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Mazda R26B SpecificationsLayout: | 4-rotor, in-line | Displacement: | 654 cc x 4-rotor | Compression ratio: | 10:1 | Induction system: | Telescopic intake manifold system | Horsepower: | 690 bhp @ 9000 rpm | Torque: | 448 lb-ft @ 6500 rpm | Weight: | 180 kgs. | The
Mazda R26B has the distinction of being the first engine made by a
Japanese manufacturer to win the 24 Hours of Le Mans outright. Calling upon the foundation
laid by its 4-rotor predecessor, the 13J-M, Mazda added a number of
refinements and racing-derived features. These included intake ports on
the periphery of the rotor housings, telescopic intake runners
(variable height tuned to engine RPM), 2-piece ceramic apex seals, and
3 spark plugs per rotor instead of the usual 2 to reduce fuel
consumption. This produced a motor capable of developing 900 hp
at upwards of 10000 rpm, although it was detuned to ~700 hp (some say
even as low as 630 hp). Check out SAE paper 920309 that further details Mazda's work on developing the engine for endurance racing.
Although
not as powerful as Jaguar's large
capacity 7.4 liter normally aspirated V12 and Mercedes' mildly
turbo-charged 5.0 liter V8, the R26 had some advantages in durability
and fuel economy over the rest of the field that year.
However, it can't be overlooked that Mazda heavily lobbied the
ACO,
and as a result the 787B wasn't required to run to the 2200 lb minimum
weight the other Category 2 competitors had to. Instead, the 787B
raced weight-unchanged from the previous year, tipping the scales at a
comparatively lithe
1830 lbs. This gave Mazda advanteges in power to weight ratio,
even at 630 hp, and reliability in not having to run beyond the 787B
chassis' original design weight. Considering the very specific
reliability issues both Jaguar and Mercedes encountered, this is
telling. |