In May 1986, Toyota was ready to release its next version of the Supra. The bonds between the Celica and the Supra were cut; they were now two completely different models. The Celica changed to front wheel drive, while the Supra kept its rear wheel drive platform. Though the Mark II and Mark III had similar designs, the engine was updated to a more powerful 3.0 200 hp (149 kW) inline 6. Although only available in naturally aspirated trim in 1986.5, a turbocharged version of the engine was introduced in the 1987 model year. The Supra was now related mechanically to the Toyota Soarer for the Japanese market.
The new Mark III Supra engine, the Toyota 7M-GE, was the flagship engine of Toyota's arsenal. Both versions of the engine contained 4 valves per cylinder and dual overhead cams. The turbocharged 7M-GTE engine was Toyota's first distributor-less engine offered in the US which used coil packs sitting on the cam covers and a cam position sensor driven by the exhaust camshaft. It was equipped with a CT26 turbocharger and was rated at 230 hp (172 kW) at 5600 rpm while the naturally aspirated 7M-GE engine was rated at 200 hp (149 kW) at 6000 rpm. Further refinement on the turbo model increased power to 232 hp (173 kW) and 254 lb·ft (344 N·m) in 1989. This was mostly due to a redesign of the wastegate.
Due to a large error in the factory head bolt torque specifications, all of these engines had severe problems with blown head gaskets. Toyota never issued a recall for any of the affected vehicles. The problem could be easily fixed by replacing the head gasket and torquing the head bolts to 75 lb·ft (102 N·m) of torque. However, due to the lack of a recall or appropriate service bulletin, the head gasket problem would recur if the gasket was replaced and the bolts were retorqued to the erroneous service manual specifications. With the head bolts torqued correctly, the engines were otherwise extremely durable.
The naturally aspirated came as standard issue with the W58 manual transmission. The turbo versions included the more robust R154 manual transmission. Both were available with the optional 4-speed A340E automatic transmission.
The third-generation Supra represented a great deal of new technology. In 1986, options available for the Supra included 3-channel ABS and TEMS which gave the driver 2 settings which affected the damper rates; a third was automatically activated at WOT, hard braking, and high speed maneuvering. HKS also made a "TEMS Controller" to hack the system and activate it on the fly, though the controllers are now nearly impossible to find.
ACIS (Acoustic Controlled Induction System), a method of controlling air compression pulses inside the intake piping to increase power, was also a part of the 7M-GE's technological arsenal. All models were fitted with double wishbone suspension front and rear. A targa top was offered along with a metal power sliding sunroof (added in '91).
Total Supra MkIII's produced: 108,565
Source: Wikipedia, 2011