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A turbocharger is a clever device that allows an engine to produce more power.
A non-turbocharged engine uses regular uncompressed air and fuel.
This works fine, but if you compress air, that is take air that normally fills, say,
a pint glass and squish it down to a half-pint glass, then inject it into the cylinder, you’ll
get a bigger bang because there’s more oxygen for the fuel to mix with.
A bigger bang makes the cylinder move faster which makes the crankshaft turn faster which
means a bigger smile on your face!
So, turbochargers use a turbine to compress the air, then feed it into the combustion chamber.
Superchargers work in exactly the same way, but the difference is how they’re powered.
Superchargers power the turbine using mechanical means,
for example by a chain attached to the driveshaft.
But this robs power from the engine.
For example, the Rolls-Royce Merlin engine used on the Spitfire took 150hp (110kW) from
the engine just to power the supercharger.
However, by compressing the air that supercharger gave the engine an additional 400hp (300kW).
Turbochargers don’t rob the engine of any power.
Instead they cleverly use the engine’s exhaust to power the turbine.
This gives the engine more overall power, but also means the turbo can only run when
you have enough exhaust gases to make it work.
That happens when the engine is running fast, meaning you only get a turbo boost at high revs.
This results in the dreaded “turbo lag” – that momentary wait you get between putting
your foot to the floor and the car taking off like a startled pony.
The earliest use of supercharging was by Gottlieb Daimler in 1885.
This was a bit of a turnaround, as Daimler had been a big proponent of atmospheric engines
while working with Nicolaus Otto before Otto’s invention of the four-stroke engine.
There was no love lost between the two men, although they’d worked together for many years.
This probably spurred Daimler on to make a superior engine with his younger partner Wilhelm Maybach.
With both Daimler and Otto trying different improvements to perfect the internal combustion
engine, it’s maybe unsurprising that Daimler thought to attach a gear-driven pump to force
air into the engine to increase its efficiency.
But in the early days of internal combustion engines for cars, there were much more fruitful
avenues to pursue to gain more power than turbocharging.
It wasn’t until 1905 that Alfred Büchi, just two years out of University, would hit
upon the idea of using exhaust gases to power the turbine.
He was frustrated that a massive 2/3 of the internal combustion engine’s energy was
lost through exhaust heat.
But his turbocharger design was only theoretical as materials weren’t yet available to build
a device that could withstand such high revolutions and heat.
However, his design laid the groundwork for the way all turbos work today.
By 1915 he had a working prototype, but it simply didn’t work reliably and it would
take another ten years until he had a workable solution.
The first practical turbocharger would be fitted to diesel marine engines and would
boost their efficiency by a colossal 40%.
Marine engines were an ideal first use for turbos.
They generally ran at slow, constant speeds and used large displacements.
All of this reduced the stress on the turbo components, allowing for a reliable system.
But turbos wouldn’t only be used for ships.
It was soon seen that superchargers and turbochargers could be useful in boosting power in aircraft engines.
Planes needed as much power as they could get from as light an engine as possible, and
early engines didn’t produce much power.
This led to aluminium engine blocks, radial engines and other tricks to get as much power
from as small a weight as possible.
Another reason for turbos was the thinner air at high altitudes.
There’s even less oxygen, which produces even less power for an engine, so compressing
the air is a priority.
This is why you don’t see those early aircraft flying to high altitudes.
The lure of supercharging and turbocharging in aviation led to experiments in turbos in
France in 1916 to provide ever more powerful aircraft for the first World War.
A year later tests were also carried out in the US.
Instead of trying to test the engine whilst in flight at high altitude, the engineers
drove the engine 4,250m (13,944ft) up the famous Pike’s Peak to run high altitude tests there.
Once higher quality parts could be produced, aircraft engines started using both superchargers
and turbochargers.
By the time of the Second World War, it was a necessity to use these on your engine to
provide the necessary power to compete in a dogfight or be high enough for a bombing raid.
Superchargers had been used on sports cars since the 1920s, but with the development
of turbochargers in aviation, turbochargers were tried out in vehicles in the 1950s.
They offered so much but were temperamental beasts.
No better example of this was the 1952 Indy 500 where Fred Agabashian secured pole position
with his turbocharged car but retired on lap 71 out of 200 with turbocharger failure.
With lower revving, higher displacement diesel engines being easier to turbocharge, it was
maybe natural that trucks would get turbos first.
Volvo would produce one of the first diesel turbocharged engines in 1954 that boosted
power from 150hp to 185 (112kW to 138kW).
The first production car to use a turbo was a version of the 1962 Oldsmobile F-85,
dubbed the “Jetfire”!
The engine it used was an old friend that keeps cropping up in Big Car videos – the
Rover V8 that was originally created by GM in 1961.
So, you can now win a pub quiz question in the very unlikely event that this ever comes up!
At that time, it was called the Buick 215 and rather fittingly the turbo allowed the
car to get 215hp (160kW), and to 60 in less than 10 seconds.
But with both the 215 engine and turbocharger being unreliable, the car was short lived.
Just one-month later GM introduced the second turbocharged car, the Chevrolet Corvair Monza Spyder.
It was powered by the “Turbo-air 6” engine, an engine that that up until then hadn’t
been anywhere near a turbo, and once the turbo was installed they changed the name to the
“Super Charged Spyder”, despite it not actually using a supercharger!
This engine and turbo combination proved more reliable and it was produced throughout the 1960s.
Turbos started to become a force to be reckoned with when Bobby Unser won the 1968 Indy 500
in his turbocharged Eagle-Offy.
It wasn’t the fastest car in the race – that belonged to the gas-turbine powered Lotus 56’s.
But it was the most reliable, and after 200 laps and 500 miles (804km) that’s what matters!
This win signalled that significant performance gains could be made using turbos and companies
rushed to use them.
Porsche would win the 1972 Can-Am series with their 917/10K.
Just one year later German rival BMW would add a turbo to their iconic 2002, but due
to excessive turbo lag and safety concerns it was withdrawn the following year.
But Porsche did manage to tame that turbo beast in 1974 when they introduced the 911 Turbo.
In fact, it’s hard not to think of the name Porsche 911 without adding “Turbo” to the end.
Turbos have been an integral part to Porsches and other sports cars ever since.
This led a rush to turbocharging engines that reached fever pitch in the 1980s with almost
all manufacturers adding turbos to give their cars a boost, such as the 1984 Ford Escort RS Turbo.
Early turbos, like the late 1970s Saab 99 could be unrefined and temperamental, but
soon they became a simple and smooth way to give a free boost to a car’s output.
Turbos first came to Formula 1 in 1977.
They soon became the only engine to use but were banned in 1989.
They made a comeback in 2014 as part of Formula 1’s drive to focus on fuel efficiency rather
than raw power.
Turbos have even been used on occasion for motorbikes.
The first was the 1978 Kawasaki Z1R-TC.
But this was one wild machine.
The Turbo Cycle Company took a stock Kawasaki Z1R, boosted its 80hp to 135hp (60-101 kW)
and made any prospective customer sign a liability waiver.
Without a rev limiter, it was easy for the valves to hit the pistons which would mean
a very sick engine, very quickly!
Throughout the 1980s and 90s turbos were refined to produce more and more output.
Twin turbos would commonly be used, each powering half of the cylinders.
This meant smaller turbines that could spin up faster, reducing turbo lag and the forces
on the turbine.
Some systems would use both a smaller and larger turbo to reduce turbo lag by relying
on the smaller turbo first, and then the larger turbo when it’s had a chance to spin up.
And with the increase in demand for diesel cars, turbo diesels became popular, combining
fuel efficiency with good acceleration.
Intercoolers were another improvement.
All this compressing air results in friction, and friction produces heat.
Hot compressed air isn’t as dense as cold compressed air and can also lead to engine
knock which can damage engines, so an intercooler takes that hot air and cools it down.
Despite the weight these components add, cars were getting ever faster.
Lotus’ Esprit only used a 2.0L 4-cylinder engine, yet by the late 1990s it could output
a reputed 500hp (373kW) that had to be tamed to just 350hp (261 kW) to prevent obliterating
the gearbox!
Nowadays turbos are just one of the weapons in a car designs arsenal in the war against not just
0-60 times, but but increasingly fuel economy.
By 2017 27% of vehicles sold in the US included a turbo.
In Europe is was a more impressive 67%.
Fuel injection has also given cars a major boost, meaning even today’s basic econoboxes
have more power and better fuel economy than some sports cars from the 1960s.
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