Steam from exhaust...Why do some cars have more than others?

[kentmotorcompany]

Petrols seem to have a lot more than diesels and Japanese cars seem to expel more than anything else. Why?

And why do they have more when they're cold?

[Willy Nilly]

it is likely that the larger the volume of the exhaust system the more steam comes out.

[wolves_wanderer]

Ive no idea but the RX8 absolutely torrents it out.

[ukzz4iroc]

Yes, my BMW is far worst than most others.

[BrownBottle]

kentmotorcompany said:

Petrols seem to have a lot more than diesels and Japanese cars seem to expel more than anything else. Why?

And why do they have more when they're cold?

I think it's just condensation that builds up in the exhaust system when it's cooling down.

[InfoRetrieval]

(Being pedantic - it's not steam it's water vapour. Steam is invisible )

In colder weather more of the water condenses out of the exhaust gases so its more visible.

[22Rgt]

And if its a Rover K series it'll pour out the exhaust as quick as you can fill the header tank..

[MrsF]

Noticed this a lot on Fiat 500's with the twinair engine fitted.

[williredale]

I thought mine was bad one morning until I pulled up behind an XKR.

It was just a portable fog machine.

[pimpchez]

My MPS is really bad for this , just seems to collect the water when its cooling down

[Jimmy No Hands]

The Corrado is bad for this, absolutely chucks it out when its cold, fine after 10 minutes.

[TinyCappo]

wolves_wanderer said:

Ive no idea but the RX8 absolutely torrents it out.

Secondary air injection system will really not be helping that at all. Also the half an oil drum that is the rear silencer on an RX8 holds a huge amount of condensation as well.

[V8covin]

Every car I've ever owned seems worse than everyone elses lol

[northwest monkey]

williredale said:

I thought mine was bad one morning until I pulled up behind an XKR.

It was just a portable fog machine.

I used to have a 2.5 V6 X-type which was a bit like this (twin exhausts). Sat stationary in the freezing cold you couldn't see the car behind you!

[carpetsoiler]

My car loves chucking out tonnes of water vapour, especially in cold weather. Big, fat, slightly inefficient straight six- lots of cylinders, valves, cubic capacity and whatnot for the supercooling effect to cause ample amounts of condensation in the engine.

[Benbay001]

williredale said:

I thought mine was bad one morning until I pulled up behind an XKR.

It was just a portable fog machine.

"They all do that, sir"

When i clicked on this thread i was thinking of my old S Type R

[amstrange1]

InfoRetrieval said:

(Being pedantic - it's not steam it's water vapour. Steam is invisible )

Someone watched QI this week!

[Riknos]

My S2000 does a lot, constantly, even when the engine is up to temp.

My old GT4 with it's big bore exhaust, freezing cold morning, starting up and reversing off the drive.. I would literally be sat in a massive cloud, unable to see out the windows. I found it fun

[rufusgti]

my 325i is really bad for at least ten minutes

[B'stard Child]

22Rgt said:

And if its a Rover K series it'll pour out the exhaust as quick as you can fill the header tank..

Boring
Predictable

Try next time with 335d mapped or MX5