Inside look: CorkSport Turbo Design

The development and evolution of the CorkSport Performance CST5 and CST6 turbochargers are uniquely intertwined.   We’ll be honest, we started with the goal of a single larger turbo than the CST4 in mind, but as development progressed we were not getting the exact results we wanted. We wanted fast spool & transient response, huge power, and to retain the internally wastegated system.  Something had to give…we realized that we were asking too much from a single turbocharger, thus we redefined what we wanted and realized that two separate and focused turbochargers for the Mazdaspeed platform were the ideal choice.

CST5 Billet Compressor
CST5 Billet Compressor

Today we will focus on the design around the glorious CST5, specifically the theory and design around the wheel selection for the CST5 and why it works.  

CST5 Wheel Design

CST5 Turbine
CST5 Turbine

The compressor wheel utilized on the CST5 is the well-known and trusted GEN1 GTX71.  Compact and efficient, this compressor is rated for 56 lbs/min flow rate with a relatively high-pressure ratio threshold.  Paired with a 4-inch anti-surge compressor housing and we have a very versatile and responsive compressor setup.

Now here is where the design begins to deviate from the standard path.  The turbine wheel is an MHI TF06 design that is designed for high-performance applications.  The TF06 turbine wheel is the key to the performance of the CST5. Let’s see how and why below.

If you are unsure of the turbine wheel size don’t worry, that will get covered shortly.  For comparison, the MHI TF06 is very similar in size to the well-known GT30, but there are a few very specific differences that affect performance.  

Turbine Blades

Turbine Blades
Turbine Blades

The first and most obvious difference is the number of turbine blades; this difference has a couple of benefits. First, less weight; even a small difference in weight can make a significant difference in the spool and transient response characteristics of the turbocharger.  Second, reduce flow restriction; with one less blade, the “open” area through the turbine wheel exducer is increased which increases the peak flow potential for top-end power.

Inducer & Exducer

Inducer & Exducer Comparison
Inducer & Exducer Comparison

Next, are the less obvious differences.  The GT30 has a 60mm inducer and 55mm exducer which equates to an 84trim turbine wheel vs the TF06 with a 61.5mm inducer and 54mm exducer which equates to a 77trim turbine wheel.   

There are two key values to pull from this:  First, the turbine wheel inducer directly relates to the peak flow of the wheel and the overall wheel size balance which we will cover next.  Second, the turbine wheel trim affects the spool and response characteristics of the turbocharger. The smaller the wheels trim the faster the spool and response.  

Sizing

CST5 Sizing
CST5 Sizing

Alright here is the most important and commonly overlooked aspect of a turbocharger.  There is a rule of thumb when sizing the compressor and turbine wheels for a turbocharger.  

If the turbine is too large then the turbocharger will be very “lazy” and have trouble building boost.  

If the turbine is too small then the compressor may be overpowering the turbine wheel causing excessive exhaust gas buildup that can rob power even though you may be running a very high boost pressure.  

So what is the right balance?  From our experience in turbocharger design, development and validation along with industry professionals we have consulted there is a rule of thumb we have found when sizing the compressor and turbine wheels.  The exducer of the compressor wheel should be 10-15% larger than the inducer of the turbine wheel as shown in the image above.

CST5

So why does this work?  Well, let’s look back a bit first.  Many think you can just install a larger and/or higher flowing compressor wheel onto the turbocharger to make more power.  Now that is true to a point, but quickly the approach becomes very inefficient for the engine. Forcing more air into the engine without improving the flow out of the engine can only go so far.  

Everything that goes into the engine must come out, right?  Increased A/R sizing and turbine wheel sizing is the key to exhausting all the gases from the engine efficiently, and efficiency is key to making power.

With both the CST5 and CST6 development we focused on the overall performance of the engine, not just the development of a high-performance turbocharger.  

Thanks for tuning in with CorkSport Mazda Performance, more to come…

-Barett @ CS

Mazdaspeed Turbo – 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 truly be.  

The original “CS Turbo” is now the CST4 to follow the turbo line-up that is soon to launch.  The CST4 took a fresh approach to “big turbo” with all the included hardware, gaskets, and of course direct drop-in fitment.  It removed the guess work 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.  

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 also.  You will now have a 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.  

We present to you the CST5

The CST5 bridges the gap between drop-in performance and 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 4in anti-surge compressor inlet which will require an up-sized intake system.

Unlike the CST6, the CST5 will be offered in both internally waste-gated and externally waste-gated setups.  This provides you with the flexibility to setup 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.

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 out powers the CST4 & CST5, but that’s point remember?  

The CST6 is a legit big turbo, spool will be later, but still sub 3900rpm for full boost, however a turbo setup like the CST6 is not intended for low-end response.  If top-end power is your goal, the CST6 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.

In the coming months, we will be sharing more information about the CorkSport Turbo Line-Up; the design, the testing, and validation of each.  For more information about the CST5 & CST6 along with the new EWG turbine housing option, check out these sneak peek pages.  

Thanks for tuning in with CorkSport Mazda Performance.

-Barett @ CS

SkyActiv 2.5T: Let’s Talk Intercooler Pipe Upgrades

We recently went over the stock intercooler & piping system for the 2018+ Mazda 6 2.5T. If you missed it, be sure to check out the blog HERE.

Today, it’s the first look at the CorkSport parts that will be coming in the near future to remedy the issues we found with the OEM system. We are not covering our upgraded intercooler just yet though; today’s focus is piping upgrades!

As you can see we’ve been busy getting the upgraded intercooler piping designed & 3D printed for test fitting (while you can’t see it I promise the cold pipe is hanging out in there too!). I’m happy to say there’s plenty of room to fit the upgraded piping sizes that we were targeting and hopefully they will net us a few HP gain without any other changes.

These horsepower gains typically comes from removing sharp bends and diameter reductions in the stock piping that cause pressure losses. Then, the turbocharger can operate more efficiently to reach the desired boost level. Now how about some more detail on how and why each pipe has changed.

Starting off with the hot side of things (piping from turbo to intercooler), check out the CAD image above. As you can see, the OEM piping (left) is smaller than the CorkSport piping (right). In fact, we plan to use 2.25” piping for the hot side. Note that the plastic OEM piping is much thicker wall than the CS aluminum piping so even if the outer diameter looks similar, the inside diameter is much larger.

In addition, we keep this same inside diameter throughout while the OEM piping has a major diameter reduction through the middle. For those of you coming from a Mazdaspeed 3, 2.25” is the same size used on the hot side of all CS intercooler kits and has proven itself to support 600+WHP on Barett’s car (more info on that HERE). While we know the Sky-T may not be to that level just yet, 2.25” is a great size that gets the hot air to the intercooler as fast as possible while retaining high horsepower capabilities.

It’s not all about size though. Instead of using many tight radius direction changes like OEM, the CorkSport hot pipe uses smooth, large radius mandrel bends throughout. This means smoother and faster airflow to your intercooler. Lastly, you may notice the CS hot pipe is significantly longer than the OEM hard plastic unit (the OEM rubber tube starts at the connection point circled in the image above). This reduces the amount of flexible connector used, limiting what could expand at high boost levels. That being said, the CorkSport kit will use high strength silicone with four fabric reinforcement layers to prevent any expansion anyways.

The cold side of the system was already a decent diameter from the factory, but as you can see, we went even larger. The rubber OEM cold pipe will be replaced with a 3” diameter aluminum pipe. This large diameter pipe and huge volume of air that comes with it right before the throttle body has proven to help throttle response and reduce boost lag on our GEN2 Mazdaspeed 3 FMIC kit. We hope to get much of the same from the SkyActiv 2.5T. The cold side also uses large radius mandrel bends for smooth and fast airflow.

Lastly, the cold side piping reduces the amount of flexible connector used. And just like the hot side, each end of the pipe will use 4-ply reinforced silicone to prevent any expansion under high boost levels.

Those of you with a keen eye will have realized that our planned silicone connectors do not use the same connection style as the OEM intercooler. This is for good reason: we believe that the OEM intercooler will run out of cooling capacity before the OEM piping really becomes an issue. So a piping upgrade by itself wouldn’t show too much of a performance advantage.

In addition, we were able to design the piping to be the best it can without using the constraints of the OEM intercooler. So yes, the upcoming CorkSport intercooler upgrade will be required for the CS piping upgrade to work, but it’s so the CS piping & FMIC combo can be the best it can be for you all!

For those of you that have stuck around this long, check out this tease of a CAD model of the CorkSport FMIC & Piping kit.

And just because we like teasing you, check this early prototype out. Testing to come soon!

Stay tuned for more, as next time we will cover the intercooler itself. Also let us know your thoughts down below, we love your input!

-Daniel @ CorkSport

The CorkSport EGR Delete Kit is Here!

If you’re looking to help your racing engine stay healthy and clean, read on as we introduce the CorkSport EGR Delete Kit for Mazdaspeed 3, 6, and Mazda CX-7 Turbo.

An exhaust gas recirculation (EGR) system is a very common control system that recirculates some exhaust gases back to the intake manifold to help reduce NOx emissions. A properly functioning system has a few other minor benefits however, on the DISI MZR the EGR system primarily gets clogged,  and/or gums up your intake valves, reducing engine health and performance (for more info, check out our blogs on EGR Cleaning and Intake Valve Cleaning).

The CorkSport EGR Delete Kit removes the two primary components in the EGR system: the EGR valve and the EGR tube. This means no more carbon and soot going into your intake valves, and when coupled with a quality Oil Catch Can, much less frequent valve cleaning.

Each CS EGR delete kit comes with everything you need for a good looking, easy install. The EGR valve is replaced with a 3/8” thick, billet aluminum block off plate. The plates are precision machined to closely match the OEM EGR valve flange to keep your install clean. Proper length bolts are supplied with the CS EGR Delete Kit to ensure you won’t damage your OEM or CS High Pressure Fuel Line.

The EGR tube delete consists of two components: a laser cut 18 gauge T304 stainless steel block off plate and a T304 stainless plug. The plate can be used underneath the tube itself for a stealth install or for an even cleaner engine bay, go for the full tube delete and use the plug to block the hole in your OEM intake manifold.

While not a typical performance mod, the EGR delete is a great addition to aid in a racing build’s future mods. To start, the EGR valve block off plate is tapped for the included 1/8”-27 NPT barb fitting. This works great for the OEM turbo’s rubber coolant line, but should you upgrade to a non-water cooled turbo or a stainless coolant line, 1/8” NPT is a very common size that should be able to accommodate almost any type of fitting.

The CorkSport EGR Delete Kit also provides some much needed room around the turbo charger. With the bulky OEM EGR valve removed turbo swaps are easier, plus, certain turbo setups will literally not fit without an EGR delete. Finally, should you decide down the road to upgrade your Intake Manifold, an EGR delete is basically a must as nearly all aftermarket intake manifolds remove the EGR port from the IM.

The CorkSport EGR Delete Kit is a relatively easy way to gain some extra engine protection without breaking the bank. If you just cleaned your valves and want to avoid it doing it for a long time, a CS EGR Delete Kit is a must.

Safely Upgrade Your Mazdaspeed Turbo

It doesn’t take long for those building power to use up the stock K04. They are prone to fail, especially when you start shoving that extra air through it. A common question is, “My Mazdaspeed is smoking, is my turbo bad?”

First things first. There is a BIG difference between replacing a bad turbo and upgrading to a more efficient one for more power. If you want to replace it, go with OEM and just plug and play, you’re good to go, wash your hands and get on with your life. This will have your car up and running pretty quickly. However, your maximum power output will be limited and you will eventually have the same problem – the KO4 will fail.

If you are saying to yourself, “It’s time to upgrade…I NEED more power in my life!” Then this blog is for you. Below, we lay out the basics needed to successfully install a CorkSport Mazdaspeed Turbo, highlighting the required supporting modifications to keep your Mazdaspeed safe. And as an added bonus, we keep our installation instructions on each of our product pages, so you can preview how easy the install will be for your experience level.

Here it is, the list is comprised of the BARE essentials to run the 18G CorkSport turbo.

 

HPFP INTERNALS

Giving you 50% more efficiency with your fueling system, as well as, a strong base to build power for your Mazdaspeed. The CorkSport Max Flow Fuel Pump Internals are built to directly replace your stock fuel pump internals and perform with immediate improvements.

CorkSport fuel pump vs. competitors

ACCESSPORT (or VERSATUNE if you have a CX-7)

The Cobb Accessport will give you the basis for tuning, and since this is required with the CorkSport turbo – you’ll want to make sure you have this in hand and ready for when you install your turbo.

These are the basic foundation to our Mazdaspeeds, without these two items you cannot operate your Mazda after installing an upgraded turbo.  You will need your Mazdaspeed tuned, and your tuner is going to say the same thing.

That’s it, that’s all you need to run the CorkSport Mazdaspeed turbo safely. With this proper foundation, you can put yourself in a position for efficiency, or more power.

Now the question is do you want to make it go fast and harness the power that this turbo is built for? Keep reading and we’ll provide some other awesome upgrades that are the next step once you have your turbo installed and running.  Oh, and if you are looking for a proven path to make 400WHP, check out our Chasing 400 WHP Blog here!

CorkSport Upgraded 3.5” Intake

The CorkSport turbo is rated for up to 450WHP with the right set up. Unless you are going for the MOON and shooting for over 700WHP a 3.5” intake will be more than sufficient for this turbo. Giving you some extra airflow to increase your power range, and harness what your Mazdaspeed3 is capable of. Note: Will require additional tuning!

 

CorkSport Mazdaspeed Downpipe

Doesn’t matter if you go with a high flow catalyst or opt-in for one without, the choice is yours. However, if you want to utilize its flow you are going to have to upgrade to a bigger diameter. Our 80mm one does really well, plus it sounds GREAT.  Note: Will require additional tuning!

The CorkSport Cat Back Exhaust System gives your new 2016 Miata the power it needs without the annoying drone.

CorkSport Cat-Back Exhaust

It’s no secret that car engines are just big air pumps, the faster you can shove air into the engine and how fast you can expel it efficiently is what it takes to make more power. No need to run the stock 63.5mm exhaust when you can run our 80mm (like to wake up the neighbors every morning, go with our non-resonated, you can’t beat the cold start)

CorkSport Top Mount Intercooler

If your power goal is 450whp or less you can get away with just upgrading your TMIC and be on your way and they look great in your engine bay.  Note: Will require additional tuning!

If you have the 2nd gen you can really utilize that hood scoop from the factory.  Not only that but you can even see a noticeable performance gain with our larger hood scoop and a TMIC set up.

 

When it comes to your Mazdaspeed we know you want to create safe power and harness the true potential of your ride. Be sure to build upon the proper foundation and head in the right direction for your build. Our techs are available for any questions you have and are ready to assist with planning your Mazdaspeed build path! Any questions – give us a call directly – (360)260-2675, email to sales@corksport.com or leave a comment and we’ll get back to you!