Mazdaspeed6 | CorkSport Mazda Performance Blog

April 2, 2020August 15, 2023

CorkSport Mazdaspeed 6 Front Mount Intercooler

The MS6 FMIC installation gives you a stealth install with minor trimming and allows you to keep the windshield washer bottle.

It’s been a long time coming but it has finally returned: the CorkSport Front Mount Intercooler Kit for Mazdaspeed 6! We’ve had many challenges on this project but we’re happy to report that it’s finally here and better than ever. We originally released this way back in 2012 (check out the release blog HERE for a throwback) but the only thing we kept from that kit was the intercooler core itself. All of the piping, silicone, and mounting has been redesigned for best fitment and minimizing trimming needed for install. Check out the images and full info below!

Superior to the factory Mazdaspeed 6 TMIC, the CorkSport FMIC gives you consistent cooling all the time without heat soak

To start things off, let’s look into the intercooler itself. It is a unique design where both the inlet and outlet point toward the driver’s side of the vehicle. This means our pipe routing is a little more complicated than most, but it makes it much easier to fit as you do not need to relocate your windshield washer bottle or deal with any of the fitment issues that come with squeezing a pipe through the passenger side of the car.

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The bolt in Mazdaspeed 6 FMIC kit which makes it the best intercooler kit available.

The intercooler core is a high flowing, bar and plate design that measures 21”x10”x3”. This is good for efficient flow up to 500-550WHP yet adds minimal boost lag, even at lower power/boost levels. This big core fits snugly behind the crashbar to eliminate trimming the crashbar or your underbody shields. There is still some trimming required to fit the core and piping, however almost all of it is trimming on plastic components, with one metal cut on a thin sheet metal bracket.

Mazdaspeed 6 FMIC fits up to a 4 inch SRI

Moving onto the piping, the CS intercooler kit uses varied piping sizes for the hot and cold side intercooler pipes. The 2.25” hot side pipe ensures the charge air reaches the intercooler as fast as possible, helping reduce boost lag. The cold side uses 2.5” piping in the first half and 3” piping in the second half. Having this large volume of cool charge air directly in front of the throttle body helps with throttle response and the large diameter further helps with peak flow capacity. This piping setup has proven itself to work great on our GEN2 MS3 FMIC kit, and has been pushed to 684WHP on Barett’s GEN1 (he modified the GEN2 piping to fit his GEN1).

Wire reinforces silicone hoses make the Speed 6 FMIC a quality product

There was painstaking care taken to ensure the kit is as easy as possible to fit on your MS6. The hot pipe has a lot more freedom for intake fitments than our previous kit and we made sure all the CS intakes fit like a glove. Other aftermarket intakes have not been test fit but check out the images, they will give you a good idea if your SRI will fit or not. All the piping is mandrel bent and comes in a polished finish, so it is ready to install right out of the box and look and perform great!

Keeping everything together is the custom designed silicone couplers. You may notice that some of the silicone sections are longer than a typical silicone coupler. This is to ensure the best fitment as some shapes can simply not be made easily in a piece of pipe.

Front Mazdaspeed 6 with Front mount intercooler CorkSport product

As with most CS silicone components, each coupler uses 4-plys of nylon reinforcement braiding and 5 layers of silicone. This is typically very good at resisting expansion under high levels of boost; however, we wanted to really make sure the long couplers of the MS6 kit do not expand. Any coupler longer than about 6” uses an extra layer reinforcement made of metal wire. This further resists expansion under boost, and even helps keep all the piping stable between mounting locations. While the outside of the coupler may look bumpy, the insides are still very smooth like a typical piece of silicone.

A complete FMIC for the speed6, everything you need to install is included except the tools

Each Mazdaspeed 6 intercooler kit comes with everything you need for install. Stainless steel T-bolt clamps are included for each connection to ensure secure, leak free joints. The intercooler mounting bracket, hardware, and full color install instructions are also included so you know you can get the job done right.

We’re happy to finally have this out and are excited to see you all get your hands on them. Be sure to drop any questions you may have below and check out the product listing for more images!

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December 12, 2019September 21, 2023

Easy and Accurate Boost Readings: The CorkSport Mazdaspeed 4.5Bar MAP Sensor

We are proud to introduce the release of a new product: the CorkSport Mazdaspeed 4.5Bar MAP Sensor for Mazdaspeed 3, Mazdaspeed 6, and Mazda CX-7 Turbo. We’ve had the CS 3.5 Bar MAP Sensor for a while now as it’s a necessity when targeting over 21psi, however, while maxing out the CST6, we found the 35psi ceiling of the 3.5Bar sensor just wasn’t enough. Enter the CS 4.5Bar MAP Sensor!

Before I get into explaining what makes this sensor tick, lets quickly go over what exactly a MAP sensor does on your Mazdaspeed. Manifold absolute pressure (MAP) sensors in a nutshell just read the pressure present in the intake manifold of your car. During normal driving conditions, the sensor is typically reading vacuum (or negative pressure) as the engine sucks in air. While in boost, the sensor reads the positive pressure (boost pressure) produced by your turbocharger. In both situations, this pressure reading is being sent to the ECU so the ECU understands exactly what the engine is doing.

The OEM sensor is a 2.5Bar unit, meaning it can do 1Bar of vacuum (negative pressure) leaving you only 1.5Bar (~21psi) before the sensor runs out of accuracy. Both the CS MAP Sensors allow you to accurately read boost levels higher than the stock sensor, so your tuner can target a higher boost pressure for more power, provided you have the right supporting mods. The sensors themselves do not increase your boost pressure, they simply enable your tuner to safely do so.

Mazdaspeed 6 plug in 4.5 bar MAP sensor installed on Intake Manifold — Placement of the Mazdaspeed MAP on Intake Manifold

Enough learning, let’s get into the 4.5Bar Sensor! The CorkSport 4.5Bar MAP Sensor can read a maximum boost pressure of ~48psi before it starts running out of accuracy. Having a huge potential boost pressure means nothing without a fast responding sensor, so we designed the CS 4.5Bar MAP Sensor to have near instantaneous response of only 2 milliseconds. This means if you have the build and turbocharger to do so, this sensor is ready for just about anything you want to throw at it.

A true plug in MAP sensor for your Mazdaspeed no adapter required

The CorkSport 4.5Bar MAP sensor uses a custom injection molded body that mimics the OEM sensor. This makes it a direct install into the OEM location and a direct plug into the OEM wiring harness. No wiring or adapter harness needed. This results in a clean install that takes as little as 15-30 minutes!

Everything needed for installation is included with the CS 4.5Bar MAP sensor. A new mounting bolt is supplied to ensure everything stays put, while a fresh O-ring is attached to the sensor to provide a good seal in your intake manifold. To top it off, calibrating for the sensor is easy as the calibration for use with Cobb Accessport is laser etched right on the body of the sensor.

September 26, 2019October 31, 2022

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!

February 28, 2019August 17, 2023

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.

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.

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!

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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February 19, 2019August 17, 2023

CST6 | Behind The CorkSport Turbo Design

A few weeks ago we discussed some of the design intent behind the CST5 turbocharger for the Mazdaspeed platform. Today, we want to follow up with the CST6. The CST5 and the CST6 both were a result of CorkSport’s desire to develop a new stock flange turbocharger that goes beyond the power limits of our FANTASTIC CST4 Turbo.

During the development of a higher power stock flange performance turbo, we found that we were asking too much of the CST4 Design. The result of our efforts is the CST5 Turbo which you can see here and the CST6 Turbo which we are about to dig into.

In this blog, we’ll dig into the wheel sizing, the CHRA, and some of the challenges we faced in the development and testing stages for the CST6.

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Compressor Wheel

The compressor wheel utilized on the CST6 is well-known and trusted, GEN1 GTX76. The GTX76 compressor is rated for 64 lb/min and is capable of boost pressures that will require a 4 bar MAP sensor upgrade. Like the CST5, the compressor housing is a 4-inch inlet with anti-surge porting.

Ball Bearing Design for the Mazdaspeed Turbo

Unlike the CST4 and CST5, the CST6 Mazdaspeed Turbo uses a completely different CHRA and bearing system, and for good reason. As the turbocharger wheel sizes increase so do the weight and potential boost pressure. This results in higher loads on the wheels, turbine shaft, and bearing system. To increase the durability and performance of the CST6, we opted to move from a conventional journal-bearing design to a more modern and robust ball-bearing design.

The ball bearing system improves durability and stability for high horsepower/high boost operation along with improved spool and transient response. Changing the CHRA did pose some new challenges, however. Ease of installation has always been a key feature with CorkSport products and that’s not lost with the CST6. The CHRA has been modified to support the use of the OE oil drain line and all necessary oil feed components and coolant components are included for seamless installation.

Turbo Compressor Wheel

Like the CST5 Turbo, we’ve put a focus on the wheel size ratio and have validated its performance. The CST6 Performance Turbo uses the Gen1 GTX76 compressor wheel paired with the Garrett GT35 turbine wheel…aka GTX3576r. This wheel combination provides us with a ratio of 1.12 which falls well within the rule of thumb discussed the in the past CST5 blog.

In testing, we found that increasing the size of the turbine wheel from a GT30 to a GT35 with the same GTX76 compressor wheel resulted in more top-end power and no penalty in spool time. This combo also provided a good power delta from the CST5 to better provide an optimal power option for the community. Since then the CST6 has proven power at 600+whp at ~34-35psi and testing will continue past 40psi.

External Wastegate

The initial testing of the CST6 Mazdaspeed turbo started with an internally wastegated turbine housing as that was the original goal with the CST5 and CST6. However, it quickly became obvious that a turbocharger of this size and power potential could not be safely controlled with an internal wastegate. The amount the wastegate port and “exhaust” or flow was not nearly adequate for proper boost control.

The boost would creep to nearly 26psi with no signs of tapering off. Nevertheless, we continue testing knowing that auxiliary fueling was necessary. Once the CST6 power and durability were validated we moved to design a turbine housing that could provide the necessary boost control and power potential.

Above is the removed CST6 internally waste-gated housing. In our testing, we pushed the turbo to nearly 600whp with 40gph of methanol auxiliary fueling. This amount of heat combined with a turbine housing that was literally being pushed to its limits resulted in a great learning experience. As you can see, the turbine housing was cracking! The GT35 turbine wheel and power was just too much.

From this discovery and analysis, we developed the EWG turbine housing with the CST6 in mind. The scroll size was increased, wall thickness increased in critical areas and the 44mm EWG port added.

With the use of the EWG turbine housing, boost control is now spot on and can easily control from spring pressure to an excess of 35+psi. Stick around as we continue to push the limits of the CST6 Mazdaspeed Turbo as we continue testing and validation of the CorkSport V2 Intake Manifold w/Port Injection.

Thanks for tuning in with CorkSport Mazda Performance.

-Barett @ CS

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-Daniel @ CorkSport

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

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Compressor Wheel

Ball Bearing Design for the Mazdaspeed Turbo

Turbo Compressor Wheel

External Wastegate

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