The W1 Drop-In Turbocharger Pt.3 – Start Fresh from Scratch

In the last blog we touched on a couple key aspects that defined the design goal of the 27WON W1 drop-in turbocharger for the Honda Civic SI, Hatch, EX, and LX equipped with the 1.5L turbo engine.

Those two aspects were 100% OE (Original Equipment) fitment “drop-in” and no core charge. In this blog we are going to break these down further to the how and why.

Let’s start from the beginning.

“Drop-in” fitment is a critical term here so let us break it down. The design of a drop-in performance turbocharger starts with the OE turbocharger. The OE turbo is reverse engineered to locate all critical surfaces, connection points, and other vital design features of the turbocharger that effect fitment. Next, the compressor and turbine housings are modeled and modified to accept larger wheels and a new larger Center Housing Rotating Assembly (CHRA). You can see the raw casting CAD model of the turbine housing above.

Once each separate component is modeled in its raw casting form, the entire assembly is modeled and 3D printed to verify the fitment. With the use of a larger CHRA and compressor/turbine wheels (more on that real soon) the OE design is modified to accommodate the larger wheels so that performance and reliability is not compromised.

With fitment verified the design moves forward with functional samples to verify power and durability. I’m sure you’ve all seen the 11sec Civic SI by now, but you can check it out here if you haven’t.

So, as you have read so far, the 27WON W1 Drop-In turbo upgrade is a 100% brand new turbocharger that requires no core charge and no long waits. It’s specifically designed for larger wheels and features a larger CHRA. Now why is a larger CHRA important? Well, a performance turbocharger is not just about bigger wheels, cooling and lubrication upgrades are critical. Nothing kills a turbo faster than insufficient lubrication and inadequate cooling.

OEM bearings on the left vs. 27WON upgraded bearings on the right

Above you see two pairs of journal bearings, the OE bearings on the left and the journal bearings used in the 27WON Performance Turbocharger on the right.

Journal bearings control the radial (side-to-side) shaft play via a dynamic fluid barrier, AKA a really thin film of oil. During peak performance operation the turbocharger can spin upwards of 135,000rpm and reach temperatures in excess of 1,200 degrees F through the turbine housing. Plain and simple, the turbocharger has a tough life.

By selecting a larger CHRA we are able to utilize larger bearings to handle the extreme RPM and loads caused by high boost operation, such as 30+psi. The larger CHRA also provides greater cooling capacity to handle the abuse.

Drop-in fitment doesn’t stop at the housings;

At 27WON Performance it means a whole lot more. Designing the turbocharger with a larger CHRA also meant we had to design new oil and coolant components. This means every single 27WON W1 Turbo comes with new oil and coolant lines for smooth installation as well as the necessary hardware and turbine gaskets.

A quick look under the hood and your race buddies are none the wiser

To support drop-in fitment we also retained all of the factory heat shields and support brackets. Once installed, the 27WON W1 Turbo nearly disappears in your Civic’s engine bay.