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Interested in purchasing our 2015 STi intake system? Check out more details on our product page linked below!

Mishimoto Subaru STI Performance Air Intake

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.

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

Interested in purchasing our 2015 STi intake system? Check out more details on our product page linked below!

Mishimoto Subaru STI Performance Air Intake

Dyno Testing

Time to see what kind of power gains we are able to achieve with our intake design! First, we strapped this Launch Edition to the dynamometer.

2015 STI on the dynamometer

2015 STI on the dyno

Then we began making pulls. On our first day we tested only the stock intake system. Once complete, we installed the Mishimoto intake system and sent the vehicle out for some road testing. We wanted to allow the ECU to adjust to the new intake before making our pulls. After well over 150 miles of road use, we returned the next day to compile dyno data for the Mishimoto intake.

2015 STI on the dyno

Testing Results

So how did we do? Well, I think the plots below summarize our results quite well.

Mishimoto intake shroud render

Thank you very much for following along with the progress of our intake. This was quite an exciting project!

We

Interested in purchasing our 2015 STi intake system? Check out more details on our product page linked below!

Mishimoto Subaru STI Performance Air Intake

Prototype Fabrication

After experimenting with some boxed designs in Part 1 of this write-up, it was time to turn our attention to a shrouded setup, similar to what we offer for the 2008-2014 models. We're hoping we could utilize the piping from our existing kit, which is well designed and has proven power gains. After placing the shroud into position, we found that it would certainly fit, but would require some modification. The fabrication work began! Check out a few shots taken during the process.

Mishimoto intake shroud modification

Mishimoto intake shroud modification

Mishimoto intake shroud modification

Once all fab work was completed, we had a functional shroud that we could use for testing purposes. We could also use this shroud to develop a 3D model for our production units. Take a look!

Mishimoto modified intake shroud

Mishimoto

Interested in purchasing our 2015 STi intake system? Check out more details on our product page linked below!

Mishimoto Subaru STI Performance Air Intake

Launch Edition Subaru STI in Mishimoto garage

Introduction

Our team is finally working on some cool components for the new 2015 Subaru STI! As you know, the 2015 STI is essentially a hybrid of old and new Impreza components. It features the newer body style paired with the trusty EJ engine, instead of the new DIT motor featured in the WRX. We won't get into which is better or which we prefer, because we have nothing but praise for the updated chassis. Our team has spent a great deal of time with both vehicles, and we are impressed with how the STI drives, handles, brakes, and functions as a comfortable yet sporty sedan.

As you may already know, we developed an intake system for the 2015 WRX recently, and we had a ton of success producing some really nice power gains. We also offer an intake system for the 2008-2014 WRX/STI equipped with

Interested in purchasing our Subaru WRX or STi intercooler kit? Check out more details on our product pages linked below!

Mishimoto Subaru WRX/STi Front-Mount Intercooler, 2001-2007

Mishimoto Subaru WRX Front-Mount Intercooler, 2008-2014

Mishimoto Subaru STi Front-Mount Intercooler, 2008-2014

Time to review our data so we can finally put a close on this project. The product development process for this front-mount intercooler has taken months and has also helped refine several of our processes. Before we move into the testing data, our first portion of this post will cover the physical benefits of our intercooler. By providing a more efficient heat exchanger, we can ensure that higher-powered vehicles are not being hindered by debilitating heat-soak and/or inefficiencies with the use of a top-mount intercooler setup.

Our first comparison point is internal flow area. This graph shows the volume of the actual air passages through the intercooler.

Comparison of internal flow area

Internal

Interested in purchasing our Subaru WRX or STi intercooler kit? Check out more details on our product pages linked below!

Mishimoto Subaru WRX/STi Front-Mount Intercooler, 2001-2007

Mishimoto Subaru WRX Front-Mount Intercooler, 2008-2014

Mishimoto Subaru STi Front-Mount Intercooler, 2008-2014

We are nearing the end of this build. As mentioned in the last post, we wanted to put our core to the test and provide some cooling efficiency data that our customers could use. We decided to modify our 2010 STi to add some heat and power to the CAC system for testing. Information regarding our vehicle is listed below.

2010 Subaru WRX STI

• 6-Speed Manual
• Mishimoto Intake
• Mishimoto Front-Mount Intercooler
• Fuel Line Modification
• 3" Downpipe
• Tune

Check out a few shots of the car on the dyno!

Mishimoto GR STI on the dyno

Mishimoto GR STI on the dyno

As you can see, we have sensors installed on the piping, both the cold- and hot-side of the intercooler. We have pressure and temperature sensors hooked up

Interested in purchasing our Subaru WRX or STi intercooler kit? Check out more details on our product pages linked below!

Mishimoto Subaru WRX/STi Front-Mount Intercooler, 2001-2007

Mishimoto Subaru WRX Front-Mount Intercooler, 2008-2014

Mishimoto Subaru STi Front-Mount Intercooler, 2008-2014

As promised, we have a couple cool images showing these kits fully installed on our test vehicles. Check them out below!

First, our full kit installed on our shop 2003 WRX Bugeye wagon!

Bugeye wagon with Mishimoto kit fully installed

This intercooler fills out the bumper completely and looks fantastic. Next up, a look at this kit fully installed on the Hawkeye.

Hawkeye with Mishimoto kit fully installed

And a couple shots of our finalized GR STi kit!

GR STi with Mishimoto kit fully installed

GR STi with Mishimoto kit fully installed

Now that we had all of our kits developed, the project is complete, right? Wrong! We haven't tested this intercooler out yet! Now, we have conducted a ton of CFD and core

Interested in purchasing our Subaru WRX or STi intercooler kit? Check out more details on our product pages linked below!

Mishimoto Subaru WRX/STi Front-Mount Intercooler, 2001-2007

Mishimoto Subaru WRX Front-Mount Intercooler, 2008-2014

Mishimoto Subaru STi Front-Mount Intercooler, 2008-2014

Time to weld up some pipes! This would be the more time-consuming portion of this project, as most of these vehicles would require a specific pipe kit. We would not be able to utilize one set of pipes across the model board, as we did with the intercooler. Going in order, we started with our Bugeye. One of our test vehicles featured a reasonably stock engine bay, as shown below.

Stock Bugeye engine bay

After ripping the stock cooler off of both our wagon and sedan test vehicles, we began to fabricate piping. Check out a few shots of what our engineers came up with for routing!

Mishimoto fabricated intercooler pipes on Bugeye

Mishimoto fabricated intercooler pipes on Bugeye

Mishimoto fabricated intercooler

Interested in purchasing our Subaru WRX or STi intercooler kit? Check out more details on our product pages linked below!

Mishimoto Subaru WRX/STi Front-Mount Intercooler, 2001-2007

Mishimoto Subaru WRX Front-Mount Intercooler, 2008-2014

Mishimoto Subaru STi Front-Mount Intercooler, 2008-2014

Time to take a quick look at our cooler and see how it fits with our test vehicles. First, a quick overview of the cooler itself. Check out our first prototype!

Mishimoto prototype intercooler

Mishimoto prototype intercooler

Alright, so here we have our raw prototype. Do note that this unit is a raw component, meaning it has no paint or powder-coat finish. The size of this cooler is extremely impressive, and our goal was to design a core length that would span as much of the front grille area as possible. The more airflow we have moving through the fins, the greater the heat transfer capability. Here are a few basic features of the prototype.

Cast End Tanks

As you can see, we have selected to manufacture