Mazdaโ€™s Dynamic Pressure Turbo โ€“ A Closer Look

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. ย Along with all this buzz, there are a lot of unknowns as well. Here at CorkSport, weโ€™ve taken the step to try and address some of these unknowns. ย What is Mazdaโ€™s โ€œDynamic Pressure Turboโ€ and how does it work? There have been diagrams bouncing around on the internet, but no close-up view of the turbocharger itself. ย Thatโ€™s about to change.

Mazda 6 Turbo

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.

Mazda 6 Turbo

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 youโ€™ve probably already seen various diagrams depicting how the dynamic pressure system works and showing Mazdaโ€™s clever 3-2-1 exhaust port design.  If you havenโ€™t, check it out below.  Image credit to Car And Driver Magazine for the fantastic diagram.  

The Mazda Turbocharger 4-3-1 design

Mazdaโ€™s 3-2-1 exhaust port design takes full advantage of the engine cylinder firing order. ย 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). ย Ok, moving on; this is great, but how does the dynamic pressure system come into the mix?

Mazda 6 Turbo Skyactiv design

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). ย The three ports are clearly visible along with the โ€œvaneโ€ that passes through the three ports. This vane rotates depending on the engine RPM to control the exhaust gas velocity entering the turbine housing. ย The vane itself is controlled by the larger blue-colored actuator.

Mazda 6 Turbo design for exhaust  velocity

Now letโ€™s take an even closer look. ย 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. ย To resolve this Mazda has designed a dynamic pressure system with two exhaust gas paths. ย Looking at the above image you can see a small opening just above the vane. This is the sub-1600rpm exhaust gas path. ย 

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.   

Mazda 6 turbocharger

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 โ€œwasteโ€ 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 Mazdaโ€™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. ย Oh, one can dream.

-Barett @ CS

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Mazdaโ€™s Dynamic Pressure Turbo โ€“ An Introduction

The SkyActiv 2.5T has been around for a few years in the CX-9 however, things started to get interesting when the engine was dropped in the Mazda 6 for 2018+ models. While lacking a manual and not a true Mazdaspeed, itโ€™s a step in the right direction for the enthusiast. With one of the new Mazda 6s in the CorkSport garage, weโ€™ve been getting curious about where all of that 310lb-ft comes from. Well, we decided to call up Mazda and purchase a turbo to see how it all works.

Mazda 6 Turbo

Thereโ€™s a lot to take in on the turbocharger and there are quite a few things that have changed from the K04 that made its home in the Speeds.

For starters, this turbocharger is pretty big. The wheels themselves are not large, with the compressor wheel very close in size to the old Mazdaspeed K04 & the turbine wheel only slightly larger than the K04 Turbo. However, with the dual inlet turbine housing, 90ยฐ compressor outlet, and lots of attached electronics, the whole package takes up a lot of room in your engine bay.

2018+ Mazda+ Turbo housing and

The turbine housing is not far from the old K04. A large five-bolt inlet flange has two rectangular inlets to work with the dynamic pressure system (more on that later) and even a port where the EGR system sources its exhaust gases. The outlet is much simpler, using a five-bolt flange to mount to the downpipe, yet does house a surprisingly large wastegate port.

From a performance standpoint, the large wastegate should help eliminate boost creep but the turbine housing will likely need a larger scroll to get some more serious power out of the engine.

OEM Mazda 6 Turbo

The compressor side is packed full of features. As usual, the wastegate actuator bolts to the compressor housing, however, Mazda has switched to an electric actuator. Interestingly, the bypass valve is also electric and is even mounted to the face of the compressor housing.

Some fancy casting design leaves a pathway between the high and low-pressure sides of the compressor and let the BPV decide when the passage is open or closed. These two electric actuators will mean easy and consistent boost control. The final plastic component on the housing we believe is a boost-assisted vacuum source for the vehicle. Finally, the inlet is a typical clamp connection while the outlet uses a 90ยฐ turn and two-bolt flange for better accessibility around the wastegate actuator.

2018+ Mazda  Turbo Housing

With the housings removed, the CHRA of the dynamic pressure turbo is very simple & standard. Oil feed in the top, two-bolt oil drain in the bottom, and standard crossflow engine coolant ports. The compressor wheel is a cast 6×6 unit and the turbine wheel is a basic 11-blade unit.

Mazda 6 Turbo Turbine

We are looking forward to waking up the Sky-T in the coming months and making the 2018+ MZ6 into something a little closer to a Speed. Stay tuned, thereโ€™s much more fun to be had from the 2.5T!

-Daniel

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CorkSport 7th Gear

Become of member of our new, exclusive program 7th Gear and get gifts, early access to new products, and more!

Youโ€™ve likely seen a quick glimpse of our 7th gear program previously, but there is NO WAY you have made it this far knowing all of the benefits and still not pulled the trigger.

There is just no way… and if so…You are MISSING OUT!

Weโ€™ve loved how this program has grown over the last year, with members giving product ideas, insight into their builds, and passing the EXCLUSIVE info on the gains weโ€™re experiencing on our prototypes; it has truly become a community of enthusiasts. With pushing one another for higher power and better builds as a center, great parts, and direct insights provide for instant feedback and inputs on projects.

Become of member of our new, exclusive program 7th Gear and get gifts, early access to new products, and more!

If you havenโ€™t heard, or looked fully into this program, here is a brief overview and some insight directly from our members!

As a 7th Gear Member, youโ€™ll receive โ€ฆ

An exclusive gift package worth $99 when you sign up.

    • You can only get these apparel items by becoming a 7th Gear member! – worth the cost of the membership by itself!!

CorkSport's exclusive new membership program, 7th Gear, is all about building a family of dedicated Mazda enthusiasts.

Access to our exclusive 7th Gear Facebook group.

    • Weโ€™ll provide insider information on our products, lifestyle, and happenings!

    • Youโ€™ll interface with other elite members of the Mazda Community and receive CorkSport answers faster than anywhere else on the web.

    • Youโ€™ll have first access to new product releases via the 7th Gear Inner Circle thanks to your membership

 

If you’re buying anything with a significant shipping cost, it would be patently stupid to not get the 7th gear membership. The hat is top quality flex-fit and the shirt is nice too, big vinyls if you’re in to that. Exclusive access to sales, skipping the line on new parts, and you get behind the scene access for product development. Combined with CS points it’s a much better offer than competitor’s “free shipping”. – Jason Gambill

Free Shipping to the lower 48 States. (Hawaii, Alaska, and International orders get reduced rate shipping.)

    • You heard us right! Free shipping to lower 48 and reduced cost shipping for our members elsewhere!

 

“Do you love buying Corksport parts for your Mazda? Then why wouldn’t you want to join 7th Gear? Early information on upcoming parts so you and your wallet can plan ahead. Corksport is one of the few companies still developing new and exciting products for the Mazda/Mazdaspeed platforms. Why not join them and get an even deeper inside scoop!  Even though I’m in Canada and I don’t get free shipping, the discount I receive does help! The cost of 7th Gear could be covered from just a couple orders.
And even the occasional sale exclusive to 7th Gear is great.” – Michael Cheek

Automatic Annual Renewal that includes an awesome anniversary gift worth, at least, the cost of membership!

    • Once again, no one has access to this exclusive gift item unless theyโ€™re a 7th Gear member!

As a 7th Gear member, rest assured that weโ€™re here to ignite your Mazda dreams into reality. With first access to parts, exclusive gear, exclusive 7th Gear promotions, and direct links to our CorkSport team, the free shipping is just a perk. Head to CorkSport.com for more information on 7th Gear today.

CorkSport Steering Wheel for ND Miatas

We love the look and feel of the CorkSport Mazdaspeed steering wheels and thought we would throw some love to the Miata guys. Designed to inspire confidence during aggressive driving while improving day to day comfort, this steering wheel is a complete package and will complement your other CorkSport Performance Upgrades. ย 

 

The CorkSport Steering wheel is a direct OE replacement as it retains all trim, buttons, airbag, and even paddle shifters for automatic models. Itโ€™s also a perfect fit for all ND Miata models (yes even those of you with a RF). Check out the image below, it shows exactly what you will get in the box (right) next to an assembled performance steering wheel (left). Once you remove your OE wheel you just need to transfer all of the trim and accessories and youโ€™re ready to install.

 

 

In designing the wheel we knew we wanted performance without sacrificing comfort. Letโ€™s face it, the steering wheel is the one thing you are (hopefully) always touching while driving. We knew right away we wanted a thicker wheel as the stock one is awkwardly thin. We increased thickness without increasing the overall diameter of the wheel.

 

The flat bottom of the wheel makes it easier to get in and out of the car, especially for those of us who barely fit in Miatas anyways. To further enhance the aggressive style we added a center stripe to the top of the wheel. Finally we carried over the deep thumb grooves from the CorkSport Mazdaspeed 3 steering wheels to really lock your hands in place during spirited driving.

 

All of the features are wrapped up in plush black leather, with perforated leather on the high use areas to keep your hands cool. If that wasnโ€™t enough weโ€™ve also added an option for alcantara inserts. Why? ย Because Racecar!

 

If youโ€™re looking for an easy mod that will upgrade the feel, comfort, and style of your ND Mx5 let the CorkSport Steering Wheel find a home in your interior.

All About That CatBack Exhaust

Mazda Catback Exhaust Installed

Ever wonder about the key factors of making a decision about your aftermarket exhaust? Why Cat-back? 

Is it the diameter of the exhaust that says performance? Or is it the type of metal used? What about fitment to your current setup? None of these questions alone answer what you need when making the decision on how to get more power out of your Mazda. Why the CorkSport Cat Back is the choice for your Mazda.

Mazda Cat Back Exhaust

At CorkSport, we have made it our #1 priority to make our customer’s dreams a reality. Whether you drive a Mazdaspeed or a regular Mazda, weโ€™ve made sure to engineer a great fitting exhaust that maximizes engine performance.

Check out the Cat-Back Exhausts by Car Model Below:

Take the Mazdaspeed 3, for example. When you purchase a Mazdaspeed Catback Exhaust, youโ€™re getting T304 stainless steel piping that has been polished to a mirror-like finish.

Mazda Cat Back Exhaust by CorkSport

Youโ€™re also getting true 80mm piping, which is slightly bigger than three inches, making our exhaust one of the biggest bolt-on catback systems.

Fitment is also a big concern for us. We make sure our exhaust systems are mandrel bent and TIG welded to ensure a perfect bolt-on fit.

Mazda 6 Power Series Cat Back Exhaust

Now that you know our exhaust is 80mm piping, polished to perfection, and made to be a direct fitment, you can bet this exhaust will increase performance and sound. By installing our cat-back exhaust, youโ€™re removing the secondary unmonitored catalyst making the exhaust flow much faster out of the motor. By increasing the velocity of exhaust gases out of the motor, you increase power and make your turbo spool up a little bit faster.

Mazda 6 Cat Back Exhaust

Among the power gains youโ€™ll see from installing the CorkSport Catback Exhaust, youโ€™ll also enjoy the deep growl your Mazda now possesses. Our exhaust has one of the best-sounding tones on the market. With a quality made exhaust, comes quality sound.

When find yourself ready for a cat-back exhaust, be sure to check out CorkSport to ensure you get the highest quality for your ride.