this is more curiosity than a problem to solve

I have a car with no cats, a cam with not a ton of overlap, etc. a fairly mild build, but all emissions removed.

I've confirmed that I don't have a blown head gasket (plug read, press test, and test strip for combustion byproducts in coolant... plus I'm only down 50ml after 10,000km) or burning oil, and my nb afr is within a good range

but I have very thick white smoke going on, that smells like chemicals n fuel. its worst at idle, and persists with a warm car, even if the ambient temperature is high.

I can reduce it by messing with timing but not by much. Im currently running 24 degrees @ idle, 900rpm.

if I'm in traffic with a bunch of cars on a cold day, i'm definitely producing way more steam than anyone else.

my understanding is that the byproduct of fairly good combustion can be quite a bit of water, and if egt is abnormal, things can pretty steamy, egt being a function of incomplete combustion reacting in the exhaust, and/or afr.

what I want is a chemistry lesson on what's going on with this steam, or any other theories.