Throwback Thursday 1962: the Oldsmobile Jetfire explained

The idea for using a turbocharger had come from GM's chief engine development engineer, Gil Burrell, who had recalled an extensive technical report on the subject that the company had made "many years before" and decided to enthusiastically continue the research, which led to him contacting Garrett.

The mechanism that resulted was described by Autocar as "extremely elaborate, with numerous safety devices".

We said: "Those who are familiar with turbocharged diesel engines [these had already long been used in locomotives and trucks] may be surprised that it should be necessary to complicate the machinery so much merely because the impeller sucks through a carburettor and not from a pure air intake.

"But a little thought will make it clear that blower pressure has to be limited. The high volumetric compression ration of 10.25:1 also makes it necessary to inject a water-alcohol mixture, and the carburettor is coupled to a metering device, with connections to a bypass should the fluid reservoir run dry."

That mixture, comically christened 'Turbo Rocket Fluid' consisted of 50% methyl alcohol and 50% distilled water and a small amount of anti-corrosion additives. It served to prevent detonation because early prototypes of the engines suffered from spark knock. The alcohol "served as an anti-freeze, making it possible to use the same fluid regardless of temperatures" and was injected between the carburettor and the compressor.

We explained further: "The nozzle is located in a part of the passage that forms a long venturi to obtain the desired pressure drop; the ratio of fuel to fluid remains close to 10:1 throughout the engine's rpm range."

Of course, in a naturally aspirated engine, this drop is created when a cylinder falls during the intake stroke, whereas turbo tech allows air to be sent into the engine at a pressure above atmospheric ('boost' pressure).

"Under cruising or coasting conditions, with the throttle partly open, there is a high vacuum in the intake manifold, so there is a check valve in the metering system to prevent fluid from being sucked into the engine at low or nil boost pressure. When the boost pressure in the manifold reaches 1psi, a diaphragm in the fluid metering valve opens a ball check valve, and the pressure in the fluid container tank forces the fluid through a jet to the injection nozzle."

Oldsmobile's V8 consumed this fluid at a rate of around 8000mpg, but the reservoir was a mere 4.7-litres, meaning it could be emptied in less than 250 miles. When it was empty, performance would drop significantly (although it was still perfectly okay to drive the car), leading to many owners who had not refilled the reservoir taking the car back to the dealerships and complaining.

Given the system's complexity, it was natural that some cars suffered mechanical issues, too, and all this lead to Oldsmobile offering to replace the complicated turbocharger mechanism with a conventional 4-barrel carburettor. This means it's now nearly impossible to find an 'original' Jetfire because just 9607 examples were produced and most owners took up the offer of a replacement.