In the heyday of Group A touring car racing Toyota campaigned the MA70 Supra as a contender in the over 3 litre category. In total 11 Group A MA70 Supras were built by TRD Japan and raced internationally. The car in the photos is number 7 of these 11 factory built cars and was raced on the Australian Group A touring car circuit by John Smith.
After the demise of the Group A category, John Smith was able to retain this vehicle rather than return it to TRD Japan. It is believed to be one of only 2 (the other wearing the blue BiJo/Fujitsu Ten livery as seen on various scale models) remaining intact.
Built to the group A formula the specifications of the car are a sign of the times.
Engine specification include: Cast magnesium 9 litre oil pan with matching high flow oil pump, Knife edged steel crank, N/A block hand picked from production line, Short skirt Mahle/TRD pistons, prepped rods and full floating pins.
Titanium fasteners were used throughout the motor. Extensive porting and re-shaping of the combustion chambers was performed with oversized titanium valves fitted. Camshafts were of 288 degree duration with their 10.88mm lift making shim under buckets a necessity along with 100lb valve springs. Titanium cam gears were also employed. Intake and exhaust manifolds were port matched. A 65mm throttle body was used. Fuel delivery consisted of 1000cc injectors and multiple fuel pumps. The ECU was MAP based rather than the traditional AFM which was found on the the production MA70 with the exception of the homologation Turbo A, of which 500 were made.
The turbocharger used on the race cars was a derivative of the CT-26 unit used on the Turbo A homologation production model but with a larger compressor wheel and more importantly a larger turbine housing and wheel. The intercooler was of a similar style core to the road going vehicles but with larger core area and larger piping. The turbine outlet employed a smaller separate outlet for the wastegate, similar to some of the aftermarket units currently available. Engine output was 580hp at the flywheel in qualifying trim (2 Bar) and the vehicle was able to achieve a maximum speed of 300km/hr on Conrod straight during the Bathurst 1000km Endurance race. In 1991 the car was running in 6th place late in the race until sidelined by a power steering failure of all things.
Drive train consisted of a Hollinger close ratio 5 speed with a direct 5th gear (all contained within the standard Toyota gearbox housing) and a TRD billet differential similar to the units commercially available but not identical, evidenced by the carrier not fitting into a standard housing explaining the slightly different housing on the race vehicle. Harrop 4 piston callipers with 15.5″ (393mm) Rotors were fitted up front, as a result 18 x 12 ” rims were required.
The vehicle was not as successful as its peers, notably the Ford Sierra and Nissan Skyline GTR, as its larger engine capacity required it to run at a higher kerb weight by the Group A regulations and also due to a lack of development relative to its competition.