An engine is nothing more than an air pump. The more air it ingests, the more fuel it can burn. And more fuel equals more power. In this post, we’ll look at turbocharger vs supercharger differences – and talk about which is better.
Sometimes an engine needs a little boost
Engineers have a few methods for increasing the volume of air that enters an engine’s cylinders, but the turbocharger has emerged as their favorite in production vehicles.
It’s easy to see why. A turbocharged, direct-injected four-cylinder engine can make as much power as a naturally aspirated six-cylinder engine.
Consider, for example, America’s best-selling vehicle – the Ford F-150. A 2021 model equipped with a 3.5L twin-turbo V-6 makes 400 horsepower, which is the same as the non-turbo 5.0L V-8. Plus, it makes 90 lb. ft. more torque and gets better gas mileage.
All that from a smaller, lighter engine. That’s why automakers are leaning heavily on turbochargers (in addition to direct fuel injection and variable valve timing) to meet increasingly strict fuel economy and emissions requirements. In fact, most new vehicles today come with a turbo as standard fare.
How does this engineering marvel work?
Turbochargers use exhaust gases to drive a turbine, which spins a compressor that pushes more air into the cylinders. More air = more fuel = more power.
Turbocharger vs supercharger
What’s the difference between a turbocharger and a supercharger? “Supercharger” sounds much cooler, for one. It also looks cooler with the menacing air intake mounted like a turret on the hood.
While turbos run on exhaust gases, superchargers are driven via a belt connected to the engine’s crankshaft. This provides a notable advantage.
Superchargers are more responsive, not suffering from what’s known as turbo lag. When you jam the accelerator in a turbocharged vehicle, the engine takes a moment to create the exhaust gases that spin (or spool up) the turbo. The slight hesitation can feel like an eternity when your right foot calls for instantaneous power.
In fairness, some modern turbocharged engines are so well refined that they’ve largely eliminated turbo lag. But a supercharger eliminates lag altogether and delivers instant boost. The tradeoff comes in the added bulk and cost, which is impractical for most daily drivers. That’s why superchargers are still relegated to high-performance vehicles and hot rods.
Turbocharger vs supercharger: which is better?
The answer depends on what you’re looking for. If you define “better” as delivering the most power and best performance, the supercharger wins. However, they come with tradeoffs, particularly higher cost.
Despite its inherent lag, a turbocharger provides a satisfying combination of improved performance, efficiency and cost-effectiveness.
Turbos also benefit from scavenging naturally occurring exhaust gases as their power source rather than using valuable crankshaft horsepower, like a supercharger. If maximum power and speed are your goals, however, the supercharger’s lack of turbo lag can overcome the added power it requires.
Most automakers, however, care as much about fuel economy as power output, so they opt for turbos, which cost less and don’t consume added energy.
As a rule of thumb, a turbo or supercharger that increases air volume by 50% will boost power by 30-40% since some power is lost to heat and the need to adjust engine timing to prevent pre-ignition.
Whatever the choice, use a high-quality synthetic oil
One byproduct of added power is heat, and heat robs engines of efficiency, meaning you can’t drive as hard. The exhaust gases that drive the turbo can exceed 1,000ºF (538°C) and spin the turbine more than 150,000 rpm.
The tremendous heat and stress turbos create can cause some oils to breakdown and form harmful bearing deposits, known as turbo coking. Over time, turbos can suffer reduced performance or fail altogether.
Synthetic oil’s improved heat resistance makes it the preferred choice for fighting deposits in these vehicles.
For example, AMSOIL Signature Series Synthetic Motor Oil protects turbos 72% better¹ than required by the GM dexos1 Gen 2 specification.
What good is the added performance of a turbocharged engine if you don’t protect it?
¹Based on independent testing of AMSOIL Signature Series 5W-30 in the GM turbo coking test.