The Benefits of Diesel VGT Turbochargers Compared to Wastegate Turbos

Diesel Engine Variable Geometry Turbocharger | Highway & Heavy Parts


There are some great benefits to using a VGT turbocharger in your diesel engine that you might be unaware of. With all of the turbocharger options out there, why pay more for a variable geometry turbo?

The key to experiencing the many benefits these turbos have to offer is to make sure you're purchasing quality parts and maintaining them. You can think of maintaining your engine the same way you need to maintain your body. Sure, it takes motivation, but regular maintenance is a good thing in the long run!

We spent time analyzing turbochargers from our vendors until we found products that meet our strict specifications.

Read on to learn the benefits these turbos provide!

Looking to upgrade your turbocharger? Talk to our ASE Certified Technicians!

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What are the Benefits of Variable Geometry Turbochargers (VGT)?

Variable geometry turbos do not have a wastegate to regulate exhaust flow. The need for a wastegated turbo is to balance the air fuel ratio. Having a wastegate lets the turbocharger act like a big turbo at low RPM, and a standard size turbo at higher RPM. This has worked well in the past, however as emission requirements have become stricter, the wastegate is not a precise enough mechanism to achieve this level of performance. You can find additional details in our blog, How Does a Wastegate Work on a Diesel Engine Turbo?

So, how did the Variable Geometry Turbocharger create the solution to this?

Diesel Engine VGT Turbocharger Vanes | Highway & Heavy Parts

The variable geometry turbocharger introduced a technology inside the turbo called vanes. These vanes are located around the turbine and are controlled by an actuator. At low RPMs, the actuator tells the vanes to stay tightly folded so air can't flow through as easily. We mentioned the air-to-fuel ratio earlier; the main function of the turbocharger is to control the air-to-fuel ratio to the engine. As RPMs start increasing, the vanes begin to open up, allowing more air to enter the engine to satisfy the ratio. You can maximize the boost your turbo provides at a much greater RPM range because of the adjusting vanes. After all, the more air and fuel going into the engine, the more horsepower.

Key features of VGTs:

  • Improved low speed torque reducing turbo lag
  • Maximum torque and horsepower for the entire RPM range
  • Better air-to-fuel ratio
  • Much cleaner burning engine better for the environment
  • Vanes regulate airflow more accurately providing adequate boost


How do VGT Turbos Affect the Air-to-Fuel Ratio?

Diesel Turbocharger Air Flow Diagram | Highway & Heavy Parts

The main function of the turbocharger is to control the air-to-fuel ratio in your diesel engine. A wastegate can't maintain this ratio precisely enough, which is what the VGT improved upon. Having an incorrect air-to-fuel ratio means your engine doesn't combust properly, leading to smoke rolling out at low RPMs, and high exhaust temperatures. It also results in high cylinder pressure and high compressor outlet temperatures. The key to solving these issues is maintaining the right ratio.

Because the VGTs have moving vanes that adjust their size based on the amount of air needed, they're able to directly control this air-to-fuel ratio at low and high RPMs. This maximizes your boost for a much greater range.

For additional information on VGT function, check out our blog, How Does a Variable Geometry Turbocharger Work in Diesel Engines.


Where can I purchase Quality VGTs for my Diesel Engine?

At HHP, we offer the best aftermarket VGT turbochargers available. Each turbo is built to strict OEM specifications, ensuring proper fit and function in your diesel engine. Not only that, you'll save up to 50% off OEM prices by shopping with HHP!

We offer a variety of VGT turbos including:

  • Long Turbos
  • Short Turbos
  • Cartridges
  • Actuators

We've picked some of our favorite VGT turbochargers to highlight below, you won't find better quality for the price anywhere else.


If you're considering purchasing a turbocharger, our ASE Certified Technicians can help you find the perfect match! Give us a call at 844-304-7688, or request a quote online!

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