Around the world, around the clock, Garrett Motion turbochargers are boosting millions of cars, vans and trucks. It’s a technology synonymous with fuel efficiency, performance and emissions reduction and it’s an essential component of powertrain design, whether for gasoline, diesel or hybrid engines.
There are two distinct stages involved in turbocharging. There’s a turbine stage, which harnesses energy from waste exhaust gases. And there’s a compressor stage, driven by the turbine, which draws in ambient air, compresses it and forces it into the combustion process.
Why is this important? Because forcing higher pressure oxygen into the combustion process creates more efficient burning of fuel and improved torque. The result is more power, cleaner emissions, enhanced fuel economy and reduced the pumping losses, offering all-around better performance.
Turbos are extremely complex machines running at very high speeds – up to 300,000 rpm – for maximum efficiency. When operating at full speed, any single point on the circumference of the wheel is traveling at over 1900 kilometers per hour.
Garrett’s leadership in turbo design creates significant value for car manufacturers and owners – and also for the garages and mechanics involved in explaining turbo replacement cost and complexity to their customers.
Each Garrett turbo is perfectly matched to a specific engine range – and there’s a model for just about every mainstream vehicle make and model. In fact, there are about 8,000 OE-grade service replacement models in the Garrett Aftermarket line-up, covering both diesel and gasoline powertrains.
In service replacement, demand is mostly for Classic or single turbochargers (rather than two-stage models). As previously mentioned, these come in lots of different sizes and specifications, with larger turbos producing more power and smaller turbos reaching full pressure faster.
Where the turbo is located in the engine bay will depend on a number of factors, such as engine design, but generally they will be packaged as close to the exhaust manifold as possible.
One thing that should always be remembered by garages and mechanics is that Garrett turbos are guaranteed to deliver the exact same quality and performance as the original part. Beware poor quality copies that can cause significant engine damage.
Wastegate technology is used to prevent turbochargers from over-speeding and over-boosting the engine. These turbos are simple in design and architecture but are very effective in controlling boost pressure by using an actuator to open a valve that allows exhaust gas to bypass the turbine.
This is a established technology that can be found on multiple engine platforms. These turbos are proven to help to improve engine performance and today account for around 20% of the turbo replacement market.
Wastegates effectively have one setting, and although extremely reliable they are not as responsive (turbo lag) as other turbo technologies in optimizing performance across the entire engine map.
Variable geometry turbine technology is much more complex than wastegate technology. Here, the turbocharger is designed to maximize boost across the entire engine operating range, significantly improving responsiveness and driveability.
This architecture uses complex precision variable vane technology controlled by pressure, vacuum, or electronic actuators linked to the engine management system.
Due to their inherent complexity, these turbos cannot reliably be repaired, so manufacturers do not supply replacement components.
Variable Nozzle Turbine (VNT™) is a groundbreaking technology developed by Garrett that has helped transform the ability of automakers to optimize performance while helping improve fuel efficiency and reduce engine-out emissions. In VNT™ turbos, a row of vanes moves to match the exact boost requirements of the engine, contributing to higher torque levels, better acceleration through improved transient response and cleaner combustion.
VNT™ technology comes in a mono setup and while the majority of VNT applications that will be seen in service replacements are for diesel engines in the 1.4L to 2.0L range, the architecture is also heavily specified in the premium 3.0L V6 diesel segment.
Garrett Variable Geometry Turbo (VNT™) is a key variable geometry turbo technology for auto manufacturers as they seek to enhance light vehicle driveability, improve fuel efficiency and reduce emissions.
A VNT Turbo is meant to improve the performance and efficiency of an engine. A standard turbocharger for example consists of a turbine and a compressor, which are linked by a shaft. The turbine is driven by exhaust gases from the engine, which causes the compressor to spin and compress air, which then goes to the engine.
A VNT, on the other hand, uses a turbine with adjustable blades that can shift the angle in response to the changes in exhaust gas flow. This process allows the turbo to operate more efficiently at different engine speeds and loads, providing better performance and fuel economy. A technology like this makes VNT a popular choice for many modern vehicles, especially for high performance or efficiency.
Such is the success of this innovation that today there are more than 50 million VNT™ turbos in operation around the world.
With various models, Two Stage turbo set-ups are typically chosen by auto manufacturers either to deliver engine downsizing auto manufacturers typically choose two-stage turbo set-ups to deliver engine downsizing or to uprate performance, typically for diesel engines in the 1.6L to 3.0L range.
In a Two Stage Serial system, a small high-pressure turbo works together with a larger low-pressure turbo, with the gas flow between the turbos controlled using by-pass valves linked to engine speed.
At low-speed – up to about 1500rpm – the two turbos work in full serial mode, with the compressor and turbine by-pass valves closed, providing a rapid ramp-up of boost pressure. Beyond 1500rpm, the turbos continue to work together until a full transition to the low-pressure turbo takes place, usually around 2,800rpm.
Mainly with diesel applications, types of turbos such as Two Stage have a home on the biggest automotive manufacturers, especially high end producers:
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