Originally Posted by t walgamuth

I think its generally agreed it was banned because it was too fast. The hot exhaust was one of the things the other teams whined about. And it was not actually banned they just reduced the allowable intake size enough to make it too slow from lack of power.

The first year they ran the turbines was '67. That was the one with the engine beside the driver. It ran on ordinary jet fuel which is pretty close to diesel in its makeup. They ran it in practice and in the race. They also were able to run any tire they liked so they ran rear (bigger) tires on the front for more grip.

The intake was reduced for 68 enough it was thought to make them uncompetitive. The cars were also restricted to using four front (smaller) tires... but Lotus was engaged to design a newer lighter car with better aero. And it was still dominant.

But they ran white gas in the race for better fuel economy and it gave them some trouble, causing the cars to flame out and die on resumption of racing speeds after a yellow light.

Lotus ran a version 56B of the same car in F1 in 1971 in a few races. It was competitive in races that were rainy, but it was too heavy and too slow in dry conditions.