Civic Type R Downpipe Design Blog Pt. 1 - The OEM Breakdown
It's time for 27WON to make the most powerful and best-sounding exhaust on the market for the FK8 complete. Our FK8 system is one of only a handful of systems to be offered with a front pipe and now it's going to be the only one on the market to be offered as a complete true turbo-back exhaust system with the introduction of our performance catted downpipe.
That’s right, we will be releasing a high-performance catted downpipe for the 2017+ Civic Type R that will bolt up both to a stock exhaust, other aftermarket units, and of course our full 3” system. FL5 fitment coming soon.
3D Rendering of 27WON Civic Type R Downpipe Design
But before we jump into all the details of the 27WON unit let’s first do a quick once over of the OEM downpipe to get the lay of the land.
The OEM downpipe was clearly designed to be manufactured as efficiently as possible sharing parts and design features from the other Civics. What this means is that Honda is able to cut costs in manufacturing but this also means that there are unnecessary restrictions limiting your OEM downpipes flow. As you know from our previous exhaust blogs, more flow equals a happier engine, a happier engine equals more ponies, and more ponies equals more smiles per gallon.
The design features we see on the OEM downpipe for the K20C1 are identical to what we saw on the L15B7 downpipe. It's a one-piece downpipe made from two stamped steel halves that are welded together. Not the prettiest to look, but cheap to make when you need to crank out thousands of them.
OEM Downpipe From a 2020 Civic Type R
Sandwiched in between the halves is a pair of three-way catalytic converter substrates designed to remove harmful gasses from the combustion process. These do a good job at cleaning up the gasses but are rather larger and dense. Because they are so dense they increase back-pressure in the exhaust system and slow down the flow. Switching a high-flow version of these cats (racing only) can help free up power.
Inlet and Outlet Ends of the OEM Honda Civic Type R Downpipe
Coming out the downpipe, the cleaned-up gasses come out of a rather small hole. 54mm to be exact. That’s just barely over 2” which is not a lot for a car that we see being pushed over 400whp.
It’s hard to REDEFINE design of an aftermarket downpipe, but there is a wrong and right way to do it. Be on the lookout for part 2 as we aim to let her breathe the right way.
-Vincent