The Yamaha OX99-11 was a sports car designed by Yamaha subsidiary Ypsilon Technology and IAD, an English engineering consultancy, which was supposed to come out in 1994.



Yamaha began competing in Formula One in 1989, and using the experience they had gained during that time they wanted to build a price-no-object car based on actual Formula One technology. Even though the Formula One team was doing poorly in competition, by 1991 the team had just come out with a new engine, the OX99, and approached a German company to come up with an initial version of the car. Yamaha was not pleased with the result as it was too similar to sport cars of that time, so they contacted IAD to continue working on the project. By the beginning of 1992, just under 12 months after starting to work on the project, IAD came with an initial version of the car. The car's design was undertaken by Takuya Yura, and was originally conceived as a single seater. However Yamaha requested a two-seater vehicle, and a tandem seating arrangement was suggested, which was in keeping with Yamaha's motorcycle expertise. This resulted in a radical and somewhat outrageous design, like its cockpit-looking roof. Other notable specs were the same carbon fiber chassis and OX99 engine as the F1 car, essentially providing the closest experience of a pure racing car to the consumer market.

However, disagreements between IAD and Yamaha over the budget made Yamaha take the project to its own Ypsilon Technology, who got 6 months to finish the project before getting axed. To make matters worse, Japan was at that time in the midst of a financial crisis, which led Yamaha to believe they wouldn't be able to find any customer for their car, which was expected to come out with a $800,000 price tag (over $1 million in 2006 dollars).

Eventually the project was delayed until 1994, before finally being cancelled. A total of three prototypes were built by IAD.