Mazdaspeed Cast Exhaust Manifold

Today is a huge day for the Speed community; one that has been coming for a long time with both celebration and frustration. Never the less time is up and this project is ready for the community as a whole!

We are proud to announce the Performance Exhaust Manifold for the Mazdaspeed 3 & 6! With over 2 years in development, the MPS exhaust manifold has been long waiting, but for good reason. A project of this scale does not happen overnight; many variables have to be considered, evaluated, and verified.  

I’m confident you have seen “leaked” images from our 6 Alpha and Beta testers over the recent month, but we can make it official.  

CorkSport

But with so many options currently available what makes the CorkSport option compelling? Why should you care?  

That’s a great question and one that can easily be answered with multiple great reasons. The most obvious is the design: this includes the overall shape and the type of material & manufacturing.  

Mazdaspeed Exhaust Manifold

Material & Manufacturing: In our initial investigation and vetting of this project we strongly considered two primary manufacturing methods; Casting and Tubular fabrication (check out the blog here). In a nutshell, we opted for a cast manufacturing method because it reduced the chance of failure modes, reduced the overall size and weight, and gave us more flexibility in design.  

Like most exhaust manifolds, we opted to use 304 stainless steel because it is corrosion-resistant, handles heat well, and is a common and cost-effective material.  

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Following up is Design: The list of details that went into the design is far too long to list here, but we can cover the major items that define the CS Exhaust Mani. With investment casting, we had a lot more flexibility in design with the bend radius, diameters, and wall thickness of the individual runners. This allowed us to increase the inner diameter of the runners to 1.59 inches, achieve a 0.200-inch wall thickness, and fine-tune the path and bends of each runner to optimize runner length and flow.  

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With that flexibility in design, we were able to increase peak flow and improve flow balance per runner. Overall we were able to increase peak flow 45% over the OEM manifold and 33% over the XS Power V3.  

Next up in design, and arguably the most exciting and unique aspect, is the modular flange system.  

Mazdaspeed Exhaust Manifold

This is unlike any other manifold available for the Mazdaspeed today…you can choose your flange between OEM Stock Flange, Precision V-Band, or T3. Sure all these options are available today from other options, but none are modular. Say you pull the trigger on the OE Stock Flange today, but a year from now you want to upgrade your build to a Precision V-band flange. With any other manifold, you would have to buy another $900+ manifold to get the new flange, but with the CorkSport Exhaust Manifold, you just have to get the new flange elbow for your setup. This is MUCH MUCH cheaper and easier to change!

CorkSport

Speaking of install, compared to the typical performance exhaust manifold the CS design is cake to install. With the modular design, you are not fighting the entire bulk for the manifold and flange at the same time. You can leave you turbocharger unmoved connected to the downpipe and intake system, you just install the flange elbow after the manifold is in and bolted to the engine.  

Mazdaspeed Exhaust Manifold

Making life even easier…we opted to develop a pre-fabbed dump tube (screamer pipe) for the Tial 44mm EWG. This is an optional feature for the kit, but one we highly suggest because it’s just so damned easy. Designed for MPS 3 and MPS 6, it fits around most standard downpipes and dumps below the sub-frame right behind the drive axle. Also included with each kit is a SS heat shield that is required for the GEN1 and GEN2 Mazdaspeed 3. You Mazdaspeed 6 guys just get a cool garage ornament.  

So how does the CS exhaust manifold stack up on power? 

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First up is a fully bolted CST4 MS3 with a 6th port fuel system: Comparing the CS EM to the OEM EM, this drop-in test we found that the turbo was spooling faster, carried more mid and upper range power and held that gain through to redline. Overall it improved power under that curve which is what truly makes a car fast and fun to drive.  

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Next up is a fully bolted and built CST6 MS3 with 8th port fuel system: Just like the previous graph, we saw an improvement in spool, mid and upper rpm ranges, and carried it to redline. The difference here is the exhaust manifold we are comparing. This is showing the difference between the CS EM and the XS Power V3.  

With that being said, the CorkSport Exhaust Mani has been proven to 685whp on this same car and with the CST6. We are confident the CS exhaust manifold has far more capacity to support; if we have anything to do with that we will prove it. 

Mazdaspeed Exhaust Manifold

Lastly is sound…we’ve been asked a lot about the sound. How will it affect the sound? Will it sound like a Honda now? Will it be louder?  

We knew the sound was critical because let’s be honest…we are all car guys/gals and Mazdaspeed has a great unique sound to it. We did not want to lose that so we did our best to hit performance goals without sacrificing the Mazdaspeed grumble.  

One of our Beta testers put together a great video comparing the sound of OEM vs CorkSport. The car is a GEN1 MS3 with a built engine, full bolt-ons, CST4, and Cobb Exhaust system. Check out this video link for sound!

In our design, we kept a varied length runner design to help maintain the Mazdaspeed grumble. We believe we succeeded in keeping that classic grumble, but also refined the sound a bit. We like to describe it as exotic. Either way, the grumble lives on, and honestly, none of our beta testers can stop grinning ear to ear with every WOT pull.  

With that being said act fast! We know these are going to fly off the shelf and we are going to do our damn very best to keep them in stock for everyone, but don’t wait!

Grab yours here!

Thanks for tuning in with CorkSport Mazda Performance.  

-Barett @ CS

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.

2007-2009 Mazdaspeed 3 Crashbar

Now, with the 4th 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. 

Gen 1 Mazdaspeed Parts

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.

Splitter Mount
CorkSport

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).

CorkSport

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 2nd 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.

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.

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.

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.

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

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

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.  

Compressor Wheel

CST6 Mazdaspeed Turbo

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

CST6 Turbo Backside

Unlike the CST4 and CST5, the CST6 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 for 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.

Compressor Wheel

CST6 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

CST6 Turbine Wheel

The initial testing of the CST6 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.

Turbo Internal Wastegate Housing

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.  

CST6 IWG vs EWG

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 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