OX99-11 – The Yamaha Supercar

Yamaha OX99-11 Supercar

Last week we brought you the previously little known story of the Kawasaki race car. Well, Yamaha also had a factory effort focused on the design and construction of, not a race car exactly, but an exotic supercar using a detuned version of Yamaha's then Formula One V12 engine and built to the highest levels of automotive engineering and sophistication, the car was known as the OX99-11.

One of the key individuals involved in the project, Dave Sullivan, tells us how this car came about. You might notice the extreme contrast between this effort and the Kawasaki race project. Of course the purpose was completely different but nevertheless, it tells the story of forays into the automotive world not well known outside of those who were directly involved. Unfortunately, however, there is a similarity to these two very different stories, at the end, events derailed both projects just short of ultimate success.

There's little I can add so I'll let Dave tell you all about it:

In 1991 I was working for a company called IAD on the south coast of England. IAD were a design and engineering consultancy for the motor industry, we had worked on the Mazda Miata, Lincoln Town Car and Bentley Continental, to name but a few. I started as a structural engineer on the Town Car in 1988, and I was also doing chassis work by 1991.

Yamaha had conceived the OX99-11 several years earlier, but had been struggling to find a partner who could help them realize their ambition. Strangely it was the sporting goods division (with products ranging from Yachts to squash racquets), rather than the motorcycle arm, that was leading the project, and it was part of a master plan that included the Formula 1 engine program.

To support the Formula 1 project Yamaha had set up a subsidiary company called Ypsilon Technology in Milton Keynes, UK, where the engines would be serviced. The factory was chosen to be big enough to produce the OX99-11 and a small team, mostly from the Aston Martin race team, were hired to set up the factory and help engineer the car.

Yamaha OX99-11 Supercar

A German company had had a go at the project, and produced a prototype that looked a lot like the sports racing cars of the time, (Aluminum fabricated chassis), but Yamaha were not happy with this. I’m not sure how the initial contact with IAD was made but it was probably through Brabham, who were using the Yamaha V12 engines in F1. Anyway, I was invited along to one of the first meetings because of my interest and knowledge of racing (I was racing a small formula car at the time). I immediately connected with the Yamaha project manager and had a good understanding of what he wanted. At the next meeting, in Japan, I presented some sketches I had done of the chassis, and we came back with the project in the bag

The design we completed, in under 12 months, had the following spec:-

Yamaha 3.5 litre V12 (De-tuned version of Formula 1 engine). Approx 400bhp at 10,000 rpm.
Carbon Fibre “tub” with engine mounted directly to rear bulkhead (Manufactured by DPS composites)
Aluminium panels hand made using traditional rolling techniques and hammer form tooling.
Front Suspension.
Double wishbones from Aero section steel tubing, fabricated uprights, push rods to inboard coil over damper units
Rear Suspension
Double wishbones from Aero section steel tubing, fabricated uprights, push rods to inboard coil over damper units mounted directly on gearbox.
FF Developments 6 speed transaxle with limited slip differential and multi-plate AP racing clutch
AP Racing 6 piston (Front) and 4 piston (Rear) billet machined calipers with Cast Iron discs.
Magnesium Alloy
Goodyear Eagle F1
Single central seat with small “pillion” seat just behind and to one side of the driver. Minimal trim
Single “Gullwing” door

Yamaha OX99-11 Supercar
Because IAD were mostly experienced with road car design and build, and hence had the necessary understanding of the regulations the OX99-11 would have to meet, Yamaha were concerned that the required race car detail design and manufacture would not be captured. So they hired a consultant to oversee the design and lend it some credibility in the press. The man they chose was Robin Herd. Robin had been one of the founders of the March F1 team, and had a good reputation in the industry. He also brought in his chief designer Tino Belli to give us some guidance on the chassis and Aerodynamic design.

The first car we built was un-painted and used as a test hack. In order to keep the car secret, all the early testing was done at night at the Millbrook Proving Ground in the UK. It was also wind tunnel tested at MIRA in the UK. I was lucky enough to drive this car during testing and was mightily impressed with the engine. It could be driven like an ordinary car up to about 6,000 rpm, then all hell broke loose as it accelerated up to the 10,000 rpm red line.

IAD built 2 further cars, one black one red, which were used to test various systems and later used for the press launch of the car, when it was driven by John Watson the ex-formula 1 driver. We also built a rolling chassis for the launch to show off the Formula 1 inspired design. The car looked fantastic and got very good reviews. The only “independent” journalist to drive it was Paul Frere who loved it.

As the car was so different from anything we had done before it was far from “right first time” and early testing showed it needed a lot of development on areas such as Aerodynamics and Handling. Unfortunately we did not get to do this as IAD and Yamaha had a disagreement over budgets and the project was taken away from IAD, to be completed by Yamaha’s own team at Ypsilon.

However, Ypsilon only got about 6 months to develop the car before the plug was pulled on the whole thing. The Japanese economy was taking a dive at the time and Yamaha figured they would not find enough buyers if they launched the car at that time. They promised to come back to it in a year or so, but of course things move on and it never happed.

About a year later McLaren launched their F1, which although technically superior to the Yamaha, lacked the flair and sheer audacity of the OX99-11 which I think would, had it been built, have been one of the most outrageous cars ever made.

The key people.

Casey Yoshida - Yamaha Project Manager
Michael Bowler - MD Ypsilon Technology and journalist
Gary Blackham - Manufacturing Manager Ypsilon
Robin Herd - Consultant and former MD of March F1 team
Tino Belli - Consultant from March F1 team
Mike Foxon - Chief Engineer IAD
Pat Selwood - Body and manufacturing team leader
Dave Sullivan - Chassis, suspension and powertrain team leader

---Thanks, Dave, for this incredibly interesting inside look at an amazing car!---


  1. Jason says

    I have the original press pack with slides included. Funnily enough, I was clearing out the attic and came across it.



  3. says

    Why didn’t they put the real OX-99 F1 engine in the Yamaha car? This engine produced 660 hp, and this is a tuned version of the ox-99? this engine produces 400 hp. Good car, but this is not a Supercar, it’s a race car.(and road-illegal)

  4. oki says

    what an ugly car. i’d prefer a ferrari. these japanesse doesn’t know anything about elegance. it’s look like cereal box car… disspointing.. i like yamaha bikes but give me a break that car is horrible


    I worked for Ypsilon in a small team of ex F1 and group C mechanics, myself ex Williams and Arrows. We did extensive track testing at snetterton and Silverstone as well as mira. High point was road trials in the swiss alps followed by Nardo speed bowl. It was faster than the Diabalo also there.Shame Yamaha pulled the plug. I still have a large framed picture on my office wall of the red car.The three cars were red black and green.

  6. Fred Rohlman says

    Yamaha has done it again gone above the rest i would buy this car for sure. But the first thing that i would do is lose the front wing and then maybe it would be a sexy looking car and since yamaha is better known for bikes how about putting a large displacement bike motor too.

  7. Marcus Hotblack says

    Just came across this…I also worked at IAD at the time and was involved with the interior/styling.
    Yamaha were very keen that the car felt like Race cars and gave as much as possible the Quality of driving an open wheeler specifically an F1 car. They also wanted it to be a two seater so early bucks examined having the passenger sitting behind with the driver in front and passenger behind like a motorcycle but with a shell race seat it was a virtual physical impossibility to use that configuration so the passenger sat at a bit of an angle with their feet on one side. I also recall itching to get stuck into the interior style and exterior but that was strictly controlled and was rigidly held to a form follows function strategy to ensure race car functionality and an engineered look was maintained It ended up being OK but I always felt it had bags more potential. The car concept was cool but the detail surface and proportions made it look ungainly and had it been maintained as a programme and reworked it could have been awesome.

  8. Frederick Spice says

    I heard quite a lot about these cars, and seen a lot of pictures too taken by my brother, who done body work and paint on them at the workshop. I cant remember, but didnt they have to add a grille on the front spoiler to be road legal in the uk? Every car got somewhat about 25 layers of paint ( from base to clear ). My brother promised me a the big yamaha badge fitted to them, but I never got it… :(