Best Mazdaspeed Turbo Upgrades – Choose Your Boost

May of 2015, CorkSport launched its first high-performance drop-in turbocharger for the Mazdaspeed platform.  Fast-forward almost 4 years and CorkSport again is about to redefine what a stock flange turbocharger for the Mazdaspeed platform can indeed be.

The Best 400 WHP for the Mazdaspeed  

The original “CS Turbo” is now the CST4 Mazdaspeed Turbo to follow the turbo line-up. It is the best turbo used to upgrade the OEM K04 Mazdaspeed Turbo. The CST4 took a fresh approach to “big turbo” with all the included hardware, gaskets, and, direct drop-in fitment.  It removed the guesswork for a quick and easy installation, but the benefits didn’t stop there. This “little big turbo” packs a punch for its compact TD05H-18G wheels.  We think it’s best for Mazdaspeed turbo to get started.

Best Mazdaspeed 3 Turbo K04 Upgrade for 400 WHP
Best Mazdaspeed 3 Turbo K04 Upgrade for 400 WHP

With the CST5 and CST6 just around the horizon, it would be easy to forget about the tried and true CST4, but don’t worry this Mazdaspeed Drop-In Turbo got some new love making it one of the best turbos on the market.  You will now have an EWG housing option for the CST4. You can pick it up in EWG setup from the start or if you already have a CST4 that you love, you can get the EWG housing kit to do the upgrade yourself.

Moving onto the CST5 & CST6 the possibilities for the MZR DISI have moved up significantly.  What started as a single “bigger big turbo” has morphed into two “bigger big turbos” that, we feel, better provide for the various power goals of the community.  

Best 500+ WHP Mazdaspeed Turbo

We present to you the CST5

CST5 is the Best 500+ WHP Mazdaspeed 3 Turbo

The CST5 Turbo bridges the gap between drop-in performance and Mazdaspeed’s big turbo power.  The journal-bearing CHRA uses a hybrid TF06-GTX71 wheel setup that provides more top-end than the CST4 with minimal spool and response penalty.  Upping the big turbo feel is a 4-inch anti-surge compressor inlet which will require an up-sized intake system.

Unlike the CST6, the CST5 turbo will be offered in internally waste-gated and externally waste-gated setups.  This provides you with the flexibility to set up your Mazdaspeed just how you see fit and both have been proven 520+ whp on our in-house dyno and tuning courtesy of Will Dawson @ Purple Drank Tuning. This has been the best turbo to achieve 500 WHP.

The Best 600+ WHP Mazdaspeed Turbo

Now… We present to you the Stock Flange Record holder…the CST6

Best Mazdaspeed 3 Turbo for 600 WHP

The CST6 redefines what the community thought was possible from the stock turbine housing flange, but first some details.  The ceramic ball bearing CHRA uses a GTX3576r wheel setup that clearly outpowers the CST4 & CST5, but that’s the point remember?  

The Mazdaspeed CST6 Turbo is a legit big turbo. The spool will be later, but still below 3900rpm for the full boost! However, a turbo setup is not intended for low-end response.  If top-end power is your goal, the CST6 is the best turbo for your Mazaspeed and will deliver. In-house testing has pushed the CST6 to 633whp at a fuel limited ~33psi and 7900rpm redline.

Unlike the CST4 & CST5, the CST6 will only be offered in EWG setup.

Best Mazdaspeed 3 EWG For Turbos CST4, CST5, and CST6

In the coming months, we will share more information about the CorkSport Turbo Line-Up; the design, the testing, and validation of each.  Check out these pages for more information about the Mazdaspeed CST5 Turbo & CST6 Turbo along with the new EWG turbine housing option. Get and boost on!

Thanks for tuning in with CorkSport Mazda Performance.

-Barett @ CS

Connect with us

Stay up-to-date on the latest news and product updates from CorkSport.

* indicates required

You may also like:

MZR DISI Injector Seals – The Correct Seal for YOUR Speed

Many years ago we helped bring a revolutionary design to the Mazdaspeed community.  Fast forward 4+ years and you’ll find that the CorkSport Tokay Injector Seals are still the best option for your Mazdaspeed.  

Recently, we had a customer ship their stock block engine core to us for a fresh Dankai 2 Built Block.  During the engine core tear-down and inspection, we found a set of CorkSport Injector Seals installed.  We realized this was a great opportunity to share what we found with the community.

When the CorkSport Injector Seals arrive at your door they look like this:

Brand new a fresh of the lathe with all of their beryllium copper brilliance.  After many thousands of miles of use and abuse they look like this:

Now to the untrained eye you may think they look bad, but the truth is they look fantastic!  The visible top of the seal has a small amount of carbon deposits present. This is to be expected because this surface is exposed to the combustion chamber.  Moving to the side of the seal you can see a distinct clean edge and no carbon deposits on the sides of the seal. This distinct clean edge is where the exterior of the seal is designed to seal in the cylinder head.  This is awesome!

Now let’s look at the inside of the used seals:

Again we see carbon deposits, but they are in and only in the expected locations.  Moving up the side of the seal you can see a “shelf” or “step” that is clean. This is the edge that the fuel injector seals against. Beyond that the inside of the seal is clean.

From this inspection we can see that the injector seal was functioning as designed and doing its job effectively.  

So you might be asking…”What is so special about this design?” Well, we wrote a two-part design blog answering that exactly.  We highly suggest spending the 10 minutes to read these.

Injector Seals Design Part 1

Injector Seals Design Part 2

This is exactly why every single CorkSport Dankai Built Long Block includes a set of CS Injector Seals, but if you’re not looking for a built block but still want the assurance of the CS Seals you can check them out right here.  The install of the seal can be a bit tricky sometimes, especially getting dirty injectors out of the cylinder head.  Because of that we’ve developed an injector puller tool that makes the job MUCH easier.  

We hope you enjoyed this quick tech inspection of the injector seals!  Thanks for tuning in with CorkSport Mazda Performance.

-Barett @ CS

An Inside Look at the CorkSport EBCS

We recently came across one of the original CorkSport EBCS prototypes which gave us a perfect opportunity to break it down and give you all an in-depth look. Read on as I go through what makes the CS EBCS tick, and more importantly how it gives you great boost control on your Mazdaspeed.

Just as a refresher before we dive in, an electronic boost control solenoid (EBCS) allows for precise boost control by using an electric solenoid to help control the wastegate. A boost reference travels to the EBCS where it can either push on the wastegate diaphragm or vent to the turbo inlet pipe. Where the air travels is controlled by the solenoid.

Obviously, the specifics change slightly depending on a number of factors with the turbocharger setup, but the concepts remain similar. Since the solenoid is electronic, it can be controlled within a tune. This means you are not wholly controlling your maximum boost with the spring in the wastegate and can hit boost targets larger than the “10psi” spring in your wastegate. For more information on boost control and the different EBCS setups, checkout Barett’s white paper on the subject.

Now the above image is a little different from the way you are usually seeing the CS EBCS. Not only is it missing the sweet black anodized finish (early prototype remember?), it needs some assembly before it can function properly. Below lists the components in the system and a short description of what they do. Obviously, we are missing a few key o-rings to keep everything nice and sealed, but all the important bits are there.

  • Manifold: This is the air distribution block. Air/boost comes in one port and leaves through a different port. Where the air goes is determined by the bullet valve.

  • Bullet Valve Assembly: More on this later, but essentially the center rod (piston) moves in and out while the black portion prevents air from reaching one of the manifold ports as needed.

  • Tension Spring: Keeps the bullet valve in the correct position when the system is not energized.

  • Coil Seat: Ensures the copper coil stays in place so the valve can operate properly.

  • Coil/Windings: Creates a magnetic field when energized that moves center rod of bullet valve.

  • Solenoid Body & Wiring: Contains the coil and other components. Also attaches the valve to the manifold.

Each one of the “thirds” of the bullet valve corresponds to one port on the EBCS manifold. They are labeled accordingly above. As EBCS is energized, the piston of the valve is pulled by the magnetic field created by the windings. There is a small amount of movement; only about 12 thousandths of an inch (0.012”) to be exact, which is enough to allow air to either reach the wastegate diaphragm or pass by into the turbo inlet pipe. Again this is simplified as it does not touch on duty cycle-the valve is typically rapidly opening and closing (seriously, check out the white paper).

The bullet valve is advanced technology that offers the utmost in fast responding fluid control. In addition, its profile offers the ability to make a pressure balanced valve and have a manifold that fits just about anywhere. All of this tech means you end up making boost faster, minimizing boost spikes, and keeping boost creep in check. If you want the best in boost control for your Mazdaspeed, be sure to pick up a CorkSport EBCS.

2010 MS3 – Best Way to Get 40+ HP

Your Mazda breathes just like you do. Maximizing the intake of air for your Mazdaspeed and freeing up the expulsion of used gasses (exhaust) will help your vehicle breath better, and go faster.

On the intake side of things, you can set yourself up with a Stage II Power Series Short Ram Intake which includes our mandrel bent turbo inlet pipe, custom designed MAF housing, and silicone coupler. This will free-up flow into the stock turbo and allow your Mazdaspeed to breath deeper. The average gains seen here are 10-15 hp.

For exhaling, you want your Mazdaspeed3 to expel all those used gasses as quick as possible. With the CorkSport turbo-back exhaust, you are reducing the back-pressure and allowing your Mazdaspeed to utilize the potential of its turbo. The kit comes with CorkSport’s full 80mm catback dual exhaust, racepipe, and downpipe. This setup will give the average MS3 owner 28-31 hp at the wheels.

Shown below is our 2010 Mazdaspeed 3 with the CorkSport Short Ram Intake & Turbo-back exhaust and stock turbo, compared to the same Mazdaspeed3 completely stock. The before number is 226 hp and came out to 272 with the SRI and Turbo-back exhaust. That is a 46 hp increase to the wheels with two products.


For those of you on more of a budget, may I suggest just the Short Ram Intake and racepipe? For this smaller investment, you can get an increase of wheel hp in upper 20’s to lower 30’s.

Intake Valve Cleaning – A Dirty Job Made Easy

Introducing the CorkSport Intake Valve Cleaning Kit. While designed specifically for the DISI MZR engine found in the Mazdaspeed 3, 6, and Mazda CX-7 turbo. Our kit is versatile enough to be used in a variety of direct injected (DI) applications and alleviates many of the pain points associated with cleaning your intake valves. For an explanation on why DI engines need their valves cleaned, check out our blog on cleaning Mazdaspeed intake valves. Read on as the CorkSport Valve Cleaning Kit could make your next maintenance job much easier.

Despite its interesting appearance the CorkSport Valve Cleaning tool was carefully designed for ease of use. Starting at the large end, the cone shape was selected to accommodate a wide variety of vacuum hose sizes (1.50-2.5- inch OD) – it even works with the oblong-shaped hose we have in the CS shop! A clamp is included to keep the tool secure on the vacuum. Due to the slightly flexible nature of multi-layer silicone, clamping the hose creates a seal useful to get great suction from the vacuum.

To provide the best fit for both the large and small intake ports of the DISI MZR, the opposite end of the valve cleaning tool also is flared. When in use, this flare compresses slightly, making for another great seal. This keeps the cleaning chemicals, media, and any carbon deposits from getting all over you and your engine bay.

Last but not least is the small diameter offshoot on the side of the CorkSport Intake Valve Cleaning Tool. This is the port for a media blaster that helps make quick work of dirty valves. It is positioned for easy use, where one hand holds the CS valve cleaning tool while the other operates the media blaster. An abrasion resistant hose is included to fit on the end of your media blaster and travel down into your intake ports for direct blasting. Unlike doing this without the tool, you do not have to permanently modify your vacuum just to do valve maintenance.

There you have it, folks, quite possibly the weirdest looking CS product ever created but it’s quite useful!  Check out the listing for more details and to see the CorkSport Intake Valve Cleaning Tool in use.