Quote Originally Posted by blower View Post
Outside of the cat pre-heat (which only occurs if the engine is between 20c and 30c on startup), mine runs ok. It's ever so slightly rougher for the first 20 seconds or so, but i'm only talking slightly - as what you thought, I put this down to the piston's being cold, since they are designed to expand a bit when at operating temperature.

When you say the compressor is wining - are you referring to the supercharger during warm-up idle, or the turbo?
Yeah, it's not a horrible idle but its ever so slightly lumpy and then goes away really quickly. And yeah I am talking about the supercharger warming up at idle.