Honda FK8 Silicone Boost Tubes – Pressure Testing Design Pt. 2

Did you know you have a couple of balloons under your hood robbing you of response from your turbo?

It’s time for round two on our Boost Tubes for the 2018+ Civic Type R but before we dig into the 27WON design we need to set a baseline with the OE rubber boost tubes. Plus, we’ve got color options we want you to check out. Let us know what you want!

If you want to catch up on Design Part 1 that introduces the OE Boost Tubes click here.


We built a simple pressure testing fixture to bench test so our testing was controllable and repeatable. The smaller, hot side boost tube, was measured in one location both horizontally and vertically; this same location was measured for all additional hot side testing. The larger, cold side boost tube, was measured in two locations both horizontally and vertically. Again, we used the same locations for all subsequent cold side testing.

Check out the two simple graphs below. Each graph shows the measured diameter for the OE boost tube at three different pressures: 0psi, 20psi, 40psi. How to understand the graph: the flatter the lines the better. This means that the tube did not expand due to pressure.


The first pressure test was performed on the OE Hot Side Boost Tube; these results were exactly what we expected.  We see an extreme increase in diameter (especially vertical) from 0psi to 20psi, then from 20psi to 40psi we see smaller change in diameter.  This means the OE tube had expanded to nearly its full amount by 20psi.

Result: The OE hot side boost tube expands up to 5.5mm in diameter during a pressure change from 0psi to 40psi.


The second pressure test was performed on the OE Cold Side Boost Tube; these results were also exactly what we expected. We see another drastic increase in diameter from 0psi to 20psi, then from 20psi to 40psi we see a small change in diameter.  Again, this means the tube had expanded nearly its full amount by 20psi.

Result: The OE cold side boost tube expands up to over 5mm in diameter from 0psi to 40psi.

So, what did we learn?

The OE rubber boost tubes do in fact expand under boost pressure and a majority of that expansion happens by 20psi which is well within normal operating conditions. You basically have balloons between your intercooler and engine. Every time you get into boost your turbo has to fill that void before your engine gets the full benefit of the boost pressure. This creates turbo lag and poor throttle response. We plan to improve both these with our performance boost tubes.  

We also want to point out that the boost tubes are not just about pressure holding ability. Durability and resilience are important considerations as well. Did you know that the boosted air leaving the turbocharger compressor is around 250 degF? Ouch! That’s why high heat tolerant materials are needed. This heat coming out of your turbo is why your Type R has an intercooler.  

As promised here are the colors we are thinking right now.

-Signature Orange -Slate Grey  -Stealth Black -Redline Red

-Signature Orange
-Slate Grey
-Stealth Black
-Redline Red

Let us know what color you want and stay tuned with 27WON Performance for some data on our FK8 Performance Boost Tubes as we continue testing and validation.

I DARE You to REDEFINE the Aftermarket