Water vapour

[Joanne3]

Whilst attempting to fix my air suspension , I had the engine running to re-inflate the rear air spring and so was watching the water vapour coming out of the exhaust form a little puddle on the driveway.

So I wondered, how much water does burning LPG produce?, more or less than petrol?, is the amount of water vapour indicate how well or badly the system is tuned?

(I also thought about how much water you could pump through a broken head gasket as well ... but then I was having a bad day )

Joanne

[stype3]

Hi Joanne,
water is one of three main compounds from burning LPG or petrol, the other two being carbon dioxide and carbon monoxide. If you run rich, then you get more carbon monoxide, and in theory more power, but worse fuel economy. If you run lean you get less carbon monoxide, but your engine will run hotter, and you will get more oxides of nitrogen.

With LPG you can expect very slightly more water, than with petrol.
(LPG should give 72g water for 44g fuel, petrol should give 162g water for 106g fuel, assuming LPG is pure propane and petrol Octane)
Once the engine and exhaust system are warmed up, you should not find water vapour condensing from your exhaust

[Gilbertd]

It's quite noticeable in the winter. Running on gas gives much more steam out of the exhaust than running on petrol.

[Joanne3]

Thanks for the replies, very informative. I suspose all this hot water vapour is why my exhausts end up rusty with holes in them ...

It's quite noticeable in the winter. Running on gas gives much more steam out of the exhaust than running on petrol.

I had noticed this, but forgotten all about it since the arrival of nice hot spring weather

Once the engine and exhaust system are warmed up, you should not find water vapour condensing from your exhaust

Yes, I had started the engine from cold and had not driven away as usual, otherwise I probably wouldn't have noticed.

Joanne

[lpg-cars]

It's quite noticeable in the winter. Running on gas gives much more steam out of the exhaust than running on petrol.

And water is much much healthier than soot. Can't understand why European govenrmnents think Diesel is better for the environment.

They will realise one day and then they will tax the hell out of the devils fuel.

[SimonHobson]

Thanks for the replies, very informative. I suspose all this hot water vapour is why my exhausts end up rusty with holes in them ...

Yup, especially since it's acidic as well (from the various "stuff" produced in the combustion process). The front end tends to do OK as it gets hot and dries out fairly quickly. But down at the back you need quite a journey at reasonable power to dry it out - and on short journeys you just never will. You can tell a car that only does short journeys - it dribbles water out the exhaust as it pulls away from junctions and the water sloshes about in the boxes

[Gilbertd]

More importantly, did you fix the air suspension?

[Joanne3]

Dear Gilbertd,

I didn't notice your reply to this thread at the time, so please accept my apologies for being one year and six months late ... but I did fix the LH air spring and now I just replaced the other one !

Joanne

[Gilbertd]

Just noticed, Stratford? I bet you had fun during the summer! Although I live in Peterborough, 2 weeks in 3 I work out of an office in Canning Town (Cody Road Industrial estate). During the Olympics I was doing it every day and found the A12 and A13 at a standstill virtually all the time.

[Joanne3]

Just noticed, Stratford? I bet you had fun during the summer! Although I live in Peterborough, 2 weeks in 3 I work out of an office in Canning Town (Cody Road Industrial estate). During the Olympics I was doing it every day and found the A12 and A13 at a standstill virtually all the time.

We had it lucky with traffic during the games, we were expecting total grid lock, but for us it was quieter than normal

We did avoid the A12/A13 and the Blackwall tunnel, but the A11 & Central London were pretty quiet.

Joanne

[SimonHobson]

I saw that complaint on the news - businesses were "unhappy" because everyone saw the warnings about it being total gridlock and stayed away, so instead of having a boost, many saw a drop in turnover.

[Gilbertd]

It was all a bit strange actually. I normally get down there around 10 (a combination of an intense dislike for early mornings and an 84 mile drive) but our hours were altered so I didn't need to be there until 11. The first couple of days were total chaos as nobody knew where they were going but after that it settled down. The main routes to the Olympic venues were pretty solid with a combination of increased traffic that didn't know where it was supposed to be going and a reduced number of lanes so they could introduce the Olympic vehicle only lanes. But side roads were empty. I found the A124 Barking road empty every day even though it runs parallel to the A13 which was jammed. Our vehicles had permission to use the Olympic lanes but most of the time we didn't bother as the 'pleb' lanes (as they became known) were clear except in the immediate vicinity of Olympic Park. The best bit was driving past the Olympic Stadium on the A12 just as the fireworks went off for the opening ceremony. I now know what WW2 pilots felt like when somebody opened up with anti-aircraft fire!