Turbo upgrade | CorkSport Mazda Performance Blog

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

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

Image: Mazdaspeed-6-big-turbo

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

You may also like:

There has been a lot of buzz about the new(ish) turbocharged SkyActiv-G 2.5L first found in the Mazda CX-9 and now in the Mazda 6. Along with all this buzz, there are a lot of unknowns as well. Here at CorkSport, we’ve taken the step to try and address some of these unknowns. What is Mazda’s “Dynamic Pressure Turbo” and how does it work? There have been diagrams bouncing around on the internet, but no close-up view of the turbocharger itself. That’s about to change.

If you haven’t already read Daniel’s first installment, “Mazda Dynamic PressureTurbo an Introduction.” You wouldn’t want to miss out on the extra information before reading on.

The turbocharger found in the 2.5T equipped CX-9 and 6 is quite complex in design. There are many aspects to the OE turbocharger we could discuss, but today we are going to focus solely on the dynamic pressure system and turbine housing.

If you are reading this, then you’ve probably already seen various diagrams depicting how the dynamic pressure system works and showing Mazda’s clever 3-2-1 exhaust port design. If you haven’t, check it out below. Image credit to Car And Driver Magazine for the fantastic diagram.

Mazda’s 3-2-1 exhaust port design takes full advantage of the engine cylinder firing order. The advantage is improved exhaust gas scavenging for the adjacent cylinder (more or less the cylinder that just fired helps pull the exhaust gases out of the next cylinder that is about to fire). Ok, moving on; this is great, but how does the dynamic pressure system come into the mix?

Shown here are the turbocharger assembly and the dynamic pressure valve assembled as one unit (the first two images also showed the fully assembled setup). The three ports are clearly visible along with the “vane” that passes through the three ports. This vane rotates depending on the engine RPM to control the exhaust gas velocity entering the turbine housing. The vane itself is controlled by the larger blue-colored actuator.

Mazda 6 Turbo design for exhaust velocity

Now let’s take an even closer look. The vane does not open until approximately 1600rpm, but the engine cannot run if there is no exhaust gas can flow out of the engine. To resolve this Mazda has designed a dynamic pressure system with two exhaust gas paths. Looking at the above image you can see a small opening just above the vane. This is the sub-1600rpm exhaust gas path.

By reducing the cross-sectional area of the exhaust gas path, the exhaust is forced to accelerate through the dynamic pressure system and into the turbine wheel. This effectively reduces turbo lag, improving the vehicle’s response at low engine RPM. Once the engine revs past 1600rpm the vane opens, allowing the larger path to be used.

Here we show the turbocharger assembly (right) and the dynamic pressure valve assembly (left) separated. Looking at the dynamic pressure valve assembly, you can now more clearly see the three small paths above the larger path with the vane inside. Then look at the turbocharger assembly and you will see the small upper path and the larger lower path.

The fact that these two assemblies are separate systems is great news for the enthusiast. The development of a performance turbocharger will be much more feasible and the dynamic pressure valve can be retained with the performance turbocharger. One more detail to point out.

Mazda 6 turbocharger design for exhaust pressure

Mazda put a lot of thought into the design of the wastegate port; let me show you why. First, looking at the inlet of the turbine housing you can see a small vertical wall in the large path. This wall creates a completely separate path to the wastegate port which is very unusual on an OE turbocharger. Combine this design with a very large wastegate port and you get a design that can “waste” or divert an excessive amount of exhaust gas.

Mazda 6 turbocharger design for skyactive-g 2.5l

This tells us the SkyActiv-G 2.5L engine is creating a lot of (currently) unused exhaust gas energy. Again this supports the feasibility of a performance turbocharger suiting Mazda’s new turbo engine quite well.

Great things are on the horizon for the Mazda 6, now if only Mazda would put this engine in the 3 paired with a 6-speed manual transmission. Oh, one can dream.

-Barett @ CS

Connect with us

You may also like

Tag: Turbo upgrade

Best Mazdaspeed Turbo Upgrades – Choose Your Boost

The Best 400 WHP for the Mazdaspeed

Best 500+ WHP Mazdaspeed Turbo

The Best 600+ WHP Mazdaspeed Turbo

Thanks for tuning in with CorkSport Mazda Performance.

Mazda’s Dynamic Pressure Turbo – A Closer Look

The Best 400 WHP for the Mazdaspeed

Best 500+ WHP Mazdaspeed Turbo

The Best 600+ WHP Mazdaspeed Turbo

Thanks for tuning in with CorkSport Mazda Performance.

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

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