A brief history of turbos: a beginner’s guide to turbochargers in cars

Turbochargers – those snail-like gadgets under many car bonnets – have revolutionised car engines by harnessing waste exhaust energy to pump more air into the engine, yielding bigger power from smaller engines. Invented over a century ago by a resourceful Swiss engineer, the turbocharger began as a way to pep up sluggish diesel engines, and today it’s a staple in modern cars – found in everything from high-performance sports cars to everyday hatchbacks, saloons, and estate cars. In this post, we’ll explore the turbocharger’s history (how it came about and who invented it), its evolution over time, how turbos are used in modern petrol vs. diesel engines, some cool turbo tech variations (like twin-scroll and twin-turbo setups), and finally answer common questions that enthusiasts often ask about turbos.

The birth of boost: early turbocharger history

Early development: Büchi’s early prototypes targeted diesel engines, which were known for their poor power-to-weight ratio. By 1915, he built the first turbocharged diesel engine, but it struggled – the available metals and bearings couldn’t reliably handle the heat and stress of a turbo spinning at high speeds. It took another decade of materials improvements and tweaking for the concept to truly prove itself.

First successes: In 1925, Büchi’s persistence paid off – he demonstrated a turbocharging system that boosted an engine’s output by over 40% compared to an identical naturally aspirated engine. Around this time, the first real-world adoptions arrived. In 1923–1925, two German ocean liners – the Preussen and Hansestadt Danzig – were equipped with turbocharged 10-cylinder marine diesel engines, achieving about 2,500 hp, compared with 1,750 hp without turbos. This was a massive jump in efficiency and power, proving that turbochargers could recover energy that would otherwise be lost to the exhaust.

Turbos take to the skies: Another early arena for turbochargers was aviation. At high altitudes, thin air strangles engine power. In 1918, General Electric engineer Sanford Moss hauled a turbocharged Liberty aircraft engine up Pikes Peak (14,000 ft) and showed it could maintain sea-level power. By the 1930s, turbos (often called “turbo-superchargers”) were common in high-altitude aircraft – crucial for WWII bombers like the Boeing B-17, which needed turbos to fly high with heavy loads.

First turbo on wheels: Using turbos in land vehicles lagged behind ships and planes. In 1938, Swiss firm Saurer introduced the first turbocharged engine for a lorry. It wasn’t very successful initially, but it planted the seed for turbocharging in transportation. A few racing cars in the 1930s experimented with turbos as well, yet for everyday road cars, the breakthrough would come later.

 Evolution of modern turbo technology

After the rocky start in the 1960s, turbochargers made a comeback and then some. Here’s how turbo tech evolved over the decades:

• 1970s – Finding a Purpose: The oil crises of the 1970s and tightening emission laws forced carmakers to seek better fuel economy. Turbos offered a clever solution: use a smaller engine for efficiency while adding a turbo to maintain power when needed. This “boost on demand” idea led to a resurgence in turbo development. Several carmakers introduced turbo models, especially in Europe. Notably, Saab became an early turbo champion with the Saab 99 Turbo in 1978. On the diesel side, Mercedes introduced the 300 SD turbodiesel in 1978 (North America) – giving diesel cars respectable performance. Turbos were proving they weren’t just gimmicks; they could be practical tools to balance power and economy. Still, 1970s turbos were relatively simple and did suffer from turbo lag and some reliability issues, so public acceptance was cautious.
• 1980s – Turbochargers Everywhere: In the 1980s, turbos went mainstream in performance cars. The poster child might be the Porsche 911 Turbo (launched mid-70s, but iconic in the 80s) – it showed that turbocharging could turn a road car into a great sports car (early 911 Turbos had wicked turbo lag, then a huge surge of power). Many sports cars followed with turbos (Ferrari, Buick GNX, etc.), and even everyday hot hatchbacks (like the Renault 5 Turbo). Meanwhile, motorsport entered a “turbo era”: Formula 1 cars, rally cars, Le Mans racers – all exploited turbocharging for massive power. In F1, engineers extracted over 1,000 bhp from tiny 1.5-litre turbo engines in qualifying by the mid-80s, before the rules reined them in. Turbos were now cool and cutting-edge, but the reputation for lag persisted – driving a turbo car required a bit of anticipation. Car makers started experimenting with ways to tame the lag (for example, the 1986 Porsche 959 introduced a sequential twin-turbo setup to smooth out power delivery).

• 1990s – Refinement and Reliability: Turbochargers in the 90s benefited from better engine management computers and materials. Electronic fuel injection and engine control units (ECUs) could carefully manage turbo boost to avoid engine knock (pre-ignition) and dial in smoother power. Water-cooled turbo housings and improved oil systems extended turbo longevity, reducing incidents of “coked” (burnt) oil. Turbos also began appearing in more diesel passenger cars in Europe, such as Peugeot and Audi models, to meet drivers’ expectations for diesel performance. However, in some markets (like the US), turbos on petrol cars actually became less common in the 90s – partly because petrol was cheap and manufacturers could use big naturally aspirated engines. Nevertheless, heavy-duty diesel trucks embraced turbos widely by the 90s (for hauling power and because by then almost every diesel needed a turbo to meet performance and emission standards). By the end of the 90s, the stage was set for turbos to make a broad comeback in cars as fuel economy and emissions became paramount.
• 2000s – The Turbo Renaissance: In the 2000s, turbos went from a performance option to a near-necessity for manufacturers. Why? Governments worldwide imposed tougher CO₂ emissions and fuel economy standards. To comply, car makers turned to “engine downsizing” en masse – replacing large engines with smaller-displacement, turbocharged ones. The result: similar power, better efficiency. Turbo hardware had improved to the point that consumers, for the most part, accepted these engines; they were reasonably reliable and much smoother than turbos of old. Turbos also became ubiquitous in diesel cars (every modern diesel from city cars to pickups had one). In this decade, if you bought a turbocharged car, it was as likely for the fuel savings as for the speed.
• 2010s and beyond – High Tech Boost: Turbochargers have become smarter and more sophisticated in recent years. Engineers introduced innovations to solve the remaining compromises of turbocharging. For instance, twin-scroll turbochargers (see below) became common to increase responsiveness. Variable Geometry Turbos (VGTs), which adjust the internal vanes to optimise flow, were widely used, especially in diesels, virtually eliminating lag and improving efficiency at all engine speeds. And now we’re seeing electrified turbos: Mercedes-AMG brought out an electric turbo for the first time in a production car in 2022, using a tiny electric motor on the turbo shaft to spool it up instantly – no waiting for exhaust gas. This tech, lifted from Formula 1’s MGU-H (energy recovery system), means a turbo engine can be even more responsive. Today, most cars on the road have turbos (especially in Europe, where both turbo petrol and turbo diesel cars dominate). Far from a quirky add-on, the turbocharger has become a standard tool in engine design, boosting efficiency and power.

Turbos Today: Petrol vs. Diesel Engines

Modern cars use turbochargers on both petrol (gasoline) and diesel engines, but often for slightly different reasons and with different outcomes. Let’s compare:

Turbo Diesels – Built for Boost: If you drive a turbodiesel car or have ridden in a diesel lorry, you’ve experienced how turbos transform diesel engines. Diesels inherently run with excess air and have very high compression. They are robust but tend to have a narrow RPM range and can struggle to breathe at higher revs. A turbocharger is almost a must-have for a diesel to perform well. In fact, virtually every modern diesel engine has a turbo; an unturbocharged (“naturally aspirated”) diesel in a car is almost extinct.

• Why diesels need turbos: Diesels burn cooler than petrol and produce a lot of exhaust gas volume, but the engines rev slower. A turbo helps force air into a diesel engine, overcoming its breathing limitations and greatly increasing torque. Early turbodiesels, like those in trucks, used relatively low boost (only 5–8 psi) because the goal was to push more air into the cylinders for complete combustion rather than to highly pressurise the cylinders (diesel combustion pressure is already very high). Even with that mild boost, the gains were huge – diesels went from feeling like underpowered chugging engines to torque monsters that could pull heavy loads. Over time, technology allowed diesels to run bigger boost safely.
• Diesel turbo design: Diesel turbos are usually larger and built for durability. Since diesel exhaust is cooler (less risk of melting the turbo) but there’s a lot of it, diesel turbos often have a bigger turbine to capture all that flow. They might spin at lower RPM than petrol turbos, but can sustain boost for longer periods (like towing uphill for hours). Modern turbodiesels commonly use Variable Geometry Turbos (VGTs) – adjustable vanes that change the turbo’s effective size on the fly. This lets a diesel turbo act small (fast spooling) at low revs and act large (high flow) at high revs, giving a broad, flat torque curve. The result: that signature diesel feeling of massive low-end torque. For example, a 2.0L turbodiesel might produce, say, 350 Nm of torque at just 1750 rpm, which used to require a much bigger engine. Turbos also help diesels run cleaner by ensuring more complete combustion (critical for meeting emission standards). The bottom line is without turbos, modern diesels would be woefully slow; with turbos, they’re efficient, sporty workhorses.
• Turbo Petrol Engines – Power on Demand: Turbocharging petrol engines (what Americans call gasoline engines) was historically about performance, but nowadays it’s just as much about efficiency. Petrol engines rev higher and generally make decent power for their size, but they benefit from turbos in several ways.
• Why petrols use turbos: In modern cars, a turbo allows a smaller petrol engine to replace a larger one, improving fuel economy when cruising or under light load (the smaller engine has less internal friction and pumping losses). Yet when the driver demands power, the turbo kicks in and the little engine punches above its weight. For example, a 1.4L or 1.6L turbo engine in a family car can deliver the power similar to an older 2.0L or even 2.5L engine, but use less fuel overall. Turbos on petrols also help meet emissions targets by enabling downsizing and increasing combustion efficiency (much like diesels). Of course, on performance cars, turbos are there to give more oomph – think of all the 2.0L turbo hot hatchbacks, or twin-turbo V8 sports and luxury cars.
• Petrol turbo characteristics: Petrol engines burn hotter and run at higher RPM than diesels, so turbo design differs. Petrol turbos are typically smaller, lighter (to spool up quickly), and built with exotic materials or water-cooling to withstand the heat. They also often run higher boost pressures than diesel turbos. It’s common for a turbo petrol to run 10–20 psi of boost (or even more in high-performance vehicles), whereas older diesel turbos might run 5–15 psi. The focus with petrol turbos is responsiveness (minimising turbo lag) and high peak power. Many petrol turbos now use twin-scroll designs (explained next) to get quicker response at low revs. One downside of a turbo petrol is that when you use the boost, you can burn a lot more fuel – so the fuel economy advantage only holds if you drive gently.

In summary, diesel turbos are about making a heavy, slow-revving engine deliver enough air for good power (essentially turning a meh diesel into a strong one), and petrol turbos are about getting extra power when needed (and allowing a smaller engine to perform). Both petrol and diesel turbos have converged in technology – both use tricks like intercoolers (to cool the compressed air), wastegates (to control boost) and sometimes twin-scroll or twin-turbo setups. But the user experience differs: a turbodiesel often has a huge surge of torque low down, then not much more at high RPM, whereas a turbo petrol might build boost a bit later and keep pulling to the redline.

To a driver, turbo diesels feel punchy and efficient (great for climbing hills or cruising with low revs), and turbo petrols feel energetic and flexible (offering a wide power band and a higher revving nature).

Common turbo types (single, twin‑scroll, VGT)

Not all turbos are created equal. Over time, engineers have developed various turbocharger designs and arrangements to optimise performance, reduce lag, and meet different engine needs. Here are some key turbo technologies and what they mean:

• Single vs. Twin Turbo: The simplest setup is a single turbocharger – one turbine + one compressor handling all cylinders. A twin-turbo setup means two turbos on the engine. Twin turbos can be arranged mainly in two ways:
  • Parallel Twin-Turbo: This is like giving each half of the engine its own turbo. It’s common on V6 or V8 engines – because a V engine has two banks of cylinders, you can put one turbo per bank. Each turbo then only has to deal with the exhaust from, say, 3 or 4 cylinders instead of all 6 or 8. The advantage is that two smaller turbos can spool up faster than one big one, reducing lag and improving low-end response. For example, many turbo V8 engines (Audi, BMW, etc.) use parallel twins – one turbo for the left bank and one for the right. They often achieve a very linear power delivery as a result. Parallel turbos are usually identical (symmetrical setup), and each gets its own intake and exhaust plumbing, sometimes with a balancing pipe between them for equal pressure. The first production car to use parallel twin turbos was the Maserati Biturbo in 1981 (parallel layout on a V6).
  • Sequential Twin-Turbo: In this more complex arrangement, one small turbo and one large turbo work in sequence, not simultaneously (at least at lower revs). At low engine speeds, only the small turbo operates, giving a quick boost with minimal lag. As revs and exhaust flow build, the system switches – the larger turbo takes over (sometimes both work together for a transition) to provide higher boost at the top end. The goal is to combine instant low-RPM response with big high-RPM power. Sequential systems were famously used on the 1986 Porsche 959 to cut lag (and later the Toyota Supra MKIV, Mazda RX-7, etc.). However, they are intricate – involving bypass valves and complex control to orchestrate the turbos – so they’re costly and can be tricky to maintain. Many modern cars instead achieve a similar effect with twin-scroll turbos or advanced electronics, as sequential setups have somewhat fallen out of favour due to their complexity. Still, some diesels use a form of sequential turbocharging (or two-stage turbos) for a wide torque band.
• Twin-Scroll Turbochargers: A twin-scroll turbo isn’t “two turbos,” but rather a single turbo with a divided inlet housing. The exhaust manifold feeds the turbo in two separate channels (scrolls), keeping pulses from different cylinders apart. Why do that? In a normal (single-scroll) turbo, the exhaust pulses from all cylinders kind of jumble together on their way into the turbine. Sometimes one pulse can interfere with another (especially if a pulse arrives while another cylinder’s exhaust valve is opening – the pressure wave can cause backpressure). Twin-scroll design pairs cylinders whose exhaust strokes don’t overlap, sending their pulses down separate paths to the turbine. This way, the energy in each pulse is used more effectively to spin the turbine rather than disturbing other cylinders. The result is a turbo that spools up more quickly at low RPM and delivers more efficient, smoother power. In practical terms, twin-scroll turbos significantly reduce turbo lag compared to a single-scroll equivalent. They also tend to improve torque in the lower and mid ranges without sacrificing top-end power. Many car makers started using twin-scroll turbos over the last 10-15 years – for example, BMW’s “TwinPower Turbo” engines (despite the confusing name) often use a single twin-scroll turbo, not necessarily two turbos. For a 4-cylinder engine, typically cylinders 1 and 4 feed one scroll and 2 and 3 feed the other, since those pairs have evenly spaced exhaust pulses. Twin-scroll setups do require a split-pulse exhaust manifold, but that’s a small price for the performance gain. It’s a simple way to get a “two-for-one” improvement in turbo response.
• Variable Geometry Turbo (VGT/VNT): Imagine if a turbo could change its shape on the fly – that’s essentially what a variable geometry turbo does. Inside the turbine housing, there are adjustable vanes (think of a camera shutter or adjustable louvres) that can alter the throat area and angle of the exhaust flow hitting the turbine. At low engine speeds, the vanes close down, narrowing the passages, which makes the exhaust gas speed up as it hits the turbine (like putting your thumb over a hose to squirt water). This makes the turbo spool up quickly, even with little exhaust, effectively acting like a small turbo. At high engine speeds, the vanes open, creating a wider passage so the turbo doesn’t restrict flow – now it acts like a big turbo, capable of high flow. Thus, a VGT can provide a good boost at low RPM without causing excessive backpressure at high RPM, giving a very broad effective operating range. VGTs (also known as VNT – Variable Nozzle Turbine) were first widely used in diesel engines, especially in turbo-diesel cars from the 1990s onward, because diesel exhaust temperatures are lower (early VGT mechanisms couldn’t withstand the heat of petrol engines). Nearly every modern turbodiesel car has a VGT, which is why the old laggy “wait…wait… and woosh!” character of 1980s turbodiesels is gone – modern turbodiesels feel much more linear. VGT is a good solution for performance, but it’s mechanically more complex (tiny moving vanes and an actuator, often controlled by a computer and sometimes requiring maintenance if soot clogs it). As emissions standards get stricter, some manufacturers have stuck to simpler twin-scroll fixed turbos or even twin-turbo setups, but VGT remains the pinnacle of turbo tech for flexibility.
• Electric Superchargers / E-Turbos: In the quest to annihilate turbo lag, the latest innovation is the electric turbocharger. This involves adding a small electric motor on the turbo’s shaft (between the turbine and compressor wheels). When the driver demands power, this electric motor can instantly spin up the turbo’s compressor even before sufficient exhaust gas is available. Essentially, it fills in the gap until the exhaust-driven side catches up. Once the exhaust flow is strong, the turbo operates normally (and in some systems, the motor then becomes a generator, recuperating energy from the exhaust). Mercedes-AMG has introduced this in a production car (the divisive 2022 AMG C43 and C63 4-cylinder engines, derived from F1 learnings). Meanwhile, Audi used a 48V electric compressor as a supplement on some diesel models (like the SQ7) – it’s not a motor on the same shaft, but a separate electrically-driven compressor in line with the intake to boost at low rpm. Regardless of configuration, the idea is to achieve an instant boost and eliminate the lag. These systems require a 48-volt electrical architecture and add cost, but they point to the future of forced induction, especially as we move toward hybrids, where an electric motor can handle low-end torque and a turbo can provide high-end power. For now, e-turbos are at the high end of the market, but we can expect them to trickle down. They provide the benefit of a supercharger (immediate boost) with the efficiency of a turbo (using exhaust energy), effectively combining the best of both worlds.

To sum up the tech: twin-scroll and VGT aim to make a single turbo more effective across RPMs, twin-turbo arrangements split the work either simultaneously (parallel) or by RPM range (sequential) for similar reasons, and electric assist helps a turbo where it’s weakest (initial spool-up). Engineers might use one or multiple of these solutions together. For example, a modern diesel might have a twin-scroll VGT turbo, and a high-performance petrol might have parallel twin-turbos with twin-scroll on each, etc. It can get intricate, but the goal is always to serve a smoother, more responsive, and more powerful engine.

Q&A

Question: How does a turbocharger work?
Answer: A turbocharger uses the engine’s exhaust gases to spin a turbine, which drives a compressor. This compressor forces more air into the engine’s cylinders, allowing more fuel to be burned and increasing power output.

Question: What’s the difference between a turbocharger and a supercharger?
Answer: A turbocharger is powered by exhaust gases, making it more efficient as it uses waste energy. A supercharger is mechanically driven by the engine’s crankshaft, providing instant boost but using some engine power to operate.

Question: What is turbo lag?
Answer: Turbo lag is the delay between pressing the accelerator and the turbo delivering boost. It occurs because the turbo needs time to spool up using exhaust pressure. Modern technologies like twin-scroll turbos and electric assistance help reduce this delay.

Question: Do turbocharged engines improve fuel economy?
Answer: Yes, when driven sensibly. Turbos allow smaller engines to produce the power of larger ones, improving efficiency. However, frequent heavy acceleration can increase fuel consumption.

Question: Are turbocharged engines reliable?
Answer: Modern turbo engines are very reliable when properly maintained. Key practices include using high-quality synthetic oil, regular servicing, allowing the engine to warm up before hard driving, and letting it cool down after spirited use.

In summary

From its humble beginnings in the early 20th century to its widespread use in everything from family hatchbacks to high-performance sports cars, the turbocharger has become a cornerstone of modern motoring. Whether it’s the punchy low-end torque of a turbodiesel estate or the thrilling surge of a modern hot hatch like the Ford Focus ST, turbos have transformed how we think about engine performance and efficiency.

Today’s turbocharged engines are more refined, reliable, and responsive than ever before, thanks to innovations such as variable-geometry turbines and electric-assisted spooling. For British drivers, turbos have powered icons like the MG Metro Turbo, the Ford Sierra RS Cosworth, and more recently, the BMW M2 and Audi RS3.

As we look to a future of hybrid and electrified powertrains, the turbocharger continues to evolve—offering a bridge between traditional combustion and the next generation of efficient, high-performance vehicles. Whether you’re a seasoned enthusiast or just getting into cars, understanding the turbo’s journey helps you appreciate the engineering under the bonnet that makes modern driving so rewarding.

Sources

• https://en.wikipedia.org/wiki/Alfred_B%C3%BCchi
• https://aet-turbos.co.uk/turbocharged-beginnings-an-early-history-of-the-turbo/
• https://www.motortrend.com/features/1806-turbochargers-a-history/
• https://engineerfix.com/when-were-turbochargers-invented-and-who-invented-them/
• https://jalopnik.com/2066018/parallel-vs-sequential-twin-turbos-differences/
• https://goldfarbinc.com/blogs/news/variable-vane-turbo-vs-normal-turbo
• https://aet-turbos.co.uk/turbo-technology-the-differences-between-petrol-and-diesel-turbos/
• https://www.carkeys.co.uk/guides/do-turbos-work-better-on-petrol-or-diesel-engines