Diesel backlash

[heebeegeetee]

ORD said:

I get the point that most car buyers dont think very deeply about the total cost of running a car, but how on Earth was anyone ever persuaded that diesel was the way to go for economy and/or the environment?

Because petrol has been so very polluting over the years. It may (or may not) be cleaner than diesel right now, but that could change at any point. The moment dpfs and Nox cats get reliable then we're back to diesel being cleaner again.

Petrol has been terribly polluting in the past. For decades petrol exhaust was one of the most efficient methods of suicide, and still is if you just use a small lawn mower or generator. Are you aware that the disappearance of football violence has been explained in some quarters as due to the removal of lead in petrol? We now have to use highly carcinogenic materials instead.

People explain away particulate emissions from petrol engines on the grounds of nothing other than they can't be seen. They completely miss the point that if they're so fine that they can't be seen then they're obviously going to remain airborne for longer and penetrate the lungs more deeply.

It's a complex issue, and it beggars belief that car enthusiasts quote abject nonsense from the daily mail as 'proof'.

Edited by heebeegeetee on Tuesday 12th August 11:28

[otolith]

daemon said:

And likewise you are allowed to change UP in a diesel car - something that a lot of petrol advocates dont seem realise - "oh oh but its all out of power at 3,500 revs"

But the comparison is always between petrols driven like diesels and diesels driven like diesels - partly because you can measure how poorly a petrol car accelerates at 2000rpm, but the manufacturers don't give you any more test cars if you start finding out how they behave at 6500rpm.

[daemon]

Matthen said:

JamesK said:

Even assuming the following:

Average price per litre of £129.75 petrol / £136.26 diesel (current national average prices)
A saving of £20,000 in fuel (the absolute minimum I can infer from your comment)
That your petrol was HALF as efficient as your diesel (25mpg / 50mpg)

You would have to do over 178,000 miles to achieve that saving.

If all that is true then well done. Yes I am bored.

I object. I paid 132 pence for a litre of diesel last week - a damn sight less than the 136 pounds you're suggesting is average. Incidentally - My diesel car returns 72 mpg @ 60 mph - the petrol equivalent returns 35... so your numbers aren't completely unrealistic.

Totally with you. If i was driving a car at 35mpg compared to my golf getting 65mpg, and fuel was 129.9 and 133.9 respectively, over the 24K miles i do, i save approx £1800 a year by driving a diesel - over 10 years thats £18,000.

Do the same miles, comparing 25 mpg and 50mpg and you would save £2750 a year, or £27,500 over 10 years (or £22,000 over 8 years)

[daemon]

otolith said:

daemon said:

And likewise you are allowed to change UP in a diesel car - something that a lot of petrol advocates dont seem realise - "oh oh but its all out of power at 3,500 revs"

But the comparison is always between petrols driven like diesels and diesels driven like diesels - partly because you can measure how poorly a petrol car accelerates at 2000rpm, but the manufacturers don't give you any more test cars if you start finding out how they behave at 6500rpm.

Yeah but in "pistonhead world", petrol advocates repeatedly talk about how when they last drove a diesel the car was gutless at high revs.

[daemon]

ORD said:

Matthen said:

JamesK said:

Even assuming the following:

Average price per litre of £129.75 petrol / £136.26 diesel (current national average prices)
A saving of £20,000 in fuel (the absolute minimum I can infer from your comment)
That your petrol was HALF as efficient as your diesel (25mpg / 50mpg)

You would have to do over 178,000 miles to achieve that saving.

If all that is true then well done. Yes I am bored.

I object. I paid 132 pence for a litre of diesel last week - a damn sight less than the 136 pounds you're suggesting is average. Incidentally - My diesel car returns 72 mpg @ 60 mph - the petrol equivalent returns 35... so your numbers aren't completely unrealistic.

I expect those numbers are closer together over a tank, though, aren't they?

I did the same run in a 320d and a Cayman S recently, driving both like a granny (except for overtaking and a few bursts of acceleration): 55mpg in the BMW, 35 mpg in the Pork.

I think a lot of the difference that most people see results from the fact that people drive fuel efficient cars in a fuel efficient way (because it's no fun no matter how you drive it), whereas it's hard to resist driving a fast petrol car like a fast petrol car. If you wanted to, though, I reckon you could push 40mpg over a tank in some pretty decent petrol cars (including NA ones).

You're forgetting however that most people doing big miles are doing so because of a commute, where you're in traffic anyway, so "spirited" driving rarely can happen.

Even IF i went for a 40mpg petrol car - and lets be honest here that is going to be a struggle to get something interesting that will do that brim to brim tank after tank - then i'd still be £1,300 better off every year in the diesel.

[g7jhp]

aeropilot said:

Censorious said:

The other downside was that it took me around an hour to walk 8 miles (I know ...I walk slow), whereas it would have taken 10 minutes by car.

One hour for 8 miles, that's hardly slow....... that's light jog, not a walk, considering that the a reasonably fit adult human is considered to be able to walk at 3 miles per hour.

An hour to walk 8 miles....

The average person probably runs a 9-10 min mile so 6-7 miles in an hour.

I'd walk circa 4 miles in an hour and run between 8-8.5 miles in an hour.

Running 8 miles in an hour (7.5min miles) is faster than a jog.

Back on topic. It's good to see a more positive stance to petrol cars as this will increase the number available.

[zeppelin101]

heebeegeetee said:

Because petrol has been so very polluting over the years. It may (or may not) be cleaner than diesel right now, but that could change at any point. The moment dpfs and Nox cats get reliable then we're back to diesel being cleaner again.

They are already very efficient. The problem with diesel particulate filters is that they have to be actively regenerated due to the cold exhaust gas - a problem that won't rear it's head on petrols due to the heat they generate when particulate filters (in the very near future) appear on petrol engines because they can passively regenerate in normal running.

SCR catalysts for NOx on diesel engines are becoming widespread on passenger cars and are very good at what they do. However, they are not as efficient in terms of cost or complexity compared with a conventional 3-way catalyst used on a petrol because - you guessed it - the heat a petrol engine can generate yields 95% + conversation rate of HCs and NOx without the need for an additional catalyst agent that needs replenishing.

heebeegeetee said:

People explain away particulate emissions from engines on the grounds of nothing other than they can't be seen. They completely miss the point that if they're so fine that they can't be seen then they're obviously going to remain airborne for longer and penetrate the lungs more deeply.

All true, but what do you do about smaller particulates? There is a trade off in engine / exhaust development between the engine actually being able to exhaust gas from a cylinder and being efficient. You cannot have both.

[C.A.R.]

People prefer diesel because it 'feels' faster.

Personally I'd love an excuse to return to petrol, but there just isn't one which makes financial sense - and that's what it all comes down to.

I'm not put off by big annual tax - moreso because of the upcoming direct-debit option which will make it less noticeable - a monthly outgoing rather than some annual bill you might not have the money available for.

But my horrid oil-burning little hatchback returns 48-55 mpg all day long, even if I rag it to death. That may be primarily because taking a diesel on a 'spirited' drive feels so wrong that you settle back into cruise mode, but nonetheless the savings are felt where it matters - in your wallet.

If they reduced the duty on petrol I'd be straight down to trade my car in, but it's not going to happen. I only do 16k per year too, I imagine it's even harder to justify for people who cover more than that.

[scubadude]

My garage this morning had both petrol and diesel at 130.9p/ltr, given that my twice as economical diesel which was only £100 more to buy than the petrol version is paying for itself with ease.
Oh and it also has 3x the torque- very handy for towing.


I find it rather hilarious people/government moaning about diesel exhaust, we've known they are more polluting since the late 1800's FFS!

[ORD]

scubadude said:

My garage this morning had both petrol and diesel at 130.9p/ltr, given that my twice as economical diesel which was only £100 more to buy than the petrol version is paying for itself with ease.
Oh and it also has 3x the torque- very handy for towing.


I find it rather hilarious people/government moaning about diesel exhaust, we've known they are more polluting since the late 1800's FFS!

So that means we should just put up with the pollution? Diesel is grossly under-taxed and a sea change is required if we want a rational system.

[heebeegeetee]

ORD said:

So that means we should just put up with the pollution? Diesel is grossly under-taxed and a sea change is required if we want a rational system.

And you need to stop believing the Daily Mail.

[p1esk]

ORD said:

scubadude said:

My garage this morning had both petrol and diesel at 130.9p/ltr, given that my twice as economical diesel which was only £100 more to buy than the petrol version is paying for itself with ease.
Oh and it also has 3x the torque- very handy for towing.


I find it rather hilarious people/government moaning about diesel exhaust, we've known they are more polluting since the late 1800's FFS!

So that means we should just put up with the pollution? Diesel is grossly under-taxed and a sea change is required if we want a rational system.

Well I haven't read all the pages here, and somebody may already have mentioned it, but one simple answer would be to abolish the current nonsensical road tax / VED regime, and adjust the tax on fuel to influence matters.

Then we wouldn't get this nonsense whereby a person who owns a relatively high polluting car, but uses it very little, pays more than somebody that has a new, lower polluting car, but covers a large annual mileage in it.

What matters here is how much pollution we are each producing, and seeing that it gets paid for on a fair basis.

[ORD]

heebeegeetee said:

And you need to stop believing the Daily Mail.

[Pan Pan]

wemorgan said:

Pan Pan said:

The ecomentalists bleat on about flying, but an airliner is just a bus with wings and possibly more efficient per passenger mile than any ground crawling bus.

But no one flies 20 miles to work. When flying you typically travel >1000 of miles. When looking at pollution per person per year then flying is quite extravagant.

The CO2 emissions from global computer use exceeds those from global aviation, does this mean we will now all stop using our computers?

[Pan Pan]

As pointed out previously, worrying about the difference between which fuel is more polluting, is a bit like worrying about which weapon might be used to kill us. It doesn't matter whether it is a bullet, and arrow, a poison dart, an axe, or even an anvil dropped on us from height the end result is exactly the same.
Try sitting in an enclosed space, with the emissions from a petrol engined truck being fed into it. Does anyone thing that the outcome will be great??
With other countries building coal fired power stations as fast as they can, does anyone really believe the difference between petrol and diesel vehicles is going to make much difference to air pollution levels in the overall scheme of things??

[daemon]

Pan Pan said:

As pointed out previously, worrying about the difference between which fuel is more polluting, is a bit like worrying about which weapon might be used to kill us. It doesn't matter whether it is a bullet, and arrow, a poison dart, an axe, or even an anvil dropped on us from height the end result is exactly the same.
Try sitting in an enclosed space, with the emissions from a petrol engined truck being fed into it. Does anyone thing that the outcome will be great??
With other countries building coal fired power stations as fast as they can, does anyone really believe the difference between petrol and diesel vehicles is going to make much difference to air pollution levels in the overall scheme of things??

+1

[celicawrc]

Seems to be alot of people on PH that like to look down their noses at people who have swapped their petrol car for a diesel.

Well i recently did just that for my daily driver. The diesel does over twice the mpg of the petrol, yet only costs £20 more to fill up. Also saves me nearly £200 a year road tax! I only cover roughly 5k miles a year, the car cost £1k.

How am i not saving by switching to diesel!? It is the gubberments fault though with the lower tax incentives.

[david_h]

Pan Pan said:

As pointed out previously, worrying about the difference between which fuel is more polluting, is a bit like worrying about which weapon might be used to kill us. It doesn't matter whether it is a bullet, and arrow, a poison dart, an axe, or even an anvil dropped on us from height the end result is exactly the same.
Try sitting in an enclosed space, with the emissions from a petrol engined truck being fed into it. Does anyone thing that the outcome will be great??
With other countries building coal fired power stations as fast as they can, does anyone really believe the difference between petrol and diesel vehicles is going to make much difference to air pollution levels in the overall scheme of things??

It is the concentration of diesel cars over petrol, where there are more particulates released, that is the problem. Large UK cities are suffering. Would be even better if we had a team network in London rather than diesel buses, feel sorry for the cyclists.

[irocfan]

p1esk said:

Well I haven't read all the pages here, and somebody may already have mentioned it, but one simple answer would be to abolish the current nonsensical road tax / VED regime, and adjust the tax on fuel to influence matters.

Then we wouldn't get this nonsense whereby a person who owns a relatively high polluting car, but uses it very little, pays more than somebody that has a new, lower polluting car, but covers a large annual mileage in it.

What matters here is how much pollution we are each producing, and seeing that it gets paid for on a fair basis.

you and your common sense - you really don't get either PH or this whole AGW scam thing

[Pan Pan]

celicawrc said:

Seems to be alot of people on PH that like to look down their noses at people who have swapped their petrol car for a diesel.

Well i recently did just that for my daily driver. The diesel does over twice the mpg of the petrol, yet only costs £20 more to fill up. Also saves me nearly £200 a year road tax! I only cover roughly 5k miles a year, the car cost £1k.

How am i not saving by switching to diesel!? It is the gubberments fault though with the lower tax incentives.

Exactly, Some seem to forget that governments encouraged people (or as in my case companies, where we were not given the choice of fuel type anyway, it had to be diesel, or nothing, so it is not down to people being thick regarding diesel to go down the diesel route)
To call for increased tax on diesel now, is nothing but duplicitous.
Motor vehicles pollute. period, we all know that, but still we choose to use them, for a variety of reasons which make sense to individuals. If people want to ban diesel, they should also ban petrol engined vehicles on the same basis.
then life would be fun for all us piston Headers, wouldn't it?