Originally Posted by Nixlimited

Quick question to my TT compatriots. My system, as below, uses the HTA2868 turbos and I have no cats and a 2.5" FI exhaust. My engine is also fairly fresh--just 5100 miles.

I am getting some fairly substantial blue smoke at times while driving the car. I assume by color and smell, that it is oil being burned. It seems to happen mostly when slowing down while in gear (i.e. while pulling a lot of vacuum) and seems to be more prevalent when the car is cold than warm, though today it happened after a quick jaunt in traffic with the car completely warmed up and very little boost. It's never happened when I start the car up, and it doesn't happen when the car idles. I also assume the amount of smoke may be a bit misleading due to the vacuum trap behind the car while it is moving causing it to build up.

I know to some extent, having no cats and such, I will get less refined exhaust gas. I have dealt with that before. However, I am concerned about the source of the oil being burnt. If it only happened when cold, I would think, maybe blowby as things warm up. But I am also curious whether I may have a bad turbo seal.

In any event, I was hoping to see whether anyone running TTs and no cats has similar experience. If not, then I may have an issue unique to my car. If so, then I may need to just consider some downstream cats and catch-cans.