The Design – 2.5L SkyActiv-G Exhaust Header

CorkSport 2.5L SkyActiv Header

A few months ago we broke down the complicated design of the exhaust manifold found on the 2014-2018 Mazda 3 & 6 2.5L SkyActiv.  Mazda put extensive R&D into the design and packaging of the OEM header to optimize the exhaust gas pulses and overlap.  

In this blog we are going to explain some of the design features in the CorkSport 4-2-1 header and why those features are important.  

Below is a diagram showing the primary, secondary and collector routing of the OE header.  

Mazda 2.5L SkyActive Header
The OEM header for the 2.5L SkyActiv engine has a 4-2-1 design.

When designing a performance header we have to ask ourselves, “what is the goal with this performance part?” and then fulfill that goal.  With the performance header for the 2.5L SkyActiv our goal was to increase mid-range torque, retain good fitment and user installation, and improve the sound output of the exhaust system.  

CorkSport Aftermarket Exhaust Header
CorkSport 2.5L SkyActiv header design.

Immediately you’ll notice a significant difference in the design of the OEM header and the CorkSport Header.  There are three major differences:

  1. Primary, secondary, and collector diameters have been increased to promote better exhaust gas flow.
  2. Primary and secondary runner lengths have been increased to optimize power/torque lower in the RPM range.
  3. The design is two-piece to drastically improve the installation process.  

The primary runners (these are the runners that mate directly to the engine) have been increased in diameter from 1.55” to 1.75” and the secondary runners (these are the runners that combine only two cylinders before the collector) have been increased in diameter from 1.87” to 2.00”.  Both of these changes improve peak flow per cylinder throughout the RPM range. Lastly, the collector has been increased from 2.00” to 3.00” to be paired with the CorkSport 60.5mm or 80mm Cat-Back Exhaust Systems.

CorkSport Exhaust Header Installed
CorkSport Header Installed.

Here’s where things got a bit tricky.  Increasing the length of the primary and secondary runners forced us to be a bit creative in routing all the piping.  In order to achieve the primary runner length we wanted, we had to route the piping upward first (as you can see below) then back down between the engine and firewall.  The results were better than we expected with a “Medusa” style header peeking out of the engine bay and the lengths we wanted.

It makes us grin every time we pop the hood open, we hope you love it as much as we do.  

CorkSport 2.5L Exhaust Header broken down for install.
The final design of the CorkSport 2.5L header is installed in two pieces.

However, the complicated CorkSport design did create a new problem.  Installation! We always try to create a performance part that can be installed by the average enthusiast in their garage and this was no exception.  In a one-piece design, the header was nearly impossible to install. We went to the drawing board and realized that separating the upper and lower halves of the header was the best option.

We considered a conventional flange, gasket and hardware setup, but realized it to was far too complex in the close quarters behind the engine.  We then moved to a v-band connection that proved to be the best setup for installation, weight, and sealing ability.

That wraps up the design, next we’ll breakdown the testing and results! Let us know if you have any questions or thoughts down below.

-Barett @ CorkSport

New & Improved: The CorkSport Aluminum Skid Plates for Mazdaspeed 3

CorkSport Aluminum Skid Plate
CorkSport Aluminum Skid Plate

Aluminum Skid Plates for 2008-2013 Mazdaspeed 3 and 2004-2013 Mazda 3.

While not a new product, there is still plenty to be excited about. Say hello to the new and improved CorkSport Aluminum Skid Plates for 2008-2013 Mazdaspeed 3 and 2004-2013 Mazda 3. We took all of the great features present in the original one-piece design, and then went back to the drawing board to improve the fitment, make installation easier, and make shipping cheaper for everyone. Read on as we go through the full details of this redesign.

CorkSport MazdaSpeed 3 Skid Tray
GEN 1 Skid Plate for 204-2009 Mazda 3.

Designing the GEN 3 Skid Plate

While designing the GEN 3 Skid Plate for 2014-2016 Mazda 3, we realized that utilizing a two-piece design is a fantastic way to save you some money on shipping. The overall design is smaller which allows us to use a smaller box to eliminate any oversized package charges from shipping companies. This is the same reason why our GEN2 Speed3 Front Lip is made of multiple parts. By designing the skid plate into two-pieces, installation on your vehicle becomes more flexible when aligning the front and rear sections. The multi-piece lineup creates wiggle room to help get everything all lined up properly on your car. Since each and every car is just a bit different, the extra wiggle room helps to achieve the best alignment possible, even on cars that have had their subframe, radiator support, and/or bumper removed and not reinstalled perfectly.

CorkSport Skid Plate for MazdaSpeed 3
Skid Plate for 2010-2013 Mazda 3 and Mazdaspeed 3

The Perfect Fitment

Going to a new design gave us the freedom to improve fitment even further. We have revised the mounting locations to ensure the easiest installation possible and reshaped a few areas to best fit on your car. Like the original though, no permanent modification to your Mazda is needed as we use all OEM mounting locations. Plus, the CorkSport Aluminum Skid Plates for Mazdaspeed 3 ship with all of the tools that you will need to install it.

CorkSport Underbody Skid Plate
CorkSport Underbody Skid Plate for MazdaSpeed 3

Ultimate Protection Without the Weight

Both GEN1 and GEN2 CorkSport skid plates are made from laser cut and precision formed 0.090” aluminum sheet. This thickness offers great protection from road debris and the occasional tall speed bump without adding a ton of weight to the front of your Mazda3. Where an OEM plastic splash shield would crack and fail, the CorkSport skidplate can take a beating, offering you peace of mind whether you’re riding at stock height or have lowered your MazdaSpeed 3. Speaking of riding low, the CS under tray sits up slightly higher than the OEM shield, giving you that little bit of extra clearance when you need it.

CorkSport Aluminum Skid Plate Installed
CorkSport Aluminum Skid Plate on MazdaSpeed 3

If this is just your next mod in a long list of mods do not worry. The CorkSport Aluminum Skid Plates fit with both GEN 1 and GEN 2 Front Mount Intercooler Kits as well as the CorkSport Lower Tie Bar. The CS GEN2 Front Lip will fit as well but may require some modification to the skid plate and/or front lip. For all of you Mazda 3 owners, just a heads up that these skid plates were designed for the Mazdaspeed models so you may require some minor trimming for best fitment, all of which can be done with a simple hand saw or razor knife.

CorkSport Aluminum Skid Plate

There you have it folks, the new and improved CorkSport Aluminum Skid Plates for GEN1 and GEN2 Mazdaspeed 3 & Mazda 3. Let us know if you have any questions down below and we will be sure to help you out!

80mm Gen3 Mazda3 Cat-Back Exhaust

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4 years ago, we released the 60.5mm Exhaust kit for the 3rd Gen Mazda 3 (both in axle back and full cat back flavors). It’s certainly been a hit, but there has been a few of you longing for more noise. Today we are proud to announce the 80mm variant of our cat back exhaust for the 2014-2018 Mazda 3 Hatchback and Sedan! At this time, just the hatchback version is available, but we will have the Sedan version ready in just a few short months.  

Now I know what you’re thinking, an 80mm exhaust seems excessively large for a naturally aspirated car making less than 200whp. But, hear me out because I think you’ll like what’s coming.

80mm piping allows for some unique & louder tones its smaller little brother can’t offer, but it wasn’t as easy as just using the old design and making the pipes larger. We had to do quite a bit of resonator experimentation and NVH analysis to get to the finished result with as little drone as possible. I’ll be upfront with you guys though, this is loud. It’s a good loud with tons of fun noises, but if you’re looking for something subtler, then our 60.5mm cat back or axle back may be a better fit. We do a good job of capturing the audio for you though so you have a good understanding of what you’re getting. Be sure to check out the product video to hear it.

For those wanting this more aggressive exhaust note, sound isn’t the only bonus. We thought about the appearance, and how we could take advantage of this time to tinker with the design. The 80mm does a nice job of not only filling the exhaust tunnel under the car, but the axle back portion is a bit more prominent when you catch a glance.

On the Hatchbacks, the exhaust tips got a nice size increase up to 100mm and they are slant cut to help follow the profile of the bumper. Sedans have also been upsized to 100mm tips, which were lowered slightly to ensure your bumper doesn’t melt with the large piping. This has the added bonus of making the tips a little more visible from the rear and side of the car. In both cases, the way the upsized exhaust accents the rear of the car provides an aftermarket look, that’s classy and somehow the way it always should have been from factory.  
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As with every CorkSport exhaust, this new 80mm variant is made from fully polished T-304 stainless steel for long lasting corrosion resistance. All flanges, hangers, and resonators are precision TIG welded in place while all of the piping is made with smooth mandrel bends. Each  resonator uses a direct flow-thru design to keep the drone down and the volume up without sacrificing power.

Speaking of power, check out the dynograph below. The upsize to 80mm showed similar power gains as the 60.5mm variant, so the extra size isn’t really needed at similar to stock power levels (aside from the great noise of course!). The only change in parts or tune between the two graphs was the exhaust. OEM exhaust (red) vs. CorkSport 80mm Exhaust (green).I

We also believe it’s also very important to be prepared. Future proofing your car for mods down the road is always a great idea, and you’ve probably heard that we have a turbo kit (yes it’s still happening!) and race header in the works. More on those projects later, but I’ll let you put 2 & 2 together…

GET YOURS HERE!!

Welcome to the Gen3 Mazda 3 Suspension Package

Want to upgrade your suspension system on your Gen3 Mazda3, but don’t want to deal with the headaches that come with lowering springs or coilovers?

Introducing the CorkSport Adjustable Shock/Strut Assembled Package for 2014+ Mazda 3. This truly is a complete package that includes CorkSport lowering springs, CorkSport adjustable shocks/struts, and CorkSport camber plates all assembled and ready to install.

 

 

We’ve discussed before how the CorkSport adjustable shocks and struts are a great compliment to the CorkSport lowering springs. Now we have included them together in a package with our camber plates to give a huge handling and adjustability upgrade to any Gen3.

In addition, this package comes assembled with new OE dust boots, pivot bearings, and bump stops that are even cut to proper length to match the lower ride height. Since this package comes assembled with new parts, installing it is a snap. No spring compressors needed at any point. Check out the image below to see exactly what you get in every box.

 

 

Whether you are looking to replace some worn out OE components and get a style bonus, or are looking for some and handling and adjustability for your racecar, the CorkSport Adjustable Shock/Strut Assembled Package can help you reach your goal.

3rd Time’s the Charm

We all know the saying the 3rd time is the charm and this year’s SCCA National Championship Runoffs was no exception to the rule.  The past 2 runoffs I have not made it to the finish.  In 2016 at Mid-O I was hit on the first lap and punctured my left front tire.  At Indy, I retired as we developed a fault in the ECU from some beta software we were running and the car dropped into limp mode and I wasn’t able to maintain full throttle.  

We have been working on the brakes for the past 3 years and during the season it limited us from running the car as much as we like.  We have also been chasing a fault/error with the ECU/control system of the car. We were still able to get the car enough starts and race finishes to get qualified for the runoffs in Sonoma.   Granted the car was not happy at most of those races and it was a struggle to get the finish.

2 weeks before the runoffs we sorted out the ECU problem and were confident enough in the car to race it.  The backup plan was to race my Spec Miata if we couldn’t get the Mazda 3 fixed as I ran it this past season as well and had enough starts/races.

With the Runoffs at Sonoma it was within 1-day driving distance unlike the past 3 runoffs at Daytona, Mid Ohio, and Indy so I got to try out the new (to me) truck and trailer.

I had raced at Sonoma one time prior, so the track wasn’t totally unknown like Mid-O and Indy, which all I had was simulator time so I was able to get up to speed quickly on a test day and find out what I needed to work on for chassis setup and driving.  The driving was easy to adjust, look at the data, see where the driver was sucking and had to man up to keep a foot to the floor in some sketchy corners.

The car, on the other hand, had what we call “a good problem to have”, too much power.  We have been running a torsen style differential in the car which works pretty good in a straight line and relatively flat tracks.  Sonoma is not a flat track which unloads the car 3-4 times per lap. With the Mazda 3 and the amount of torque it makes means I was unloading the tire enough for it to spin the inside tire.  Most people think what is the big deal with a little tire wheel spin? It is a problem when you enter turn 10 at Sonoma at 97MPH and you start lighting off your right front tire. Look at the picture below and you can see that front inside tires is barely on the ground and the rear isn’t.  The speedometer would jump around and you could see the right front wheel speed turning at 5-10 mph more in the data.

We tried several suspension changes and driving style changes to make the best of it but in the end, we were way off the pace by 2-3 seconds of the rear wheel drive cars in the class.

The good part about not being at the front of the field, there was zero stress when race day came.

Like any race there was a fun challenge, we would be heading into turn 2 blind as the race was at 4 pm in the afternoon and the sun would be shining directly down the hill.  Since I wanted to see the end of the race I a little cautious at the start and Ali in the other Mazda 3 got around me at the start.

We fought it out for 8 laps and he went into turn 6 too hot and I was able to get under him and pass him on the inside.

After a few laps I put a 4-5 second lead on Ali I was basically in no man’s land, slower than the front guys and faster than the back half of the field so I spent my time working on tire management (it is easy to overheat your left front tire at Sonoma) and made it to the end of the race.

My official finishing place was 10th but after some adventures in tech, I was moved to 9th in the final results.  This isn’t where I wanted to be by any means but the 3rd time was the charm and I made it to the end of the race.

Huge thanks to the support we get racing the car from CorkSport, BFGRacing, Monarch Inspections, G-Loc Brakes, and Mazda Motorsports.

 

Derrick Ambrose