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beautifullyengineered:

The Mazda 787B is Beautifully Engineered.

4-rotors. Naturally Aspirated. 700hp at 9000rpm. 1991 Le Mans winner.

In 1990 Mazda debuted the all-new 787 in the 24 Hours of Le Mans. Like the company’s previous prototypes, the chassis was designed by Nigel Stroud and constructed in England. The tubs were then sent to Japan for completion by Mazda’s racing subsidiary Mazdaspeed. What set it apart from the earlier designs, was the use of carbon-fibre composites with a honeycomb structure for the complete chassis. For 1991 the suspension geometry was changed to accommodate for larger wheels and carbon-ceramic discs were fitted for the first time to create the 787B.

Three decades of constant development had resulted in the R26B rotary engine, which featured four rotors, variable inlet trumpets and three spark plugs per rotor. One of the biggest modifications compared to the 1990 version of the R26B was the variable trumpet system, which was now continuously variable instead of sliding between several predetermined positions. At 9,000 rpm the compact engine produced an impressive 700 bhp and torque was increased to 608 Nm at 6,500.

Efficiency was a key factor in this period at Le Mans due to the restricted amount of fuel available for each car. In preparation for the race, Mazdaspeed’s engineers figured that completing 367 laps in 24 hours would be sufficient for victory, so they set about optimising the new 787B to achieve that goal. As a result the maximum engine revs were limited to 8,500 rpm, restricting the power to 650 bhp. Much emphasis was also put on achieving the highest cornering speeds possible as that would improve performance without affecting consumption.

During the race the Mazda drivers were given a very specific lap time to run with an eye on completing the calculated 367 laps without running out of fuel. This pace was higher than the competition could have imagined and especially caught out the Jaguar cars, which had to slow down in the morning to preserve fuel. Faster still were the Sauber-Mercedes C11s but the additional weight they were forced to carry also had an effect on reliability.

The bright-orange and green #55 turned out to be the faster of the two 787Bs and it was running second when the leading Sauber was forced into the pit for a prolonged stop. This handed the lead to the very skilfully driven Mazda 787B with less than three hours to go. The flawless performance resulted in the historic victory; the first for a Japanese car, the first for a rotary engine and the first with carbon-ceramic brakes. The other two Mazdas finished in a more than commendable 6th and 8th.

SPEC:

Configuration:     R26B R4

Location:     Mid, longitudinally mounted

Displacement:     2.616 liter / 159.6 cu in

Fuel feed:     Electronic Fuel Injection

Aspiration:     Naturally Aspirated

Power:     700 bhp / 522 KW @ 9000 rpm

Torque:     608 Nm / 448 ft lbs @ 6500 rpm

BHP/Liter:     268 bhp / liter

Chassis:     carbon fibre monocoque

Suspension: (fr/r)     double wishbones, inboard coil springs over shock absorbers, anti-roll bar

Steering:     rack-and-pinion

Brakes:     carbon-ceramic discs, all-round

Gearbox:     Mazda-Porsche 5 speed Manual

Drive:     Rear wheel drive

Weight:     830 kilo / 1829.8 lbs

Power to weight:     0.84 bhp / kg

Want to see and hear the 787B in all of it’s screaming 4-rotor glory? Check out these links:

Start and Rev

787B at Miyoshi Proving Ground (Limited to 7000rpm)

Onboard Lap filmed at 2011 Le Mans

787B at Mine Circuit (Extremely loud volume, but awesome)