Diesel - why clouds of black smoke?

andygb

I am just asking this, because we own a seven year old 1.9D Octavia, and as I watched the missus leave for work this morning, I realised that there was something missing - clouds of black smoke - even a hint of smoke.
So why do I see even relatively new cars, of reputable make, churn out a cloud of black filth when they pull away or accelerate?
There is nothing like this with ours, and we are both quite spirited with it, so what is happening with the other cars?

Iceweasel

I'll ask only one question before I make any comment.

What brand of diesel do you use?

Herzlos

It's something VAG diesels seem to do; I assume they just overfuel on high throttle to get power. Either that or it's just blowing all the soot build up out of the exhaust system.

andygb

Iceweasel wrote: »

I'll ask only one question before I make any comment.

What brand of diesel do you use?

In the UK (98% of the time), bog standard Sainsbury's diesel, and on the Continent, anything which the cheapest supermarket can supply.
I have done over 25K miles in the car (it is coming up for 120K), and it is smooth, quiet, powerful for its size, and returns over 50MPG regularly.

Why?

andygb

Herzlos wrote: »

It's something VAG diesels seem to do; I assume they just overfuel on high throttle to get power. Either that or it's just blowing all the soot build up out of the exhaust system.

I don't think you understand - our car is NOT chucking out any dark smoke.;)

WTFH

I'm not sure how many diesel cars you see on the roads, but maybe the only time you see cars you think are diesel is when you see black smoke.
If you consider that 50% of new car sales in the UK are diesel cars, it's no longer a tiny minority.

Most modern diesels do not chuck out loads of smoke unless they are doing a DPF regen or there is a problem with them.
It's not about the brand of fuel.
The other alternative answer is that you are looking at cars where the owners have decided to remove (or drill out) the DPF. (normally done by silly little boys who put loud stereos in their cars and have low profile tyres to add to the background noise)

I should add that I drive an Alfa diesel and my wife drives a VW diesel. Neither car chucks out clouds of black smoke.

andygb

Maybe I should have made it clearer - why is our car running so clean?

WTFH

andygb wrote: »

Maybe I should have made it clearer - why is our car running so clean?

Likewise - must be something wrong with ours too!

andygb

WTFH wrote: »

I'm not sure how many diesel cars you see on the roads, but maybe the only time you see cars you think are diesel is when you see black smoke.
If you consider that 50% of new car sales in the UK are diesel cars, it's no longer a tiny minority.

After 35 years driving, and owning over thirty cars, I think I know what a diesel is;)

andygb

WTFH wrote: »

I should add that I drive an Alfa diesel and my wife drives a VW diesel. Neither car chucks out clouds of black smoke.

There seem to be an awful lot around my area which do, and I always seem to be behind them when the "death smog" is released:eek:

Iceweasel

I asked because at work we have had an ongoing discussion (quite heated at times) regards cheapy supermarket diesel causing smoke.

We agreed that Morrisons is the worst.

Sainsbury actually would be the odd one out among the supermarkets in that some of them actually tell you who their supplier is. Often it's BP.

A while back when Tesco had an offer where you could get several discounts off fuel, Mrs Iceweasel had accumulated enough vouchers to get 50p off per litre.

Even I couldn't pass that one up - but the car - a 2004 Freelander - did smoke a bit more than normal.

In our BMW we normally use Shell V-Power or similar from other brands, but I'm struggling to justify it.

I'm keeping an accurate fuel record to see if we get any better mpg.

Unlike the Freelander, the BMW never produces smoke - even on the cheapy diesel from Carrefour in France.

Possibly it's due to the Diesel Particulate Filter which the Freelander doesn't have.