Cool Your Charge! The 2015 WRX Front-Mount Intercooler Build, Part 3: Pipe Routing and Fabrication

Front-mount intercooler installed
Front-mount intercooler installed

In the last portion of this series we completed the fabrication of our prototype intercooler core and tanks, as well as our new bumper beam. We now had everything in place to construct a piping kit that would route air from the turbocharger to the intercooler and back to the engine.

Hot-Side Piping

We started our piping with the hot-side of the intercooler system. The stock compressor housing uses a two-bolt flange connection, similar to what you would see on a 2008–2014 WRX. As you probably know, the FA20 turbocharger is on the lower front area of the engine, essentially right below the drive belt system. Because of this, our piping for the hot-side would be significantly shorter compared to the traditional turbo location featured on the EJ engine.

We started by 3D printing the flange that connects to the compressor housing. We could then work our piping from here to the cooler.

3D-printed flange for compressor housing
3D-printed flange for compressor housing

We then worked off the flange to route our piping around the core support to the end tank of the cooler.

Hot-side intercooler piping fabrication
Hot-side intercooler piping fabrication

Initially we cut our pieces and temporarily secured them into position for mockup purposes.

Hot-side intercooler piping fabrication
Hot-side intercooler piping fabrication

This pipe was then fully welded.

Hot-side intercooler piping fabrication
Hot-side intercooler piping fabrication

On the stock hot-side charge pipe there is a connection point for the BPV. This would need to be considered with the design of our piping. We will be relocating the BPV slightly and will include all necessary components to do so. This kit will function with the stock unit, or any BPV/BOV that is similar in style to the stock piece. Check out the mockup of one of the silicone pieces that moves the BPV to a better position for fitment.

BPV relocation hose
BPV relocation hose

This unit will be a one-piece silicone component with a molded CNC-machined fitting that will function with the stock BPV and turbocharger inlet tube. By designing and including these components, we are creating an entirely direct-fit kit that will require no modification or additional purchases for this install.

Cold-Side Piping

Now that we have sorted out airflow moving to the intercooler, it’s time to cover the post-intercooler section. This pipe would be slightly longer and would follow a path similar to the previous generation FMIC piping. We started at the throttle body by wrapping the pipe around the intake manifold toward the front of the vehicle.

Cold-side intercooler pipe fabrication
Cold-side intercooler pipe fabrication

The cold-side pipe would be made in two pieces for easy installation. After the upper half was in place, we starting routing this pipe around the windshield reservoir and battery, through the core support, and out of the engine bay.

Once through the core support, our engineers fabricated the remaining piping. Fitment is quite tight in this area, requiring extreme precision and a few tests of trial and error. The result was a nice-looking second portion of this cold-side piping.

Cold-side intercooler pipe fabrication
Cold-side intercooler pipe fabrication

That wraps up our piping for this kit! Check out a shot of the fully welded pipes that we will be using for dyno testing.

Prototype intercooler piping
Prototype intercooler piping

The Finished Kit!

In just three articles we’ve started and finished a full front-mount intercooler prototype. Hours of labor, measuring, evaluating, fabrication, and discussions have produced the fully completed prototype you see below!

Full prototype front-mount intercooler kit installed
Full prototype front-mount intercooler kit installed
Full prototype front-mount intercooler kit installed
Full prototype front-mount intercooler kit installed

Our kit fits perfectly with the stock bumper and will not require any cutting or trimming of your brand new WRX!

Prototype front-mount intercooler kit installed with bumper
Prototype front-mount intercooler kit installed with bumper

Next time we will be fitting our sensors and making some dyno pulls to gather some data on the performance of this core on the 2015 model! Check back with us next week for some dyno shots, videos, and plots from the runs. We will leave you with a teaser shot!

Preparing for dyno pulls
Preparing for dyno pulls

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Does the 2015 WRX Need an Upgraded Intercooler? Part 5: Testing and Results

Dyno Preparation

Time to finally answer the question we have been discussing for months. Would the 2015 WRX benefit from an upgraded intercooler?

To test both the stock unit and the Mishimoto prototype unit, we would need to drill and tap the coolers to accept our temperature and pressure sensors.

First, we installed a sensor bung in our silicone throttle-body hose. This would capture post intercooler data for all three coolers.

Mishimoto throttle-body hose with sensor bung
Mishimoto throttle-body hose with sensor bung

The stock cooler hot side was then drilled and tapped to accept our 1/8” NPT sensors.

Stock intercooler tapped for sensors
Stock intercooler tapped for sensors

Tapping the cold side of the Mishimoto prototype intercoolers was easy thanks to the bung location we have built into the tank.

Mishimoto prototype intercooler tapped for sensors
Mishimoto prototype intercooler tapped for sensors

Once we were set for testing, the WRX was strapped to the dyno for our first round of tests.

2015 WRX on dynamometer
2015 WRX on dynamometer

Testing for Core Selection

Our first round of tests was conducted to determine which intercooler core we would be selecting for our final product. As noted earlier in this series of articles, we were testing two different cores to determine which one would be more effective for handling the airflow created by the WRX.

MM Core 1: Tight core composition with small bar-and-fin heights for greater surface area and heat transfer.

Potential Pitfall: A core with an overly tight bar-and-fin configuration could restrict airflow from passing through the core. Instead, the air would go around, taking the path of least resistance.

MM Core 2: A Slightly less tight core composition with larger bar-and-fin heights.

Potential Pitfall: A looser core might not promote optimal heat transfer due to the fewer contact points.

With this in mind we made several pulls with each cooler to determine the effects on outlet temperatures. After we averaged the runs, we put together the plot shown below.

All 3 Core Temp Compares

All cores begin the pull at 3,500 rpm in the range of 90 degree cold-side intercooler temperatures. From there, we made a 3rd-gear pull all the way to 6,700 rpm. The stock intercooler temperatures rose to around 125°F by the end of the pull. Both Mishimoto intercoolers outperformed the stock cooler; however, we did find that core #1 performed better, essentially keeping temperatures at 90°F for the entire pull. This is a significant 35 degree drop on a bone stock vehicle.

With these data points in mind, we chose the first core, which featured the tighter bar-and-fin composition. This lined up with the CFD (computational fluid dynamics) analysis we performed prior to testing.

Now, despite this significant decrease in temperatures, we did not see any impact on power output when installing our intercooler with the stock tune.

Luckily, we have more than one 2015 WRX. Our next test subject featured a nice variety of Mishimoto components including our J-pipe, intake, and tune. This vehicle was making right around 250 whp and 280 wtq. Not only would this vehicle make more power, but the tune was also creating higher boost numbers that would have an impact on heat output. This would be a great test for our intercooler.

Modified Vehicle Temperature Comparison

First, take a look at the temperature results.

Inlet & Outlet Temp Compares

Once again, outlet temperatures begin right around 90°F, while inlet temperatures start at around 125°F. At around 4,200 rpm, the Mishimoto intercooler begins to distinguish itself from the factory cooler and continues to do so through redline. By the end of the pull, inlet temperatures approached 250°F, yet the Mishimoto intercooler outlet temperatures remained at 90°F. At this power level, the stock cooler once again maintained a peak temperature of around 125°F by the end of the pull. These results are similar to what we saw with the vehicle in stock form, around a 35 degree difference between the Mishimoto and stock intercooler.

Power Output Gains

We also compared power output on our tuned vehicle. Check out the results!

Modified vehicle dyno chart
Modified vehicle dyno chart

Once again, we are seeing some huge benefits here with the Mishimoto intercooler. Power gains begin down low in both torque and horsepower. We also saw huge gains at 4,200–6,200 rpm. This rpm level also correlates with the separation we see in outlet temperatures on the plot above.

Gains are summarized below!

Maximum Gains: 20 whp / 21 wtq

Peak Gains: 15 whp / 8 wtq

Pressure Drop Comparison

We didn’t stop here,. We also wanted to take a closer look at pressure drop across the intercooler core for the Mishimoto cooler and the stock unit.

Pressure drop comparison
Pressure drop comparison

Pressure drop is a comparison of pressure values from the inlet to the outlet of the intercooler. Both cores follow a similar drop in pressure, with the Mishimoto cooler being slightly higher than the factory unit (less than 1 psi). This is likely a result of our denser core composition and is completely acceptable, especially considering the temperature and power benefits.

Charge-Pipe Testing

Our last chart depicts the benefits of installing our charge pipe compared with the stock unit. A few folks have questioned whether the greater volume would have an impact on spool time.

Inlet boost pressure results
Inlet boost pressure results

Spool time occurs from around 2,200 to 3,000 rpm, where it levels out to a relatively steady rate. As you can see on the plot above, the Mishimoto charge pipe is causing greater boost levels at lower rpm. This means we have effectively increased spool quickness to around 10% with the addition of our charge pipe!

Summary of Intercooler and Charge Pipe Results

After reviewing all the data, we are extremely pleased with the design of our intercooler and charge pipe. The benefits are quite substantial for both stock and modified vehicles. Check out some of the highlights below.

  • 35°F intercooler outlet temperature drop on both stock and modified vehicle (intake, downpipe, tune, around 250 whp / 280 wtq)
  • Maximum gains of 20 whp and 21 wtq on modified vehicle
  • Peak gains of 15 whp and 8 wtq on modified vehicle
  • Similar pressure drop compared to stock intercooler
  • 10% quicker spool time with Mishimoto charge pipe

That wraps up the development of our intercooler and charge pipe for the 2015 WRX. We are working to develop and test an air splitter that would improve the dispersion of air across the entire larger core. Details on this component coming soon!

Additionally, we are hoping to launch a presale for our TMIC components within the next few weeks. Stay tuned for details.

2015 WRX on dynamometer
2015 WRX on dynamometer

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Improve The Cooling Of Your Wrangler, Part 1: Fabrication Work

Jeep YJ in Mishimoto shop
Jeep YJ in Mishimoto shop

Project Intro

After a few successful electric fan conversion projects, we chose yet another vehicle that could benefit from the removal of the stock clutch fan. Our previous endeavors involved BMWs that experienced frequent failures of the plastic stock clutch fan. After checking through potential applications and scouring the forums, our team chose the Wrangler as a prime subject for a reliable and efficient electric fan conversion kit.

Along with providing greater reliability, replacing the mechanical fan with an electric fan would reduce rotating mass and possibly free up a bit of power. Extra power is always welcome!

Stock Fan Setup

First, let’s take a look at the stock fan setup equipped on both the Wrangler 4.0L and 2.5L vehicles. First up, the 4.0L.

YJ 4.0L stock engine bay
YJ 4.0L stock engine bay
YJ 4.0L stock fan and shroud
YJ 4.0L stock fan and shroud

This is our second test vehicle, a 2.5L powered TJ.

TJ 2.5L stock engine bay
TJ 2.5L stock engine bay

The design of these systems is quite interesting. To make up for the additional space on the 4-cylinder model, a massive shroud is used to pull air properly through the radiator. By eliminating the mechanical fan connected to the engine, we could free up a ton of space in the engine bays of both vehicles.

Initial Fabrication

We decided to jump into this project by fabricating the shroud. We started with our 16” electric slim fan. This fan has been proven effective on a variety of other vehicles, so it should provide more than enough airflow to keep your Wrangler cool. Considering that many Wranglers spend substantial time at low speeds crawling through trails, a reliable fan solution is crucial.

Additionally, we would be testing this unit to ensure proper operation and cooling.

We started by designing a shroud to fit the footprint of the radiator core. The hole for our 16” fan was also cut from the center of the shroud.

Shroud fabrication
Shroud fabrication

Next, we 3D-printed some templates for the mounting brackets and mocked them into place on our aluminum radiator. This shroud is being designed to function with both the stock radiator and our aluminum counterpart.

Shroud mounting brackets
Shroud mounting brackets
Shroud mounting brackets
Shroud mounting brackets
Shroud mounting brackets
Shroud mounting brackets

We then fired up the TIG and welded these brackets to the shroud.

Welding Wrangler shroud
Welding Wrangler shroud

Our first prototype was ready for test fitting!

First fabricated prototype
First fabricated prototype

Next time we will be installing this first prototype in both a YJ and TJ Wrangler to confirm fitment and make any necessary design adjustments.

Thanks for reading!

Filtering Your 6.4L Coolant, Part 2: Final Prototype and Installation

Final Prototype Bracket

Welcome back! Our final bracket prototype is in and ready for installation. Check it out!

Mishimoto 6.4L coolant filter bracket
Mishimoto 6.4L coolant filter bracket
Mishimoto 6.4L coolant filter bracket
Mishimoto 6.4L coolant filter bracket

This bracket is constructed from 1/8” steel and is powder coated for additional protection against damage from road debris. We overbuilt this unit to ensure longevity and optimal resistance against potential damage.

Check out the hardware we will be using to attach our housing to the bracket. This hardware is also powder coated to prevent corrosion.

Coolant filtration kit hardware
Coolant filtration kit hardware

Next, we assembled our filter housing, filter, and bracket together.

Coolant filtration kit assembled
Coolant filtration kit assembled

We then installed this system to ensure fitment on our test vehicle.

Coolant filtration kit installed
Coolant filtration kit installed
Coolant filtration kit installed
Coolant filtration kit installed

As you can see, we are using ball valves at the hose connection point to our filter housing. By shutting these valves, one can perform filter changes without draining a substantial amount of fluid. Here is a closer look!

Valve
Valve

We are also utilizing silicone lines to route coolant from the heater hose to our filtration system, and then back to the degas port. Check out the route of these lines.

Coolant filtration hose routing
Coolant filtration hose routing

Once installed, the primary components of this kit are hidden from view. Here is what you will see once this kit is in place.

Coolant filtration system installed
Coolant filtration system installed

As with our other kits, this will be offered with your choice of black, blue, or red silicone hoses.

And that’s it, the project is complete. Check out a shot of all components included in this kit!

Coolant filtration system components
Coolant filtration system components

Thanks for following along with our development progress. For those interested in picking up this kit, we will be launching a discounted pre-sale next week!

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Mishimoto 2015+ Subaru STi Performance Cold-Air Intake System, Part 4: Race Intake System

As noted earlier in this article series, we would be tackling a race intake system to go along with our bolt-on unit. So what makes the race system different? For this particular system we are using a larger-diameter intake pipe with a larger MAF housing. This means greater intake flow, but it also means it will no longer function with the factory tune. This system is meant specifically for drivers who want aggressive professional tunes so they can take advantage of airflow modifications such as larger turbochargers and high boost pressures.

Because the 15’ model shares the EJ from the previous generation, we would be using the same intake pipe and filter as we did with our 2008–2014 kit. This unit is shown below.

Race intake pipe
Mishimoto air filter

Here is a look at this system fitted to a 2010 STi!

Mishimoto 2008–2014 Race Intake installed

So, all we truly needed was to design an airbox that would accommodate this pipe and function with the body of the new 15’ model.

We hit Solidworks and came up with the design you see below!

Mishimoto 2015 STi Race Intake rendering
Mishimoto 2015 STi Race Intake rendering
Mishimoto 2015 STi Race Intake rendering
Mishimoto 2015 STi Race Intake rendering

We are working towards completing this kit alongside our bolt-on intake. Keep an eye out for a pre-sale on both kits coming next week!

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An inside look at the engineering of Mishimoto products.

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