Mishimoto Build Thread: 2008-2014 STi TMIC

[Mishimoto]

Hey guys,

Check out the build thread for our new 2008-2014 STi top-mount intercooler! This build and many others can be found on our engineering blog at the link below.

Engineering Blog

2008–2014 Subaru STI Performance Top-Mount Intercooler, Part 1: Product Goals and Initial Design Process

Did you think we would just develop a top-mount intercooler (TMIC) for the GD WRX and leave out the STI? No way! At around the same time we began development on the WRX, we picked up a new shop vehicle, a 2010 STI. When a new vehicle makes its way into shop service, we need to be sure it accelerates and handles properly. The STI passed our checkup. We then set out to determine what products we wanted to develop first. We already had a few items on the market, including a performance aluminum radiator and a silicone radiator hose kit. Our first target had been a direct-fit oil cooler that proved to be extremely successful, providing a 20°F drop in oil temperatures during our testing. Next we created a plug-n-play fan shroud with dual 12” electric fans. The key component of this shroud was the use of stock-style fan connectors and a very slim profile. Finally, we tackled one of our favorite projects, a performance cold-air intake. This was actually the first performance intake we developed, and it was quite a learning experience. With a garage stocked with fabrication tools and testing equipment, we were able to prove a power increase of 25 whp and 25 wtq by simply bolting on this intake. Yes, you read correctly, no tune is required for these power gains, and AFRs remain well within spec. With all these projects complete, we now turned our attention toward improving air charge temperatures. So we began with a TMIC and would later move to development of a front-mount intercooler (FMIC). Keep an eye on our blog for information regarding both projects.

Check out our 2010 STI shop ride!


Mishimoto 2010 STI shop vehicle


Mishimoto 2010 STI shop vehicle

This vehicle has been great for hauling supplies, product testing, displaying our current products, and occasional lunch trips (don’t tell the boss). In fact, I have been waiting for my S4 to break in the parking lot (shouldn’t be long, it’s a C4) so I have an excuse to take it home.

So, on to the project at hand. We started by evaluating products currently on the market, because our product will need to stand out from the others in some way. We developed a few goals and then set our engineers loose to see what they could do.

Project Goals

1. Must be direct fit and require very limited vehicle modification
2. Support vehicles having up to 400 whp
3. Provide reduced IATs
4. Increase core volume
5. Improve power output

Direct Fit
This is a simple goal for all the products we develop. There is nothing more frustrating than having to modify that brand new component you purchased. We want our customers to have a hassle-free installation, so we will be including any additional components needed for proper installation. We will be test fitting this intercooler on numerous occasions to be sure any bugs are worked out.

Power Support
The stock top-mount is reasonably efficient; however, with higher-than-stock boost levels, IAT’s are prone to rise. Heat-soak is also fairly common with the tube-and-fin core used with the stock cooler. I am in no way implying that the stock intercooler is insufficient. Our goal is to provide improved IATs for stock vehicles up to our 400 whp power range. At any point above this, we highly recommend an efficient FMIC, which would eliminate any residual heat-soak and provide the temperatures needed for rotated or high-boost setups. As we have seen on many of our other intercooler projects, reaching 400 whp will not be an issue because of the space we have to expand this intercooler.

All about Coolness
Everyone wants to be cool; this is the primary target of this project. The reason for upgrading your intercooler is to achieve lower induction temperatures. If we fail on this front, the product will not reach shelves. We are hoping to provide concrete data of temperature improvements on both a stock and lightly modified vehicle.

Large and In-Charge
This goal ties into the others we have for power support and temperature reduction. The consensus is that a larger TMIC would help with both these components. That being said, there is certainly a sweet spot of size, heat transfer, and flow that would be the true challenge for this project. A core that is too dense is going to impact air flow, which may even reduce power. This component will require precision on the part of our expert engineering team.

Power
An intercooler upgrade is a supporting modification, not technically targeted toward power increases. Obtaining additional power by bolting on a new cooler can be quite a challenge. We’re hoping that we can pull a few ponies out of our design via flow increases or increased timing from lower temperatures. Although this will be a pending or secondary goal, we are hoping to achieve it even if the numbers are not substantial.
Jumping right into the project! We needed to evaluate the stock intercooler, determine our design constraints, and begin creating a prototype. Let’s take a quick look at the stock intercooler.


Stock 2008–2014 STI engine bay

The intercooler removed!


Stock 2008–2014 STI intercooler


Stock 2008–2014 STI intercooler core, external


Stock 2008–2014 STI intercooler core, internal fins

And the engine bay we are left with upon cooler removal!


Engine bay without intercooler

The stock intercooler is constructed completely from aluminum, unlike the plastic end-tank cooler used on the WRX. The end tanks on this unit are cast and crimped to the tube-and-fin core with a rubber gasket to seal this connection point. Overall the cooler is rather well designed, fits well, and the flow is reasonably efficient. At one point during development we evaluated the Y-pipe system for the inlet and found that it is well designed. Airflow through this section is more than sufficient for our planned power level support, so we would not need to modify the Y-pipe in any way.
Additionally, as you see above, the intercooler features a dense tube-and-fin core. It will be interesting to see how the heat transfer capabilities compare to our planned bar-and-plate core design. The core dimensions are as follows:

Length: 20.75”
Height: 6.75”
Depth: 2.5”
Volume: 350 cu in

Total intercooler weight for the stock unit comes in at 10 lb, good information to keep in mind for those trying to keep weight down.
With all the stock dimensions noted and a vehicle at our disposal, our engineering team began designing a prototype using Solidworks software. Once complete and reviewed several times, we manufactured a prototype for testing purposes. Check out this raw prototype!


Mishimoto raw aluminum prototype

Check back next time for full details on our prototype unit!

Thanks

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[mitch808]

This has my interest!

[Mishimoto]

Originally Posted by mitch808

This has my interest!

Thanks for reading Mitch!

[Mishimoto]

Part two is up! Check it out below.

http://engineering.mishimoto.com/201...nd-evaluation/

2008–2014 Subaru STI Performance Top-Mount Intercooler, Part 2: Prototype Introduction and Evaluation

The wait is over! Time to reveal the full details of our prototype top-mount intercooler (TMIC). This unit is unpainted, and one of the more obvious features is its massive size! First, a few overview images of this cooler.


Mishimoto raw aluminum TMIC prototype


Mishimoto raw aluminum TMIC prototype


Mishimoto raw aluminum TMIC prototype

As you can see we designed two fully casted end tanks for this cooler. Both the BPV flange and Y-pipe flanges are CNC-machined. The thickness and construction of our casting will provide the durability needed to run much higher pressures than your STI will ever see. Each tank is then TIG-welded to our core. As with other projects, we are using a bar-and-plate core for improved heat transfer and resistance to heat soak. Let’s take a closer look at the core itself.


Mishimoto TMIC prototype, external core


Mishimoto TMIC prototype, external core


Mishimoto TMIC prototype, internal core


Mishimoto TMIC prototype, internal core

For both the internal and external fins we are using an offset style. This means our heat-transfer contact points are significantly increased, which will result in a higher rate of transfer. We crammed a ton of fins into this core; our testing will show if this has any negative impact on flow and pressure.

In recent projects, we have been trying to find creative yet subtle ways to put our branding onto our products. We understand that some customers might not be interested in promoting the brand of the products they use. For this particular cooler, we used two simple M logos cast into the tanks. Our team really digs it!


Mishimoto TMIC prototype, end-tank logo


Mishimoto TMIC prototype, end-tank logo

After confirming fitment of this prototype, we also had a few units powder-coated for testing and video purposes.

Next we would be comparing the size and features of our prototype to the stock intercooler. Check back in a few days for updates!

Thanks

[rexworx]

Very nice. That core looks familiar...

[STIRiot]

subscribed.

[mitch808]

Ah, now this looks like a nice replacement for my GD sti unit...

[Mishimoto]

Originally Posted by rexworx

Very nice. That core looks familiar...

Originally Posted by STIRiot

subscribed.

Originally Posted by mitch808

Ah, now this looks like a nice replacement for my GD sti unit...

Thanks guys!

[Mishimoto]

Part 3 of this build is up! Check it out on our blog.

http://engineering.mishimoto.com/201...ck-comparison/

2008–2014 Subaru STI Performance Top-Mount Intercooler, Part 3: Prototype and Stock Comparison

So just how much better is the Mishimoto top-mount intercooler (TMIC) compared to the stock unit? Well … only our testing will confirm this. Physically we can already see several improvements. Let’s compare the core size in a simple chart.



A shot of the thickness comparison!


Comparison of core thickness in stock intercooler (left) and Mishimoto TMIC prototype


A look at the bottom of both intercoolers reveals quite a few differences.


Stock vs Mishimoto TMIC prototype


Stock vs Mishimoto TMIC prototype

In addition to the increased size, you will also notice that our inlets are different than those on the stock cooler. This feature sets our cooler apart from any other product on the market. We designed these ports with both flow and air dispersion in mind. Check out the close-up below.


Stock (top) vs Mishimoto TMIC prototype, intercooler inlets

The most obvious change is the diverters we have placed in the center of each port. Through CFD testing we found that by adding these diverters we are better able to disperse air throughout the length of the core. Improved dispersion means that more of the core is being used to transfer heat; therefore, we are optimizing the size of our core for actual results.

Check out the CFD comparison of the stock cooler and the Mishimoto prototype below. The dot is a graphical representation of airflow. The dot color denotes the velocity of air at that point in the cooler: red (highest velocity), yellow, green, and blue (slowest). This analysis shows that the factory Y-pipe is rather efficient for airflow. It also shows the effectiveness of our diverter and end-tank design at pushing airflow to the entire core.


CFD analysis of stock cooler (top) and Mishimoto TMIC prototype cooler

Additionally, we have increased the size of these ports to improve flow. Yes, these will still mate up to the factory Y-pipe; however, a larger gasket is needed to take advantage of this flow increase. We are including a gasket for both inlets! Check out the comparison of the stock sizing to the Mishimoto unit.


Stock intercooler inlet sizing


Mishimoto prototype intercooler inlet sizing

Now, a few millimeters may not seem like much, but if you know anything about porting you will understand that every little bit helps. Our size gains are summarized in the chart below.



One more look at the inlet on our powder-coated prototype!


Mishimoto intercooler inlet

[Mishimoto]

Last, take a quick look at the end tank comparison of the factory unit against our prototype. We designed quite a beefy unit!


Comparison of Mishimoto end tank (left) vs. stock end tank


Comparison of stock end tank (left) vs. Mishimoto end tank

And finally we have a few really neat renderings of the end tanks for our prototype unit. Extreme care and precision went into the design of these components and it really shows here.


Rendering of Mishimoto prototype cold-side end tank


Rendering of Mishimoto prototype cold-side end tank


Rendering of Mishimoto prototype hot-side end tank


Rendering of Mishimoto prototype hot-side end tank


Rendering of Mishimoto prototype hot-side end tank

That about wraps up our initial comparison of the stock unit to our prototype. Check back next week when we will be preparing the coolers for testing and collecting our data on the dyno!

Thanks!

[STIGR-Wagon-Dad]

Will you keep the bypass valve mounting location in the same level as the factory? The reason why I'm asking is because I had bought an aftermarket tmic from a reputable company and I could not mount my aftermarket Diverter valve because the mounting was raised higher than stock.

[_dash_]

Very interested in this... please keep us updated!!!

[Mishimoto]

Originally Posted by STIGR-Wagon-Dad

Will you keep the bypass valve mounting location in the same level as the factory? The reason why I'm asking is because I had bought an aftermarket tmic from a reputable company and I could not mount my aftermarket Diverter valve because the mounting was raised higher than stock.

Yes we do! The factory bypass valve mounts to our cooler in the same location as the stock intercooler.

Originally Posted by _dash_

Very interested in this... please keep us updated!!!

Thanks for reading!

[Mishimoto]

Check out the last part of our build for this intercooler!

http://engineering.mishimoto.com/201...ct-completion/

2008–2014 Subaru STI Performance Top-Mount Intercooler, Part 4: Testing, Data Compilation, and Product Completion

Testing day! After a long ride through development and design, it was finally time to see the fruits of our labor. Before strapping the STI to the dynamometer, we needed to prepare the coolers for testing. This included drilling and tapping the coolers for our temperature and pressure sensors at both the inlet tank and outlet tank.

Check out a few preparation shots of our stock cooler!


Stock intercooler testing preparation


Stock intercooler tapped for sensors


Stock intercooler with sensor installed

Next up is the Mishimoto cooler. For testing we used our powder-coated cooler rather than the raw aluminum unit. (The finish has little to no effect on performance.) This version of the cooler is identical to what we have planned for mass production, assuming our testing is successful.


Mishimoto intercooler tapped


Mishimoto intercooler with sensor installed

Time to get this guy onto the dyno and start making a few pulls.


Mishimoto 2010 STI on dyno


Mishimoto 2010 STI on dyno


Mishimoto 2010 STI on dyno

We then strapped the vehicle down and set up our top-mount intercooler (TMIC) fan.


Mishimoto 2010 STI on dyno

Next, we performed pulls on both the stock intercooler and the Mishimoto prototype. Three to five pulls were made with each cooler or until we obtained three consistent runs that could be averaged. Breaks between each pull were timed to ensure accurate data.


Mishimoto 2010 STI on dyno

[Mishimoto]

Mishimoto 2010 STI on dyno

You didn't think we would make a bunch of dyno pulls without capturing video, did you? Check out this quick video that includes a few pulls with each cooler!

YouTube (Short URL)

YouTube (Short URL)

Time to review our data! First we took a look at some of the comparisons of the stock intercooler to the Mishimoto unit. A few easy-to-view charts put the gains into perspective.





Both the internal flow area and core volume of the Mishimoto intercooler showed a huge increase compared to the stock intercooler. This is reflected in the benefits we saw from testing.

Now, let's evaluate power output. Check out the plot below.



This plot shows that the Mishimoto intercooler provided gains of 4-5 whp compared to the stock intercooler throughout the run. Although this may not seem like a huge number, keep in mind our primary goal with this product is to decrease intake temperatures. Doing so will allow for more aggressive tuning and therefore improved power output. So, how did we do with our temperature data? Check out the data below from our dyno testing.



After reviewing the results, we were not entirely pleased with the temperature benefits of our cooler. As you can see, temperatures are relatively close, with the Mishimoto unit providing gains only toward the end of the run. This test was compiled on a dyno with a blower fan providing 40 mph of airflow. After reviewing the data and discussing it with the team, we decided it was necessary to perform some road testing to determine if airflow was limiting the efficiency of our intercooler design. All testing was performed on a closed course, with pulls made from first to third gear using all the same equipment used on the dyno.



These are the gains we were looking for! During the first to third gearpulls we saw an average drop in temperatures of 10°F. Now that we had concrete, real-world testing data, we could evaluate the efficiency of our cooler against the stock unit.



Gains in efficiency totaled 15%, which are great numbers for a TMIC. Lastly, we needed to check our pressure drop across the core to be sure we were not overworking the turbo to obtain the temperature drops.



As you can see, the Mishimoto intercooler follows the stock pressure rather closely, with decreases limited to about 0.25 psi. This is an acceptable number considering the increased heat transfer and density of our core.

Now that our data is compiled and deemed successful, our last task is to review our initial goals to be sure we could close the book on this project.

Project Goals

1. Must be direct fit and require very limited vehicle modification

This intercooler is a direct fit and requires no cutting or drilling on your WRX. We include new gaskets for installation as well as a new silicone PCV hose that runs across the front of the cooler to replace the stock metal line. Installation is quick and requires only normal hand tools.

2. Support vehicles up to 400 whp

With the added volume and core density of the Mishimoto intercooler, our engineers have given the "thumbs up" for vehicles up to 400 whp.

3. Provide reduced IATs

Our road testing showed an average IAT decrease of 10°F when using the Mishimoto TMIC. On a higher-horsepower/boost vehicle our engineers estimate even greater performance gains compared to the stock cooler.

4. Increase core volume

Core volume was increased by 39% compared to the stock tube-and-fin intercooler.

5. Improve power output

Our testing showed that the Mishimoto TMIC had average increases of 4-5 whp across the entire rpm range. Additional power is certainly possible with tuning.

That's it for the Mishimoto 2008-2014 STI TMIC! This is a great cooler that will provide substantial benefits to both stock and modified vehicles.

Thanks for reading, and be sure to check out our blog at the link below for updates on our new front-mount intercooler design!

Engineering Blog

Thanks!

[_dash_]

Cant wait to see some production units hit the road.

-dash

[Mishimoto]

Originally Posted by _dash_

Cant wait to see some production units hit the road.

-dash

Thanks! We are excited to see independent reviews posted on the forums. This intercooler is now available for purchase! Check it out at the link below.

http://www.mishimoto.com/subaru-wrx-...kit-08-14.html

Thanks
-John

[SUBARIFFIC]

Will this thing fit on a 2002-2007 WRX/STI
Because i'll like one in black

[Mishimoto]

Originally Posted by SUBARIFFIC

Will this thing fit on a 2002-2007 WRX/STI
Because i'll like one in black

Thanks for the interest! This intercooler is designed specifically for the 08-14 STi. We tested this unit on an 02-07 WRX and unfortunately it made contact with the waste-gate actuator on the turbo. It is possible that this cooler fits the 04-07 STi, however we have yet to test fit this.

We currently offer an intercooler setup specifically for the 02-07 WRX and STi, check it out at the link below.

http://www.mishimoto.com/subaru-wrx-...kit-01-07.html

Let me know if you have any additional questions!

Thanks

[SUBARIFFIC]

Originally Posted by Mishimoto

Thanks for the interest! This intercooler is designed specifically for the 08-14 STi. We tested this unit on an 02-07 WRX and unfortunately it made contact with the waste-gate actuator on the turbo. It is possible that this cooler fits the 04-07 STi, however we have yet to test fit this.

We currently offer an intercooler setup specifically for the 02-07 WRX and STi, check it out at the link below.

http://www.mishimoto.com/subaru-wrx-...kit-01-07.html

Let me know if you have any additional questions!

Thanks

Yeah but that intercooler isn't as potent as the one you made for the 08-14 STi. I think you guys should make one that is comparable that can handle 500-400 whp on the 02-07

[Mishimoto]

Originally Posted by SUBARIFFIC

Yeah but that intercooler isn't as potent as the one you made for the 08-14 STi. I think you guys should make one that is comparable that can handle 500-400 whp on the 02-07

Thanks for the recommendation! We currently rate our 02-07 TMIC at 350 whp, beyond this power level we highly recommend upgrading to a front-mount intercooler. We are actually planning to release our front-mount setup within the next few days! Keep an eye out for that!

Thanks again!

[Ruzty1311]

Whatever happened to the development of the 08-14 wrx Top mount? I noticed that thread is closed? Also, I could have sworn you guys make a short ram intake with box similar to the cobbsf with box for the 08-14 wrx/sti also but I couldn't find that thread anywhere anymore lol