White exhaust vapour?

[Futuramic]

No I haven't blown my head gasket, but I have a question so socially unacceptable that the dark caves of here are the ideal place to broach it.With winter upon us cars, such as mine, are producing impressive plumes of white vapour from their exhaust pipes in the cold morning air. I think this looks cool; and quite enjoy trailing a decent cumulus cloud on my way to work. I understand the scientific principles behind this phenomenon; basically the water produced in the combustion of petrol condenses as it moves down the cold exhaust pipe and is emitted as visible vapour.Great, but why do different cars seem to produce hugely varying amounts of the stuff? My Bluebird could never be persuaded to steam, even idling on a sub-freezing day produced barely a glimpse of white smoke; whereas my Orion would make James Bond envious by spewing forth a dense fog from mid September to early May.I wondered if exhaust cats made a difference. During my brief Xantia interlde, I again saw very little smoke; in fact none at all when the engine was warm. However the Mondeo obscures all behind it with luxuriant, white clouds. Maybe engine design is responsible? It would seem not as I have seen Bluebirds with he same engine as I had steaming like the Titanic. Does anyone have a definitive answer?

[55bloke]

Doesn't this only happen 'til the engine warms up? I always thought it was water-vapour rather than smoke.

[pompei]

My CRX did this in all weathers during the 8 years I owned it - it was a common thing according to those on the forum. I don't know if this is connected but some cars also seem to produce lots of water (not even vapour) from the exhaust - Rover 214s spring to mind.

[j-j]

I'm sure this is a cold start thing too. Tho I also thought that post catalyst cars somehow didn't steam but maybe not. Diesels possibly don't do the white steam so much as the black smog when they're cold maybe?My LPG fired car seems to produce very little visible outputs - a bit of steam from the tail pipe when cold but running the same car on patrol it doesn't half bring in the overcast

[seth]

Probablt related to exhaust pipe design and wether there are places for condensation to collect that is then evaporated by the warm/hot exhaust on start up.

[STUNO]

Has most to do with exhaust design and how far you drive every day . A hot exhaust will have very little vapour in it.And that is MY scientific explaination.

[Milford Cubicle]

My Subaru Justy used to puff out loads until it warmed up, even in the summer.

[pogweasel]

Yes, exhaust design, shape etc. My BMW has a pipe that encourages everything to go 'up', meaning a total white-out upon first setting off each morning.