Honda Civic Type R Intercooler OE Breakdown – Design Pt. 2

It’s been a few months; it’s time for an update on the 27WON Performance Intercooler for the 2017+ Honda Civic Type R. 

We stated that our goal was to develop an intercooler unlike anything else available as we do with all our 27WON Performance products. Today let’s dig into how we are making that goal happen.


Here you can see a CAD rendering of the complete FK8 Intercooler. There are TONS of details we could go into about the design but for this blog we are going to focus on one design element…the intercooler inlet endtank (aka hotside endtank). We want to focus on this because this is one of the major features where we REDEFINE the FK8 FMIC.

To clarify, the above images are of the final 27WON design. Below, we are going to show you a design we investigated and discarded to illustrate why the endtank design is so important.


The OEM intercooler measures in at 5.63in tall; 27WON is increasing this to 7.95in (a 41% increase in height) but this comes with some design challenges that had to be dealt with. As the height of the intercooler gets taller it gets more and more difficult to evenly distribute the airflow through the core from top to bottom. If the airflow distribution is poor then the performance of the intercooler will also be compromised.


Here is one of our early design iterations in green. This design maintains the OEM flange location and size; this is the design we tested and discarded. Through flow simulation, we found the severe angles at the top and bottom of the hotside endtank restricted airflow. The black arrows show the runners that were getting less optimal airflow to them. Unfortunately, these severe angles could not be avoided while maintaining the stock flange connection. 

With this realization, we decided to scrap the requirement to maintain the stock flange location and pursue a more open design to better optimize airflow.


We reassembled the OEM intercooler and OEM hotside inlet pipe to evaluate the entire intercooler system. Here we found our opportunity to REDEFINE. We decided to combine the OEM inlet pipe into the 27WON hotside endtank. The result is what you saw at the start of the blog.

27WON opening compared to OEM and most common aftermarket units

27WON opening compared to OEM and most common aftermarket units

This is an image of the cross-sectional area for both the 27WON cast endtank and the OEM flange connection at the same location. By integrating the hotside inlet pipe into the design of the endtank we were able to substantially increase the cross-sectional area. Just as importantly, we were able to optimize the flow path of the boosted air.


Here is a side view, you can see our discarded (green) OEM flange design compared with our final design overlaid. The yellow arrows represent the restricted flow path with the OEM flange connection and the orange arrows represent the non-restrictive and optimized flow path of the final 27WON design. There is a key point to remember here; maintaining the stock flange location with a taller intercooler core results in suboptimal airflow through the core.


Sharp turns and bends like the OEM design require our turbo and engine to work harder than it needs to

Back to the top view, you can see how the OEM flange creates a severe (nearly 90 degree) bend that the airflow had to follow (yellow arrows).  By removing the OEM flange we were able to design a continuous and smooth bend for the boosted airflow. 

In a nutshell, air does not like to suddenly expand or change directions quickly. These sudden changes create inefficiencies in the system which robs you of potential power. Our goal with the 27WON Hotside Endtank was to remove these deficiencies to increase the overall efficiency of the performance intercooler. 

Stay tuned as we continue to share our development of the 27WON FK8 Intercooler Kit and other projects for the Civic Type R. 

I DARE You to REDEFINE the Aftermarket