Zach’s Road to CorkSport

The Journey to CorkSport

Ever wonder what it was like to win the lottery. You ever let your mind wander and think what it would be like to actually “Live the dream.” I know I have, well, until I joined CorkSport! My name is Zach Sprague, and I wanted to share with you my experience of joining, what I believe to be, the best well known and respected company in the Mazda Community. Let’s take a look at my journey.

I’ve always been into cars and have had a pretty big obsession with FWD Hatchbacks. My passion for this platform started back in 2014. I sold cars for Toyota in Southwest Washington for about four years. During my tenure, I drove some pretty amazing vehicles, one of them being a 2013 VRM MS3 Tech pack. I knew what a Mazdaspeed was, a Turbo FWD Hatchback, and at that time that was more than enough to pique my interest in the platform. It was temporarily sitting on my lot, and I had to drive it back down to Portland to our sister store.

Before jumping into the seat, I didn’t know any horsepower or torque figures. I didn’t know what kind of emotion it was going to spark when I drove it. I had NO idea that it would become the screen saver on my computer. I slid in and pushed the button. (You know those Cold Starts) This car’s exhaust made my heart drop and gave me goosebumps. I honestly felt like an 8-year-old on Christmas Morning. 

Once on the ramp, I slowly shift into third at about three and a half grand on the tach and just sent it. Torque steer was prevalent as I was gently pushed back into my seat. I slammed 4th, and I hear this intoxicating PSSHHHHHH. I was done, I was hooked, addicted and didn’t know what to do with myself. I was so intrigued I stopped at every rest stop on the way down so that I could feel this car accelerate back onto the freeway. <insert uncontrolled giggling here>.

Flash forward a couple of years, and a guy I worked with, now one of my best friends, went out and bought a VRM Speed6. Everything on that car from top to bottom was stock down to the wheels. I slowly watched his build progress over the year and transform into one of the most inspiring builds I have ever seen. In that time he was kind enough to let me pick his brain about these cars and what they like, what they don’t like.

In 2018 this is when things got interesting! After a few months of looking and 100 YouTube videos later, I was finally ready to pull the trigger on one of my bucket list cars. I snagged a 2013 MazdaSpeed3 in liquid Silver. I drove almost 4 hours and paid an arm and a leg for sales tax, but it was worth it.

Miles of Smiles 

I was grinning ear to ear the entire way home; 4th gear dumps on the freeway, testing the grip of the tires out at a few stoplights, full-on shenanigans. I tell you what; I made it home a lot quicker than the drive up.  

I had the car for 3 weeks before I added my first mod. I already had a vision for the car, but first things first, I had to take care of those sloppy shifts. My shifter bushings and short shift plate showed up from CorkSport. At that time I knew they made great parts and were one of the very few places that even made parts for this car. What a difference that made! It felt robust and more responsive.

The Opportunity of a Lifetime

I always joked with my friends about working for a company like CorkSport. I just thought it was this elusive dream that I’d be sitting behind a desk helping other people build their dream cars. I never thought in my life that an opportunity like this would come into fruition. 

My buddy, who helped me get into Mazdaspeeds, sent me a message on FB, letting me know that CS was hiring. I thought to myself; this is no lie. “There is no way on god’s green earth I’d ever get that lucky.” However, I applied. What’s the worst thing that could happen, right? 

CorkSport isn’t a revolving door, and the team is made up of a close-knit group of professionals that also happen to be car nuts. They carefully consider who’s going to be a good fit with their existing team and identify candidates that are going to get the right shit done well. I knew this was a different company, and their standards were high because they didn’t just accept my resume; there was a pre-test.  

A funny little story. I got a message from CorkSport saying they wanted to set up a phone interview! I couldn’t believe it! That Friday, I called to set up a meeting for Monday. This is where the humor known as my life kicked in; I BROKE MY PHONE ON SUNDAY! *RED ALERT* My dream job was calling me on Monday, and I didn’t have a phone, so I went out and bought a little prepaid flip phone. 

Although I almost missed this opportunity, it went well enough for CorkSport to schedule a second interview over Skype. I must add, this occurred over two weeks. I was losing my mind; I couldn’t believe it was happening. All my buddies knew I had the job, they knew how obsessed I am with cars, especially my speed 3. I still was in shock couldn’t believe I had my second interview.

When CorkSport called me to let me know, I had a final interview with the Company’s President, Corey – Hello nervousness, glad to see you again! I can’t put into words how excited I was; it was pure bliss and absolute disbelief. “IS THIS REALLY HAPPENING!” I screamed at the top of my lungs when I got off the phone. I showed up a half-hour early. It was cool; I got to meet someone I’ve stalked on Instagram for a while and who has been a significant influence on me since I got into the Mazda community – Brett White.

It’s so surreal when you get an interview for a job you’ve always wanted. Above all, I remember from the interview is telling Corey, “Even if I don’t get the job, knowing I made it this far and am sitting here with you having this interview is honestly a dream come true.” It’s unreal to think that one mistake, such as breaking my phone the day before my first interview, could have kept me from writing this blog for a company I’ve looked up to since I’ve been into Mazda’s.

I cannot believe I’ve been here a little over a year already! It’s a fun environment where everyone is looking out for one another. I’ve been able to FLY in the fastest thing I’ve ever been in (Barett’s monster Gen Juan), and had the chance to drive a car I’ve drooled over on social media (Brett’s Baby) for years. 

Barett’s monster Gen Juan

Looking back, it wasn’t even four days after joining the company before the guys a CS put lowering springs on my car. It took a little over a week for me to buy an AccessPort and a Dual VTA Bypass Valve, and that was just the start! You don’t want to be an employee driving a stock Speed with a CorkSport Sticker on it.

Stay tuned to see where CorkSport and I go with my car. I’ll catch you on the flipside and, thanks for reading my first blog!

Zäch Fröm CorkSport

CST5 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.

We started with the internal wastegate option, to validate the CST5 for drop-in fitment. Since we’ve had 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 fit 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!

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 that 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 can be tuned to be stock block friendly and still make good power.

Then came the testing on the EWG variant of the CST5. We had developed fitment for the CST6 which meant the CST5 had no issues upon install on both MS3 and MS6. 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 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 and the upcoming CST6 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

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 Mazda6 Turbo uses a lot of the same components as the GEN3 Mazda3 and Mazda6, 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 largely 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 springs 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.

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, 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.

What do these measures mean for your car though? If we keep the rate the same but only change 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.

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 to ensure enough suspension travel in case there’s a full load of passengers and a full trunk.

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!

-Daniel @ CorkSport

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

CorkSport Mazda6 2.5T Boost Tube

We are proud to release the https://corksport.com/2018-mazda-6-2.5l-turbo-boost-tubes.htmlCorkSport Upgraded Boost Tube for 2018+ Mazda 6 2.5T and 2016+ CX-9 2.5T. The CorkSport boost tube is larger, stronger, more reliable, and of course better looking than the OEM rubber tube. Increase throttle response down low, hit boost targets easier and future proof your ride for mods down the road with a simple 1-hour install. Read on for full details and be sure to check out the R&D blogs here and here for the backstory.

In case you haven’t read the previous blog installments, the CorkSport Boost Tube improves on the OEM boost tube by first strengthening the tube. Instead of using rubber with one reinforcement layer, the CS boost tube use silicone with 5 layers of reinforcement. Aside from the extra layers of reinforcement, silicone stays strong at high engine bay temperatures that may cause rubber to flex excessively. In addition, silicone lasts longer and will better resist cracking as your Mazda 6 Turbo ages. The OEM boost tube is made from materials very similar to the OEM Mazdaspeed 3 boost tubes that showed signs from aging extremely quickly, especially when subjected to higher than OEM boost levels. Cracking or splitting of the OEM tubes results in boost leaks and a poorly running car, definitely not what you want from your brand new SkyActiv 2.5T.

The added strength prevents the CorkSport Upgraded Boost Tube from expanding excessively when subjected to pressure. When pressure tested at 20psi (the largest pressure we have seen at the intercooler outlet), the OEM tube was shown to expand 12% at the internal cross-sectional area. The CS tube tested under the same conditions expanded 3x LESS. This difference would get even larger when subjected to the same pressure at a higher temperature. What does this mean for performance though? When you get on the gas, the boosted air will have to expand the tube before it can enter your engine. The less the tube expands, the easier it is to hit boost targets, and the better throttle response you have, especially down low in the RPM range.

The CS Boost Tube also is a larger inside diameter than your OEM tube. It is 3” through the middle vs. the OEM ~2.44”. Since this area of the charge piping system is directly ahead of the throttle body, this large volume of air has the same effect as it does with our GEN2 Mazdaspeed3 FMIC kit, reducing boost lag and increasing throttle response. For full info on why this happens, check out the release blog for that kit here. As a basic overview, the large volume of air right before the throttle body fools the engine into thinking it has a larger intake manifold plenum than it really does. While not as severe of an effect with just changing this boost tube, try it for yourself and see what you think!

Installing the boost tube is a little tricky due to where it is located, but we include high quality installation instructions to make it easier. Even so, it can be installed in an hour or less in most cases. We also include polished stainless steel T-bolt clamps to ensure a complete seal and add a subtle visual boost.

Be sure to check out the product listing for more pictures, the install instructions, and a detailed product video. Let us know if you have any questions, we’ll be sure to help you any way we can!
Lastly, if any of you are looking for a more serious upgrade, stay patient, our FMIC upgrade & full piping upgrade kit are coming soon!