Having to top up the oil reguler, when the cars cruising along the by.pass, it runs fine, but when I get to the roundabout, blip the throttle and theres loads of blue smoke out of the excaust. thought it was the turbo, but fitted a new one, stage one, and its still the same, could it be valve stem seals, rings? New to the cossie world so anyhelp well appreciated, hope its not rebuild time.