Turbochargers: A General Guide


It makes your engine more powerful and it helps with efficiency. Your turbocharger helps increase the power of your engine without the need to increase its size. Its goal is to get air efficiently into the combustion chamber to increase the engine’s output. But there’s a lot more to turbochargers than that! This post will take you through some of the basics of diesel engine turbochargers and their role in your engine.


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How does a turbocharger work?

As we mentioned, a turbocharger works to get more air into the combustion chamber to help increase the power of the engine. It accomplishes this by utilizing the exhaust gas, an otherwise wasted source of power, and turning it back into energy to power the turbine.

More specifically, the process begins with gas being pulled into the turbo. It spins the turbine and then exits the housing through an exhaust outlet. Attached to the turbine by a steel shaft is a compressor wheel. As the turbine spins, the compressor wheel spins as well. This pulls air into the compressor, where it is compressed. This makes the air much more dense, and it raises its temperature. The air then goes through a charge air cooler, which cools it down and makes the air even more dense. This extremely dense air then goes to into the engine itself. The engine then burns more fuel and produces more power.

That is just the technical way of saying that a turbocharger takes wasted energy and turns it into something you care about—power for your engine.


VGT and non-VGT

While there are different types of turbochargers, two categories often come up for debate—Variable Geometry Turbos (VGTs) and non-Variable Geometry Turbos. The turbines on a VGT has vanes that move in accordance with the requirements of the engine. They can either pivot or slide, depending on the manufacturer.

When the vanes change position, the geometry of the housing changes as well (that’s where the name comes from). This in turn affects how fast the turbine spins, changing the speed of the air that passes into the compression chamber. With a VGT, the vanes can be adjusted to the ideal setting for your engine model, giving you the best balance of power and efficiency.

A VGT can help control emissions for your engine, helping to keep it in line with EPA guidelines. Because it and the EGR system work together, the air speed can be completely controlled, allowing for Diesel Particulate Filter regeneration, which calls for precise air speed.

VGTs have many advantages, allowing for more power in the engine, reducing turbo lag, and increasing efficiency. Yet there are reasons why people are still hesitant to purchase a VGT. First, depending on your engine type, you may not be able to get one to install. You also can’t convert a VGT engine to be non-VGT, because it’s illegal under current regulations. If you were to do so, service shops will refuse to work on your engine.

More than that, VGTs are more expensive than their non-VGT counterpart, and they are more prone to fail sooner. This is due to the increase in components in a VGT, which creates more opportunities for failure. For additional information on VGTs, check out our other blog post.


Turbo Maintenance

To keep your engine running with the power you want, it's vital to keep your turbo in tip-top shape. This will also save you some costly repairs. We touch on this briefly in another blog, but here are a few things you can do to help keep everything running smoothly.

One of the most important things you should do is change your oil. Clean oil is vital to lubricating your turbo and keeping it running properly. Because of the speed of turbine, dirty oil can really do some damage to your turbo. Without proper lubrication, there could be metal on metal contact, which could lead to a complete turbo failure. Make sure you're using the right kind of oil for your engine to prevent any additional problems.

Similarly, make sure your air filter is clean. A dirty air filter allows for dirt and debris to enter your system, creating more engine problems. Make sure you replace your filters at the recommended intervals to help prevent this buildup of soot and debris.

Proper operating practices can help save your turbo as well. Accelerating too quickly can put a large strain on your turbo, and doing this too often can lead to premature failure.

Like with most things, proper care can go a long way. Doing these few little things can help make your turbo last for miles to come.


Common Turbo Problems

Despite your best efforts, sometimes failures still occur. Here are some common problems you might experience with your turbocharger:


Leaks can occur on both the compressor and turbine side of the turbo. On the compressor side, these can be caused by a plugged air cleaner or excessive crankcase pressure. A leak on the turbine side can also be caused by excessive crankcase pressure, but restrictions in the drainline or a valve guide seal or piston ring failure could cause this as well. You might also notice a whistling noise that could point to a leak in the turbo system.

Other Turbo Problems

Sometimes a foreign object can get into your turbo and damage the components like the compressor wheel. Bearing failure can also damage the compressor wheel. Carbon buildup can lead to a damaged turbine wheel, as can bearing failure or a failure in another part of the engine. Make sure that not only are you replacing all damaged parts to address the turbo failure, but that you're also diagnosing the overall failure that caused the damage to avoid having the problem happen again. It'd be unfortunate to replace or repair a bunch of parts only to have the turbo problems happen again.


Still have questions about your turbo? Or maybe another part of your diesel engine? Our certified technicians can get you answers! Give 'em a call at 844-304-7688. Or, request a quote online.

Originally Posted February 14, 2019; Edited July 29, 2019