Had nothing to do with this type of turbo up until last week, had a Galaxy TDI in at work which, if used at WOT for longer than 0.5mile would go into a limp home mode until the ignition was cycled from off back to run. Checked the DTCs and it threw up a code relating to excess boost pressure, using datalogger on our diagnostic machine we can monitor the boost pressure, which was spiking over 36 psi 2.1 (32psi) bar max according to the spec... Checked out all the relevant pipework and control valve and only thing left was to look at the Turbo itself. Huh,where's the wastegate?? It's got a flap arrangement inside which a steel ring actuates to regulate the boost, this was rusted into the housing !!!which accounted for the overboost situation. As this was a car which boss has been trying to sell for the last few months, he didn't want to fork out for a new unit, so a quick GVK clean up of the rusty housing and the Turbo was back on the car Road test time, boost holding at about 30psi no lack of power,no DTCs,result! Top bodging Some blerb on VVTs Edited by: G_V_K
there's a few different types of variable geometry turbo's - variable vane and variable nozzle to name but two. wait until the variable geometry compressors come out tt
variable geometry? what changes? pitch on the blades like a outboard motor kind of thing? [hey techie eh!]
Variable geometry turbochargers have more complex functions to carry out, balancing the pressure between the intake manifold and exhaust manifold ensuring flow into the intake system at all times is relevant to optimum EGR operation. They are also useful for engine braking to be applied when needed. hmmmmmmm one on a 228mph truck
Defo complex bit of kit. They can stick due to lack of use i.e. not revved enuff! The vanes seize thus overboosting.
