Build It As A System
BorgWarner’s new EFR Series consists of a range of turbochargers, with turbines from 55 to 80 millimeters in diameter and compressors from 62 to 91 mm in diameter. The range of sizes allows the turbocharger to be tailored to specific applications. The EFR turbine housings are made with investment castings in high-temperature and corrosion-resistant stainless steel, yielding a surface that rivals machined finishes. The housing includes an integrated high-volume wastegate and boost control solenoid valve, eliminating the need to package additional components during installation. Inside the stainless steel housing, the turbine on the exhaust side is an investment casting of Gamma Titanium aluminide, an exotic material that forms an inter-metallic composite that is halfway between a ceramic and a metal. Gamma-Ti is under study for gas-turbine aircraft engines and BorgWarner’s use of the material is one of the first industrial applications. The density of the inter-metallic is about half that of conventional high-nickel steel, making a turbine wheel that weighs half as much and is very similar in mass to the aluminum compressor wheel on the other end of the shaft. This lessens the inertia of the system and allows the turbo to spin up faster, producing boost quicker. The turbo spins at up to 168,000 rpm and lightweight ceramic balls are used in the bearings that support the main shaft, allowing the turbo to spin up even more quickly and reduces losses at low turbo speeds to improve fuel efficiency.
How Much And Where?
All of this technology comes at a price, but Fraser insists the EFR system provides good value. When you look at it from a system perspective, it’s actually a cheaper solution than buying a premium turbo, a blow-off valve, and an external wastegate, Fraser says. BorgWarner has no direct aftermarket sales channel, relying instead upon a system of distributors, some of which were directly involved in testing prototypes of the new EFR system components. Finding a distributor or tuner who can sell you a single EFR turbocharger or a system designed for your car is only as far away as a simple search of the Internet and validates Brock Fraser’s conviction that the introduction of new technologies that enthusiasts want can be accelerated by doing it in the aftermarket first.