If you have been in the car scene for a while, you have probably seen or heard of performance exhaust manifolds. Like any other component on the engine that affects flow, performance exhaust manifolds can have a significant improvement to the engine’s peak performance and power under the curve amongst other aspects that the exhaust manifold can affect.
You have also probably asked the question. “What type of exhaust manifold do I need?” In this blog, we at CorkSport would like to help you better understand the differences between cast and tubular so you can make the best decision for your Mazdaspeed.
There are two main styles on performance exhaust manifolds; tubular and cast. Both have their pros and cons to consider as an end user (that’s you the enthusiast) and as the designer/manufacturer (that’s us at CorkSport).
First, let’s look at tubular as it’s the most common in the performance industry. Tubular is the most popular option because of it manufacturing flexibility. Unlike casting, tubular does not require expensive molds to develop even a single prototype. Not needing expensive molds allow great flexibility in design and manufacturing, which lends the tubular manifold as an exceptional option for one-off builds.
To fabricate a tubular exhaust manifold you need just the raw components: flanges, tubular sections, collector and fabrication supplies, and of course the expertise to fabricate the manifold. Let me emphasize the necessity of fabrication skills here. To produce a reliable and performance proven tubular exhaust manifold takes the correct skills, tools, and patience…it’s honestly a work of art.
With this work of art does come some compromises. To create the necessary runner routing, many tubular sections will need to be welded together. This increases the chance for weld impurities and slag which can later result in cracking and poor performance. Any reputable fabricator should be able to avoid this, but it does come at a premium due to the many man hours that must go into each and every manifold.
Next up is cast. Manufacturing via casting provides a different set of opportunities and difficulties to overcome. The process of casting alone has restrictions that must be considered; such as mold design and molten flow in the casting. Assuming these issues are overcome casting can provide unique opportunities for the design to improve reliability, performance, and packaging.
A well-designed cast exhaust manifold can have great reliability due to its one-piece design. There are no welded joints that can crack or fail and casting typically has a higher threshold to heat before issues arise. The wall thickness of the casting can also be defined for the application which can improve strength if the exhaust manifold is the only part supporting the weight of the turbocharger.
Overall performance can also be affected due to the casting design flexibility with each runner. Unlike tubular, a cast is not restricted to standard tubular elbows and straits. The runners can bend and change profile as desired to aid in performance and packaging.
Speaking of packaging, casting can really change the game here. Since each runner does not have to be accessible for welding, the entire design and each runner can be tightly packaged together to reduce the overall size of the exhaust manifold and better retain heat which aids with turbocharger response.
Lastly, comes the cost to you the enthusiast. Although the upfront cost of a cast manifold can be high, typically the unit cost and necessary man-hours are low which helps keep cost down for you.
As a designer and manufacturer of performance parts for you Mazdaspeed, these are all things we have to consider providing you with the best parts possible. We’ve explored both and are happy to stick with casting as we feel it provides the best balance reliability, cost, and performance. Keep a look out for future projects and updates!
Thanks for tuning in with CorkSport.
-Barett @ CS
Even More Stopping Power for your Mazdaspeed 3
In our drive to make more power, we often forget about adding measures to keep us safe at the greater speeds we are achieving. The CorkSport Big Brake Caliper Kit is a great place to start, however if you wish you could stop even faster say hello to the CorkSport 13inch Big Brake Kit. Designed for serious stopping power, it includes 13” directional rotors, powder-coated 4-piston calipers, upgraded pads, and everything you need to install it on your Mazdaspeed3.
Read on for a breakdown of all the components
The rotors have been designed to provide optimum stopping power while minimizing noise for street use. The upgrade to 13inch diameter rotors provides greater braking torque for an equivalent braking force (like how a longer wrench makes it easier to loosen a tight bolt). The larger diameter combined with an increased thickness of 28mm (vs 25mm for OE) provides better cooling as there is a larger mass to reject heat into.
In addition, slots were added to the friction surface to help sweep away any debris, brake dust, or gases that can otherwise affect your braking characteristics. We avoided drilling the rotors as holes decrease your total friction area and increase the chance that the rotor will crack. By moving to a two-piece design, we were able to decrease the overall weight of the rotor and by making the center section out of aluminum, it can help dissipate heat from the rest of the rotor better. Semi-Floating mounting between the inner and outer sections allows for quieter rotor vs having a full-floating center section.
Finally, the vanes in the rotor are atypical; these vanes are the “fins” that connect the inside and outside of the rotor. By using curved vanes instead of the typical straight vanes, the rotor becomes directional and has to be used on a specific side of the vehicle; however, it also provides more efficient cooling. When the rotor turns, the curved vanes draw air through the center of the rotor and out through the edge, providing greater airflow than a straight vane and thus better cooling. There is another bonus to heat dissipation as the curved vanes have a larger surface area that will come in contact with air than an equivalent number of straight vanes.
Forged aluminum, four-piston performance calipers are included with the kit in a choice of powder-coated blue, red, or black.
Although each piston is individually smaller in diameter than the single OE caliper piston, the total surface area is increased so the braking force at a specific brake pressure is increased. Larger piston surface area means larger brake pads can be used as well. You also get more even braking force on each side of the rotor due to the opposed piston design. This encourages even pad wear, even rotor wear, and consistent braking characteristics.
The pistons themselves were specifically chosen for optimum braking endurance and reliability. They are staggered in size, with the pistons on the leading edge being slightly smaller than the trailing edge pistons. This is another protection for even pad wear. Each piston is made completely out of stainless steel for its low conductive heat transfer. What this means is that the pistons themselves will transfer less heat to the brake fluid than an aluminum or steel piston, decreasing the chances of overheated brake fluid.
Street performance brake pads are included with the kit that bridges the gap between Mazdaspeed3 street and track pads. They are larger and a more aggressive compound than the pads included with the CorkSport MS3 Big Brake Caliper Kit but are not a full track pad. They will produce less dust and noise than a track pad but still need to be warmed up for optimum performance. Should you need new pads or want to change to a different pad, you have a bunch of options from G-Lock, Carbotech, EBC, Hawk, and various other manufacturers.
Lines, Brackets, and Hardware
The rest of the CorkSport 13inch BBK is composed of exactly what you need to properly and safely install the kit on your Mazdaspeed3. Stainless steel brake lines are included to remove any risk of a soft brake pedal and ensure the calipers are operating optimally. High strength steel brackets properly position the four-piston calipers on the new rotors using the OE bracket locations. All components are locked down using Grade 12.9 hardware with a corrosion resistant coating for lasting durability.
The CorkSport Mazdaspeed 3 13” Big Brake Kit has everything you need to keep you safe at increased horsepower levels. If you’re looking for more than the stock brakes have to offer, let the CS Mazdaspeed3 BBK be a part of your build.
Brett’s Mazdaspeed 3 Build
It all started in Phoenix AZ, back in 2014 when I was graduating tech school. I was finally working enough to buy a car that I had wanted for a while. At this time, it probably would have been smart for me to just start saving, instead of taking on a hefty car payment. But, as a car enthusiast, I’m sure you understand the temptations we often face, and I went for it. Since then, I’ve never looked back.
I found my 2013 Mazdaspeed3 in the fall. Completely spotless, 6k miles on it, and bone stock. It was truly a blank canvas. At that time I was barely making enough to own the car and pay for insurance. So, modding wasn’t an option at the time. So, as I saved and Saved, I was introduced to Nator Arizona by Thomas Graham, who later became a good friend of mine. He got me involved in the community, and on the right track for learning. From that point on, everything changed, and I loved it.
At the time, I was nothing more than a technician, fresh out of school and stuck on the lube rack for a bit. So, as you can imagine when I finally had enough to get my Accessport and Fuel Pump internals for the MS3, I was STOKED. I caught the modding bug, and before I knew it, I had bigger aspirations for the car than ever thought I would have had. The next year was filled with countless Nator garage days, fun drives, Mexico pulls, and slowly adding parts when I could afford them.
By mid-2015, my time in AZ was coming to a close. At this point, I had all the basic bolt-ons offered for the Mazdaspeed 3. Rear motor mount, short ram intake, upgraded BPV, upgraded TMIC, and turbo back exhaust. The car otherwise looked completely stock, just MUCH louder! The icing on the cake was the pro-tune 320 WHP on Stock turbo with some e85. A couple days later I departed AZ for my next chapter and got the MS3 on the trailer.
Funny looking back now, how I thought I was done with my Mazdaspeed, and that was enough power to keep me happy. Not even close! The next couple years would be the catalyst that started to shape my MS3 into what it looks like now. Stay tuned for Part 2!
Cleaning Your EGR System
The exhaust gas recirculation (EGR for short) system present in all Mazdaspeed 3 and Mazdaspeed 6 vehicles is known to have some issues. It is present from the factory to help with NOx emissions and likes to clog, throwing a check engine light in the process. The common solution to this is to do a full EGR delete, and use an AccessPort to clear the CEL.
While likely the best solution, it is not possible for all people to do, especially if you live in an area with extensive emissions testing. If this sounds familiar, read on as I explain what the EGR system does, how to clean it, and how to ensure you will pass emissions afterward.
The EGR system does exactly what the name says; it recirculates some of the exhaust gasses back into the intake system.
Through some fancy chemistry, this reduces the total amount of NOx that comes out of your exhaust pipe. In Mazdaspeeds the system consists primarily of the EGR valve and the tube that connects the valve back to the intake manifold. Over time, the carbon present in the exhaust builds up, causing issues for the system. If the valve cannot open/close all the way or the tube gets clogged, your car will likely throw a P0401 code, for insufficient EGR flow. Aside from being another pesky CEL, a clogged system can cause rough idling, poor MPG, and slow startups.
Tools and Products Needed:
Degreaser/Carbon Cleaner – This will really help break up the stubborn carbon, making it easier to clean the EGR valve/tube. B-12 Chemtool works the best, but regular brake parts cleaner or other strong degreasers will work as well.
Picks/Scrapers – The cleaner will get the carbon softened but you will need something to scrape at it and get the pieces out.
Flexible Round Brush – The EGR tube can be cleaned by just soaking in the degreaser and picking out the big chunks but a round brush works even better. I used a straight brush but I think this flexible one will work better.
Coolant – The EGR valve has a coolant passage so you will lose most if not all of the coolant in your overflow tank. Be sure to buy OEM Mazda coolant or at least coolant with phosphate organic acids to keep your cooling system healthy.
Assorted Tools – You will need a regular assortment of sockets and hand tools for this job. The only irregular tools are a 22mm wrench (you can use an adjustable wrench) and some small needle nose pliers.
OBDII Code Reader – Okay you don’t NEED this for EGR cleaning but who doesn’t love new toys? This one is great for reading any CEL codes and seeing when you’re ready for emissions (more on that later).
Now let’s get started!
Start by removing the OE battery, battery box/tray, top mount intercooler, airbox lid, and turbo inlet pipe. Getting to the EGR valve is really the hardest part of this entire process. If you’re new to your Mazdaspeed and need some help removing any of these parts, MazdaSpeed Forums has a lot of resources if you just search for them. Be very careful when removing the small vacuum line on your turbo inlet pipe. The plastic barb likes to break off, causing all sorts of headaches down the road.
Locate & remove the EGR valve. It is the small aluminum piece with a round plastic top. Loosen the clamp on the black rubber hose and drain the coolant that will come out. You will lose about what is present in your overflow tank, catching it with a cup prevents a mess in your engine bay. Remove the electrical connector and the two bolts that hold the EGR valve to the engine and the whole valve will come free. Be sure to keep track of the gasket between it and the engine.
Remove the throttle body. You must first remove the two coolant lines that run to the TB. Clamp them closed to prevent any extra coolant leakage. Remove the four bolts, and the throttle body will come free. Once again keep track of the gasket.
Remove the EGR tube. There are two bolts located by where the EGR valve was removed. Another gasket located here. Trace the metal tube back to the front of the engine and remove the large 22mm nut. You may need some penetrating fluid to help loosen this nut. The EGR tube then pulls out of the intake manifold.
Start cleaning by using a pick to remove some of the carbon from where you removed the EGR tube. There’s a bunch of gunk in there but it’s not easy to clean so do what you can.
Spray some of your degreaser inside the EGR tube and let sit while to start loosening up the carbon buildup while you clean the EGR valve.
Disassemble the EGR valve. Remove the four screws from the plastic section. The two halves should separate. These screws strip extremely easily, use care to not damage them and be sure to keep track of the gasket.
You will now have access to a plunger. This is what opens and closes the EGR valve. Push it to help you clean around the valve. Use the picks, degreaser, and whatever else you need to remove as much carbon as you can. Focus especially on the areas around the valve. Ensure it has smooth operation and can fully open and close. Take your time here.
Using the round brush, degreaser, and picks, clean the EGR tube as best as you can. I found the majority of the carbon was located toward the end with the 22mm nut. Take your time, once again, you don’t want to have to redo this.
Reassemble everything. Ensure you reconnect all hoses, reconnect all electrical connectors, use all gaskets, and tighten all bolts. Add coolant to your reservoir until you reach the max line.
You should now have a squeaky clean EGR system! Start up the car and check for any leaks or strange noises.
Now if you’re like me and had to clean the EGR system for emissions, you will need to complete a “drive cycle” to pass. All the sensors for the emissions system have to run tests to ensure that they are operating correctly. Since you had the battery unplugged, the sensors have basically reset and need to run all of the tests again. In most states, there is a limit to how many sensors can read “not ready” and still pass emissions. Guidelines to reset most if not all of the sensors are as follows (sourced from MSF):
Before you start to be sure you have: no CELs, fuel level between 15-85%, all accessories off, cold engine.
Start and idle for 5 minutes.
Rev engine in neutral to 2300-2700 RPM for 15 seconds.
Rev engine in neutral to 3800-4200 RPM for 15 seconds.
Idle engine for 20 seconds.
Accelerate to 52-55 MPH, maintain speed in 6th gear for 1.5 minutes.
Decelerate to 15 MPH, drive for 13 minutes at speeds between 15 and 35 MPH.
Drive at 25MPH for 50 seconds.
This order of steps activated all but one of my sensors, meaning that in Washington State I was able to pass emissions in my 2007 Mazdaspeed 6.
Hopefully, this will help out a few of you that are stuck with an EGR system. This procedure saves a few hundred dollars over replacing the valve, making that next modification happen just a little bit sooner!
If you have any additional tips or tricks be sure to share them in the comments, we’d love to hear your experiences!