The 2011 Buick Regal Turbo is the first direct-injected turbocharged production car capable of running on any blend of gasoline or E85 ethanol.
The E85 capability means that, with typical production-car overhead, the fuel injectors may have enough flow rate left over to handle pure ethanol. Turbochargers use the energy in the hot exhaust gas flow to drive a compressor that forces more air into the combustion chamber for on-demand power delivery. The twin-scroll turbocharger on the Ecotec engine provides two inlet paths to the turbine to maximize the kinetic and thermal energy delivered to the turbine.
“Since ethanol requires a richer air-fuel mixture than gasoline, flex-fuel engines need higher flow-rate injectors,” GM said in a statement. “However, a flex-fuel engine can potentially have any combination of gasoline or up to 85 percent ethanol in the tank, so a sensor in the fuel system measures the blend in real-time.”
Estimated EPA fuel economy numbers for the new turbo running on gasoline are 20-mpg city/32 hwy mpg (manual) and 18 mpg city/28 mpg hwy (automatic). Running on pure E85 would result in about a 20% decrease in fuel economy, GM said.
There are no performance differences between the standard 2.0-liter turbo engine and its flex-fuel variant, as output remains at 220 horsepower and 258 lb-ft of torque.