A new episode of "Jay Leno's Garage" features an obscure piece of racing history. It's the Howmet TX (Turbine Experimental), a turbine-powered race car built in 1968 that's still in running condition today.

Four of these cars were built by Bob McKee, whose other engineering credits range from Can-Am race cars to an experimental diesel-electric hybrid powertrain for the U.S. military. This one is now owned by venture capitalist Phillip Sarofim. He's one of the people behind the revived Meyers Manx company, and clearly enjoys cars with unusual engines. He previously brought a Manx with an aircraft radial engine to the show.

1968 Howmet TX turbine-powered race car on Jay Leno's Garage

1968 Howmet TX turbine-powered race car on Jay Leno's Garage

Turbines were on trend in the 1960s. Chrysler built a limited run of turbine cars to test the engine type's suitably in road cars, and several race cars and already been built by the time the Howmet TX came along, including the STP-Paxton Turbocar Indianapolis 500 racer. But the Howmet TX was the only turbine car to win a race, McKee notes in the video, admitting that it was "less consequential" than Indy.

McKee was commissioned to develop the TX by driver Ray Heppenstall, who went to Howmet Corporation (now Howmet Aerospace) for funding. The company built parts for turbine engines, and so the race car project was pitched as a way to promote its products. The chassis was designed by McKee, incorporating bits from other cars such as Can-Am racer fenders and a Porsche 906 windshield. 

Turbines have some advantages over conventional piston engines, including massive power for their size, and smooth, vibration-free operation. But fuel economy is generally poor, and there is significant lag when getting on or off the throttle. The starting procedure is a bit complex too. Many switches must be thrown, and the car needs a little push to move away.

While there have been some more recent attempts at turbine cars, including Leno's own EcoJet, these issues make them more suited to the sky than the road. The Howmet TX does make an incredible noise, though, which can be experienced via the video.