Honda reportedly is spending US$355m at plants in Ohio.

According to the Detroit News, citing a Honda spokesman, the projects include $166m of improvements at East Liberty and a $64m stamping press at Marysville. Honda has also added its first US wind tunnel and other additions to its engineering centre in Raymond but wouldn’t discuss costs.

“The driver of the projects is to improve all our characteristics,” the spokesman said in an interview, declining to say whether the changes will lead to greater output. “If we end up increasing production capacity as a result, that’s fine,” he said, without elaborating.

The report said Honda is refurbishing factories as it prepares to restore full North American production next month after parts shortages triggered by Japan’s March earthquake.

Honda was the first Japanese automaker to build cars in so called ‘transplants’ in the US, beginning in 1982 at Marysville with the Accord sedan.

Honda’s North America engineering and production units are among the region’s most sophisticated, Jeffrey Liker, professor of engineering at the University of Michigan in Ann Arbor, told the paper.

The Raymond R&D center near the Marysville and East Liberty plants is Honda’s main vehicle development facility for the Americas. It’s responsible for designing and engineering the Pilot and Acura MDX sport utility vehicles, Ridgeline pickup, Acura ZDX wagon and TL sedan, and North American version of the Odyssey minivan, all of which are built only in the region, the Detroit News noted.

It added that Honda hadn’t previously acknowledged the Ohio wind tunnel that was built in late 2010.

Honda’s is a “half-scale” tunnel, intended for early prototypes. Such a device may cost $25m while a full-size wind tunnel is at least $100m, said Frank Ohlemacher, project manager at Ohio State University’s CENTER FOR AUTOMOTIVE RESEARCH in Columbus.

“This is sophisticated equipment, not just a big fan,” Ohlemacher said.