Whether or not you identify as a motorsport or automotive enthusiast, you’ve undoubtedly heard the terms “supercharged” and “turbocharged” before in your day-to-day existence. Synonymous with bolstering speed, power, efficiency, and intensity, these two types of forced induction are widely employed by vehicle manufacturers and race teams alike. And, while most people understand that these chargers improve a vehicle’s raw performance prowess, a much smaller percentage of the population fully grasps what these are and how they function, much less their respective strengths and weaknesses.
So, to help pull back the curtain on how these forced induction systems operate, we’ve put together this easy-to-follow guide to turbochargers versus superchargers. Obviously there are numerous factors at play when discussing powertrains — such as displacement and engine configuration among quite a few others — and what makes them tick, however, few, if any systems, upgrades, or modifications are capable of squeezing as much horsepower from an engine as a super or turbocharger.
Forced Induction Origins
The History Of Turbo & Superchargers
The earliest use of turbo and superchargers dates back to the late 1800s. The first supercharged production car rolled onto the scene in 1921 with Mercedes-Benz’ 6/25/40hp (and 10/40/54hp) — technology borrowed from aircraft engine architecture of the time. It wouldn’t be for another 40+ years that the first turbocharged production model entered the market when General Motors unveiled the Oldsmobile F-85 Jetfire (Turbo Rocket). Forced induction production models would remain sporadic until the mid-to-late 1970s, at which point the technology exploded, leading to it becoming the status quo in the auto industry like it is today.
A Basic Guide To Forced Induction
To understand the principles behind turbo and superchargers, it’s vital that one has a general understanding of engine aspiration. Engines without turbo and superchargers (known as “naturally aspirated”) combust fuel and air at atmospheric pressure — aka the same atmospheric pressure we breathe and walk around in every day. Super and turbochargers bestow powertrains with condenses air that is forced into an engine’s cylinders, hence the moniker of “forced induction,” which describes a turbocharged or supercharged mill. Put very simply: the concept of forced induction isn’t that different from stoking a flame; the more air its afforded, the stronger it gets.
The Mechanisms Of Forced Induction
The Physical Function Of A Turbocharger & Supercharger
A turbocharger is an air compressor driven by an exhaust gas turbine. Instead of spent fumes being ejected from the exhaust, the gasses are recycled back through the system, powering a turbine (typically going through an inner-cooler), and then going into the intake manifold, resulting in boost.
Superchargers, on the other hand, use a belt that runs off the engine — more specifically, the crank) to spin, thereby compressing air and forcing into the cylinders of an engine. When fed to the cylinders, this compressed air affords more oomph.
Methods Of Forcing Air
The Different Types Of Turbo & Superchargers
There are three main types of superchargers: Centrifugal; Roots-type superchargers (which date back to the mid-1800s); and Twin-Screw superchargers. For turbochargers, there are two main kinds: journal bearing; and ball bearing. Superchargers also come in both the top and side-mounted varieties.
The Pros Of Turbochargers
Benefits Of Blown
Turbochargers allow for an engine to make markedly more horsepower and torque without increasing displacement. Turbos — or “blowers” as they’re often called — can also bolster fuel economy, plus, they enable smaller engines to produce substantially more oomph (compared to superchargers of a similar size). And because they aren’t connected to the engine’s crank like a supercharger, turbochargers can spin much faster, at RPM’s well into the six-figure range. For the same reason, turbos don’t leech power off an engine the way that superchargers do.
The Dark Side Of Snails
While turbos make more power than superchargers, it does come at several costs. Often appearing on high-dollar hypercars, turbos are more complicated systems that are harder (and more expensive) to install, typically requiring the addition of blow-off valves, oil-lines, and a number of other engine modifications. Additionally, turbos almost always require inner-coolers, too, as being connected directly to an exhaust manifold results in turbos getting really hot.
A turbo’s biggest shortcoming is objectively its lag. Because they have to get spooled up to ideal operating RPM, they afford relatively little to no boost in the lower RPM range. Lag is also to blame for the lack of precision related to the control of there boost, and unlike superchargers, turbos are prone to sudden surges of power.
Benefits Of Superchargers
Whining In A Good Way
Just like with turbos, superchargers can add a lot of oomph to a vehicle’s power output. Unlike turbos, however, superchargers aren’t hindered by the lag effect that turbos suffer from. On top of instant boost, superchargers can also provide consistent power across the entire torque curve.
And because superchargers are connected directly to an engine’s crank pulley (and therefor RPM), they spin up right away and don’t suffer from any lag. For the same reason, superchargers can also produce substantially more low-end boost. Superchargers are also made up of fewer parts, making them easier (and markedly cheaper) to install and more reliable as there are fewer components that can possibly fail. They’re also less prone to grinding an engine.
Not So Super
The Negatives Of Superchargers
Because a supercharger relies on an engine’s crank, they leech a small amount of power from an engine. This parasitic effect makes them slightly less efficient than turbos, as well as less economical with fuel. Superchargers can also be on the heavier side which can negatively impact a car’s weight placement and distribution. Ultimately, the biggest downside to superchargers is that they make relatively little power when compared to a turbocharger.
Which Is Better
Weighing In On The Forced Induction Debate
Whenever discussing the topic of forced induction, it’s inevitable that the age-old question of “which is better” is sure to pop up. And considering the ubiquity of forced induction systems in the car scene and the fact that there are two main types, it’s not all that surprising. The reality, however, is that there is no objectively correct answer to which of the two is superior.
Rather, the correct answer is that each boasts its own unique strengths and weaknesses, making each more (or less) conducive to specific applications. Turbochargers are undeniably more popular — especially on production models — though one could argue the reason for this stems more from emissions and fuel-economy regulations than it does the raw performance merits of each type.
The Best Of Both Worlds
Twin-Charging & Electro-Boosting
An engine fitted with both a supercharger and a turbocharger is referred to as “twin-charged”. These setups have existed on production models for decades — such as with Lancia’s iconic Delta S4 of 1985 — and remain popular today. Another increasingly popular modern configuration is pairing turbochargers with electric motors that enable the turbos to get spooled up to operating RPM, lessening (if not entirely eliminating) the lag turbos are notorious for. Many of the late model hybrid super and hypercars utilize these electric motor-supplemented turbo setups — same with Formal 1’s ERS system.
What’s The Difference: Torque vs. Horsepower
Enjoy learning about what’s going on under the hood and what makes an engine tick? Our explanatory guide to the difference between torque vs. horsepower is another must-read feature for any aspiring gearhead.