Description
History
In early 1963 Giovanni Michelotti from Standard-Triumph the order to create a GT – to design a version of their recently introduced Spitfire 4 (also designed by Michelotti). An unmodified Spitfire 4 was delivered to Michelotti's design studios in Italy and in late 1963 the prototype Spitfire GT4 was returned to England for evaluation. The vehicle's styling was a success, but the additional weight of the GT body resulted in extremely poor performance from the 1.147 cc (70 cu in) Standard SC engine of the Spitfire, and plans for production of the Spitfire GT4 were shelved.
Michelotti's fastback design for the Spitfire GT4 prototype was adopted by the Triumph racing program for the 1964 season, as it offered an aerodynamic advantage over the standard Spitfire body shape. Fiberglass copies of the Spitfire GT4 fastback were grafted onto the race-modified Spitfires intended for competition. The Spitfire racing program was successful and resulted in a 1965th overall and 13st in class at the prestigious 1 24 Hours of Le Mans (defeating their main rivals, the MG Midgets). The competitive success of the Spitfire and the continued commercial success of the production vehicle led Triumph to re-evaluate its shelved plans for a GT version of the Spitfire. To overcome the lack of performance inherent in the heavier body style, the Spitfire' The 4-cylinder engine was replaced by the more powerful 2.0 L (1.996 cc) Triumph inline 6 which was originally derived from the SC and subsequently in use in the Triumph Vitesse (which shared a similar chassis with the Spitfire and Triumph Herald ). The car was further developed and refined and was eventually launched as the Triumph GT6 (omitting the “Spitfire” prefix) to emphasize the GT styling and 6-cylinder engine.
Contemporary Triumph marketing advertised that the GT6 was developed from the “race-winning Le Mans Spitfires” to capitalize on their aesthetic similarities, while the Le Mans Spitfires and the GT6 were actually two completely separate development programs (the GT program predating the racing program). However, the marketing spin was so successful that many people mistakenly thought the Le Mans Spitfires were actually GT6s.
GT6 Mk III
The last major facelift for the GT6 came in 1970 in the form of the Mk III. This time the entire bodywork was revised to match the changes made to the Spitfire Mk IV: changes included a cut-off rear, recessed door handles and a smoother front end. Only detail changes were made to the mechanicals, but in 1973 – close to the end of the car's production life – the rear suspension was changed again, this time for the cheaper (but still effective) “swing-spring” layout that MK IV was mounted on the Spitfire. This was a modification of the swing axle rear suspension used on the Herald-derived models, with the transverse leaf spring mounted on a pivot, eliminating rear roll stiffness and significantly reducing the jacking effect under cornering loads. To compensate for this loss of roll stiffness, a larger front stabilizer bar has been fitted. A power brake was also added in 1973 and the seats were changed from vinyl to cloth. There was still a fairly extensive options list, but the beaters wire wheels were no longer available. Curb weight increased slightly to 2030 pounds (920 kg).
Engine power and torque for the Mk III was comparable to the Mk II, but better aerodynamics led to a new top speed of 112 mph (180 km/h) and a 0–60 mph (0–97 km/h) time of 10,1 seconds. Performance was now well ahead of the MGB GT, reaching around 13 mph (105 km/h) and 169-0 mph (60-0 km/h) in around 97 seconds. Fuel economy was also improved to 28 mpg -imp (10 l/100 km; 23 mpg -US ). The latest American models performed relatively poorly because compression ratios were lowered to accommodate the use of unleaded gasoline with a bearing octane number to make possible.
The Mk III never sold in the numbers Triumph had hoped and was completely defeated in the market by the MGB. Triumph refused to release an official convertible version of the GT6 and, after poor sales, it was dropped from the Triumph range at the end of 1973, although a few cars were sold the following year.
