Mazda | CorkSport Mazda Performance Blog

May 6, 2020July 31, 2023

Barett’s 1/2 Mile Mazdaspeed 3 Build – Part 1

Hey Everyone, if you don’t know me already I’m the engineering manager at CorkSport Performance & @Halfmilespeed3. I want to make a formal greeting and invite you to follow along as I take the next huge step with my personal build. I drive a 2009 Mazdaspeed 3 that has been through many iterations. I bought it nearly 6 years ago and have since used it in excess to support CorkSport R&D. Hundreds if not thousands of passes on the dyno with so many parts…it’s been a beaten test mule. The time has come to set a focus.

Now, with the 4^th engine going in it, I’m setting the build focus for ½ Mile Drag Racing. Power, Aero, and some “Mad Scientist” R&D is going into this build. (see WTF is THAT)

Mad Scientist Add-ons — 600hp Mazdaspeed Build Path – CorkSport Barett’s 2009 Mazdaspeed

My goals are 700whp on the CST6 stock flange (with Will @ PD Tuning giving it the sauce) and 180mph in the standing ½ mile. I plan to play in the 1320, but half mile is the focus. My first event was going to be Never Lift @ Coalinga Munical Airport in Late March, but with recent events, this was canceled and a new date has not been set. Fingers crossed the country gets through this and the next events hosted by Shift S3ctor Airstrip Attack in June and November hold.

Back to the build…I know that pushing a Mazdaspeed through the air at 180mph is a lofty goal and that physics are against me. With the help and advice of Aaron O’neal @ English Racing I am exploring high-speed aero design.

The primary goal is stability at high speed. I want to be safe in this type of racing so I need to do what I can to make the car stable and predictable at speed. This means I need the car to cut through the air as smoothly as possible, and if possible, generate downforce.

To do this I’ve made a prototype drag wing (which I will share more detail on in a later blog) per the advice of Aaron and my research. This wing is two feet long at the top! And with the closed sides, this should reduce the amount of lift generated at the back of the car.

There is still a lot more work to do here but you get the idea so far.

Upfront I am still very much in the conceptual phase of design. Nearly the whole front bumper will be sealed off with a single sheet of ABS plastic formed to the front of the car. The only opening will be a rectangle about the size of the intercooler for cooling airflow. I also plan to build a chassis mounted splitter. The red parts in the image above are the one-off brackets I designed to mount the splitter to the chassis and still be able to adjust the height (Again I’ll share more detail in future blogs as the prototype comes together).

The other less intuitive aero bit I’m doing on the front of the Speed is hood venting. Thanks to Jonathan Castro @ JC Speedworks for the hood vent I’m able to kill two birds with one stone here. If you’ve done any type of racing you know heat is a killer and must be managed. With this hood vent, I am both evacuating any high-pressure air build up in the engine bay and promoting more efficient airflow through the intercooler and radiator.

With the 300 miles I’ve put on the car, I can already see a huge difference in normal operating temps. Maybe more vents are in the works? 😉 Oh and shout out to @mz_rawr (Aaron Maves) for cutting holes in my hood.

CorkSport Mazdaspeed 3 Transmission Mount Blog

In the process of getting the engine and transmission together, I wanted to fix a 2^nd gear drop out issue I had. Over a weekend @thatonepnwguy (Bryce Peterson) and I split my transmission and replaced the shift forks. We certainly did it the wrong way and had to chase some balls around and get them back into their respective locations; despite all that, don’t be afraid to tear into things and learn the hard way.

How To Achieve 400 WHP In Your Mazdaspeed Blog

The powerplant made it in the car and is running great. Right now I’ve got about 300 miles on the engine. I’ve been working out some little details with heat management and setup of the Vacuum Pump (WTF is THAT). I am just now starting to do logs and tuning with Will Dawson at Purple Drank Tuning. With these goals, I still intend to keep the car street legal and driven on a nearly daily basis (I wish you could see the stares I get from people). I’m putting this out to all of you as an invite to follow along with the build on Instagram @halfmilespeed3. All the inside info and goodies are there for you to see along with @corksport for other stories and build updates. I’m stoked for this season and to explore a racing series that has largely been untouched by the Mazdaspeed community. I will be finding limits and new challenges for the platform that I hope to overcome.

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March 14, 2019August 14, 2023

Let’s Get Chilly: CorkSport Intercooler for SkyActiv 2.5T

It’s time to break down our design for the CorkSport Performance Intercooler Upgrade for the Mazda 6 2.5T. We have covered both the OEM intercooler and piping, and our design plan for the upcoming Sky-T intercooler piping upgrade in previous blogs, but today’s focus is the intercooler itself. Intercoolers are a delicate balancing act between size, cooling efficiency, and pressure drop so naturally things can get a little complicated. Buckle up and stay with us, and be sure to drop any questions you may have down below.

Taking a look at the stock intercooler mounted on the Mazda 6 (shown above) shows us quickly where our size constraints lie. With the large crash bar, we cannot go too much larger in height without trimming the crash bar, bumper, or both. However, there is a ton of room for added thickness and better end-tank design that can really help increase the width of the intercooler. The stock intercooler core is 24.5” wide, 5.5” tall, and 2.625” thick. Our plan is to fit a 27” wide, 6” tall, and 3.5” core without any trimming. This sizing combined with a low-pressure drop will be good for 400WHP with no issues! Because the Mazda 6 comes with just around 200WHP from the factory, this sized core provides plenty of room for upgrading down the road without causing excessive boost lag that can occur if an intercooler is simply too big. Check out a prototype CorkSport intercooler mounted on the car below.

Mazda 6 Front Mount Intercooler Installed

Now that size is taken care of, let’s move on to cooling efficiency and pressure drop of the CorkSport intercooler for the SkyActiv 2.5T. These are tied closely together as getting extremely high cooling efficiency usually means high-pressure drop and vice versa. Just so we’re on the same page, cooling efficiency is how well the intercooler cools off the pressurized air that passes through it. So a highly efficient intercooler will be able to bring the boost temperatures down similar to the ambient air temperature. Pressure drop is exactly what it sounds like, a loss in pressure from the inlet to the outlet of the intercooler which can be caused by a number of things: poor end-tank design, too many intercooler fins, or simply poor flow distribution in the intercooler. Too large of a pressure drop means lower boost pressures reaching your engine and/or your turbocharger working harder to achieve the same boost levels.

Mazda 6 Front Mount Intercooler product photo by CorkSport

Pressure drop and cooling efficiency are influenced primarily by two things: fin density and end-tank design. Fin density is basically how many fins the boosted air must pass over when traversing the intercooler. More fins = better cooling efficiency, but also more pressure drop. To choose the best core for the SkyActiv 2.5T we plan to use multiple different fin densities and test each for power, cooling efficiency, and pressure drop. While we can get pretty close based on our work from the CS Mazdaspeed Intercoolers, it’s always best to test and identify the best one for each platform. With this extensive testing, we can reach our goal of improved cooling efficiency, lower pressure drop, more power, and no CELs.

End-tank design is critical as it determines how the air reaches the core of the intercooler. Sharp bends, poor air distribution, and small inlet/outlet size all adversely affect the performance of the intercooler. To fit the core size we want, we had to do away with the plastic inlet and outlet pipes of the stock intercooler. This was advantageous as it gave us more room to have a smooth-flowing end-tank that distributes air well to all the runners and does away with the sharp corners present in the OEM end-tanks. In addition, we were able to increase the inlet and outlet size of the intercooler to 2.5”. This is a fairly standard size that has shown to work well for the Mazdaspeeds with stock power and without choking flow way up to Barett’s 600+ WHP.

CAD design of the 2.5T SkyActiv Intecooler

Those of you with a keen eye have realized that the connection between the CorkSport front mount intercooler (FMIC) and the OEM Intercooler is not the same. As shown in the CAD rendering above, each intercooler kit will come with the silicone and custom adapters that are needed to work with the OEM piping. If you decide to upgrade to the CS intercooler piping kit, later on, the CorkSport Intercooler for SkyActiv 2.5T will not need to be removed, and you will only need to change some silicone parts.

We will have more info on this kit coming soon, with the next blog covering our testing of the different core designs using a few new toys from AEM Electronics. Be sure to check out the product listing for more info, and to be notified when the intercooler is available. Last but not least, CX-9 Turbo and CX-5 Turbo owners, we are 99% sure this kit will also work on your rides but we plan on validating fitment before release!

-Daniel @ CorkSport

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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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February 7, 2019September 27, 2023

Mazda 6 2.5T Stock Spring Evaluation

Today we’re taking another dive into OEM Mazda parts to better understand how they function. Specifically, OEM suspension springs, since there are CorkSport Lowering Springs coming soon for the 2018+ Mazda 6 2.5T. While a simple concept, springs are very important to the handling, appearance, and comfort of your vehicle.

The new Mazda 6 Turbo uses a lot of the same components as the GEN 3 Mazda 3 and Mazda 6, however, the suspension has been optimized for the new “premium” feel and to deal with the extra weight that comes when adding a turbo. The SkyActiv chassis has primarily remained the same though, with the same MacPherson strut front suspension and multi-link rear suspension shown below.

Now, onto the springs themselves; both the front and rear suspension of the Mazda 6 use standard compression springs. The spring’s job is to support the weight of the vehicle when at rest and adsorb impacts when hitting bumps or going quickly around a corner. That’s it. Seems simple enough right? Since the springs are the parts of the suspension that “suspends” the vehicle though, their characteristics and how they interact with the rest of the suspension system are critical.

Lowering springs design by CorkSport for Mazda 6

There are two main characteristics that define a spring: rate and free length. Both are pretty easy to understand. Free length is simply the length of the spring with no weight or force acting on it. So set a spring by itself on a table, measure how tall it is, and there’s your free length.

Spring rate is a little more complex, as it is the measure of how much weight it takes to compress a spring a given distance. So, if you have the same weight and put it on two different springs the one with the higher rate will compress less. The rate is usually measured in kg/mm (often shortened to K) or lbs/in.

For example, if you had a 2K spring and a 4K spring and applied 100kg to each, the 2K would compress 50mm and the 4K would only compress 25mm.

The spring view of the CorkSport Mazda springs

What do these measures mean for your car though? If we keep the rate the same but only change the free length, the shorter the spring, the lower the car. For a given car, a spring can be too short, causing poor ride (sitting on the bump stops all the time), or the risk of a spring coming out of place, causing noises or at worst, the spring falling out of the vehicle.

If we change the spring rate and leave the free length the same, things are a little more complicated. The higher the rate, the stiffer the ride is, plus your ride height will increase. Since the weight of the car is not changing, the higher rate spring will now compress less when the car sits on it, meaning your car sits higher at rest. Too large of a rate and your OEM shocks cannot keep up causing a bouncy ride, and vice-versa if too soft you are hitting bump stops over the smallest bump. Obviously, there is a balancing act to get the spring rate and free length correct for the application for the best in appearance, handling, and comfort.

Mazda 6 2.5L Turbo with lowering springs

Now that the basics are covered, let’s look specifically at the Mazda 6 2.5T. The OEM springs give a good ride as to be expected (likely very soft spring rates) as this can be a huge issue for potential customers if the car ride quality is harsh. Handling is decent overall but has a few quirks. When going around a corner quickly, the car rolls over onto the rear springs excessively before settling and getting through the corner. When at the limit of traction, the car understeers severely, like most cars sold today.

Finally, the ride height is pretty high, likely to prevent any issue with driveways saying hello to the new front fascia. Interestingly, the MZ6T sits a little higher in the rear; we think it ensures enough suspension travel in case there’s a full load of passengers and a full trunk.

Side view of Mazdsa 6 Turbo lowering springs height

For further analysis, we also had the OEM springs tested for rate and ended up with the following: 3.05K front, 5.05K rear. While these numbers are fairly arbitrary right now, they are a necessary data point to have when designing lowering springs. These rates also contradict a very common misconception. Many people think that because there is less weight in the rear of a front-wheel drive car, the spring rates must be softer in the rear for a good ride & handling. This is simply not true in most cases, after all why would Mazda do the opposite? Due to the design of the rear suspension, the spring is basically being pushed on by a lever. This means the spring needs to be stiffer in order to support the same amount of weight as if the lever wasn’t there.

So overall, the OEM springs are good, but have plenty of room for improvement. I just touched the surface of suspension design and as we go through more of this project we’ll get into dampers, natural frequency, and much more. Stay tuned for more info and if you have any questions, don’t be afraid to ask! Check out the release blog for the Mazda 6 lowering springs.

-Daniel @ CorkSport

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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.

Stay Up-to-date with CorkSport

-Daniel @ CorkSport

Connect with us

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

Stay Up-to-date with CorkSport

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.

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