SkyActiv 2.5T: Let’s Talk Intercooler Pipe Upgrades

We recently went over the stock intercooler & piping system for the 2018+ Mazda 6 2.5T. If you missed it, be sure to check out the blog HERE.

Today, it’s the first look at the CorkSport parts that will be coming in the near future to remedy the issues we found with the OEM system. We are not covering our upgraded intercooler just yet though; today’s focus is piping upgrades!

Mazda 6 SkyActiv 2.5T engine with Intercooler Pipe

As you can see we’ve been busy getting the Mazda 6 upgraded intercooler piping designed & 3D printed for test fitting (while you can’t see it I promise the cold pipe is hanging out in there too!). I’m happy to say there’s plenty of room to fit the upgraded piping sizes that we were targeting and hopefully, they will net us a few HP gains without any other changes.

These horsepower gains typically come from removing sharp bends and diameter reductions in the stock piping that cause pressure losses. Then, the turbocharger can operate more efficiently to reach the desired boost level. Now how about some more detail on how and why each pipe has changed.

Modeling and design for FMIC piping upgrade for Mazda 6

Starting off with the hot side of things (piping from turbo to intercooler), check out the CAD image above. As you can see, the OEM piping (left) is smaller than the CorkSport Mazdsa 6 piping (right). In fact, we plan to use 2.25” piping for the hot side. Note that the plastic OEM piping is much thicker wall than the CS aluminum piping so even if the outer diameter looks similar, the inside diameter is much larger.

In addition, we keep this same inside diameter throughout while the OEM piping has a major diameter reduction through the middle. For those of you coming from a Mazdaspeed 3, 2.25” is the same size used on the hot side of all CS intercooler kits and has proven itself to support 600+WHP on Barett’s car (more info on that HERE). While we know the Sky-T may not be to that level just yet, 2.25” is a great size that gets the hot air to the intercooler as fast as possible while retaining high horsepower capabilities.

It’s not all about size though. Instead of using many tight radius direction changes like OEM, the CorkSport hot pipe uses smooth, large-radius mandrel bends throughout. This means smoother and faster airflow to your intercooler. Lastly, you may notice the CS hot pipe is significantly longer than the OEM hard plastic unit (the OEM rubber tube starts at the connection point circled in the image above). This reduces the amount of flexible connectors used, limiting what could expand at high boost levels. That being said, the CorkSport kit will use high-strength silicone with four fabric reinforcement layers to prevent any expansion anyways.

The cold side of the system was already a decent diameter from the factory, but as you can see, we went even larger. The rubber OEM cold pipe will be replaced with a 3” diameter aluminum pipe. This large diameter pipe and huge volume of air that comes with it right before the throttle body has proven to help throttle response and reduce boost lag on our GEN2 Mazdaspeed 3 FMIC kit. We hope to get much of the same from the SkyActiv 2.5T. The cold side also uses large radius mandrel bends for smooth and fast airflow.

Lastly, the cold side piping reduces the amount of flexible connectors used. And just like the hot side, each end of the pipe will use 4-ply reinforced silicone to prevent any expansion under high boost levels.

Those of you with a keen eye will have realized that our planned silicone connectors do not use the same connection style as the OEM intercooler. This is for good reason: we believe that the OEM intercooler will run out of cooling capacity before the OEM piping really becomes an issue. So a piping upgrade by itself wouldn’t show too much of a performance advantage.

In addition, we were able to design the piping to be the best it can without using the constraints of the OEM intercooler. So yes, the upcoming CorkSport intercooler upgrade will be required for the CS Mazda 6 piping upgrade to work, but it’s so the CS piping & FMIC combo can be the best it can be for you all!

For those of you that have stuck around this long, check out this tease of a CAD model of the CorkSport FMIC & Piping kit.

Mazda 6 Intercooler Pipe Design with FMIC

And just because we like teasing you, check this early prototype out. Testing to come soon!

Stay tuned for more, as next time we will cover the intercooler itself. Also, let us know your thoughts down below, we love your input!

-Daniel @ CorkSport

December 6, 2018February 15, 2023

2018+ Mazda 6 2.5T OEM Intercooler & Piping Analysis

We’ve already mentioned briefly that we have an upgraded intercooler kit in the works for the SkyActiv 2.5T, but now it’s officially time to dive in and get into how and why a Mazda 6 upgraded intercooler kit is a good fit. To understand how to make a performance part, we first have to understand what makes the stock parts tick and where we can improve them, which is what we will be covering today!

For those of you that are new to the boosted lifestyle, I feel that I should go over a few terms that will be thrown around frequently later in this blog.

Hot Side Piping: Also known as just “hot side” or “hot pipes” this piping section carries the pressurized air (boost!) from the turbocharger to the intercooler. As it is before the intercooler, the air has not been cooled and the “hot” name is quite accurate (think 200-250°F. or even more on a turbo that’s too small). Shown above on the right side.
Intercooler: A basic heat exchanger. Air flows through the inside and is cooled by air flowing through the outside while you drive down the road. The same way a radiator works except with air inside instead of coolant. It is made up of three parts the “end tanks” and the “core”. The end tanks are what transfer the air from the piping to the core while the core is the actual heat exchanging portion. Shown front and center in the above image.
Cold Side Piping: Also known as just “cold side” or “cold pipes” this piping section carries the pressurized air from the intercooler to the engine. As it is after the intercooler, the air has been cooled to make more power. Shown above on the left side.

Now into the details…

The hot side piping must make its way all the way from the rear of the engine to the front of the car. The OEM piping takes a pretty direct route, and is a decent diameter for stock piping, starting & finishing at just under 2” inner diameter. This, however, is where the good things end.

To start, the two rubber sections of the hot side are single ply. These allow for good flexibility on install and to allow for engine movement but will start to expand on higher than stock boost levels, increasing boost lag and decreasing throttle response. In the image above, the main rubber section squishes under the small weight of the upper plastic section of the hot pipe. This isn’t even the main issue with the hot side piping!

The upper plastic section of the hot side has quite a few small radius bends, and a few areas where the pipe reduces in diameter severely, affecting the maximum flow and restricting the power of your 2.5T. Check out the worst area below, it’s tiny!

And what might be causing this reduction in diameter you may ask?

That’s right, its clearance for a hose clamp. Mazda, I’ve got to call you out on this one, couldn’t you have just rotated the clamp, and kept the diameter in the pipe? Anyways, on to the intercooler itself.

The intercooler itself isn’t too bad, a decent sized core with lots of fins to help cool as good as it can. That being said, there’s still plenty of room for improvements. First: make it bigger. The intercooler mounting could’ve been simplified to get more width, and there’s a bunch of room to go thicker. While thick is not the best for heat transfer efficiency, it will still help cool off the air better. Height is already more or less maxed out without cutting up the crash beam, but we should be able to make enough extra volume elsewhere to make a big difference.

Intercoolers are a delicate balancing act between cooling efficiency and pressure drop. Cores that cool extremely well usually have a larger pressure drop (loss of pressure from inlet to outlet) and vice versa. With the high fin density of the OEM intercooler, we can expect a relatively high-pressure drop (2-4psi would be my rough guess) but pretty good cooling. From early dyno testing on the CorkSport Short Ram Intake, the intercooler does a good job cooling but loses power on back to back dyno runs. I expect that this is the intercooler “heat soaking”. Heatsoak is what happens when an intercooler is undersized or is not getting enough airflow, it heats up and is no longer able to cool the boost off, robbing you of power.

The two images above show the real Achilles heel of the OEM intercooler and what is likely causing the heatsoak issues: the end tank design. Since the charge air enters and exits the core at an upward angle, it’s being directed away from the lower runners of the core. There is a sharp angle that would be hard for the air to turn, meaning the bottom three internal runners (shown with the red box) are likely not actually doing much. So you’ve got intercooler taking up space that is likely not doing much… We aim to fix this.

The cold side of the system is actually pretty good-inner diameter of just under 2.25” on the ends (even larger in the middle) and a short path into the throttle body. We’ve already covered the basics of it when discussing the upcoming CorkSport boost tube HERE. Like with the hot side, the rubber connector is prone to expansion under increased boost levels. While the CorkSport silicone boost tube will still be coming on its own, we plan to offer something even stiffer that is optimized for our upgraded Mazda 6 Front Mount Intercooler kit.

Much more information to come in following blogs as we’ve been busy working away on this project. Stay tuned for full details on the upcoming CorkSport FMIC kit, and if you’ve got any questions, leave them down below.

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December 4, 2018July 11, 2019

Mazdaspeed 6 FMIC Comeback!

Since so many of you have asked, we are happy to oblige. The MS6 front mount intercooler kit is making a comeback! Before you get too excited though, there’s still a little bit of a wait before it’s actually being released. We wanted to let all of you Mazdaspeed6 owners know that we haven’t forgotten about you and we have taken our time to ensure this kit comes back better than ever before.

MS6 CorkSport FMIC fitment testing front — MS6 CorkSport FMIC fitment testing

As you can see, the 21”x10”x3” core is staying the same but we are improving the kit everywhere else. This means better fitment, more freedom for SRI selection, and the proven piping design philosophy used in the GEN2 Mazdaspeed 3 FMIC kit. While the MS6 was definitely not designed for an FMIC, the redesigned CorkSport kit makes it easy to say goodbye to the heat soak headache that is the stock TMIC.

MS6 CorkSport FMIC fitment testing Side — *MS6 CorkSport FMIC fitment testing*

We are still putting the finishing touches on the redesign, and obviously, have a few alignment issues to work out with another round of 3D prints. We can’t say for certain when this will be releasing, but the goal is late spring/early summer 2019. That being said, we will be sure to keep you updated as we inch closer to release.

While we’ve got your attention MS6 owners, are there any features that are a must have for you on this kit? Any other MS6 specific products you’d like to see? Let us know down in the comments (and I’m sorry but orange will not be a piping color option ☺).

Lastly, if you’d like to learn more about what to expect from the intercooler itself, check out the original release blog from way back in 2012 HERE.

June 9, 2016July 28, 2016

The Little Things Count With CorkSport

CorkSport is all about making direct drop-in aftermarket Mazda parts, as well as making sure the customer is 100% happy. We make sure to put all our energy, time, and reputation into making the best parts on the market. Because of that service, our customers give great feedback and let us know when there’s a problem or if the part is fantastic. We love this because our customers are our number one source for feedback on how a part fits, works, and looks. There’s a ton of competition in this industry; making something different is what sets CorkSport apart from all other companies.

Continue reading “The Little Things Count With CorkSport”

July 25, 2013October 8, 2024

“Which intercooler should I get?” The Pros and Cons of a TMIC & FMIC

“Which intercooler should I get?” At Corksport, we get this question almost every day. The debate of top mount intercooler vs. front mount intercooler has been one that has raged on in the forums for years. Just looking around you will see both options on all sorts of cars. So what is the answer?

The Mazdaspeed 3 and Mazdaspeed 6 both come with a top mount intercooler (TMIC) from the factory. There are many reasons for this, but the main one is that it is much cheaper to manufacture and install. A top-mounted intercooler can be installed directly into the engine at the factory so it is ready to drop into the car, saving both time and money.

Pros of the TMIC

The upside of the TMIC is that it uses the shortest possible path from the turbo to the engine. This reduces the amount of time it takes for the car to accelerate, this feeling can be amplified between shifts when the power comes back on very quickly. The TMIC is also very simple and compact, with very few connections and possible places for air leaks. A TMIC will also weigh very little compared to a FMIC setup and usually is in a place with very good airflow. With our TMIC, it’s a simple replacement as it fits like OEM. Generally, it is more affordable than an FMIC. So, if you’re on a budget, the TMIC may be what you want.

CorkSport-Intercooler-Mazda-Mazdaspeed-3-Front-Mount-vs-Top-Mount-2

Cons of the TMIC

The downside of TMICs is that they are generally limited in size by the design of the car. Often times they are much smaller than most FMICs. They are typically placed very high in the engine bay, raising the car’s center of gravity. Most importantly, the biggest downside of the TMIC is that it sits in a hot engine bay. Just by sitting on top of the motor, the TMIC can soak up heat, thereby decreasing its effectiveness in cooling the air compressed by your turbo.

CorkSport-Intercooler-Mazda-Mazdaspeed-3-Front-Mount-vs-Top-Mount

Pros of an FMIC

The principles are mostly the same for the pros and cons of the FMIC. The core of an FMIC can be much larger and, in the case of a properly designed system, can cool temperatures much more effectively. Being placed further away from the engine and out into the stream of air of your car can make the FMIC much cooler and, more importantly, more consistent. One last reason that many people love FMIC’s is the look, nothing says I mean business more than a massive bar and plate core smiling in your rear view.

CorkSport Front Mount intercooler for 2007-2013 Madaspeed

Cons of an FMIC

The biggest downside of an FMIC is that the installation process is much longer, requiring your car to be out while you do the work. Another downside of an FMIC can be the much longer piping needed to route compressed air to them. This piping can increase turbo lag and usually has many couplers that may cause the potential for air leaks or other issues.

So what does CorkSport say? As a general rule, we would say that if you don’t plan to add more than 50-100 horsepower, a top mount intercooler will work just fine and be much easier on your plans and wallet. If you eventually want to go wild with your car and build it up much higher than stock, you will want to seriously consider a front mount intercooler. Our advice would be to try to plan in advance what you want out of the car so that you only have to buy parts once.

Happy spooling!

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