Project Car | CorkSport Mazda Performance Blog

May 1, 2024December 30, 2024

The Rear End Drivetrain – Mazdaspeed 3 AWD Swap ( Part 5)

Welcome to part 5 of the Mazdaspeed3 AWD Swap (sorry for the delay; things got really busy for a bit)! This blog covers the rear-end drivetrain and the huge modification that makes it all work.

There are a lot of images and explanations of those images so you can see and understand the differences between the Mazdaspeed 6 and CX7 rear drivetrain.

What is the Rear Differential

Jumping right into it, let’s identify what the rear differential is. The rear differential transfers power from the transfer case via a PTO/driveshaft, through the ring and pinion, out to the axles, and then to the wheels and tires.

Mazdaspeed 3 AWD Rear Differential Swap Comparison Mazdaspeed vs CX7 — CX-7 vs Mazdaspeed Differential Comparison

However, as with many modern AWD systems in compact cars, there is a clutch mechanism between the PTO/driveshaft and the differential. This clutch mechanism controls the percentage of engine torque transferred to the rear tires.

In the diagram below, we’ve identified the two major sections of the differential assembly. The line demonstrates the connection point between the two sections. The rear section is the gear housing, and the front is the clutch housing.

Differential Gear Housing and clutch housing diagram

Now that you understand the differential assembly. Let’s identify the difference between Mazdaspeed 6 and CX7. There are two major differences.

Differences In Differential

The first difference is the clutch housing mounting points for the front subframe mounting brackets. In the image below, you will see two mounting points with threaded holes on the right side of the differential, while the other differential does not have those mounting points.

The CX7 differential is on the left, and the Speed 6 is on the right. The CX7 on the left)has TWO front mounting points whereas, the Speed 6 only has a ONE mount. While this may not be a big deal for a daily driver with modest power levels, it’s a huge advantage for a racecar with nearly 900whp.

Comparison of CX7 and Mazdaspeed 6 differential side by side — Left to Right: CX-7 and Mazdaspeed Differential

Moving to the inside of the gear housings, the CX7 uses an open differential setup, vs the Mazdaspeed 6, uses a Mazda proprietary LSD (limited slip differential). The LSD is more desirable because it will provide better power distribution to both rear tires vs the open differential.

Fun Fact: the Mazda-developed LSD uses “friction cone washers” sandwiched between the spider gears and differential carrier housing to create the limited slip effect. As load is applied through the spider gears, the increased load presses the spider gears against the friction washer, which makes this a very street-friendly and progressive type of LSD. Check it out below.

So here we are at a point where we need to use the CX7 differential because it has the ideal two-mounting front section, and we have a CX7 subframe, so…duh, but we want the rear LSD for better power distribution.

Time to split these differentials in half and see if we can swap things around.

Mazdaspeed 3 AWD Differential Swap separated — Rear Differential Separated

Splitting them in half to separate the clutch housing and gear housing, we can see a splined connection that interlocks the two halves.

Mazdaspeed 6 Rear Differential Gear Housing

On the gear housing side, the pinion gears are retained by an internal nut, which is good because splitting the assemblies did not affect the pre-load on the bearings.

Mazdaspeed 6 Rear Differential Clutch Housing

Let’s look at the clutch housing side. The clutch pack is retained by the external nut on the driveshaft flange; again, splitting the assemblies did not affect any bearing pre-load.

Things are looking great! And with that, we assembled the CX7 clutch housings with the Speed6 gear housings without issues!

Now to review: if you are doing this swap, you will NEED a CX7 rear differential assembly, but you DO NOT NEED a speed6 rear differential assembly. We only did that to learn and to get the LSD. You can use the CX7 as is because the gear ratio is the same, and the LSD is not required.

Next up are the suspension trailing arms; when using the OEM Speed3 suspension, the trailing arms need to be modified to use the OEM CX7 wheel bearings.

Modifying the Trail Arms of the Mazdaspeed

Mazdaspeed 3 trailing arm plate — Mazdaspeed 3 Trailing Arm Plate

The OEM trailing arm has a beefy steel plate welded to the stamped steel structure. While the bolt and center holes look correct, they are slightly different in bore and location.

Mazdaspeed 3 trailing arm showing fitment — Mazdaspeed Trailing Arm

To make the Mazdaspeed 3 trailing arm work, modification was needed via welding the original bolt holes shut and then redrilling the holes in the correct bolt pattern for the CX7 wheel bearing. Along with that, the center bore diameter had to be increased slightly as well.

New Welded Holes for the Mazdaspeed
fitting cx7 bearings — New Welded Holes for the Mazdaspeed

Fitment of the Rear Trailing Arms & CX7 Wheel Bearing

Modifying the rear trailing arms is only 1 of 3 major fabrication projects needed for the AWD swap. The others are building a Rear Motor Mount (which I designed a badass billet one for) and the center driveshaft mounting plate which I also designed.

Now, with the trailing arms and wheel bearings in place, we can finally figure out the rear axle lengths. Checking both the Speed 6 and CX7 rear OEM axles, I found they use the same wheel bearing and differential inputs, which is great. However, The lengths are not the same.

Unfortunately, in test fitting the Speed 6 and CX7, we found that both needed to be shorter for the Speed 3 application. With that fact, the cost is a lot more expensive for anyone swapping because of the needed custom rear axles.

I was personally going to get custom rear axles either way due to the power levels and use of the Halfmilespeed3, but it’s not a requirement.

Rear Custom Axles for the Mazdaspeed 3 — 700WHP Rated Custom Rear Axles

Fast forward many weeks, and we have a set of custom-length 700WHP-rated rear axles to compliment the front DSS 5.9 axles.

Rear Custom Axles installed on the 2007-2009 Mazdaspeed 3

All bolted in and looking great! While doing this I learned a few things and realized that one of my assumptions was wrong.

The front axles work and don’t work from the MS3. The driver front MS3 axles will interface perfectly with the Mazdaspeed6 transmission. However, the inboard CV housing/spline section for the passenger side front will need to be replaced/modified to work with the speed6 intermediate shaft.
The rear ABS sensor for the Mazdaspeed3 will not work with a Speed6-style ABS trigger wheel. They use a much different and more modern magnetic trigger wheel incorporated in the rear ABS sensor for the Mazdaspeed3 will not work with a Speed6-style ABS trigger wheel. They use a much different and more modern magnetic trigger wheel incorporated inside the wheel bearings…which we don’t have when using the CX7 wheel bearings. This has led me to develop custom ABS trigger wheels to work with the OEM Mazdaspeed 3 sensor. More on that later.

Alright, that wraps up the rear drivetrain setup. There are plenty more huge milestones to overcome, which are coming up in this multi-part blog series!

I hope you are enjoying this series about the Mazdaspeed 3 AWD Swap. Stay tuned for more blogs to come!

You can also find updates on my IG @halfmilespeed3, the CorkSport 7^th Gear Membership, and on mazdaspeeds.org.

Thanks for tuning in!

-Barett @ CS

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August 16, 2023August 23, 2023

Mazda 3 TC Bodywork

We (CorkSport) showed off our work-in-progress TC America TC Class Mazda 3 race car at the CorkSport Mazda Showdown event on August 5th. If you are asking yourself why this is a big deal and why I am reading a blog post about it, here’s the explanation.

On October 1st, 2019, Mazda announced they would join the TCR ranks with the car attending the 2020 season opener at Daytona with IMSA. The bodywork was excellent; it captured the body lines and presented an absolute WOW factor!

Unfortunately, the car was a no-show at the first round or any round scheduled in 2020. On August 15th, Emily Taylor from Mazda announced they had canceled the TCR program, citing the coronavirus as the explanation.

What About The Body Kit?

So what happened to everything from Mazda’s race program, and why is the bodywork a big deal? There were two sets of original molds made for the bodywork. The 1st set of molds went to the constructor Long Road Racing, and the second set sat at Mazda’s design center in Irvine, California.

The molds in Irvine were the first set made off of TCR “Show Car” bodywork and were not production-ready. The “Show Car” Mazda used for their 2019 announcement and future marketing campaigns wasn’t an actual race car. It was a production car with the bodywork on it, but the engine & drivetrain was stock.

CorkSport has been racing a 3rd generation Mazda 3 in the TC class for several years as the development tool for the Skyactiv Turbo kit we offer.

When running in a professional series, the series works with manufacturers and wants the newest models competing on the track to keep the series fresh and relevant for marketing for both the auto manufacturer and the race series. The last 3^rd Gen Mazda rolled off the production line in early 2018, making our race car over a year old when the TCR program was announced and over two years old when the program was canceled.

We needed to race the 4^th Gen Mazda 3s to keep competing in TC America,

The Journey For the Mazda 3 TCR Kit

This may seem like an exaggeration, but I spent over 200 hours on the phone, in meetings, writing emails, and talking with employees, ex-employees, and contractors that Mazda used to chase down where the bodywork went, who was ultimately in charge of it, and to see if we could get our hands on it.

Once I knew the molds still existed, additional meetings, phone calls, and emails were required before signing an, “OK, we will consider it. Your plan and history jive with a company (CorkSport) that can use the parts and provides a benefit to Mazda.” type of agreement. During this time, I learned the first set of molds had been destroyed, making the motorsports molds the only set left.

In October 2022, snagging the TCR bodywork molds became a strong possibility. I was headed to Texas to drop off some racing equipment to a friend. I decided to leave my truck and trailer in Texas since the bodywork molds were now located on the East Coast. If Mazda agreed we could pick up the molds in the next few months, the truck and trailer would already be halfway there.

December 12th, 2022, Mazda gave me the green light to gain access to the molds after several more phone calls, ZOOM meetings, and agreements were made. I flew back to Texas and headed to Multimatic in Mooresville, NC, to complete this epic quest. After one very long drive, including a massive ice storm, and making it home on Christmas Eve, Mazda’s TCR molds were at CorkSport.

Since then we have been planning and slowly building the new TC Car – We cannot thank Mazda Motorsports enough for choosing to partner with us as we continue to shape our racing program!

The body kit is thick and the ride height was not adjusted prior to the reveal .

Rear wing is not to racing spec and was added temporarily to represent what it
might look like in the future – rear window will eventually be plexiglass.

Are These The Real Thing?

A common question that will get asked is, “I have seen the Mazda 3 TCR kit overseas, how is what you have the real thing?” Well, my friends, Technology and replication are a wonderful thing.

I asked the same question about the hill climb machine that TCP put together for Mike. If you compare the kits, you can see there are some differences in the kits with the aero, brake cooling, grill area, and more.

It was unofficially stated there were body scans done of the show car with Mazda Japan and those are the results. I cannot speak about the Thailand car but a handheld scanner and some import auto salon are my best guess.

Look forward to more updates on our build over the next several months, This is going to be fun!

-Derrick

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May 16, 2023October 24, 2023

How To Build A 900 Mazdaspeed 3 AWD Swap – Rocker Arm Suspension (Part 4)

Welcome to part 4 of the Mazdaspeed3 AWD Swap! If you missed the previous posts, you can catch the Intro, (Part 2), and Part 3. This blog will cover the rear suspension design, specifically the rocker arms, and how we came to the size, shape, and overall design. This will get technical with numbers, angles, and CAD models.

Before we get into the technical jargon, let’s cover the “what” with rocker arm suspension.

Mazdaspeed 3 AWD Swap Rocker Arm Suspension

Let’s break down this diagram as it is 100% not OEM for the Mazdaspeed 3:

Rocker Arm: This is the keystone of the suspension design and does all the work. The rocker arm connects the push rod and the damper to transfer suspension force at a different angle. The rocker arms can also go by a few names: rocker arm, bell crank, cantilever, and pivot arm, to name a few.
Push Rod: This is a simple rod with spherical rod ends on each end. This connects the OEM suspension to the rocker arm. The push rod is in a similar location as the OEM suspension.
Suspension Mounting Bracket: This is the mounting point for the push rod to the OEM suspension trailing arm. This must be added because the OEM damper mount is below the now-new axle shaft.
Coilover/Damper: This is an off-the-shelf damper that can have a coil spring installed on it. It features independent rebound and compression damping adjustability.
Cross Member: This is the cross member that is welded between the chassis shock towers in the car to support the new rocker arm suspension.

Here you can see the design tack welded in the car. This should help you understand how the design fits and is used in the car itself.

Mazdaspeed AWD Suspension Corss Member Tacked

Mazdaspeed AWD Suspension Push Rod Mount

Now that we have a basic understanding of this rocker arm-style suspension let’s get into some more details!

First, let’s talk about suspension and the forces they deal with. Gravity pushes you and your car down to the ground, and road imperfections (bumps, potholes, unlevel surfaces) try to push you and your car up/down/all around while driving. If vehicles did not have suspension and instead the wheels were rigidly attached to the vehicle chassis, we would have all sorts of issues. Comfort, control, and tractions are the big concerns, amongst many others.

The suspension’s job is to soak up and move with many road imperfections like bumps, potholes, and unlevel surfaces. Every time your tire goes over a bump or pothole, it moves up or down, resulting in a force transferred into the suspension.

Check out this quick illustration to see the rocker arm suspension in motion:

As the tire moves up/down, you can see that the rocker arm pivots and transfers that motion into the coilover/damper.

Now let’s break down those forces a bit more. The rocker arm allows us to change the angle of the forces transferred to a new angle that is easier for us to deal with. Instead of being required to have a coilover/damper in a vertical suspension down around the tire (like OEM), I can now change the angle so I can put the coilover/damper in a position that is much easier to deal with.

Rocker Arm Suspension Mazdaspeed Swap Forces

The rocker arm has two major features about it.

The angle change of transferred forces, as we just discussed. This is mainly to help with “positioning” the suspension components.
The rocker arm lengths allow us to define the “motion ratio” of the suspension. Looking at the diagram, you can see a blue line and a green line. These effective rocker arm lengths affect the suspension and result in a motion ratio.
1. The resulting ratio is 1:0.7 meaning the damper compresses 70% of the amount that the wheel moves up/down.
2. The wheel/tire has a maximum range of 5.55 inches of travel, while the damper has a maximum travel of 3.875 inches.

Designing the rocker arm with this 1:0.7 motion ratio allowed me to use a smaller, lighter damper design with limited travel and still get the desired wheel suspension travel I needed. We use a stiffer spring to compensate for the extra leverage of the motion ratio.

Motion ratios in suspension are common. For example, the Mazdaspeed 3 suspension has a unique motion ratio in the front (1:0.98) and rear (1:0.71) from our calculations. These numbers are typical of the style of suspension found in many commuter cars these days.

Now that we understand the forces and the intent with the rocker am…we have to design its shape and size to do the job. Angles are the tricky parts of the rocker arm design. Defining the angles (and thus shape) comes down to understanding the push rod input angles and the desired damper output angles while in motion.

Rocker Arm Suspension Mazdaspeed AWD Swap Angles

When we say “angles,” we are talking about the red arrows in the above diagram. These red arrows are the angles between the rocker arm and the push rod, as well as the rocker arm and the damper. Ideally, these angles are always 90 degrees through the entire motion you see in the GIF, but that is not physically possible, so we had to find the correct balance of angles while in motion.

A whole lot of math encompasses this, but the upcoming diagrams will help break it down to a very understandable level for everyone! We are breaking it down to the three major suspension travel points: droop, bump and ride height.

First, we are going to look at the angles for the push rod in Bump, Ride Height, and Droop.

Bump is when the suspension is fully compressed.
Ride Height is when the car is sitting stationary (static).
Droop is when the suspension is fully decompressed. Image your car sitting on jack stands with the tires hanging in the air.

Mazdaspeed 3 AWD Rocker Arm Angle Bump Pushrod

In full bump, the push rod angle to the rocker arm decreases to 67 degrees which is 23 degrees off the “ideal” 90.

Mazdaspeed 3 AWD Rocker Arm Angle Ride Height Pushrod

Then looking at ride height as the suspension moves downward from full bump. The damper-to-rocker arm angle decreases to 82 degrees which is 8 degrees off the “ideal” 90.

Mazdaspeed 3 AWD Rocker Arm Angle Droop Push Rod

Lastly, with the suspension traveling to full droop. The push rod to rocker arm angle increases to 117.5 degrees which is 27.5 degrees off the “ideal” 90.

What does this mean? This is great, actually! Ride height is where the suspension will function most of the time, and that is only 5 degrees off the ideal 90-degree angle. When the car is launched in a drag race, the suspension is going to compress, and that angle will decrease, passing through the ideal 90-degree angle and further. This is precisely the balance we are looking for with the rocker arm design. To keep it functioning most of the time as close to 90 degrees as possible.

Ok, let’s look at the angles from the damper side of the rocker arm.

Mazdaspeed 3 AWD Rocker Arm Angle Bump Damper

In full bump, the damper angle to the rocker arm increases to 111.5 degrees which is 21.5 degrees off the “ideal” 90.

Mazdaspeed 3 AWD Rocker Arm Angle Ride Height Damper

Then looking at ride height as the suspension moves downward from the full bump. The damper-to-rocker arm angle decreases to 82 degrees which is 8 degrees off the “ideal” 90.

Mazdaspeed 3 AWD Rocker Angle Droop Damper

With the suspension traveling to full droop, the damper-to-rocker arm angle decreases to 62 degrees which is 28 degrees off the “ideal” 90.

Again we have the damper near the “ideal” 90-degree angle at ride height and then pass through the 90-degree angle zone when the suspension compresses at launch. Again, the balanced angles we are trying to design for so the suspension function in the “ideal” angle range most of the time.

Why are the angles so important? The further you get from the “ideal” 90-degree angle, the more non-linear the suspension acts. When the suspension acts in a linear function, it is tunable and predictable to drive. If it is non-linear, then it makes tuning and use much more difficult…this results in inconsistent launching and driving, which is not good in a racing environment.

This seems like a lot of work…why do it?

A few reasons, really:

Moving to the rocker arm design gave me a lot of control over how I set up my Mazdaspeed for racing.
It also gave me the ability to use readily available off-the-shelf dampers. This allowed me to get double adjustable dampers (rebound and compressor) for a very cost-effective price.
The CX7 AWD swap rear axle shafts did not allow me to use the OEM dampers anyways.
This design moves more of the suspension component’s weight to “sprung mass” which is better.
I love the challenge of designing a suspension system like this, and this was a great opportunity!

Before we wrap things up, note the rocker arms are 6061-T6 billet and are massive! We knew they were big, but it didn’t really sink in until we saw them firsthand.

Alright, that wraps up the rocker arm suspension design, a huge novelty for the build. There are plenty more huge milestones to overcome, and those are coming up in this multi-part blog series!

I hope you are enjoying this series about the AWD Swap Mazdaspeed3, stay tuned for more blogs to come!

You can also find updates on my IG @halfmilespeed3, the CorkSport 7^th Gear Membership, and on mazdaspeeds.org.

Thanks for tuning in!

-Barett @ CS

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April 4, 2023October 24, 2023

How to Get A 900 Horsepower Mazdaspeed 3 AWD Swap – The Intro

Have you ever felt like you try and try and try, but just can’t get the traction to make forward progress on your Mazdaspeed 3 car build? Ya, it happens to the best of us and the 2022 season was my time…both in literal traction and life.

If you haven’t seen my build yet, the @halfmilespeed3, go check it out. It’s an awesome combo of DIY, Teamwork, Innovations, and CorkSport goodies you all love.

Back to this traction conundrum. Racing an 800+hp FWD Mazdaspeed 3 on small airport airstrips with no prep and plenty of dust has proven to be challenging. There have been many successes and many challenges, but ultimately it comes down to those two tiny patches of rubber that meet the road.

LITERALLY NO TRACTION

Yes, Motec helped substantially with traction control and Justin’s ramp-up in power delivery also helps, but really…I just didn’t have any damn traction. Sticky tires with meaty sidewalls also help, but again traction was such an issue! There had to be a better way!

Wheel & Tire Setup:

Front: Toyo TQ 255/50 on 16×8+38

Rear: Toyo R888R 255/40 on 17×9+45

And there was and I had been talking about the idea for a year or so already. Then life happened.

As you can see with the racecar; I like to go fast. I carried that enthusiasm into my love of mountain biking one day in June 2022 and well…I got a lesson in physics let me tell you.

Five broken ribs, a double punctured lung, level 3 AC separation, and a fractured collar bone and scapula. Resulting in weeks of hospital stays and three surgeries; then months of recovery and physical therapy. Let’s just say the 2022 season did not go as planned.

But it did get me focused on solving my traction problems…

Mazdaspeed 3 drag racing 800 hp CorkSport

Mazdaspeed 3 performance parts racing — Mazdaspeed 3 with CorkSport Mazda Performance Parts Back (AKA HalfMileSpeed3)

The Goal…Mazdaspeed 3 AWD Swap

So I decided it was time to stop talking about it and actually take action (well as soon as I physically could that is). I made a plan and figured out the details and order of operations to finally get my traction back.

It was time to AWD Swap the Halfmilespeed3.

While I am not the first to do a Mazdaspeed AWD swap. I did have a goal to make my build unique in the sense that the AWD swap is catered to racing performance. Meaning the strength of custom parts and the rear suspension design and the new fuel system are capable of handling the 4-digit horsepower goal I have and the abuse of racing.

Talking horsepower…what does the car make right now?

Dynograph of Mazdaspeed 3 AWD Swap 800 WHP

This is at a modest 40-41psi using a Xona Rotor 9569s with the X3C compressor housing and 1.03A/R turbine housing. Later Justin @freektune and I turned it up a bit more to see how close we can get to the 600wtq threshold and hold it. Clipping off an 881whp run…damn! This was supported by the many CorkSport Mazda performance parts you can get for your Mazdaspeed as well. From engine mounts to manifolds, anything that isn’t a one-off custom is CS.

Anyways…I have since updated the compressor wheel to a 99 lb/min design compared to the above 95 lb/min design and a larger compressor housing which is more efficient. This setup has not been dyno tested yet, but talking to the engineers at Xona…2023 is going to be spicy!

Close up because who doesn’t like billet turbo shots!?

Dare I say this is the largest turbo in the stock location ever on a Mazdaspeed? Go ahead…prove me wrong. To compare, this competes with a Precision 6870.

Mazda 3 performance parts awd swap Mazdaspeed 3

The Start of the Mazdaspeed 3 AWD Swap

Anyways, this is the introduction to my Mazdaspeed 3 AWD swap here at CorkSport HQ. I actually started the swap in October 2022 and have been making big steps each month. We are going to be sharing blog updates rapidly as I wrap up the swap over the next couple of months.

There will be much more technical info and images coming up so grab a drink and enjoy!

You can also find updates on my IG @halfmilespeed3, the CorkSport 7^th Gear Membership, and on mazdaspeeds.org.

https://mazdaspeeds.org/index.php?threads/awd-speed-3-project-halfmilespeed3.15154/

Thanks for tuning in!

-Barett @ CS

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August 30, 2021May 9, 2024

Half Mile Drag Racing Mazdaspeed – @halfmilespeed3 Goes to Indy

Can you believe it’s already August of 2021? It’s crazy how this year has flown by! Between the engineering projects at CorkSport and the racing with @halfmilespeed3…the weeks have become a blurr. BUT sometimes you just have to put your foot down and go racing. That’s what I want to tell you about.

Barett here, Driver of Halfmilespeed 3, where my goal is to race a 2009 Mazdaspeed 3 in the standing half mile. Much like the quarter-mile drag racing you have most likely seen or even participated in, but we stretch the race an extra ¼ mile and we race on no-prep airstrips. The added ¼ mile helps us reach speeds of 150+ up to 250mph for the crazy 2500whp builds. I’d like to invite you to see what’s happened with my 09’ Speed 3 over the last few months and what we hope to achieve at Shift Sector Indy this coming weekend (August 14^th – 15^th).

Let’s jump back to April 2021; the first race of the season at Coalinga CA. Like all the half-mile races I am participating in, this race was hosted by Shift Sector. If you want to check out Shift Sector more or see if they race you check it out here.

Anyways, the lesson learned was “Don’t change a bunch of shit on your car before the race”. I realize that’s extremely difficult it seems but trust me.

We nuked 3^rd and 4^th gear in my transmission Saturday AM because we thought it was a great idea to change the shifter assembly and cables a few days before the race. Those take time to get set up correctly or you can do damage…obviously. So, we found a used transmission locally (albeit a GEN 1 trans which is not ideal gearing) and got to work. By 330am (Sunday AM) we had the car running again and back in the trailer…off to the track by 8 am that morning.

Long story short, the car did drive off the trailer but then had an electrical issue that never let the car run again that day. The event was a bust…we eventually figured out the electrical issue was bad ground that was caused by the midnight transmission swap. Lesson learned!

The next event was a Roll Race hosted by Shift Sector down south at Willow Springs Raceway. I was excited to do my first roll race because we all know these cars are not great from a dig, but from a roll, they can really kick some ass.

If you haven’t done a legit (non-Mexico) roll race and get the chance…do it! It was an awesome experience and will be doing many more in the future. With that being said the race was held on the front straight of Big Willow Racetrack…so that meant we were lining up and launching at the exit of the last corner…that was interesting to say the least. The morning was four hours of practice and testing. The car was doing great, but the heat was really starting to wear on me and the car. By the end of practice, I was starting to see the heat really build up with 180+ degF intake temps and boost air temps in the 140+ degF range.

We let the car sit for almost a couple hours before the actual competition started. This helped alot, but damn was it still hot outside with ambient air temps over 100 degF. When my race came along I lined up with a 335i with a big single turbo and hood exit exhaust…we set off with a target hit speed of 40-50mph. Luckily this was right in the sweet spot for 3^rd gear and just a bit of brake boosting to hit the launch hard. As we got to the finish line the light flashed and we went for it….but the heat said nope.

Unfortunately my car stumbled and cut power. I went a bit to aggressive on the brake boosting and super-heated my boost air temps. This caused the ECU to pull power for a split second…just enough for the BMW to pull ahead.

Despite this I pushed forward and was reeling him in but there just wasn’t enough straight to catch him.

Video Link if Possible: “Built with Barett Episode 3”

Another lesson learned…I need to get my cooling in check before the next event. That next event is Shift Sector Indy. This is a standing half mile drag race at Marion Municipal Airport in Marion Indiana.

Image: shift-sector-indy-2021

As I write this, my Speed is sitting in a transport truck operated by English Racing along with nine other cars going to the same event. Quoting Myles Kerr @ English Racing…”4 GTR’s, 2 damn Honda’s, a Mazda, NSX, 570 and a 720.”

Yup, the Mazda is riding with the big boys. If I could take a guess, those two big rigs are holding upwards of 15,000+ whp of racecar…HOLY SHIT. I think my humble little Mazda is the only car not making 4 digit power…

Anyways, we made some changes for the Indy race for power, traction, heat control and reliability.

Heat killed us last time so let’s resolve that with a hole in the headlight (haha yes I said that) and force CO2 cooling on the intercooler.

So, to solve the high intake air temperature issue I cut a big ol’ hole in my headlight. Now I have a direct source of ambient air hitting the air intake system. Unfortunately, the CO2 cooling system did not arrive in time to get installed so let’s just hope it’s not so damn hot in Indiana.

For power and traction, I have finally moved from the restrictive stock ECU to the amazing Motec M142 ECU. With help from some awesome friends, I was able to get the Motec installed and running most of my desired auxiliary sensors (coolant pressure, oil pressure, PI fuel rain pressure, eMAP, EGT). There are two major benefits of Motec over the stock ECU (right now).

First, the Motec allows proper tuning control to 10k+ engine RPM whereas the stock ECU in the GEN1 flat lines control at 7k RPM. While the car/engine can rev out past 7k, the ECU stops actively controlling the tuning, and therefore power falls off. The new power band for the halfmilespeed3 carries to 8500rpm thanks to Motec and Justin @ Freektune!

Video Link if Possible: “Built with Barett Episode 4”

Just so you are aware, the engine is a complete CorkSport catalog build featuring an Overspeed Built Block (for 1000hp) with CorkSport manifolds, 4” intake, 3.5” exhaust, port injection fuel system and Kelford D camshafts. The turbocharger is still a stock flange CorkSport CST6.

So with that wish me luck and I hope to see you at the airstrip. Get out and drive your car…you don’t have to have a bonkers build and power number to compete and enjoy your Mazdaspeed. Go get a number and send it down a runway!

Image: how-to-race-your-mazdaspeed

Thanks for checking out the latest update with @halfmilespeed3. Follow on Instagram for more updates and checkout the live link for the Shift Sector Indy event in my bio.

Barett @ CS

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