The Volt's chief engineer, Andrew Farah, told AutoblogGreen that the change was due to today's Volt owners explaining they were not happy paying for top-shelf petroleum. "The ability to use regular unleaded was based directly on customer feedback," he said. "Since the range extender is an all-new engine, it was optimized to use regular unleaded at the outset. Using regular fuel will not have effect on vehicle acceleration or other performance factors."
As Larry Nitz, GM's executive director of vehicle electrification, told AutoblogGreen yesterday, the new engine is more powerful and quieter than the outgoing 1.4-liter engine that's used in the current Volt. Fuel economy and EV range specs for the next-gen Volt are not expected until the full car is revealed at the Detroit Auto Show in January.