Turbocharging 101: Learn About Basic Turbocharger Operation

You’ve probably heard phrases that utilize variants of the word turbocharger, as in “This coffee really gave me a turbo boost!” or “Turbocharge your sales!”.

But why do people use “turbocharge” related words and phrases in this way? It all comes down to what a turbocharger is and how it helps combustion engines operate more efficiently.

At its most basic level, what a turbocharger does is make more efficient use of an engine’s given combustion setup, thereby increasing its horsepower output. It does so by using forced induction.But before we get ahead of ourselves, let’s break down the basic principles of turbochargers further so you can develop a complete understanding of not just how they work, but also why adding one to your vehicle might just be the best decision you’ve ever made, you little speed demon, you!

What is Turbocharging & How Does it Work?

Turbocharging, or forced induction, increases an engine's efficiency and power output by forcing extra compressed air into the combustion chamber. It does this by gathering exhaust gasses, compressing them, cooling them with an intercooler, and then directing them into the intake manifold, or the part of an internal combustion engine that supplies the fuel/air mixture to the cylinders.

Forced induction increases an engine's power output by forcing more air molecules into the engine's cylinders than it could naturally pull in, essentially meaning there’s more fodder for the constant explosions that make up combustion engine operation, and therefore, increased horsepower output.

Turbocharged vs. Naturally Aspirated Engines

All automotive internal combustion engines are essentially big, complex pumps that “breathe in” air and “exhale it” out to create power.

Let’s talk atmospheric pressure for a hot minute (temperature pun very much intended). All air has weight and presses against everything it touches. The measure of this pressure (the pressure of the earth’s atmosphere), is what’s commonly referred to as atmospheric pressure.

If you’ve ever heard of a naturally aspirated engine before, these engines operate only on atmospheric pressure. In other words, they take in air at normal atmospheric pressure.

This differs from turbocharged engines, which rely on the turbocharger or “turbo” for short, to force air in with added pressure.

Components of a Turbocharger

Here are the main components of a turbocharger, on a basic level:

• An intake manifold where exhaust gasses make their way into a turbine wheel
• A “hot side” which includes a turbine wheel
• A “cold side” which includes a compressor wheel
• A shaft that connects the turbine and compressor wheels similar to how a car’s axle connects its wheels in a fixed position
• A diffuser that forces the air from the compressor into a narrow space, pressurizing it (volume and pressure of a gas are inversely proportional per Boyle’s law)
• An exhaust outlet where compressed air makes its way into the engine’s intake manifold
• A wastegate and blow-off valve that regulate pressure

Because heat increases proportionally with pressure (heat and pressure are directly related) according to Gay Lussac's Law, as turbochargers pressurize air, the temperature of this air also increases, and must therefore be cooled before it can be combusted in the cylinders to create the driving force that makes an engine fire and a car move.

This is why most turbo engines also include an intercooler, the function of which is to cool down these hot exhaust gasses.

How Turbochargers Work

The process of turbocharging exhaust gasses to create a “boost” of power goes a little something like this:

1. Exhaust gasses enter the intake manifold, spinning the turbine, which is affixed to the compressor by a shaft.
2. The compressor then moves the air into the diffuser, where it is converted from fast moving and low pressure to slow moving and high pressure. Most automotive compressors are radial, meaning they suck air in in one direction and compress it in another. It’s during this step that a wastegate and/or blow-off valve modulate pressure, if need be, since in a closed system, a turbocharger could create more pressure than an engine could handle.
3. Once the air makes its way out of the diffuser, it heads into the intercooler, or charge air cooler. This increases its density (because remember, cooler air is more dense than hotter air).
4. Next, the air makes its way into the intake manifold to be utilized in combustion, the byproduct of which is exhaust gas, and the process repeats itself.

Types of Turbochargers

There are three main types of turbochargers used in Audi, VW, and Porsche vehicles:

• Single Turbo: Simple, cost-effective, and common, single turbo setups use one turbocharger to compress the intake air and force it into the engine.
• Twin-Turbo: Twin-turbo systems use two turbochargers to manage air compression. They can be configured in two main ways: sequentially or in parallel.
  • Sequential: They employ a smaller turbo that operates at low RPMs, providing quick spool-up and reducing lag in addition to a second, larger turbo that kicks in at higher RPMs for maximum power.
  • In Parallel: Two identical turbos work together to split the exhaust flow, each handling half of the engine's cylinders.
• Variable Geometry Turbo (VGT): VGTs feature movable vanes within the turbocharger housing that adjust to optimize airflow and boost pressure across the engine’s entire RPM range.

Turbocharging FAQs:

What are the benefits of turbocharging?

Turbocharging increases your engine's horsepower and torque without increasing displacement, thereby improving acceleration and overall performance.

It also enhances fuel efficiency by allowing smaller engines to produce more power. Additionally, turbocharging provides a more responsive and exciting driving experience.

What should I do before I turbo my car?

Research your goals and model-specific turbo options. Ensure your engine is in good condition and all maintenance is up to date. Consult with professionals and budget for the turbo kit and any additional costs. Choose your turbocharger brand wisely!

What do I need to upgrade to turbo my car?

You'll need a complete turbocharger kit, ECU tuning, and upgraded fuel injectors and pump. Also, consider a high-flow exhaust system, improved cooling system, and strengthened internal engine components. Installing monitoring gauges like a boost gauge is also essential.

Shop Audi, VW, and Porsche Turbos at Integrated Engineering

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A wide world of high-quality, precision-engineered, power-boosting Audi, VW, and Porsche turbochargers and superchargers awaits you at Integrated Engineering.