simon_g, I had heard that Honda's figures were very optimistic and the Honda diesel while being thought of as a great engine was never considered particularly economical.

And yet under the standardised EU tests that's what it's supposedly capable of. I only ever crack 50 if it's a long motorway run – I stick roughly to the limit, keep tyre pressures right, don't use roofbars or anything like that. What's the point of mpg figures these days if they have seemingly no link to reality?

All that's happening is that new car sales are getting driven by these supposedly more economical cars while real-world fuel economy seems to have barely changed.

EDIT: simon_g – no idea why the Honda doesn't achieve it. I think the combined figure for my car is 53.6mpg & I get 55mpg so I'm pretty chuffed with that.

thisisnotaspoon –

a) apologies for the MGB slur.

b) so your service costs are doing them yourself….hmmm.
In that case – the parts for mine are about the same.

c)so if I drove your car to work instead of mine it would cost me £81.72/week in fuel as opposed to £59.43 in mine (assuming 600 miles @ 120p/litre fuel & 40mpg in yours & 55mpg in mine), which is a difference of about £1047 over 47 weeks of the year (assuming 5 weeks holiday). And that's just commuting mileage.
That's too much of a difference to make it worth me driving a 'classic' just for a bit of pop/burble and the odd conversation with random MG fans. And how many days would I spend stood at the side of the road waiting for my 'classic' car to be repaired?

Fine for a weekend car – I get that. But an everyday proposition for me….? No thanks. Have fun with it though – I wish I could get away with a lesser commute.

I found the opposite. Diesels had a usable rev range of about 500rpm from arround 1500 to 2000. Below that there was no turbo (so great economy, but no power), above that nothing really happpened as the turbo was already blowing as much air as it could.

That's the old VAG PD engines that are like that, only the pwoer band was more like 1500 to 3000 rpm not 2000.

Modern CR diesels are a lot better, with a torque curve more like a petrol.

Don't make me get the graphs out again please.

Molgrips – I already know that you luuurv your Passat. Hats off to you, and all that. Nobody needs to see your graphs.

Simon_g – the reason that the 'standardised EU tests' have no bearing on reality is because they're not real. They'll give you a comparison between cars if you're looking at the figures but they won't tell you what your car's going to get to the gallon. They're not real world figures – they're calculated from the CO2 emissions. I've got a pal with a Peugeot 207 van with their 1.6HDi90 engine and he's getting 67mpg off his trip and the official combined is closer to 50. He just drives extremely economically. I don't, so I get slightly worse figures than the offical list………

in the petrol it replaced you had to change a gear or two and get the revs up to make a safe overtake.

So what engine did the old Golf it replaced have?

Can someone explain the price difference thing please?

Petrol is 1p a litre cheaper than diesel at the moment, so where are people getting their figures from about 'don't buy a diesel car unless you're doing over 12000 miles a year'? By my reckoning if you do more than 5 miles a year, get a diesel.

Can someone explain the price difference thing please?

usually, a car with a diesel engine costs more than the same car with a petrol engine.

It's cos diesels are more expensive to buy.

Then factor in additional oil needed and additional servicing costs.

And additional costs to wash all the clothes that get covered in diesel every time you fill up.

They're not real world figures – they're calculated from the CO2 emissions

No they're not – they calculate the CO2 figures from the fuel economy tests. The fuel economy tests however are unrealistic – they drive something like 2 miles on a rolling road with a set pattern. And the manufacturers do them, so they can do various things to fudge the results.

Molgrips – I already know that you luuurv your Passat. Hats off to you, and all that. Nobody needs to see your graphs.

I just get pissed off with people saying diesels have only a 500rpm power band. It just isn't true!

aah right ta. I think you might want to review those figures though. I agree our audi probably cost more than a petrol to buy and maybe more than a petrol to service but our honda, no way. A full service was less than 200 quid (which included a full valet) and it won't need another one now for a year.

And all petrol stations have plastic gloves on the bins nowadays.

I'll race you in my 2.0l petrol against your diesel Molgrips – we'll soon see whose has the best power band 😈

Interesting reading this discussion as someone who is involved in the pollution/health field. Does anyone consider anything other than MPG or running cost when purchasing a car?

It might interest people to know that PM/NOx pollution, largely attributable to diesel vehicles, is responsible for more deaths than passive smoking and road traffic accidents combined. In fact in London your life expectancy is 7 – 8 years less largely due to diesel vehicle pollution, and 7-8 months less UK wide (but this does include people living in the sticks as well as cities).

There are impending EU emissions targets which the UK is currently struggling to meet, and again this can be attributed to the diesel fleet. In order to meet these targets one of the things being discussed is diesel fuel pricing, so the fuel prices might not be as similar as they are now. Petrol and diesel prices are only going to go one way, but I think that diesel will incur the greatest rise. Another thing is more Low Emission Zones, where driving a diesel will be expensive. Also there is talk of forcing diesel vehicles to retrofit further emissions control, again that is not going to be cheap.

Not trying to come across holier than thou as I have a (petrol) car that I use for weekend biking so I'm doing my bit for pollution as everyone else is. However what I would say is that petrol driving costs for the future look pretty stable, whereas diesel may increase quite a lot relative to now – if all we're interested in is running costs

Theres a lot more to it, as we run out of nice light oils, diesel is going to become cheeper (than petrol) as its easier to turn heavy oils into diesel than petrol.

Fuel is going to get very expensive very quickly regardless. Within the decade I reckon the question will be hydrocarbons or XYZ, whatever XYZ turns out to be, hydrogen generated by some form of nuclear power would be a good bet. Although we still haven't worked out how to make it or store it yet.

Maybe in terms of production price, but the government aren't simply going to let diesel get cheaper than petrol I don't think, whether it be through increased taxation or other means such as retrofit emissions technologies etc. Poor health due to Air Quality costs £8.5 – 20.2 billion a year in the UK, not to mention the £300 millions worth of fines that we'll probably have to pay as well.

We do definitely need to think about a cleaner fuel though, but with the rate of progression as it is I can't see any major shift or uptake in the next 10 years.

As with all these things there are various angles you can take. It would have been useful if UK government had thought about this though some time ago rather than panicking now they know how much AQ is costing them and the fines are going to come in! The result is we'll all end up paying more to do what we do now.

just for all the diesel PM10 moaners – how about petrol PM2.5s? Probably even more health affecting?
Anyway in London anyone that lives east of Heathrow is heavily affected by the partially burnt jetfuel off of landing planes and particularly those in the Richmond/ Hounslow area are very affected by overweight planes dumping fuel on final approach.
We have a diesel Focus partly because we got 40% off RRP from new, it'll do over 600 [oops] miles on a single tank and even in town driving gets just under 40mpg (which is quite a disappointment TBH). Oh, and it goes, stops and goes round corners which is all we want it to do. What is this "driver enjoyment" you folks from the shires are going on about?

aP I think is still open to interpretation with regard to PM2.5. Not measured much in comparison yet, partly due to cost and availability of equipment to do so. This will change in the near future though as suitable equipment is becoming more commercially available.

In summary in London you're shafted!

LOL – but it has been lovely and quiet the last few days, and no nasty rainbow colours on the top of my pint either.

The ironic thing is that a lot of AQ people get jobs in London, where the AQ is the worst in Europe, for that very reason. Yet they know all about the impact upon them and everyone else. A strange situation to be in.

To try and go back to cars a bit one of the main reasons against the Heathrow expansion is not the increase in flight traffic/plane pollution but the impact on AQ due to the increased vehicle traffic that it would bring.

so why are diesels more expensive to produce?

Less demand so higher unit cost?

Oh right, you're an attention whore.

molgrips, why do you insist on throwing these insults around about people you don't know? It's getting very tiresome now

And additional costs to wash all the clothes that get covered in diesel every time you fill up.

messy bugger 😉

I'd love to know where these people live & work that get remotely near the manufacturers' claimed MPG. perhaps they live 2 minutes from 1 motorway junction and work at a motorway service station…

Then again the case for H3 was based on 80% emmissions reduction for both planes and cars by 2020.
I'm always amused by those that require a 'drivers car' to go shopping in Feltham at the weekend.

aP the government can always juggle up the figures it wants to support whatever idea it has it seems. I don't believe them on H3 and a prominent member from my department is on the record saying a lot of their H3 justification is bull.

Another vote here for preferring driving diesels.

As long is the power is there, the torque is up there with far more powerful petrol engined cars. Less need to change gear is a plus too.

The only reason to buy a diesel with the sort of mileage you're doing is if you're going to be towing stuff or doing a lot of fully loaded trips.

If you not doing these things then petrol is your default fuel for overall economy.

molgrips, why do you insist on throwing these insults around about people you don't know? It's getting very tiresome now

It's meant to be humour. I enjoy ribbing TINAS about his car, that's all. I was hoping it'd be taken in the spirit which it's intended, but thorough apologies if it's not 🙂

As for the air quality thing, that's an interesting point. I'm aware of NOx pollution and so on after having had endless discussions with my American father in law as to why diesels are so unpopular over there – NOx is one of the reasons. If you think our emissions control systems are complex, you should read about how VW made their diesels comply with the stringent new California regulations. They have a NOx trap as well as a DPF which is quite a piece of engineering I think.

I can afford to pay to fill a nice beefy petrol sports car, but I choose at least some semblance of economy with my diesel Passat. To be honest I do wish I'd bought something smaller, less powerful or at least with a manual gearbox, but it was a snap decision under pressure. Although I'm sure it'll come in handy when towing.

I decided that, because I don't live in London or say Los Angeles, NOx is less of an issue than CO2 for me.

In all honesty I'd rather have another petrol hybrid as a second car, but they're not designed for towing unfortunately. Petrol hybrids are the way forward in terms of emissions, both at the tailpipe and when refining the fuel, so I'm told. Now all I need is one with plug in capability and that can run on UK grown bio-ethanol and I'm good to go 🙂

I recommend an Astra 1.9CDTi 150 Estate – sold one last year that we had for four years from new. Comfy, good on fuel, handled well, usefully quick (especially for overtaking and up hill), well specced and because it's a Vauxhall, can be picked up for very little money.

Now got a 335d Touring that really is rather nippy. Also got (well wife has got) a little Jimny (!) for towing a dinky boat, parking anywhere and a bit of off roading – both cars cover all angles. The BMW is utterly useless off tarmac for example.

Well, we were looking at the 1.7 diesel Astra and after anti diesel comments yesterday, we started looking at the 1.4 petrol Astra estates. Certainly seem to get more car for your money. Would loev a hybrid but I'm not aware of any estate versions and certainly not on the second hand market withn out £5k budget.

I can afford to pay to fill a nice beefy petrol sports car, but I choose at least some semblance of economy with my diesel Passat.

I can get 45mpg on a run in my sporty petrol car. Around 33mpg around town. I would class that as 'some semblance of economy'.

So what engine did the old Golf it replaced have?

Not a Golf, 2.3 Turbo (Volvo V70 T5) > Golf GT (2.0 diesel)

Yes but can you fit any people or shopping in it?

I get 33ish mpg round town, 40ish out of town and can carry five people and loads of gear then hit 60 in under 6s, 100 in 13.3 and get to over 160 in my family estate car 😉

Shame it has a whiff of "hearse" about it.

Would loev a hybrid but I'm not aware of any estate versions and certainly not on the second hand market withn out £5k budget.

Well Prius boot is estate big (almost) with seats down, but small with seats up. And I used to ride past one with full equippment and leather in Bristol that was a 56 plate for £6k last year.

I thought the green footprint of the Prius was worse than most other cars out there due to the batteries.

Yep – 2.5 times worse than a V8 Range Rover due to being made all over the World and using nasty stuff in the batteries. Not good. The Prius makes me angry.

I thought the green footprint of the Prius was worse than most other cars out there due to the batteries.

Only if you believe the sheer b*llocks put about by an American so-called research company being paid by the US oil industry.

It's not true folks. That report made out that the total energy cost of a Prius was half a million dollars. So Toyota make $470,000 loss on each one then? Okay.

Edit: a Landrover weighs almost double what a Prius weighs. So you're saying that 28kg of NiMH battery (made mostly from recycled nickel) takes more energy to produce than 1200kg of steel, engine, gearbox and associated plastic crap?

Yes but can you fit any people or shopping in it?

It can fit four people in it. Granted the passengers in the back can only sit upright if they are under 5ft (seriously).

I can get two bikes in the boot with the back seats down. Just.

🙂

Not a Golf, 2.3 Turbo (Volvo V70 T5) > Golf GT (2.0 diesel)

I am very surprised in your claim then. Less torque and substantially less bhp coming from the Golf compared to the Volvo. And 2 seconds slower to 60 too!

I get a LOT of Audi A3/A4 and Golf/Passat 2.0 diesels up my backside being lairy for no reason. They have less than half the bhp and over 200lbs-ft less torque but still think they are in something "sporty." I usually ignore it but occasionally I open the sunroof, stomp on the throttle and wave politely as they are left choking in my soot fumes 😉