I was going to local rally in the vectra at the week end and i slowed down coming to a roundabout but when i gave her the boot it let this loud noice out of it and lost all power i looked in my rear view mirror and the road was covered in white smoke! I was thinking it mite be the turbo but what was the bang noise! I turned the car off tryed to start it again and an awful rattle sound came from under the bonnet! Not good! I got it remapped 2weeks ago i was thinking would this have anything to do with it either?