2004-2013 Mazda 3 and 2010-2013 Mazdaspeed 3 Aluminum Coolant Reservoir is back

2004-2013 Mazda 3 bolt in coolant reservoir

We’re happy to welcome another product we have resurrected from the dead: the CorkSport Aluminum Coolant Reservoir for 2004-2013 Mazda 3 and 2010-2013 Mazdaspeed 3. We also have one for the Gen 1 Mazaspeed coolant tank. Back and better than ever, we have completely redesigned the tank from the ground up. We ended up with a tank that performs just like OEM yet will stand up to the test of time and look a hell of a lot better while doing it!

2004-2013 Mazda 3 & Mazdaspeed 3 bolt in coolant reservoir

As the Mazdaspeed GEN1 and GEN2 get older, the OEM plastic tanks become more and more prone to failure. The constant changes in pressure and temperature, plus the chemicals in the coolant cause the plastic to weaken over time. The aluminum used for the CS coolant tank will hold up better over time, ridding you of the hassle of a leaky coolant tank. To ensure proper functionality, the CS coolant res includes internal baffling, just like OEM. The baffling keeps air bubbles from entering the cooling system under aggressive driving conditions and ensures your cooling system will be operating as intended, regardless of how you’re driving.

A replacement for the ugly plastic coolant tank for the 2010, 2011, 2012, and 2013 Mazdaspeed 3

The CorkSport Mazdaspeed coolant reservoir is designed specifically as a replacement for the OEM Mazda tank, which means no drilling, fabrication, or other modifications. The OEM coolant hoses even work perfectly with the CS tank. To check the coolant level in the CS res, since you obviously can’t see through the aluminum, we include a sight tube on the front of the tank that easily displays how much coolant is present. As an additional upgrade from OEM, we include a 1.5bar (~22psi) radiator cap for better protection against overheating. Plus, should you want even a higher pressure cap, it uses a typical radiator cap connection, so upgrading is easy. Finally, an overflow hose is included, which can easily be adapted to fit with a catch tank, should you need one when racing at a track.

Replacement for the OEM plastic coolant tank for the 2010-2013 Speed3

We haven’t yet touched on what is possibly the best part of the CorkSport coolant reservoir: appearance! With its simple design and sleek wrinkle black powder coat finish, it is a great fit in almost any engine bay. Let’s be honest, the OEM tanks look okay at best when brand new, yet within a few months, they become yellowed and ugly. The CS coolant tank is a great finishing touch for your Mazda’s engine bay. We even hid the mounting locations to provide you with the cleanest look!

2010-2013 Mazda 3 coolant tank upgrade

Each CorkSport Mazdaspeed Coolant Reservoir gets a lot of love before it heads out our doors. The tanks are first laser cut from 11 gauge aluminum and then precision formed before being TIG welded together. Each tank gets a cap, sight tube, and fittings which are all chosen specifically for use with pressure and automotive coolant so they will hold up over the years. Finally, once assembled, we pressure test every tank to ensure no leaks for your Mazda. All of this comes with the hardware needed for installation, color instructions, and CS support!

Mazda MPS3 coolant surge tank replacement

Be sure to check out the product listing for more pictures of the CS coolant reservoir. Give us a call if you want any additional info. We can’t wait to see you all get your hands on these tanks!

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The CorkSport CST4 – The Best Turbo for the Mazdaspeed 3/6

How to get 400whp from your Mazdaspeed 3

Back in 2015, CorkSport announced the launch of the “CorkSport Turbo” or “CorkSport 18G” a high-performance drop-in turbo upgrade for the MazdaSpeed 3, Mazdaspeed 6, and CX-7. Fast forward to 2020, this potent turbo is now called the CST4 with the introduction of the CorkSport CST5 and CST6 Turbochargers.

The CST4 has found home in thousands of community members Mazdaspeeds since launch and continues to be a highly sought-after upgrade today…a testament to the CST4’s performance and durability. Starting from scratch, the CST4 is a 100% brand-new performance unit.  No core, no revised K04 parts…this is a performance turbocharger from the ground up.  

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Best Mazdaspeed 3 Turbo bolt on 400whp

Let’s recap what makes the CST4 the best turbo and a great fit for the MazdaSpeed.  A proven MHI journal bearing center section, these offer great cooling capabilities and fantastic reliability, especially when combined with our high-performance journal bearings and 360° high-performance thrust bearing. The CST4 Mazdaspeed Turbo can seriously take a beating and does it in a package that fits perfectly in the OEM location.

Upgrade Your Turbo with the CST4
Mazdaspeed 3 Mitsubishi 18G CHRA

Attached to this center section is a compressor and turbine wheel combo that is a little unconventional. Creating boost is a custom MHI 18Gbillet compressor wheel that is rated at 50lb/min while the turbine that drives the CST4 Mazdaspeed Turbo is a MHI TD05H 9 blade design. Compared to a traditional 12-blade turbine wheel, the CorkSport design is lighter weight for faster spool times and has fewer blades for higher maximum flow capacity.

Best Mazdaspeed3 turbocharger high flow exhaust wheel

The wheels are wrapped in new housings. On the compressor side, there is an OEM diameter inlet to simplify the installation with any intake system you had setup with your K04 Turbo. The turbine housing maintains the stock flange design for easy fitment with any exhaust manifold and downpipe that is bolted to the K04. 

The best mazdaspeed 3 turbo upgrade internal or external wastegate, better than the BNR S3.

So what’s the hype now?  Great question!  The community has pushed this turbo to the limits and has asked for more…with the development of the 500whp CST5 and 600whp CST6, we found that an EWG turbine housing can be very beneficial to boost control.  That development bleeds over to the CST4 in the form of an EWG turbine housing for increased boost control and an increase in A/R size. 

Mazdaspeed 3 turbo upgrade dyno sheet

Like the CST5, you can now choose your boost control.  Internal wastegate for a stealth and simple install or go for the EWG turbine housing for extra noise and a little more top-end power potential.  The choice is now yours. 

Best Mazdaspeed 3 EWG bolt on turbo kit

Now what does all of this tech mean for you and your car? If you have a stock block you can easily max out power (~380WHP depending on fuel and bolt-ons) and keep some of the K04 Turbo spools you love.  With professional tuning, you can keep a safe tune that hits hard and carries power.

The wheel and housing options deliver great response as well as great power. When pushed to its limits on a built block, 20psi was hit at 3300-3400RPM with a peak boost around 27-28psi carried to 7000rpm. Obviously, this isn’t stable for a stock block but is possible on fully built cars with full bolt-ons and a high-flowing head.

Mazdaspeed 3 Turbocharger installation hardware

Both the IWG and EWG options come with a full hardware kit that includes everything you need for installation. This means all coolant/oil lines, new gaskets, new crush washers, and even new studs and crimps nuts for both the turbine and downpipe flanges. The EWG setup includes a custom-designed elbow for excellent EWG actuator fitment on MS3 and MS6, and the correct clamp to attach it to the housing. More info to come later on an add-on screamer pipe option.

Best Bolt on Mazdaspeed 3 turbo EWG dump tube kit

Each Mazdaspeed CST4 Turbo comes with full CorkSport support, including full-color install instructions, a 1-year warranty, and assistance with any questions you may have. We are extremely excited for you all to get your hands on the CST4 and start taking your FBO Mazdaspeed to the next level.  Check out the product listing for full details and to place to order.

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For A limited time get $125 off the CST4. Enjoy a more boost and increase your Mazda WHP up to 400!

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Zach’s Road to CorkSport

The Journey to CorkSport

Ever wonder what it was like to win the lottery. You ever let your mind wander and think what it would be like to actually “Live the dream.” I know I have, well, until I joined CorkSport! My name is Zach Sprague, and I wanted to share with you my experience of joining, what I believe to be, the best well known and respected company in the Mazda Community. Let’s take a look at my journey.

I’ve always been into cars and have had a pretty big obsession with FWD Hatchbacks. My passion for this platform started back in 2014. I sold cars for Toyota in Southwest Washington for about four years. During my tenure, I drove some pretty amazing vehicles, one of them being a 2013 VRM MS3 Tech pack. I knew what a Mazdaspeed was, a Turbo FWD Hatchback, and at that time that was more than enough to pique my interest in the platform. It was temporarily sitting on my lot, and I had to drive it back down to Portland to our sister store.

Before jumping into the seat, I didn’t know any horsepower or torque figures. I didn’t know what kind of emotion it was going to spark when I drove it. I had NO idea that it would become the screen saver on my computer. I slid in and pushed the button. (You know those Cold Starts) This Mazdaspeed’s exhaust made my heart drop and gave me goosebumps. I honestly felt like an 8-year-old on Christmas Morning. 

Once on the ramp, I slowly shift into third at about three and a half grand on the tach and just sent it. Torque steer was prevalent as I was gently pushed back into my seat. I slammed 4th, and I hear this intoxicating PSSHHHHHH from the short ram intake. I was done, I was hooked, addicted and didn’t know what to do with myself. I was so intrigued I stopped at every rest stop on the way down so that I could feel this car accelerate back onto the freeway. <insert uncontrolled giggling here>.

Flash forward a couple of years, and a guy I worked with, now one of my best friends, went out and bought a VRM Mazdaspeed6. Everything on that car from top to bottom was stock down to the wheels. I slowly watched his build progress over the year and transform into one of the most inspiring builds I have ever seen. In that time he was kind enough to let me pick his brain about these cars and what they like, what they don’t like.

In 2018 this is when things got interesting! After a few months of looking and 100 YouTube videos later, I was finally ready to pull the trigger on one of my bucket list cars. I snagged a 2013 MazdaSpeed3 in liquid Silver. I drove almost 4 hours and paid an arm and a leg for sales tax, but it was worth it.

Mazdaspeed 3 2013

Miles of Smiles 

I was grinning ear to ear the entire way home; 4th gear dumps on the freeway, testing the grip of the tires out at a few stoplights, full-on shenanigans. I tell you what; I made it home a lot quicker than the drive up.  

I had the car for 3 weeks before I added my first mod. I already had a vision for the car, but first things first, I had to take care of those sloppy shifts. My shifter bushings and short shift plate showed up from CorkSport. At that time I knew they made great parts and were one of the very few places that even made parts for this car. What a difference that made! It felt robust and more responsive.

The Opportunity of a Lifetime

I always joked with my friends about working for a company like CorkSport. I just thought it was this elusive dream that I’d be sitting behind a desk helping other people build their dream cars. I never thought in my life that an opportunity like this would come into fruition. 

My buddy, who helped me get into Mazdaspeeds, sent me a message on FB, letting me know that CS was hiring. I thought to myself; this is no lie. “There is no way on god’s green earth I’d ever get that lucky.” However, I applied. What’s the worst thing that could happen, right? 

CorkSport isn’t a revolving door, and the team is made up of a close-knit group of professionals that also happen to be car nuts. They carefully consider who’s going to be a good fit with their existing team and identify candidates that are going to get the right shit done well. I knew this was a different company, and their standards were high because they didn’t just accept my resume; there was a pre-test.  

A funny little story. I got a message from CorkSport saying they wanted to set up a phone interview! I couldn’t believe it! That Friday, I called to set up a meeting for Monday. This is where the humor known as my life kicked in; I BROKE MY PHONE ON SUNDAY! *RED ALERT* My dream job was calling me on Monday, and I didn’t have a phone, so I went out and bought a little prepaid flip phone. 

Although I almost missed this opportunity, it went well enough for CorkSport to schedule a second interview over Skype. I must add, this occurred over two weeks. I was losing my mind; I couldn’t believe it was happening. All my buddies knew I had the job, they knew how obsessed I am with cars, especially my Mazdaspeed 3. I still was in shock couldn’t believe I had my second interview.

When CorkSport called me to let me know, I had a final interview with the Company’s President, Corey – Hello nervousness, glad to see you again! I can’t put into words how excited I was; it was pure bliss and absolute disbelief. “IS THIS REALLY HAPPENING!” I screamed at the top of my lungs when I got off the phone. I showed up a half-hour early. It was cool; I got to meet someone I’ve stalked on Instagram for a while and who has been a significant influence on me since I got into the Mazda community – Brett White.

It’s so surreal when you get an interview for a job you’ve always wanted. Above all, I remember from the interview is telling Corey, “Even if I don’t get the job, knowing I made it this far and am sitting here with you having this interview is honestly a dream come true.” It’s unreal to think that one mistake, such as breaking my phone the day before my first interview, could have kept me from writing this blog for a company I’ve looked up to since I’ve been into Mazda’s.

I cannot believe I’ve been here a little over a year already! It’s a fun environment where everyone is looking out for one another. I’ve been able to FLY in the fastest thing I’ve ever been in (Barett’s monster Gen Juan), and had the chance to drive a car I’ve drooled over on social media (Brett’s Baby) for years. 

Barett Mazdaspeed 3
Barett’s monster Gen Juan

Looking back, it wasn’t even four days after joining the company before the guys a CS put lowering springs on my car. It took a little over a week for me to buy an AccessPort and a Dual VTA Bypass Valve, and that was just the start! You don’t want to be an employee driving a stock Speed with a CorkSport Sticker on it.

Stay tuned to see where CorkSport and I go with my car. I’ll catch you on the flipside and, thanks for reading my first blog!

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Mazdaspeed EWGs Made Easy!

We’ve talked a lot about external wastegates with our recent CST6 development but today we are happy to announce the standalone CorkSport External Wastegate Housings for the CST4 and CST5. Available right now as an update for your existing IWG CST4 or CST5, the CS EWG housings make it easy to get the best in boost control for your Mazdaspeed 3, Mazdaspeed 6, or Mazda CX-7 Turbo.

Bolton upgrade to go external wastegate with your Mazdaspeed

While the CST6 will only come with an EWG housing, the external wastegate (EWG for short) is a new concept for the CST4 and CST5. Both of these turbos originally hit the market with an internal wastegate (IWG) only option that has a small flapper valve on the inside of the turbine housing to let off excess exhaust gases. Instead, the CorkSport EWG housings use an offshoot from the turbine scroll that has a v-band flange on the end. This flange allows for the fitment of an external wastegate for improved boost control. To run an EWG on an original CST4 or CST5 previously, you needed an EWG capable exhaust manifold and some sort of block off for the IWG port.


Mazdaspeed 3 turbo internal and external wastegate housings

The new CS EWG housings make running an EWG on your Mazdaspeed3 easier than ever. Each housing comes with the elbow and clamp needed for great fitment. We even offer a dump tube/screamer pipe that works for both MS3 and MS6 as an add-on option. If you pick up the screamer pipe to go with your housing, all you need to supply is the EWG itself. 

Mazdaspeed external wastegate installation kit includes everything but the Tial wastegate

We strongly recommend a Tial MV-R 44mm wastegate as all design work and testing used this specific wastegate. Other wastegates may require modification for use. The 44mm size is a great fit for the Mazdaspeed engines, whether you are running an upgraded turbo on the stock block or fully built one that you intend to push to the limits.


Tial wastegates are a proven turbo commodity for the Mazdaspeed 3

So why would you want an EWG? For starters, EWGs truly offer the best boost control setup for any turbocharged car. Because the wastegate is separate from the turbocharger itself, it is easier to place for optimum boost control, plus, the design of the actuator itself can be optimized. As a result you get a wastegate that hits boost targets more accurately and responds quicker to changes in boost. This means no more boost spikes right when the boost hits (a common problem with poor quality IWG setups), and a near-flat boost curve. The isolated actuator also makes for faster and easier spring changes should you need to service or change your wastegate preload. For more info on the design behind the CS EWG housing, check out the full blog HERE.

A direct flow path for the exhaust gas on the Mazdaspeed 3

One of the best parts of EWG over IWG is the sounds that come with a screamer pipe! While only intended for off-road use, a screamer pipe dumps the exhaust from the EWG directly to the air. This allows for a fantastic noise during a WOT pull, that sounds truly unique. It’s not all just noise though, by venting the EWG to the atmosphere instead of venting the IWG in your downpipe, you are decreasing exhaust turbulence right after the turbine wheel, reducing backpressure. On very high horsepower setups, this often generates some extra power as the turbine housing can be used more efficiently. Check out the product video below for some great EWG sounds from Barett’s MS3.

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There’s one final benefit of the CS EWG housings: housing design itself. Without having the IWG in the way to worry about, we were able to do some optimizing on the scroll and A/R. For CST4 owners, this means an increase in A/R from 0.66 to 0.82. Typically an A/R change like this will cause a slight decrease in spool time but an increase in max power potential. CST5 owners have this 0.82 A/R even with the IWG setup but there’s another benefit: greater swallowing capacity. This refers to the amount of volume in the turbine scroll. By increasing the swallowing capacity the turbine can ingest air more efficiently at the peak, which is especially important if you have an upgraded exhaust manifold or high flowing head. After all, an engine is an air pump – what good is shoving more air in if you can’t get it out?

Easy bolt up external wastegate upgrade for your Mazdaspeed 3

If you’re in the market for a change on your Mazdaspeed, check out the CorkSport EWG housings for the CST4 and CST5 turbochargers. Better boost control, a more efficient housing, and best of all, a great new sound. Be sure to check out the listing for even more images and don’t be shy to ask questions we’ll be happy to help!

CST5 Mazdaspeed Turbo Spools!! Testing and Validation

We’re back on the new CorkSport turbocharger lineup again with today’s blog, this time focusing on the testing & validation of the “medium big” turbo, the CST5. Just in case you missed it, the CST4 (formerly known as the CorkSport 18G) is getting some company to go along with its new swanky name. Check out the full lineup here and the design behind the CST5 here. Now that you’ve read all that, let’s get into what you’re really here for, testing & dyno numbers.

Mazdaspeed turbo CST5 Replacement for K04 Turbo

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We started with the internal wastegate option, to validate the CST5 for drop-in fitment. Since we’ve had a great experience with the drop-in CST4, we knew how to design a turbo around the tight confines of the Mazdaspeed engine bay. The CST5 Mazdaspeed Turbo fits great in the OEM location with just a few minor revisions for proper fitment. It looks pretty good in there too if we do say so ourselves!

Mazdaspeed turbo installed with the CST5

Next the car got put on the dyno for tuning and to push the new CST5 to its limits. With a little help from our friend Will at PD Tuning, the CST5 was soon putting down some impressive numbers. We started off with a “calm” boost level of ~25psi. This netted us 450WHP and spool time which surprised us, achieving 20psi by 3500-3600RPM. Turning up the boost and pushing the turbo to its limits, we achieved 519WHP at ~30-31psi on Barett’s built GEN1 MS3. Check out the dyno graph below.

Dynograph of CST5

Taking the car out on the street surprised us further at just how early the car was building boost for this size of turbo. Road logs showed that we were making 20psi slightly sooner than on the dyno (3400-3500RPM) but even more surprisingly the CST5 was making 30psi by 3700-3800RPM! Obviously, this is an aggressive tune that would most likely kill a stock block, but, the CST5 Turbo can be tuned to be stock block friendly and still make good power.

Best Mazdaspeed turbo for K04 Replacement

Then came the testing on the EWG variant of the CST5. We had developed a fitment for the CST6 which meant the CST5 had no issues upon install on both Mazdaspeed 3 and Mazdaspeed 6. Next was a quick retune and some power runs. The larger swallowing capacity of the EWG housing meant some extra power at peak, yet spool was nearly unchanged. We made 525WHP at the same ~30-31psi.

Mazdaspeed turbo 500+ whp dynograph

Comparing the IWG and EWG turbine housings you can see a small variation in the graphs.  This variation is mainly due to the change from internally waste-gated and externally waste-gated.  The EWG setup provides more precise boost control through the RPM range. The EWG setup allows us to better tune the “torque spike” around 4200rpm vs the IWG setup.  For peak power the IWG and EWG housings are within the margin of error which makes since because they are both 0.82 A/R housings.

Further supporting the IWG and EWG setups, both options allow you to tune the spring pressure so you can better setup your CST5 Turbo and Speed for the fuel and boost levels you want and of course the most noticeable difference is what you hear. What’s an EWG without a screamer pipe!  

500+ WHP Madaspeed Turbo Dynograph

Wrapping up testing showed exactly what we were hoping for with the CST5: a great middle ground between the existing CST4 Turbo and the upcoming CST6 Turbo that can be used on both high-powered stock block and fully built cars. Our testing continues as this blog is written as the CST5 is being beta tested by a close friend of CS with a freshly built Dankai 2.

There’s more to come from the new CorkSport turbo lineup so stay tuned for more info on the CST5, CST6, and EWG housings.

-Daniel @ CorkSport

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