CorkSport’s Mazdaspeed 3 Stage II Engine Mount

You may be surprised to hear that there is yet another Rear Motor Mount available for the Mazdaspeed 3 platform in a market with more than a handful of options; however, this one is different. This RMM takes the idea box and kicks it to side as it makes a great leap towards style, performance and refinement. Ladies and Gentlemen, this is the new CorkSport Stage 2 Rear Motor Mount.

If you are even remotely familiar with the OE style (and many aftermarket options) RMM then you can clearly see that the CorkSport Stage 2 RMM is drastically different. Now let me explain why this is a good thing.

We all understand that the engine mounts isolate the engine from the chassis in an attempt to reduce and/or eliminate undesirable vibrations and noise experienced by the driver. That’s great and all, but what is really important is how the isolation is executed, specifically by the RMM. First, some background information.

There are three motor mounts working together to suspend the engine so let’s talk about the other two real quick. The transmission and passenger side motor mounts reside on the furthest ends of the assembled transmission and engine, respectively. These do most of the work supporting the engine given their positions, but a side effect of that is the aggressive rotational force they allow the engine to exert due to their transverse setup. This is where the rear motor mount comes in by managing the rotational force from the engine when applying power to the axles/tires.

Let’s take a look at the diagram below:

In the diagram we are looking at the OE RMM installed on the vehicle. This view is looking at the RMM from the right hand side of the vehicle. The diagram also attempts to show the general location of the transmission mount which is approximately where the transverse pivot point of the engine lies.

The engine exerts the rotational force onto the RMM shown with the double end red arrow. This can be further broken down into directional components as shown with the blue arrows. The forward force is unavoidable due to the design of the system in a whole, but the downward force can be reduced or even eliminated with a clever design such as relocating the damping material from the OE location to a location closer the engine pivot point. Note the length of the blue arrows as it will be different in the following diagram.

There are two key aspects of the CorkSport Stage 2 RMM that contribute to its superior performance and low NVH (noise, vibration, & harshness). First is the rigid design of the mount that installs into the sub-frame. This nearly eliminates any up and down pivot capabilities at the sub-frame thus reducing the magnitude of the up/down motion the RMM will allow. This feature has been used by a couple other manufacturers in the community because of is superiority. Second, and more importantly, is the location and orientation of the polyurethane bushings. The horizontal orientation of the bushing allows the bushings to function and support load in the same direction the engine exerts force. This results in a more durable design with less NVH.

Now comes the big game changer…the location of the bushings are in a location never done before in the Mazdaspeed 3 platforms. Comparing the OE RMM pivot location vs the CorkSport pivot location you will see that the CorkSport design moves the pivot point of the RMM forward in the vehicle. This is important because of how it relates to the natural pivot location of the entire engine/transmission. Moving the RMM pivot location further forward reduces the amount of downward force applied to the RMM at the sub-frame, thus reducing the NVH without compromising performance. This is shown with the different length blue arrows in the diagram. This allowed us to use very stiff 95A durometer polyurethane without compromising driver and passenger comfort.

Anyways, enough with the technical stuff; check out this video comparing the OE RMM and CorkSport Stage 2 RMM in action.

If this hasn’t blown you away already then let Jason Atwell’s Beta test review set it in stone for you…

“Tested out the new CS RMM and I’ve gotta say; I was dead set on the gold RMM I was currently using. Once I got the CS one, I installed it right away. The fitment was spot, I hoped in the car and took it for drive and noticed an even more solid feel in the shifts. The vibes are about the same as the gold RMM so all in all I’d have to say it’s a fantastic product and would recommend.” – Jason Atwell

Get your CorkSport Stage 2 RMM today here!

2017 Race Season Is Here!

2017 Race Season at CorkSport

The wait is over! It’s finally the time of year where we shed the car covers, finish our tunes and builds, and make any last modifications to get fully prepared for the 1,320-feet road course racing season. As you can imagine, all of us here at CorkSport now have an extra pep in our step with the weather improving and our goals becoming clear.

Built for speed

2017 Race Season at CorkSport

Because I live for racing, I’ve built my car specifically for the drag strip. I have a 2009 Mazdaspeed 3 decked out with:

CorkSport built for speed receipt

Running faster in 2017

During last year’s season, I was able to lay down a pretty raw pass with my full bolt-ons, stock block, and CorkSport turbo. I was happy with a 12.7 elapsed time (ET) at 115 mph — a respectable number if you ask me! This year with my new built bottom end, I am hoping to have more midrange, spray more meth, and run faster. I have a personal goal of trapping 120 mph on the CorkSport turbo. Just imagine how sweet it would be to have a Mazdaspeed 3 trapping 120 mph in the 1,320 with almost no turbo lag!

Whether a racing victory is your goal, or you just want a modded-out dope-looking ride, we want to make sure you guys think about CorkSport when you are looking for parts. I’m proof that our turbo with full bolt-ons is capable of impressive speed. Whether you need suspension components, turbo components, or you just want to have a chat, you know where to find us!

Cheers,

Luke

New Product: MazdaSpeed Dual VTA Bypass Valve

Many months ago here at CorkSport we decided it was time to bring a new high performance BPV to the market. The goal was to design a BPV that was compact, durable, and performed beyond just making noise; most importantly this BPV had to feature VTA functionality that was a right balance of daily driver friendly and performance. Ladies and Gentlemen, boys and girls, I give you the new CorkSport VTA BPV.

A beautiful picture of the outside looks nice, but does not even begin to show the many features designed into this BPV. Let’s take a look inside.

mazdaspeed bypass valve cutaway idle
Figure 1: Cutaway view in idle position

Looking at the first cutaway view shown in Figure 1, you’ll immediately notice the three O-rings. Two are located on the sides of the piston and one is located at the bottom of the piston. These are important for a couple reasons: the O-rings allow the piston to actuate/slide easily when combined with a proper lubricant and provide air tight seals in all piston positions. This allows the valve to hold 50psi of pressure without leaking.

I specifically identified the VTA port because it location is critical to the BPV design and the drivability of the vehicle. In the idle position the piston sits at approximately the same position as shown above due to the vacuum pressure sourced from the intake manifold. At idle the VTA ports are closed, keeping your fuel trims in check.

Next, let’s look at the BPV in positive pressure (building boost) situation.

mazdaspeed bypass valve cutaway pressure
Figure 2: Cutaway view in positive pressure position

Immediately after applying throttle, the intake manifold begins to increase in pressure due to the turbocharger building boost. At the same time the BPV piston is forced closed as shown in Figure 2. Like the idle position, the VTA ports are closed keeping fuel trims in check. The piston also creates an airtight seal against the base flange improving boost response.

Next you shift or get off the throttle which causes a sudden pressure change in the intake manifold and the charge pipe pre-throttle body. The excessive pressure build up in the charge pipe combined with the vacuum from the intake manifold cause the piston to open as shown in Figure 3 below.

mazdaspeed bypass valve cutaway high boost
Figure 3: Cutaway view in high boost lift off position

Unlike the idle position, the piston has moved up past the VTA ports. This is due to the excessive pressure differential between the piston vacuum chamber and the charge pipe pressure. The greater this pressure differential the faster the piston will respond and vent more air to the VTA ports. Testing has shown that the VTA ports begin activating at ~15psi or greater boost pressures on a K04 equipped vehicle.

So that’s how the CorkSport VTA BPV works, but what makes it so efficient in doing so? A combination of simple and effective features all wrapped up into one design.

Response is key to a great performing BPV, plain and simple. The piston inside the BPV must respond and accelerate extremely fast in order to reduce the pressure in the charge pipe and protect the turbocharger. Attaining that response comes down to simple physics in the form of Force = Mass * Acceleration. We can directly affect the mass of the piston via design and materials, which we were able to get down to a mere 38 grams w/O-rings. We can semi-directly affect the force required to accelerate the piston which various spring rates. Therefore by reducing the weight of the piston and optimizing the force applied to the piston we were able obtain a remarkable response time.

vta bpv response
Figure 4: CorkSport VTA BPV response time during high boost throttle close situation

Looking at Figure 4, you can see two separate graphs shown. The blue graph shows the intake manifold pressure in a 0-5volt range. Boost pressure was leveling at ~23.5psi on a CorkSport turbo equipped vehicle. The red graph shows the charge pipe pressure just ahead of the throttle body approximately where the BPV is located.

During the test the car is held steady at ~6000rpm so that boost can level off for ~5sec, then the throttle is abruptly closed; this is shown in the blue graph with the sudden decay. This causes sudden vacuum in the intake manifold and increased pressure in the charge pipe pre-throttle body. The pressure delta causes the BPV piston to react and vent which is shown with the slight increase and then decay of the red graph. The response time of the BPV is time delta from the intake manifold going into vacuum and the BPV beginning to open and vent. The resulting time delta is a remarkable 50 milli-sec or 0.050sec in general terms.

The piston isn’t the only optimized part of the BPV. The piston design and the BPV cap were designed to work together. Looking at Figure 3 you can see that the hose barb fitting is integrated into the cap design and more importantly is “inside” the piston as much as possible. By reducing the volume of the vacuum/boost signal chamber in the BPV, we have reduced the total volume that must be removed from the chamber before full vacuum occurs and can begin moving the piston. You could compare this to “shot-gunning” a can of beer. The tall boy is going to take longer than your standard 12oz right? Same idea with the BPV, but we are trying to shave milli-seconds.

bpv flange adjustability
Figure 5: CorkSport BPV flange adjustability

Another awesome feature on the CorkSport VTA BPV comes in the form of installation flexibility. Not only is the BPV compact at just 2.50 inches tall, but the flange can be adjusted to a total of five positions. The center BPV in Figure 5 shows the typical position for a Mazdaspeed BPV. From there the flange can be adjusted 15 or 30 degrees clockwise or counter-clockwise to aid in installation.

cad flow simulation
Figure 6: CAD flow simulation at ~220CFM with piston BPV fully open

Lastly, and arguably most important, the CorkSport VTA BPV flows great. Figure 6 shows a CAD flow simulation of the BPV fully open with inlet condition 23psia @ 110F and outlet condition 7 inches of H2O vacuum. Mach flow or commonly called “choke flow” is the situation when the air velocity reaches Mach 1. At this point no more airflow can be pulled through the BPV without increasing the pressure at the BPV inlet (charge pipe). In the CorkSport VTA BPV, Mach flows begins to occur at the nozzle throat shown in Figure 6. This is to be expected with the compact design and was a compromise made in the design process; however you will notice that the CAD simulation does not take into account the potential flow of the five VTA ports. These will only increase the maximum potential flow of the BPV.

To top it all off, the CorkSport VTA BPV makes an array of noises ranging from subtle whistles to loud whooshes. I invite you to check out the video found in the product listing as words just cannot give it justice.

We set out to design a high performing VTA BPV for the Mazdaspeed community that delivered with performance, style, and entertainment. We believe we delivered with a leak-proof, fast responding and glorious sound BPV. We hope you enjoy your new CorkSport VTA BPV as much as we enjoyed designing it.

-Barett

Barett Strecker-01

CorkSport Oil Pressure, Oil Temperature, and Boost Gauges with Adapter Plate

Have you had your COBB Accessport running in gauge mode, but with so many things displayed it makes it hard to take a quick glance under full-throttle to see what is going on? Or did you make a pass at the local drag strip and forget to turn on logging to see what the maximum boost level or temps you are getting?

We here at CorkSport are in the same boat. So, we decided to take care of the problem with our new gauges. We selected the “Critical 3” that you should be running in your Mazda: Boost, Oil Pressure, and Oil Temperature.

Gauges Mazdaspeed Cobb Accessport

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