Understanding Turbo Engines

November 21st, 2017 by

What is a turbo? Am I turbo?

Thinking about buying a turbocharged engine, but you have no idea what a turbo is? You’re not alone. Here’s everything you need to know about turbochargers.

What Is a Turbocharger?

A turbocharger is a turbine-driven forced induction device. Okay. What is a “turbine-driven forced induction device?” It is simply a device that drives air into the combustion chamber. The combustion chamber is where the rapid expansion of air and gasoline applies direct force to the piston and drives the engine. And normally aspirated engines rely on the air that is passively induced. The greater amount of air (and gasoline) forced into the combustion chamber by turbochargers translates to a greater power output.

The beauty of turbochargers is that they are powered by exhaust. As the exhaust exits the engine, it spins the turbine which spins a compressor, which does something else – it’s like a Rube Goldberg machine. I don’t know. Listen, the point I’m trying to make is that it’s basically free power. And that’s not nearly the only upside to having a turbocharger under the hood.

Why Turbochargers?

Turbochargers are an ingenious solution for drawing greater power from fewer cylinders. Many turbocharged, four-cylinder engines match regular V6s in terms of horsepower and torque. But having two fewer cylinders reduces the engine weight significantly and improves fuel economy at low speeds. That Turbochargers also run off of exhaust gases, so they’re more efficient and less wasteful. That sounds great, so what’s the problem.

Why Not Turbochargers

A phenomenon called “turbo lag.” This refers to the delay between pressing the accelerator and feeling the. Turbochargers take a moment to spool up, meaning the boost they provide is not instantly available. Turbochargers generate a lot of heat, and use more of your engine’s oil. Typically, six and eight-cylinder engines have superior low RPM torque.

However, even a layperson (like myself) would suspect that six cylinders under a moderate workload will prove more durable than four cylinders under an extreme workload. But, in the past, turbocharged engines have proven just as reliable as other engines – if we presume two things.

As a disclaimer: this applies mostly to older turbos.

First, we must presume that the turbo was factory-installed or, at least, that the engine was tuned to accommodate a turbo. Aftermarket turbochargers will put strain on engines not built to accommodate the extra power. Plus we can assume (profiling) that anyone who installs an aftermarket turbocharger won’t have driven the vehicle very… sensibly.

Secondly, we must presume that the previous owner maintained it properly. The most important parts of turbo maintenance are frequent oil changes. Turbos get hot – very hot. And they rely on engine oil to cool down and to lubricate. If you’re low on engine oil, your turbo will suffer. You should also wait a few moments after starting your vehicle before driving off. It takes time for oil to reach your turbocharger and to reach the appropriate temperature. In winter, it can take a very long time for this time to happen. If you just turn your vehicle on and drive, your turbocharger is not long for this world. At the very least, drive gently after starting it up.

The same goes for shutdown. Your turbocharger continues to spin when you stop. Once you park, you need to wait for it slow down (and cool down) before switching the engine off. Otherwise, oil coking will destroy your turbo. So, unless you specifically know that your vehicle continues to circulate oil after you switch the engine off, you need to idle for a few minutes.

The Turbo Myth (?)

However, you can ignore most of those warnings if your turbocharger features liquid cooling, like the EcoBoost series (and most new turbochargers). EcoBoost engines do not need to cool down before you switch the engine off. Presumably, these innovations turn the lifespan problems of turbochargers into myth. However, that does not resolve the problem of putting more strain on fewer cylinders. Intuitively, a turbo four generating the same horsepower and torque as a V6 won’t last as long because of the increased strain on fewer cylinder. However, only time will tell if that is true.

Here to Stay

In the short-term, you better get used to turbocharged engines. They’re smaller, have better fuel economy, and they sound cool in marketing brochures. Tons of automakers are ditching V6s for turbo fours. You’ll find them in larger sedans and even SUVs.

Not Here to Stay

Then again, the world has stuck a bullseye squarely on the internal combustion engine. Within 20 years, we’ll all be driving electric vehicles (yeah, even you, truck drivers). So, we won’t really have to worry about the merits of turbochargers vs V6s (vs. superchargers).

What do you prefer: a naturally aspirated V6 or a turbocharged four-cylinder?

Posted in How To, Service & Parts