Barett Mazdaspeed | CorkSport Mazda Performance Blog

May 1, 2024May 13, 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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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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May 9, 2023October 24, 2023

How to Make A 900 Horsepower Mazdaspeed 3 AWD Swap – CX7 Rear Subframe (Part 3)

Welcome to part 3 of the Mazdaspeed3 AWD Swap! If you missed part 1 and part 2 blog posts, then catch up by visiting these links. Lots of images in this blog as I get the CX7 rear subframe installed and figure out the correct control arms to use for the rear suspension.

Typically when I mention the AWD swap Mazdaspeed 3 to a fellow Mazdaspeed enthusiast, they assume I am using the rear subframe from a Mazdaspeed 6. While I understand their logic, incorporating one would require extensive fabrication.

Here’s why: the Mazdaspeed 6 has a very different chassis architecture vs the Mazdaspeed 3. It is important to note because it directly affects the subframe and chassis interface.

If it’s not the speed6 then what do I use? Good news! The Mazdaspeed 3 uses a chassis design based on a Ford global chassis used with various models in Mazda, Ford, and Volvo. Enter the Mazda CX7.

Mazdaspeed junkyard performance parts — Car AWD Hunt for CX-7 Subframe

So I went hunting for a Turbo AWD CX7 model year 2006-2007…this is a great time to bring your buddies along for some junkyard fun!

Luckily I found one in a local junkyard that was still complete enough. Not knowing exactly what I needed from the rear-end suspension and drivetrain, I opted to take everything; driveshaft to differential, plus the ENTIRE rear subframe and suspension.

Mazdaspeed awd swap cx7 rear subframe — CX-7 Rear Subframe

$380 later, we are driving home with our newfound treasure and ready to take on the swap! I was eager to see how this would bolt into the Mazdaspeed 3, so we went straight to the shop.

We wasted no time removing the speed3 rear subframe… literally six bolts and removing the brake calipers is all that is required.

Mazda 3 performance parts awd swap ms3 — Mazdaspeed 3 Rear subframe removed

Mazda 3 awd swap performance parts turbo — OEM Fuel Tank

Knowing the OEM fuel tank is in the way of the mid-driveshaft, we opted to just remove it right then as well. A handful of bolts and some fighting of the fuel tank filler and it’s out also. At this point, we are maybe 1.5 hours into this and the car is ready to accept its fate.

Mazdaspeed fuel tank removal awd swap — OEM Mazdaspeed Fuel Tank Removed

With both the MS3 and CX7 rear subframes out and sitting side-by-side, we took the opportunity to compare them. Checking the most important things first, we looked at the mounting points for the subframe to chassis. These all checked out visually and again after measuring to be the same…but this is where the similarities ended.

Mazdaspeed vs cx7 rear subframe on pallet — Comparison of the Mazdaspeed and CX-7 Rear Subframe Side by Side

The trailing arm/hub assembly is very different between the two models. The CX7 appears to be much heavier duty and more complex. Doing some research, we found that the CX7 uses a different style of parking brake. The parking brake is actually a drum brake inside the rotor hat of the disc. Either way, the CX7 suspension looks heavy…which is not ideal for Racecar. The width also appears to be wider by a few inches.

The last noticeable difference is the addition of a rear differential – which is the whole goal of the project – so that is a good thing! That said, the OEM spare tire location in the MS3 will interfere with the fitment of the differential.

Mazdaspeed 3 under car image no drivetrain

Not an issue for Racecar and my Sawzall! I cut the entire spare tire tub out since my new fuel cell will be going there.

Mazdaspeed 3 spare tire tub removed — Removed Mazdaspeed Spare Tire Compartment

We are ready to mock up the complete CX7 rear suspension with the spare tire tub removed. Knowing that the mounting points are the same, we installed the entire CX7 system to see how it fit.

mazdaspeed 3 with cx7 rear subframe installed 1

The six mounting points lined up perfectly, confirming our initial measurements – it’s almost as if it was meant to be! Next, we tried to get the trailing arm forward mounting points bolted in but fought them, eventually giving up. We are confident the springs were fighting us, and the trailing arms would have bolted in had we removed the springs.

Mazdaspeed 3 with cx7 rear subframe installed 2 — Installing the CX-7 Rear Subframe to the Mazdaspeed

Moving on, we wanted to see how the track width looked before spending any more time on the trailing arms.

Mazdaspeed 3 stance car cx7 width — The Track Width of the New Rear Subframe

As we suspected, the setup was too wide – unless you want wider – which I did not want for a high-speed straight-line drag racer.

Mazdaspeed AWD swap after CX-7 Mazda intall — Ride Height with the Mazda CX-7 Subframe on Mazdaspeed

From the side view, the wheel’s centerline looks good, and the meaty 255/50R16 looks badass, but the CX7 springs obviously do not play nice. The monster truck ride height won’t work.

We planned a “hybrid” of CX7 and MS3 suspension parts, as advised by a friend, @junkiebuilt, that did a GEN1 AWD swap using a Honda drivetrain. We will use the CX7 subframe only and the MS3 trailing arm/bearing hub and control arms.

mazdaspeed 3 awd swap done the right way

This combo was the ticket! The Mazdaspeed 3 control arms bolted into the CX7 subframe without issue, allowing me to retain my CorkSport Camber Arms and CorkSport Toe Arms, as well as the lower OEM control arm. Along with that, I get to keep the Mazdaspeed 3 trailing arm, which is not nearly as heavy or complex.

This setup also retains the OEM parking brake, my Mazda 5 rotor, and my MS3 calipers. Ultimately this is looking like a very straightforward swap with no fabrication. Don’t mind @farvaspeed6 looking at, um, something.

With the hybrid CX7/MS3 setup on the car, we wanted to see how things were lining up. The meats went back on!

Mazdaspeed 3 stance race tire — After the hybrid swap track width

After adjustments the Mazdaspeed AWD swap ride height — Mazdaspeed AWD Swap Hybrid Ride Height

Ah, much better this time. The wider stance is gone, and the wheel tire looks right at home. Surprisingly the tire tucks under the fender with just a tad amount of rubbing.

With the day of excitement winding down, I wanted to check on the last thing to see if this truly was a direct bolt-on swap. Unfortunately, the OEM MS3 rear wheel bearing is not the same as the CX7 wheel bearing. Being FWD, the MS3 wheel bearing does not have splines for an axle…duh. So I have to use CX7 wheel bearings on the MS3 trailing arm/hub assembly.

This is where my luck ended.

With the MS3 wheel bearing removed and the CX7 wheel bearing set next to the trailing arms…things look good. But they are ever so slightly different.

awd swap mazdaspeed 3 cx7 wheel gearing 2

The CX7 wheel bearing has a slightly larger bore size, and the bolt pattern is somewhat different. I will never understand why Mazda went through the effort to make these so close but not the same. Either way, this was not a job a hand drill and grinder could fix. This needed proper measurements and machining.

I reverse-engineered the CX7 bolt pattern and hub bore. 3DP printed that to verify then off to the machine shop to get the one-off work done.

The existing bolt holes were welded closed, the ground flat, and the new holes were drilled following my measurements. The hub bore was also enlarged to match the CX7 wheel bearing.

Mazdaspeed 3 awd swap machined trailing arm 1

With that one and only fab job complete, we had actually finished the CX7 to MS3 rear swap.

Mazdaspeed 3 awd swap machined trailing arm 2

Minus the machining for the wheel bearings, the rear subframe, and the suspension swap was actually very easy and straightforward. This is great news because it could have been the death (or very expensive aspect) of the swap. Ultimately this part of the swap being so easy makes it a much more viable project for the average enthusiast.

Alright, that wraps up the rear subframe swap, a huge milestone for the build. There are plenty more 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 Mazdaspeed 3, 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 18, 2023February 14, 2024

How to Get A 900 Horsepower MazdaSpeed 3 AWD Swap – Baseline Weight & Cantilever Suspension (Part 2)

Part 2 of the Mazdaspeed3 AWD Swap blogs, we are going to get a baseline weight, show you some of the parts going into the car and finally tease you with cantilever suspension. Have a seat and grab a drink!

Read Part 1 How to Get A 900 Horsepower Mazdaspeed 3 AWD Swap – The Intro

Before I started the AWD swap on my half-mile drag-racing Mazdaspeed 3 I wanted to get a baseline weight and weight distribution. Without a driver, my 2009 Mazdaspeed 3 weighed in at 3000 pounds on the money with just under 2000 pounds on the front wheels and just over 1000 pounds on the rear axle.

Corner weights are actually pretty damn good, but this is without my weight in the car. Adding me to the equation would throw that off a good amount. Either we have a baseline that we can compare to later once the car is back to 100% with AWD.

Now this may not be a perfect back-to-back test but it’s something…which is better than nothing. At the time of weigh-in, the Speed3 has an 8-point cage, composite driver seat and basic reclining aftermarket passenger seat, harnesses for both, stripped interior for everything behind the driver.

The components that are changing for the AWD swap:

Transmission: MS3 to MS6
Rear Subframe: MS3 to CX7
Fuel Tank: OEM Fuel Tank to a Radium 10gal Fuel Cell w/Surge Tank built-in
Rear Suspension: Changing from outboard OEM style to inboard cantilever style
Rear Tires/Wheels: Going from a 17×9+45 w/255/40 tire to a 16×8+38 w/255/50 tire
Rear Crashbar: Removing the OEM crashbar for a custom tubular crashbar with parachute mount

The components that are being added for the AWD swap:

Transfer Case from Mazdaspeed 6
Mid-Drive Shaft connecting the T-Case to the Differential
Rear Differential from Mazdaspeed 6 and CX7. (We will discuss this more in a later blog.)
Rear Axles
Firewall Structure to separate the Radium Fuel Cell from the driver compartment

Alright so let’s talk about some of these components that are changing. Firstly is the fuel system. Currently, I am running a dual fuel system featuring the CorkSport Fender Fuel Cell with E98 in it feeding the port injection system and the stock fuel tank with an E48 blend in it.

While this kit has taken me to 650+whp with the CorkSport CST6 Turbo and nearly 900 WHP with a larger turbo and fuel pump…it’s time to really focus the build to a more dedicated racing fuel system.

Enter the Radium “FCST” System; this is a full standalone fuel system that is FIA-certified and incorporates the 10-gallon fuel cell, an internal surge tank, and a fuel level sensor.

For my setup, I will be using a single 525LPH “in-tank” pump inside the fuel cell feeding the surge tank which then feeds to external pumps. This 525LPH fuel pump is mounted to the stainless steel bracket you see below inside the fuel cell.

mazda racing fuel cell system radium 525lph

Then the external pumps are a Quantum 044 style pump feeding the direct injection OEM fuel system and a MagnaFuel 525 gear-driven pump feeding the port injection fuel system.

So why the big change? Well, there are a few reasons really:

With the AWD swap, I couldn’t retain the OEM fuel tank due to the mid-driveshaft so I had to find a new solution. There is some Volvo OEM fuel tank that works with some basic modifications, but this is a racecar. I did not want to retain the same limitations as OEM.
With the power I am pushing and plan to push in the future, I need all the octane I can get so it made sense to use a single tank feeding both DI and PI fuel systems.
Typically, in drag racing, you specifically use a small (less than 3 gallon) fuel cell in the front of the car, much like the CS Fender Fuel Cell. However, my car still sees street use, at events, and may or may not always be a drag racing-only car so I wanted a fuel cell system that could do anything I wanted now and in the future.

Next up is the rear suspension…this is my favorite part…except for the actual AWD of course! With the rear suspension, I am taking a much more unique approach by using an inboard mounting cantilever coilover suspension. While this seems over complicated upfront, and it is, it will also provide me with a lot of flexibility and control later when using and tuning the suspension.

But what’s wrong with the OEM suspension design?

Mazda 3 performance parts suspension setup

Nothing is “wrong”, it’s just not ideal. The lower control arm that supports the coil spring is very heavy, the OEM damper mount can’t be used due to the driveshaft so I will need to create a new mount elsewhere with cantilever or OEM style suspension and lastly, I want double adjustable (rebound and compression) dampers which would be more difficult and expensive to source that will work in the OEM style arrangement.

All of those factors lead me to the path of developing my own suspension setup.

mazda performance parts double-adjustable dampers

Doing some research I found QA1 dampers have great reviews, are very cost-effective, come in many different sizes/lengths, and have double adjustable options. They seem very fitting for my goals.

The double adjustable control is important for any type of competitive racing, but with drag racing, I had a specific need. When the car is launched from a standstill, there is an extreme amount of weight transfer happening that needs to be allowed to “transfer” to the rear but then needs to be controlled and maintained in that position.

Lastly, what is this cantilever suspension and what does it look like? Here’s a teaser of my design.

While I am planning to dig into the design around this in more details, that will have to wait til the next blog in this series. In a nutshell, the outboard suspension that the wheel and tire is connected to pushes a “push-rod” to a larger rocker arm (cantilever) that then pushes a coilover damper and spring setup. Other than the rod itself, this entire system is inside the car between the rear damper towers.

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.

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

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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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Stay up-to-date on the latest news and product updates from CorkSport.

Stay up-to-date on the latest news and product updates from CorkSport.

Stay up-to-date on the latest news and product updates from CorkSport.

Stay up-to-date on the latest news and product updates from CorkSport.

The Goal…Mazdaspeed 3 AWD Swap

The Start of the Mazdaspeed 3 AWD Swap

Stay up-to-date on the latest news and product updates from CorkSport.