Subaru STI Type RA NBR Runs a WRX-Sourced 2.0-liter; Why Prodrive Uses it to Set a New Record [Video]
When the new 2018 Subaru WRX STI Type RA production model arrives, it’s powered by the standard 2.5-liter turbocharged boxer engine. That’s no surprise, but the WRX STI Type RA NBR Special that will attempt to set a new Nurburgring track record runs the 2.0-liter turbo mill. Why does Prodrive use the WRX-sourced 2.0-liter EJ20 mill and not the standard EJ25 2.5-liter turbo boxer?
Richard Thompson, Prodrive's top engineer on the project, gave a revealing interview to Motor Authority at the Goodwood Festival of Speed in the video below. Prodrive has built the 2.0-liter turbo mill for a number of WRC projects and it’s the engine that broke the IOM TT record. To say the least, they like the EJ20 and know how to squeeze every bit of horsepower out of it.
Thanks to Prodrive’s vast experience with this powerplant, the WRX-sourced, 2.0-liter, turbocharged, boxer engine has three positions producing either 550, 575, or 600 horsepower, depending on what the driver needs to dial in. It gets a new re-designed crankshaft, connecting rods, and pistons over what the Isle of Man TT record-breaking car had. It uses port fuel injection and runs a high-octane racing fuel with ultra high pressures.
Because it’s slamming through the corners, Prodrive had to swap out the wet sump for a dry sump oiling system to deal with the extra lateral g forces the super-wide, super-sticky tires help generate in Nurburgring’s corners. Without it, the engine gets starved for oil.
The car will travel up to 180 mph on the straights making it the fastest STI on the planet. They can reach those speeds because of the specially-built 6-speed semi-automatic sequential transmission with no conventional gearing. It comes with an $8000 triple-plate carbon fiber clutch, and the special Prodrive-prepared STI will sprint from 0-100 km/h in just 3.1 seconds.
Subaru will stick with the EJ25 2.5-liter turbo boxer in the new 2018 Subaru WRX STI Type RA production car when it arrives next year. Prodrive will use the WRX-sourced EJ20 powerplant to set a new Nurburgring sedan track record soon. Stay tuned.
Watch the Subaru WRX STI RA Tech Talk with Prodrive’s Richard Thompson
Photo credit: Subaru