Effect of 2-stroke in DI?

[JHZR2]

Yeah, it really isnt soot in the sense of the typical black ring you sometimes see. This is an oily trail... And Ive used zero oil.

Im thinking that the oil is not volatile enough to combust when directly injected. When put in a non-DI engine, it hits a hot valve face and can pick up some extra heat, but in the DI application is just right there and doesnt combust.

Ive seen oil out the exhaust of small 2-stroke engines, why would it be any different here?

 

[sunfire]

Out of curiosity I looked up the flash point of both. Saber actually has a slightly lower flash point. Which may or may not effect how quickly the oil burns.

Amsoil Saber
Flash Point °C (°F) (ASTM D-92) 114 (237)
Fire Point °C (°F) (ASTM D-92) 114 (237)

SI-1
FLASH POINT: 250°F (121°C)

 

[severach]

In MI and PA you won't find many carbon free pipes. Even very new cars can have carbon. Down in Louisiana soot is harder to find. The tools aren't any sharper so I'd say the problem is that the additive level isn't sufficient for the cold weather. Boosting the add pack clears up the carbon. From my parking lot scans I'd say that 80% of northern pipes and 20% of southern pipes are sooty.

I'm driving a 2006 Chevy Cobalt 2.2L gasoline DI. No clatter! The engine is smooth as silk. Coming from a Buick Roadmaster the body seems like a kick-the-can contest.

 

[UG_Passat]

The Cobalt 2.2L motor is not DI.

 

[severach]

My mistake. I expected it to be DI with as much trouble as they took to put the injectors in the head.

 

[zyxelenator]

Hmm, new 2010 mini copper s (it is like 5.5k miles on it) also has same oily pipe. I think I even saw it drip there(Oil or oily water). Not sure is it DI or not,but it is twin scroll turbo. Or maybe it is heavy oiled from factory...
It still has factory fill, want to change oil and filter there.