If you were to pull apart your Variable Geometry Turbo from your Cummins you’d find a steel ring attached to a bunch of fins (or vanes as they’re called in the automotive world).

This probably isn’t how the engineers would explain a VGT, but you get the idea. Even though it’s the same amount of water coming out, you’ve created a lot more force by controlling the size of the opening. Put your finger over the end of the hose, and you can get it to shoot halfway across your lawn. Think of it like a garden hose, when the tap is all the way on, the water shoots out the hose a couple of feet but that’s it. VGT is offered in all-new diesel pickups, and each manufacturer controls their turbo in their own way, but the common function is to control the exhaust housing size, which in turn will control how much exhaust pressure is forced to turn the turbine wheel of the turbocharger. We get countless calls about Cummins VGT failure, and usually, the first sign you’re going to notice is that you’ll suddenly have no exhaust brake. However, the downside to this turbo is a common failure that the turbo sees. A VGT turbo has many advantages such as a decrease in turbo lag while taking off from a stop, integrated exhaust braking, and infinite adjustment to load demand while driving. This was the first Cummins in the pickup line to offer a Variable Geometry Turbocharger (VGT). The 6.7L Cummins engine was first introduced halfway through 2007 in the Dodge Ram Heavy Duty Pickups.

5.9 cummins rear main seal towing