G 2.5L Turbo engine alongside the dozens of Mazda 3 performance parts we have released to the community.  

With recent rumblings of a reworked OEM turbo option circulating through social media, we thought it was time to officially share the R&D we have been quietly working on.

Best Mazda 3 Turbo Upgrade replacement turbo design by CorkSport

As you can see, we have a 100% complete and new design in the 3D CAD model above. We are developing a performance turbo upgrade from scratch with larger and performance-optimized housings, CHRA, and wheels, all designed to work together. 

Choosing this design path takes a lot more time, effort, and money to create a finished product. Despite the increased resource requirements, this is what it takes to develop an efficient and reliable performance drop-in turbo for the Mazda community. Now, let’s apply some context to that statement.

Back in 2018, we wrote a couple of blogs dissecting the OEM turbo found on the Mazda 6 2.5T.  At that time the Mazda 3 did not have a turbo option yet.  

Read the posts

We inspected the housings, wheels, CHRA, and Mazda’s “Dynamic Pressure” system. We quickly realized that the OEM turbo would be a HUGE limitation on the Mazda Turbo engine’s performance – even once tuning was fully available. Fast forward to the announcement of the Mazda 3 Turbo option, and we got to work on an improved turbo design.

Best CorkSport Mazda 3 Turbo Upgrade with Larger Turbine

Hybrid Compressor Wheel (left) 50.4mm Inducer & 63.3mm Exducer with extended tip vs OEM ~43mm Inducer & ~56mm Exducer

OEM Mazda 3 Turbo extruder and inducer

Hybrid Turbine Wheel (left) 50.2mm Inducer & 45.5mm Exducer vs OEM ~47mm Inducer & ~41mm Exducer

The Issues of a Hybrid Turbo

One of the first steps we took was building a “hybrid” OEM turbo to see how that would perform vs the OEM turbo.  A hybrid turbo means an OEM turbo that has been modified to use larger than OEM wheels.  Above you can see the larger compressor and turbine wheels next to the OEM wheels. 

Our testing showed some potential with a “hybrid” setup turbo, but there were still limitations to the power potential.  We saw a bit slower spool and a bit more mid-range power potential, but top-end power was still struggling to hold.  Granted this was very early in the tuning developments for the platform. 

A major concern we had was around the hybrid turbo, was the reliability and further cracking of the OEM housing once it was modified for the larger wheels.  The OEM turbine housing is very small, specifically the turbine scroll which is the most critical part of the turbine housing.  The OEM housing just didn’t have a lot of extra material to work with (remove) to safely accommodate a larger turbine wheel. 

Mazda 3 Turbo Inlet Housing reliability

Check out this image of the turbine housing after it was machined to accept the larger turbine wheel.  The thin edge marked by the blue arrows is very thin due to removing so much material.  This area of the turbine funnels the exhaust gases into the turbine wheel inducer and directly affects the efficiency of the wheel.  Had we machined any more material for a larger wheel, we would have started to affect how the exhaust gases enter the turbine wheel.  

OEM Mazda 3 Turbo housing crack for inlet pipe

In the image above, the inlet divider inside the turbine housing is cracking. In the image below, an internal portion of the scroll is cracking as seen through the wastegate port. 

OEM Mazda 3 Turbo Housing Crack for the wastegate port

We’ve already seen OEM housings cracking from normal use, so the idea of thinning the turbine housing in critical areas did not seem like the right approach for a performance turbo upgrade.

A hybrid turbo may have a place in the performance aftermarket and it may have some performance benefits (if the housing is up to the task), but if we are going to stand behind the product; we are going to develop it from the ground up to proactively eliminate reliability concerns.

So that’s exactly what we are doing!

Our Development Expertise

Leaning on our development expertise with the CST Turbo line for the Mazdaspeed platform, we are designing a new turbo from scratch for the Mazda 3 Turbo and other models that share the same engine. 

2021+ Mazda 3 turbo performance-turbo upgrade CAD

Starting from the ground up gives us the ability to optimize the turbo for performance applications.  Like the Mazdaspeed CST Turbo line, we can directly control the size of the housings, CHRA, wheels, wastegate, material thickness, and material type.  

Designing the Mazda 3 Turbo

Now let’s dive into the design of the housings for the upcoming Mazda 3 Turbo upgrade. Starting with the compressor housing; A LOT is going on with the compressor housing design.  We call this a feature-rich part and you can see why below. 

Mazda 3 Turbo Compressor Front Face design

The OEM compressor housing (right) has a handful of integrated features: the obvious compressor inlet and outlets, the electronic wastegate mounting, the electronic bypass valve, and the EVAP/Breather port.  When designing a performance drop-in turbo, our goal is to retain all these OEM features so that installation and use are very simple and easy. 

Alongside the OEM features are the changes we have made to increase performance potential which includes a slightly larger scroll A/R of 0.60.  Note: This even exceeds our CST Turbos and has been proven to be responsive and support a flow of 700whp.  

Mazda 3 Turbo and CX-30 Turbo Upgrade Model

Here you can see the blue lines showing the larger compressor scroll.  CorkSport is on the left and OEM is on the right. Increasing the size of the scroll A/R helps improve the compressor wheel efficiency and max flow capacity.  Along with a larger scroll, we have also designed the housing to have either a stock-size inlet or a 3.5” anti-surge inlet for the larger turbo option.  

Yup…there’s going to be more than one size available. More on that later…

To do this we have to move some things around, but don’t you worry every part of this development is verified on a car with 3D printed prototypes and then functional prototypes.  This is a critical part of the development to make sure everything fits like OEM but punches like the hot hatch we all asked Mazda for.  

Test Fitment for the Best Turbo for 2021+ Mazda 3 Turbo upgrade

A Larger Responsive Turbo

Now let’s check out the party side of the turbo…the turbine housing. In my personal opinion, turbines make power and compressors just support the required flow.  So what are we doing on the turbine side of things to make more power? 

Several changes have been applied on the turbine side to increase performance and reliability.  Here are the CorkSport (left) and OEM (right) turbine housings next to each other.  

CorkSprot Masda 3 Turbo Drop-in Turbo Upgrade Design

Our goal is to develop a turbo that is fun, responsive, and carries power like you would expect.  Referencing the blue lines you can see a drastic difference in the size of the turbine housing scroll.  While the CS design is a large increase in size over OEM, it is not “bigger” than a typical aftermarket generic fitment turbo – highlighting just how tiny and limiting the OEM turbine housing really is. 

Now let’s take a look inside the housing so you can understand what is changing. 

2021 Mazda 3 drop in turbo CorkSport cutaway design

An Improved Design

Both turbines (CS & OEM) are single scroll designs, but you will notice two major differences.  

Firstly, the spiral section of the CS design is drastically larger than OEM; this is the true “scroll” of the housing and thus the section of the housing that funnels the exhaust gas into the turbine wheel.  We changed two aspects of the scroll design: 

  1. The “swallowing capacity” of the scroll has been increased so that the peak flow capacity of the turbine is much greater than OEM. This is the cross-sectional area at the beginning of the scroll shown by the blue arrow. 
  2. The scroll A/R (Area/Radius) has been increased from 0.53 to 0.71.  This ratio number affects how “quickly” the exhaust gas is forced into the turbine wheel.  The smaller ratio is a faster spool but poor top-end power and a larger is slower spool but more top-end power.  The goal here is to find the right balance of spool/response and top-end power.  

Second, you may have noticed the CS turbo is missing the red blocky section that the OEM turbo has.  It’s missing for good reason. 

Mazda 6 Turbo AWD Example

In the above image, you can see the OEM turbo with the turbo on the right and the dynamic pressure valve on the left.  Mazda uses this control valve to help spool the turbo below 2000 RPM and it seems to do the job, but it has cracking issues from what we’ve seen and is going to be a huge flow restriction on higher power setups. 

We are getting rid of it!

Mazda 3 turbo upgrade without the dynamic valve

The Pursuit of Reliable Performance

In the pursuit of performance and reliability, the dynamic valve and its housing had to go.  Like the OEM turbine housing, we’ve seen cracks forming in the dynamic valve housings so we know they are a reliability issues and Mazda knows as well. 

Mazda is also getting rid of the dynamic valve system…the CX50 Turbo has a much simpler twin-scroll turbo design with no dynamic valve and I assume that change will find its way into all 2.5T models sooner, rather than later. 

Mazda 3 Dynamic Valve Housing Prototype for 2021+ Mazda 3 Turbo

To keep things as simple as possible for you, the enthusiast, the CorkSport-designed turbine housing mounts directly to the cylinder head and still takes advantage of Mazda’s trick 4-3-1 exhaust port design.  Along with that change, the OEM EGR port is retained and new heat shields will be part of the kit.  

That covers the housings for the upcoming CorkSport Drop-In Turbo Upgrade for the Mazda 3 Turbo.  We are excited about this project and even more excited to bring this to the community.  Who doesn’t love boost right? 

Expect to hear more as we roll further into 2024 and until then enjoy these teaser shots of the raw castings. 

2021+ Mazda 3 Turbo Compressor Housing
CorkSport Mazda 3 Turbo Turbine Housing Prototype

-Barett @ CS

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The All New CorkSport 2019+ Mazda 3 Sedan Lip Spoiler

It’s time to liven up your 4th GEN Mazda 3 Sedan with the new CorkSport Performance Lip Spoiler for 2019+ Mazda 3 Sedan and 2021+ Mazda3 Turbo Sedan. While Mazda did a good job creating classy styling for the newest 3, we find it to be a little boring, especially when on lowering springs and a nice set of wheels. The CS spoiler offers a much more aggressive trunk lip than the small OEM Mazda unit, without detracting from the great OEM styling. Its features incorporate the original Mazda body lines to stand out without being obnoxious. Keep on reading for full info and pictures!

Forged Carbon Fiber Spoiler 2019+ Mazda 3

A Stylish Spoiler For The Mazda 3

Like its hatchback counterpart, the CorkSport sedan spoiler offers an “OEM+” look. We took the body lines and design cues of the Mazda 3 and adapted them into a more aggressive spoiler than is offered by Mazda. It extends and raises the rear edge of the trunk to finish off the vehicle’s rear better. The CS spoiler also carries over the tops of the rear quarter panels and ties into the main body line. The rear face of the spoiler follows the taillights before moving upward at the same angle as the end of the lights for extra detail. Finally, the spoiler’s top and rear faces are concave for a bit of a “duckbill” type of look. These features combine to ensure the CS spoiler looks at home on a 4th GEN sedan and will make you wonder why Mazda did not have something similar from the factory.

2019+ Mazda 3 Trunk Lip Sedan Spoiler profile view

The Best Spoiler Fitment for The Mazda 3

Fitment was as important as styling, so the design began with a 3D scan of the trunk and rear quarter panel area. This scan was used as the base for the entire design that was completed in CAD software. After many test fits and iterations for best fitment, we were left with a final design that matches the OEM curves very well and can be installed with no drilling or trimming.

2019+ Mazda 3 Trunk Lip Spoiler Twill Carbon Fiber

Carbon Fiber & Fiberglass Options

After the fantastic response we received on our material choices for the 4th GEN Mazda hatchback spoiler, we knew we had to do the same thing for the 4th GEN 3 sedan. Each CS trunk lip is made from a fiberglass foundation before being topped with your choice of 3 materials. Full fiberglass, woven carbon fiber, and forged carbon fiber are all available. The two carbon options are finished off in a UV-resistant glossy clear coat with a mirror-like finish. The regular fiberglass will come in a satin black finish that is ready for light sanding and a finish coat of paint or wrap. Each material has the same shape, but you can personalize the look to match your build and budget.

Rear view of Forged Carbon Fiber for the 4th Gen Mazda 3

Easy to Install

Installation of the CorkSport Mazda3 trunk spoiler could not be any easier. It is attached with included 3M VHB tape for a simple and secure fit with NO DRILLING. If you have the OEM Mazda lip spoiler, installation is a little more difficult as you have to remove it to install the CS, but we include covers for the holes that are no longer used with the CorkSport spoiler. Full-color installation instructions are also available so you can transform the rear of your sedan in as little as 30 minutes!

2019+ Mazda 3 Sedan Forged Carbon Fiber Spoiler

If you want to add the CorkSport 2019+ Mazda 3 Sedan Spoiler to your ride, head to the product page for even more pictures and angles. Feel free to reach out with any questions; we are glad to help!

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Best Mazda 3 Cat Back Exhaust System for the 4th Gen

Check out the the Best CorkSport Mazda 3 Cat Back Exhaust for 4th Gen models (2019-2024)! Building upon the already great CS Axle Back exhaust, the Mazda 3 CBE replaces the entire OEM exhaust system from the header back with high flowing 63.5mm piping and flow-thru resonators. This adds an aggressive sound that is great for tearing up the backroad, yet is still comfortable for cruising on the daily commute. Read on for more details and be sure to listen to the sound clips below.

Installed 2019+ Mazda 3 Cat Back Exhaust System

The Mazda 3 Cat Back Design

The primary focus of the CorkSport cat back is to add a great sound that spices up your new Mazda 3. The restrictive OEM axle back exhaust is replaced with the unique CS Mazda 3 Axle Back Exhaust. The large resonator eliminates the drone fantastically, while the asymmetrical design offers a great tone and interesting exhaust notes. Moving to the front, the OEM, mid pipes are replaced with full 63.5mm (2.5”) mandrel bent piping that incorporates a large oval-shaped resonator. This resonator was chosen for its ability to eliminate any drone and undesirable sounds while retaining a straight-thru design to remove any exhaust restriction. The result is a sound that is louder and more aggressive than the CorkSport axle back alone, without being annoying or bothersome on long drives.

CorkSport 2019-2024 Mazda 3 Cat Back Exhaust System

Cat Back Improves Performance

Dyno for Mazda 3 Cat Back Exhaust netting wHP

The increase in volume also comes with an increase in horsepower. The axle back alone was able to net 3-5WHP across the RPM range. In our testing, the Mazda 3 Short Ram Intake was installed with both the OEM and CorkSport Cat Back Exhaust. With the removal of the restrictive OEM mid pipe and mid pipe resonators, the CBE netted us approximately 20wTQ and 10-18wHP in our testing!

Easy Installation

Best Mazda 3 Cat Back Exhaust system with mid pipe visible

While both improvements in power and sound are great, they mean nothing if it’s a pain to install. Don’t worry though, the CorkSport cat back exhaust installs just like the OEM exhaust. We used both a FWD and AWD exhaust system during our development to ensure correct fitment for whichever drivetrain you have. While the pipe routing of the CS mid pipes are slightly different for the different drivetrain options, the resonators setup is exactly the same, so you can be confident that both AWD and FWD Mazda 3’s sound fantastic.

4 Gen Mazda 3 2019-2024 Cat Back Exhaust installed

If you have a Mazda 3 with Cylinder Deactivation, this is not an issue with the CorkSport CBE. We include a bracket made from 304 stainless steel, which holds the cylinder deactivation motor securely up and out of the way. The purpose behind this bracket is so that no check engine lights are set off by having it disconnected and also to get rid of the extra complexity and restriction of having a valve in the exhaust. 

Cat Back Provides Best Mazda 3 Fitment

Mazda 3 Cat Back Exhaust tip sizes

Like the CorkSport Axle Back exhaust, the CS cat back exhaust system has a variety of tip options to best suit your vehicle setup. We have different tip fitments for hatchback, hatchback with the OEM Mazda aero kit and sedan. The sedan tip option is the longest in order to fit the longer rear end of the sedan models.

We specifically designed two different length tips for the Mazda 3 Hatchback due to the design of the Mazda Appearance Package. The rear bumper skirt adds a lot of length to the car…hiding the tips from view. With the Appearance Package-specific design, the tips are prominent in the rear bumper skirt as they should be. (The Hatchback Appearance Package tips are 45mm longer than standard Hatchback tips).

Each setup uses a different length to ensure great fitment no matter your car. All tip options use a 90mm tip diameter to help fill out the bumper cutouts. Plus, each tip is finished off with a laser-engraved CorkSport logo plate to give a great look.

Cat Back Exhaust’s Quality Finishes

Mazda 3 Cat Back Exhaust showing Mandrel Bent Stainless Steel

As with all CorkSport exhausts, the GEN4 Mazda 3 cat back exhaust is made from fully polished, mandrel bent, 304 stainless steel. This offers a fantastic look and smooth flow, with corrosion resistance to stand up to the test of time. Every exhaust is fully TIG welded and for further strength, each hanger location has extra reinforcement to keep your exhaust secure. The CorkSport CBE also comes with all the hardware and gaskets you need to make your installation a breeze!

2019 Mazda 3 with Cat Back Exhaust Installed

That about does it for details on the CorkSport Best 2019+ Mazda 3 Cat Back Exhaust! We strongly recommend you check out the video for sound clips, you’re going to love it! Give us a call for any questions and submit a product request at this LINK for any and all products you want us to investigate for future mods for your Mazda!

P.S.  Already have the Mazda 3 Axle Back Exhaust and want to upgrade to the full Cat Back Exhaust? Check out the Mazda 3 Mid Pipe Kit to complete your exhaust system!

P.P.S.S  Have a turbo model and want to know if the exhaust fits? Good news! The CS CBE does fit but, we have a larger cat back exhaust designed specifically for turbo models, to ensure plenty of exhaust flow for future power upgrades!

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Improve Handling for Your 4th Gen Mazda 3 Hatch with the Rear Hatch Brace 

Looking to elevate the handling of your Gen 4 Mazda 3 Hatch to new levels? If that is the case then you may be interested in the new CorkSport Rear Hatch Brace. The 4th GEN Mazda 3 Rear Hatch Brace (aka Rear Strut Brace) is designed for any 2019+ Mazda 3 Hatchback Turbo & non-Turbo model and is a must-have for those wanting to improve chassis stiffness. If you already have CorkSport’s Front Tower Bar, Rear Motor Mount, or Rear Sway Bar installed, this will be the perfect complement for your 2019+ Mazda 3 Hatchback.

We actually introduced this back in April 2023 with a Tech Blog that you can check out here.  Now here is the final product!

2021 Mazda 3 turbo chassis brace

The Need For A Rear Hatch Brace

First, let’s start by addressing why the CS Mazda 3 Rear Hatch Brace is only available for the hatch and not the sedan as well. One of the main benefits of a hatch is that you get ~50% more cargo area than what the sedan offers. This makes it very practical for day-to-day use and road trips but does come with some tradeoffs. The one that is most relevant to us as car enthusiasts is the removal of the support structure that is behind the rear seats. This support structure helps the chassis to better resist flexing and twisting. Since this support structure is missing in the hatch, it results in lower performance when comparing chassis rigidity. This is where the CorkSport Rear Hatch Brace comes into play and leads to an increase in the torsional rigidity of your Mazda 3 hatch, so you get even better handling characteristics 

The Mazda 3 Rear Hatch Brace Has 2 Configurations

Mazda 3 hatchback rear reinforcement bar

Available in two configurations, you can choose just how aggressive of a setup you want. Even if you start with the Stage 1, you can always upgrade to the Stage 2 down the road and carry over the parts you already have. Below we’ll get into more specifics of why you should consider picking up the CorkSport Rear Hatch Brace for your Mazda 3 Hatch.    

Stage 1 – Single Top Cross-Bar

Mazda 3 rear brace stage 2

Stage 2 – Top Cross-bar with Triangulate Lower Bars & Lower Mount

Full Rear Hatch Brace Installed

The Components of the RHB

The CorkSport RHB is made up of two main types of components, the first being the brackets and the other the cross bar/s. The brackets are made out of 3/16in thick carbon steel so the cross bars have a rock-solid base to mount to. The cross bars on the other hand are made from 0.083in wall rectangular carbon steel tubing to provide a strong connection between the brackets. Both brackets and the crossbar get powder coated in textured black to provide a look that will blend in with the interior to give you an OEM look and feel.   

Mazda 3 Hatchback Rear Brace with CorkSport logo and hex bolts

Functional and Stylish Hardware

Connecting everything is stainless steel hardware, but not just your boring hex head bolts.  Being a centerpiece of your hatchback, we wanted the hardware to not just be functional, but look great.  To do that we used countersink head screws with conical washers to give a clean and purposeful look to the CS Rear Hatch Brace and your Mazda 3 Turbo.  

Rear Hatch Brace hardware for the Mazda 3 Turbo

Thanks for checking out the CorkSport Rear Hatch Brace for the 4th Gen Mazda 3 hatchback! If you want to add this mod to your Mazda and get all the benefits discussed above, be sure to head over to the product page for more details.   

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Race Better with the Mazda 3 Transmission Gears Upgrade

Racing is brutal! When pushing a vehicle to the razor’s edge, you tend to find the platform’s limitations rather quickly – then set out to overcome them! This is precisely where the CorkSport 3rd & 4th Upgrade Gears come in. 

 Mazda 3 manual transmission gear upgrade

In the years of racing our Touring Car class Mazda 3, we found many pitfalls that have been easy to overcome. However, we found the gears’ limit with the 317whp/355wtq of the CorkSport Turbo Kit pumping through the manual transmission. Pair that with a limited-slip differential and wide sticky racing tires…well, it’s shocking the drivetrain has held up as well as it has.

Mazda 3 TC Racecar performance parts

Destroying a transmission during a race weekend was not a viable path to success, so we developed our own race-quality CorkSport High Strength Gears to solve the problem. As you might imagine, this posed some significant challenges. For example, to retain the 6-speed setup, we had to stick with the same gear widths – which are very narrow.

Mazda 3 performance upgraded gears manual transmission

To gain the strength and durability needed, we opted to use a higher strength material; SAE9310 steel, and to further increase the durability, the surfaces are shot peened. The shot peening process helps durability by reducing the chances for stress cracks to develop, increasing fatigue life and bending strength.

mazda 3 racing full send with gears

Since then, we have been running these gears in our TC Racing Car for a complete season to validate that there are, in fact, better than OEM. Racing is the ultimate test for performance parts, and we are happy to report the transmission has caught every shift!

So why might you need these upgrade gears?  Do you have a turbo or supercharger kit on your manual Mazda 3 or Mazda 6?  Do you like driving your car hard and even doing some structured racing events? If yes, these may be in your future, so you can push your Mazda to the limits without worrying.

Thanks for tuning in!

Barett @ CS

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