2018+ Mazda6 Performance Exhaust for the 2018-up 2.5T

Mazda did a great job bringing a turbocharged engine back to the Mazda 6 (Mazda 3 next please?), but may have done too good of a job of keeping it quiet. Say hello to the CorkSport 80mm Cat Back Exhaust and Axle Back Exhaust for 2018+ Mazda6 equipped with the turbocharged 2.5L engine. If you’re interested in waking up your SkyActiv-T in both excitement and power, read on as we breakdown the newest CS exhaust.

As with all CorkSport exhausts, the goal of the MZ6 2.5T exhaust is to improve power and sound by improving the flow of the OEM exhaust. We started by increasing the size of the piping from 60mm to 80mm. That is an increase of over three-quarters of an inch to really help your turbocharger breathe better. In addition, the CS exhaust system eliminates the crushed areas present in the OEM exhaust and replaces the restrictive muffler sections with pass-through resonators. These resonators control volume and drone without affecting power output.

All that extra flow does mean a power increase. In our in-house dyno testing, we saw an increase in 5-6WHP just by bolting on the CorkSport  Cat Back Exhaust. Check out the dyno sheet down below to see. This increase came with no tuning changes, no check engine lights, and the only other mod being the CorkSport Short Ram Intake, which was installed for both tests. With the 80mm piping size, this exhaust is ready to support future modifications and would likely show more power gains with proper tuning.

The CorkSport MZ6T exhaust is more than just function. We went through multiple iterations and designs to ensure the best sounding exhaust for your 6. The finished product ups the volume without being annoying to daily drive yet still sounds great when in hard acceleration. We strongly recommend you watch the video below to hear what to expect from this exhaust.

If you feel the video below gives you too much volume for the daily, then check out the Axle Back Only Exhaust.  Recently added to the CorkSport line-up, the Axle Back alone adds a mellower, but still noticeable tone to the exhaust.  This is a great middle ground between the CorkSport Cat Back and the stock exhaust.

To give a great looking, long-lasting finish to each exhaust, they are manufactured from fully polished 304 stainless steel. To ensure a high quality fitment, all components are precision TIG welded together on jigs made from OEM exhaust components. Lastly as a finishing touch, we use 100mm dual wall exhaust tips. They fill out the bumper cutouts and are extended slightly to give a classy look and enhance the new Mazda 6’s styling.

The CS Mazda 6 Turbo Exhaust comes with all the hardware and gaskets you need for installation, high quality instructions, and CorkSport support for any questions you may have. Pick up a CorkSport MZ6 2.5T Exhaust today and liven up that daily commute.

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

Mazdaspeed 3 4.5 bar MAP sensor

We are proud to introduce the release of a new product: the CorkSport 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!

Mazdaspeed 3 4.5 bar 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

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.

Speed3 3 bar MAP sensor

Mazdaspeed 3 Exhaust Manifold Break Down

Today we want to break down the OEM exhaust manifold for the Mazdaspeed platform so that you can better understand how and why the CorkSport Manifold makes power.  

If you haven’t heard, CorkSport has been developing a performance cast exhaust manifold for the Mazdaspeed platform.  We’ve tested and validated samples on Mazdaspeeds ranging from 350whp to 684whp. We’ve done dyno testing on the OEM exhaust manifold vs the CS manifold, as well as on the XS Power V3 manifold vs the CS manifold with the man, Will Dawson of Purple Drank Tuning, setting the calibrations. Both tests showed good gains from just the CorkSport Exhaust Manifold alone.   However, we can get into those details later.  

Mazda Exhaust Manifold Design

Mazdaspeed Exhaust Manifold Flange
OEM Exhaust Manifold Flange

This is the OEM (original equipment manufacturer) exhaust manifold found on the 2007-2013 Mazdaspeed 3 and 2006-2007 Mazdaspeed 6.  Manufactured from cast iron and very compact in design, the OEM design leaves A LOT on the table in the performance department.   

In the image, we’ve labeled each cylinder since that will be important for later discussion.  

OEM Manifold Exhaust Flow

So now let’s talk flow.  Fluids (or exhaust gases in this situation), will always take the path of least resistance.  When the flow path is not clearly defined for the exhaust gas, such as a merge between different cylinders, turbulence is created which reduces the efficiency of the exhaust manifold. 

A prime example of turbulence is shown in the image above with the orange arrows at the merge for cylinder 1 and cylinder 2.  Cylinder 2 comes to a “T” and therefore could flow left or right.  This creates turbulence which causes a loss in potential power.  

Next is the yellow arrow.  This is identifying the inner diameter of the runners in the OEM exhaust manifold.  To our surprise, the inner diameter of the OEM exhaust manifold is actually pretty decent at ~1.48 inches.  This diameter partially defines the power a manifold can support efficiently. Bigger is better in this situation, but small changes here will make big differences in the final performance. 

Surprisingly, there are “performance” exhaust manifolds on the market for the Mazdaspeed platform that have smaller inner diameter runners… 

Mazdaspeed Exhaust Manifold Gasket
OEM Exhaust Manifold Gasket

We also wanted to point out an unusual but important aspect of the Mazdaspeed exhaust manifold and gasket.  Have you ever noticed the seemingly useless extend flange off of cylinder 4? This extended flange acts as part of the passage for the exhaust gas recirculation port.  

You can more clearly see this port path in the gasket.  

OEM Exhaust Manifold
OEM Exhaust Manifold

Designing For Efficiency

In this image, we want to direct your attention to a very unique and troubling design feature of the OEM exhaust manifold.  There is a right way and wrong way to pair cylinders on an exhaust manifold for a 4 cylinder engine… and this is the wrong way. 

Referencing our cylinder callouts in the first image above; you can see that the OEM design pair cylinder 1 & 2 together and cylinder 3 & 4 together.  This design physically works, but it is not ideal from a performance standpoint. In a divided manifold you should pair cylinders 1 & 4 together and cylinders 2 & 3 together for optimal cylinder exhaust gas scavenging. To learn more about exhaust scavenging you can check out a blog on that here, or watch the video below!

Exhaust Gas Scavenging. See the difference between the CS and OEM Manifolds.

Before we wrap here we do have one good thing to say about the OEM exhaust manifold.  It does sound really good and gives the Mazdaspeed platform a unique exhaust note, but don’t worry you don’t lose your unique rumble with the CorkSport design.   

Thanks for checking in with CorkSport Mazda Performance.  Stay tuned for more info about the CorkSport Performance Exhaust Manifold.  

-Barett @ CS

Testing & Validation: CorkSport 2.5L SkyActiv Race Header

mazda 6 exhaust header

Over the past few months, we’ve been teasing you with tidbits of info on the CorkSport Race Header for the Mazda 3 2.5L SkyActiv-G in the GEN3’s. Today’s blog is a big one as we go through the testing we performed on the header and share some results, including power! Before we get too deep though, be sure to get up to speed with a breakdown of the OEM header and our design goals for the CS header.

mazda 3 skyactiv header
2014+ Mazda 3 Header Installed

Addressing Underhood Heat

In our previous blog, some of you keen-eyed individuals were asking about underhood temperatures with the ram-horn style CorkSport header. Well, we went through testing to ensure everything will function as before when the new header is added. We’re happy to let you know that we saw very similar under the hood temperatures as the OEM header. As a double check, we applied some temperature sensitive stickers to some areas near to the CS header, as shown below. These stickers will fill in with color if a temperature listed is reached. While these ended up reaching higher temps than with the OEM header, no areas are at risk of damage or malfunction. Furthermore, both the CorkSport racecar and our beta tester have run the 2014+ Mazda 3 race header at the track with no issues with overheating, power losses, or engine bay damage!

2.5l SkyActive Race Header testing
2.5l SkyActive Race Header testing with temperature sensitive stickers

How Does The Header Sound?

Before we get into the really good stuff, let’s go through a side effect of freeing up the headers on any engine: volume. We tested the Mazda 3 SkyActiv race header with multiple different setups: OEM cat back, CS 60mm cat back, CS 80mm cat back, and straight pipe. The race header on an OEM cat back is something that will not likely be used often (who runs a racecar with a stock exhaust?) but offers some nice growl and extra volume over the OEM exhaust. Both the CS 60mm and 80mm exhausts sound fantastic, with the 80mm being louder and having higher power potential than the 60mm. Even so, the 80mm is not uncomfortably loud and could be daily driven if full catalytic converter deletes are street legal in your area. We cannot recommend the straight pipe though. It is extremely loud and very uncomfortable. If you want a tease of sound with the 80mm cat back, check out our feature on our beta tester’s car in the video below.

80mm Cat Back with the 2014+ Mazda 3 Header!

The SkyActiv-G Race Header Adds Power

Full Race Header for the Mazda 2.5l SkyActiv Engine
Full Race Header for the 2.5l SkyActiv Engine

Alright, I’ve kept you waiting long enough, let’s talk power. The 4-2-1 design is very evident in our tests, as we did not see huge gains at peak WHP/WTQ. We did see very good gains throughout the midrange. From 2000RPM or lower all the way up to about 5300RPM we made 4-8WHP and 5-15WTQ. On our beta tester’s car with a good tune and supporting mods, this meant 194WHP and 226WTQ on 91 octane pump gas. The graph below shows a direct comparison of a 2016 Mazda 6 with a CS short ram intake, CS 60mm exhaust, and the same tune with and without the race header. Keep in mind, there is more optimization to be had with tuning with the header installed, and greater gains with an 80mm exhaust. The midrange gain may not seem like much but is extremely noticeable when driving the car.

Mazda 6 Race Header Dynograph
Comparison of a 2016 Mazda 6 with a CS short ram intake, CS 60mm exhaust, and the same tune with and without the race header.

That’s about it for our testing and validation blog. Next time you’ll hear about the CorkSport Race Header for the 2014+ Mazda 3, it will be released! Be sure to stay tuned to all the CS channels if you’re interested in being one of the first to pick one up.

-Barett @ CorkSport

P.S. We noticed a lot of you asking if this header will fit the auto transmission or 2.0L. The automatic transmission is 2-3” larger right where the lower section of the header sits, so for optimum pipe routing, we had to do away with automatic fitment. The 2.0L has a different bolt pattern and exhaust port spacing on the engine, so the 2.0L will not work with the CS race header either.

Please
submit a product idea here if you would like to see automatic fitment, 2.0L fitment, or any other product for your car. The more submissions, the more likely we are to produce one so tell your car buddies!

SkyActiv-G 2.5T Intercooler & Piping Testing

The CorkSport Intercooler and Piping upgrade kits for the Mazda SkyActiv-G 2.5T are inching closer to release and it’s time to share more of the R&D that goes into making these kits perform the best. We went through extensive testing to determine which intercooler was the best fit and to validate that our changes were worthwhile. If you missed any of the previous blogs on these kits be sure to check them out: OEM IC & Piping Breakdown, CS Piping Upgrade Design, and CS Intercooler Design.

AEM CD-5 Digital Dash on Mazda 6

AEM CD-5 Digital Dash

Testing Preparation

To start, we got some new toys from AEM Electronics. The main brain of the entire testing operation for the intercooler is an AEM CD-5L digital dash with logging. This dash allows us to tap into the vehicle’s ECU to see the same information that the OEM sensors are reading. To go along with the CD-5L, we got new AEM sensors that can be positioned to get the data that we need to see how our intercoolers perform.

We used the CD-5 to datalog our dyno runs so we can see what the car is doing while simultaneously seeing power levels from the dyno. To get the data we need, we tapped into the OEM intercooler and 3 intercooler core designs that we created to get pressure and temperature data before and after the intercooler core. In case you were wondering, drilling into a brand new intercooler is stressful!

Mazda 6 on Dyno
SkyActiv-G 2.5T Intercooler Testing

Once we got everything wired up and the AEM properly set up, we were ready for testing to begin. There were multiple rounds of testing, each consisting of a string of dyno pulls back-to-back to test heat soak. We also performed standalone power runs with the intercooler setups. During testing, we used the full OEM intercooler and piping kit, and each of the CorkSport Intercoolers with the CorkSport piping. Of the three CorkSport intercoolers, we took the best setup and tested it with and without our piping kit.

Conditions were near identical for all tests, with the CS intercooler tests being ~10°F. warmer than the OEM tests (65° vs 55°).

Testing Intercooler Pressure Drop

OEM Intercooler pressure testing graph
Pressure testing the OEM intercooler.

Starting with pressure drop, the OEM intercooler performed better than we initially expected. The graph above shows the pressure drop across the core through a dyno run. In this case, the smaller the number the better. Starting at around 0.5psi at low RPM and peaking at around 2.4psi at higher RPM is pretty good for a core with fins that are fairly dense.

CorkSport Intercoolers pressure testing graph

Pressure testing the CorkSport intercooler cores.

Shown in the graph above are the CorkSport intercooler pressure drop results. Core A has the densest fins, while Core C has the least dense fins. Looking at the graph above, you can see that Core A and B had a larger drop in pressure than OEM. Meanwhile, Core C had a smaller pressure drop than the OEM core. Having a smaller pressure drop than OEM means that your turbocharger can make less boost at the turbo yet still hit the boost target in the intake manifold. In other words, your turbo is working less to make the same power levels! Based on our results, option C appears to be the best option due to the low drop in pressure, but first, we will test temperature drop to be certain.

Testing Intercooler Temperature Drop

OEM Intercooler Change in Temperature Graph
OEM Intercooler Change in Temperature from Inlet to Outlet.

The graph above shows the change in temperature from the inlet to the outlet of the OEM intercooler during a dyno run. As you can see, there is a temperature delta (the amount of heat being removed from the boost air) of approximately 100-110°F through the majority of the dyno run. Not bad for the OEM intercooler as larger the better here, but we can do better.

CorkSport Intercoolers Change in Temperature Graph

CorkSport Intercoolers Change in Temperature from Inlet to Outlet.

The graph above shows the same temperature drop data for each of the three prototype cores. Please note, the difference at the beginning of the runs is a result of using the run with the best temperature change for each core. With this comparison, larger numbers mean that the intercooler is cooling the boosted air efficiently. As you can see, the very dense cores (A and B) with a high-pressure drop, cool better. However, there are diminishing returns that come when you make a core denser. Through the meat of the dyno run, Core C has approximately 140-150°F of temperature drop, Core A has 150-180°F of temperature drop, and Core B has 140-170°F of temperature drop. This data shows that Core C cools almost as well as A and B despite having a drastically lower pressure drop. Core C is definitely our winner, but we have one last thing to test: heat soak.

Testing Intercooler Heat Soak

OEM Intercooler Heat Soak Graph
OEM Intercooler Heat Soak

The graph above shows the OEM intercooler tested for heat soak by being run on a dyno in back to back runs. The graph is showing the intercooler inlet and outlet temperatures, so the boost temperature before the intercooler and the boost temperature after the intercooler that your engine sees. Over the runs, the inlet temp increases as the engine and turbo get hot. The OEM core does a pretty good job at preventing the outlet from increasing over the pulls (heat soak), but the CorkSport core can do better.

CorkSport Intercooler Heat Soak Graph
CorkSport Intercooler Core C Heat Soak

The graph above shows the results of the same test that was performed with the CorkSport prototype Core C. The inlet temp follows a similar path of heating up drastically as the run’s progress, but the improved cooling efficiency is highlighted when you look at the outlet temps. The CorkSport intercooler core cools better and also shows less heat soak, leaving you with 20+ degree cooler temps after the same tests. During testing of the CorkSport core, ambient temps were slightly higher than the OEM test, having been done on a relatively cool day in the mid to upper 50s. If the tests had been performed at 100% identical ambient temps or overall higher ambient temps, the results would be further skewed in the CorkSport kit’s favor!

Testing Intercooler Power

Last, but certainly not least, is power. We tested back to back with the OEM setup, CS FMIC only, and then the CS FMIC with the full piping kit. With the CorkSport FMIC alone, we picked up 3WHP at peak but more importantly, 3-9WHP and 3-12WTQ from 2250-4250RPM. Seen in the graph below.

Dyograph comparison between CorkSport and Mazda Intercooler Cores
Dyno Testing OEM Intercooler and CorkSport Intercooler

With the CS intercooler and piping Kit, we picked up around 6WHP at peak compared to full OEM but even more WHP and WTQ through the midrange. For clarity, the graph below is the full CS setup vs. full OEM setup; without tuning!

Dyograph comparison between CorkSport and Mazda Intercooler setups

Dyno Testing OEM Intercooler and CorkSport Intercooler with Upgraded Piping

While these gains are decent, the intercooler and piping kit will truly shine once we are able to tune the car for different boost and load targets. In addition, we checked for changes to spool time and throttle response with the piping kit but only noticed marginal gains as we are limited by the current tune on the car. Based on our testing though, it is clear that we are increasing the efficiency of the turbocharging and the intercooling system, which future proofs your ride for further mods and tuning down the road.

Let us know if you have any questions regarding our testing, we can’t wait for you all to get these parts. Look for the CorkSport Intercooler Upgrade and CS Piping Kit coming soon, along with more fun parts for the 2.5T!

-Daniel

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