Comment by mr_toad

7 hours ago

For every car enthusiast there are probably a hundred poorly maintained vehicles on the road. Black smoke is likely soot, and white smoke is almost certainly an oil leak.

Oil in the exhaust in quantities high enough to produce acrid white smoke is extremely common on a number of ICE engines, like blown head gaskets on E25s (found in most Subarus before their Toyota involvement in 2010) for example