What's the most common cause for this? It got worse after a trackday, and is supposedly dribbling oil out of the MBC now.....

Stuffed rings? Owner says car still runs OK, but with a .25 bar held boost fluctuation (probably caused by the oil in the controller). What else would cause too much crankcase or cam area pressure?

Thanks
Richard

You have piston ring blow by pressurising the crank case and forcing oil vapour out of the breather and into the inlet pipe. Does the car use much oil when cruising around ?

bob

Thanks Bob,

I'm waiting for feedback on whether it's only happening 'on boost' or not.

Richard