Mazdaslow to Mazdaspeed

Let me take you to an extraordinarily dull time in my life, the last time I started my Mazdaspeed when it was still stock.

September 14th, 2018 was a beautiful September day in Washington. I started my car at 6:45 am, just like every other weekday. The Speed3 burbled to life, but it was relatively quiet, flat, and a bit uninteresting. No one knew I was leaving for work – I wasn’t shaking any windows, but that was going to change.

CorkSport mod budget. Employee incentive.
At CorkSport

Once I arrived at work and spread some Friday cheer, I settled in. Almost immediately, I could feel the pile of parts in the corner behind my desk, glaring at the back of my head. I thought to myself, “Don’t turn around – focus damn it!” The day had finally come – install day. Thankfully with our awesome half-day Fridays, I was out of the office and on my way to Brett’s house before 12:30 pm.ย 

After we loaded up Brett’s Rodeo with a load of parts, we set sail to our destination, a place where many tears have been shed, knuckles have been busted, and where dreams have come true; Brett’s garage. Every tool you’ve ever needed and gadgets you didn’t know existed. There were even a few specialty items present, that if he didn’t have quite frankly, this couldn’t have happened.

CorkSport employee mazdaspeed getting washed
Shop all Mazdaspeed 3 Parts

We started with thorough degreasing of the engine bay and setting up the essential supplies- because what is an install day without beer and snacks! Once the car has cooled down, I started with taking out the battery box, intake, and intercooler; and then the fun really started. I’ve read the horror stories, I’ve watched the videos, and I thought I spent enough time mentally preparing myself for what was about to come – I was wrong.

The Downpipe

We all know about the Mazdaspeed downpipe on our cars. The devil engineered the placement of this thing, and he had his minions tighten the bolts. There isn’t enough PB blaster in the world to help the corrosion and excessive heat that these bolts withstand. We got the first one out with little to no issue, but it just got progressively harder from there. It was only a matter of time before rounding off the edges of that last bolt. Thankfully Brett has an extractor tool that we hammered on there, and with the small act of god, it was successfully extracted.

My experience with removing the downpipe from the exhaust, as is everyone’s experience, was different. Mine was influenced by the previous owner adding a 2.5″ resonated exhaust on it from the second cat back. The downpipe didn’t want to come out until I wiggled a pry bar in between the flange and put Brett’s Caliper spreader in there (again tools I didn’t even know I needed) and applied sheer grunt force. I got the flange to bend, and after learning a few new choice words, we got it out. By this time, it was 11:30 pm, and we still had a few other things to unbolt before the exhaust came out. Instead of using power tools and waking every neighbor up in a two-block radius, we called it a night.

The Morning After

After some much-needed coffee, we made it back from the hardware store (replaced the downpipe nut from hell) it’s time to party. We started with sliding in my new downpipe with the High flow Cat what a breeze compared to taking it out. Next came my intake, I went with the 3.5″ so I don’t have to buy another one when I finally go with our CorkSport CST4 turbo. Still might go with the new CST5. Then I put in my ECU Relocation Box, and I have to say, what a clean looking piece to have in your engine bay! 

CorkSport Mazdaspeed engine bay parts TMIC with Intake, battery box, turbo
Mazdaspeed 3 TMIC Top Mount Intercooler

We changed out the OEM spark plugs for some NGK 6510 gapped to .026 and started to put on my new TMIC that is rated up to 450WHP after we got the TMIC it was time to put on my shiny new boost tubes Engine bay= Complete.

Now time to get underneath and put on my highly anticipated Non-Resonated Cat-Back exhaust and my Stage II RMM. Goodbye, torque steer! Once we had the exhaust mostly in place, I realized if I didn’t have the CS exhaust hangers I would have been in trouble. The person before me had his exhaust welded quite poorly in place of the hangers, and I didn’t have an option to use my OEM ones. 

Moment of Truth

After everything was double-checked and rechecked, it was time for the moment of truth. I hooked up my battery, I flashed my new tune from Erik Bjork at Drama Tune, and now it was Go Time! I will say hearing my car make those sweet sounds was one of the best moments of my life. I’ve been waiting for this moment since I purchased my car, and it was one of the most surreal experiences I have ever had.

We let the car run for a few minutes and checked to make sure I didn’t have any leaks, and then we headed out for a test drive.

In the immortal words of George Takei “Oh My!”

That was my thought, EVEN on just a base map. My car felt and sounded 1000% different than before. The intake was amplifying fun new mechanical noises – like I was hearing my turbo and BOV dance for the first time. The crackle from the exhaust on a hard 2nd to 3rd upshift was intoxicating, all the while my RMM putting in work to make sure I didn’t torque steer into someone’s front lawn. What an experience! I would even call this life-changing for me. The funny part of the story is that I wasn’t planning on buying all these items at once – true intentions of a foolish car enthusiast. Thankfully for me, I have a fantastic career within CorkSport and have a great friend who helped me make my dreams come true. Who wants a stock car when you work for the number one place in the world for Mazda Performance, not this guy?

Mazdaspeed 3 2010-2013 Front Gray with CorkSport hood scoop
Zach from CorkSport

Keep an eye out for my turbo blog, because it’s only a matter of time until the mod bug bites me again.

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Inside look: CorkSport Mazdaspeed Turbo Design

The development and evolution of the CorkSport Performance CST5 and CST6 turbochargers are uniquely intertwined. ย ย Weโ€™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 internal wastegate system. ย Something had to giveโ€ฆwe 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 Mazdaspeed Turbo Billet Compressor
CST5 Billet Compressor

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

CST5 Wheel Design

CST5 Turbine for the Mazdaspeed turbo
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 Mazdaspeed Turbo. Letโ€™s see how and why below.

If you are unsure of the turbine wheel size donโ€™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 Mazdaspeed Turbo
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 โ€œopenโ€ area through the turbine wheel exducer is increased which increases the peak flow potential for top-end power.

Mazdaspeed Turbo Inducer & Exducer

Inducer & Exducer Comparison for the Mazdaspeed turbo and K04
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.  

Size Matters in the Mazdaspeed Turbo

Mazdaspeed CST5 turbo 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 โ€œlazyโ€ 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 turbo for the Mazdaspeed

So why does this work?  Well, letโ€™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 Turbo 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

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Product Release: 2010-2013 Mazdaspeed 3 Exhaust Mid Pipe

CorkSport is happy to announce the release of our long awaited 2010-2013 Mazdaspeed 3 Exhaust Mid Pipe. Designed by our engineers to be a simple, bolt on upgrade for your Mazdaspeed 3. The CorkSport mid pipe changes the exhaust note only slightly and gives a pleasant tone unlike some Mazdaspeed exhausts on the market which can sound hollow and buzzy. The exhaust features 80mm piping and a single resonator, all constructed from T304 Stainless Steel.

Mazdaspeed 3 exhaust mid pipe

As with all of our CorkSport exhaust components, the Mazdaspeed 3 mid pipe features mandrel bent, polished stainless steel T304 construction for corrosion resistance and a clean stylish look. It has a distinctive performance sound that is mild but noticeable at cruise and idle but packs a bit more of a rumble when you’re really getting on the throttle.

For more information please visit our Mazdaspeed 3 Exhaust Mid Pipe product listing for details.

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