What is a variable geometry turbo
A variable geometry turbo is a conventional turbo (an exhaust turbine that uses the engine exhaust gases to rotate a compressor wheel which creates air pressure) but has a variable valve system for the regulation of the speed of its gas turbine, thus for the direct regulation of its boost pressure.
The advantage of regulating the turbine with this system is to be able to control it at a much higher engine speed range than with a conventional system (wastegate). We can create a boost pressure at low engine speed, and maintain it up to high engine speed, in addition to having a much more precise control at all times.
The opening of the wastegate is controlled by a valve (also called actuator or "wastegate") which, through the vacuum it receives, allows it to move and move the position of the variable geometry. The most modern turbochargers are controlled by 100% electric actuators, which make them even more reactive and precise when adjusting the turbo's work at all times.
The advantage of regulating the turbine with this system is to be able to control it at a much higher engine speed range than with a conventional system (wastegate). We can create a boost pressure at low engine speed, and maintain it up to high engine speed, in addition to having a much more precise control at all times.
The opening of the wastegate is controlled by a valve (also called actuator or "wastegate") which, through the vacuum it receives, allows it to move and move the position of the variable geometry. The most modern turbochargers are controlled by 100% electric actuators, which make them even more reactive and precise when adjusting the turbo's work at all times.
This system has many advantages mentioned above, but it should be noted that it is also a source of breakdowns in the vehicle since the geometries, with the remains of combustion such as carbon, can seize and leave the turbo unable to regulate properly, causing engine failures type P0299 / P2563 / P2565 / P0234 / P0328, which are all failures indicating a bad positioning of the actuator rod and / or a lack of pressure or overpressure in the intake manifold.