Petrol or diesel

[ackers]

Now that the price difference between petrol and diesel has swung the other way, what is the advantage of a diesel over a petrol engine, if any.

 

[st13phil]

As you've identified, the economic arguments for owning a diesel or a petrol engined car are swayed heavily by taxation regimes.

Back in September last year I did the maths comparing a new W204 C220CDI and a C200K and based upon 15k miles pa over 3 years the C220CDI was fractionally cheaper (circa £600 over the 3 years) for my type of driving. If you are doing mega miles or lots of stop/start city driving then the diesel starts to make better financial sense, but the converse is also true in that at less than 12k miles a year and the diesel costs you more than the petrol on a total cost of ownership basis. As well as the fuel cost consideration, the biggest cost of car ownership is still depreciation and Mercedes-Benz cars are a little unusual in that diesels retain marginally more of their value than a petrol engined equivalent. The final elements are servicing costs (similar) and VED (generally less for diesels).

Personally, I prefer the power delivery of the diesel engine and the greater range between fill ups so the small financial advantage of the diesel for me is just icing on the cake.

 

[jberks]

As you say, in pure fuel cost terms it's a hard argument. You do still save on fuel but it's a much smaller saving than it would be if we had a credible goverment. Even engine longevity is a hard one these days though a diesel should still handle 150k+ better than a petrol.

The key advantage of diesel these days is VED. My E270 costs less in road tax than a friends small little 2L Peugeot cabrio, despite being more expensive to buy, much bigger and a lot faster too.

Depreciation is the other key. To get a petrol with the same mtorway capabilites (low down torque) as my 270, I'd have had to buy at least an E320 petrol (the 240 can't keep up without kickdown). I'm failry confident I could sell an E270cdi on the used market. I'd be a lot less confident on a 320 petrol. Add in the fuel difference between the 2 and the VED and the costs start to become significant.

 

[stumpy]

I would say that taking everything into account from a financial point of view it evens out a bit. Petrols are generally cheaper to buy though more expensive to run. But as jberks says, selling on a diesel is much easier than a petrol. Diesels are more relaxing to drive but a petrol is easier on the ear. This goverment seem to be using the CO2 argument to determine our car choice. Fine, but once we are all in diesels (which produce plenty of other nasties) they will target them.

Slightly off topic, but I spent the weekend with a friend who runs an 06 Cooper S conv. She pays more VED than I do in my Bentley. This government has to go.

 

[Ashley H]

I've driven a mix over the years and had always assumed a diesel would make more sense at higher mileages but I agree with other posts that it's far from clear cut these days.

The direct fuel price is diverging at a frightening (if you drive a lot of miles in a diesel, as I do) rate and if your style of driving is reasonably spirited the fuel economy isn't even necessarily fantastic. Over 23,221 miles in 7 months since I boght the car, my overall is 31.4 mpg (E320 CDi on an '02 plate) and that's 75%+ on motorways. When you look at a current price of £1.12 ~ £1.15 per litre...

Being a bit anal, I keep a really detailed track of costs and, so far, they break down as (pence per mile):
Fuel 15.5
Routine Maint. 4.0
Repairs 4.9
Taxes 0.9
Insurance 1.4
Other 0.7
TOTAL 27.4 pence per mile

This ignores depreciation but shows that, over a reasonably high mileage, the tax & insurance are relatively insignificant. Includes a second set of rear tyres after 16,000 miles on Michelins...

 

[A210AMG]

Hello,

Assuming your buying out off warranty, would LPG powered over a Diesal be maybe the way?

For example my car say does 20Mpg average (ML350) so on Gas would do 40mpg on a desent run I can get 25-28mpg to that would be close to 50mpg on gas

A ML270Cdi would probably do 30mpg

The ML270cdi would cost more than the petrol car to buy in the first place even taking into account a multi point new LPG conversion.

It seems only the loss or torque a derv gives would you miss, and I tow with mine and I've not missed any power yet towing

Just another thought?

 

[jberks]

LPG is another option but whilst the price is half, the MPG isn't as good so it doesn't work out quite as good as you'd think. Then you need to find somehwere to put a big enough tank to make it viable. I looked at it with the 240. I would have had to do nearly 40k to break even and would have had to refill every couple of days (100 miles per day). As the nearest LPG station was nowhere near my house, it would have been a real pain, plus I wasn't intending to keep the car that long.

 

[verytalldave]

A factor nobody has mentioned yet is the noise factor. I drove both a petrol and a diesel C class before deciding eventually deciding upon the petrol version. This was based purely on the fact that IN MY OPINION the diesel sounded like a taxi - which I didnt like. The petrol was quieter and more refined.
Its something worth bearing in mind.




Stands back ready to get flamed...........................

 

[jberks]

Stands back ready to get flamed...........................

Not at all. If my mileage was lower I'd be with you.

 

[stumpy]

A factor nobody has mentioned yet is the noise factor. I drove both a petrol and a diesel C class before deciding eventually deciding upon the petrol version. This was based purely on the fact that IN MY OPINION the diesel sounded like a taxi - which I didnt like. The petrol was quieter and more refined.
Its something worth bearing in mind.




Stands back ready to get flamed...........................

Whilst the noise is an issue on 4 cyl diesels, I'd say that sixes are not as bad. Our 535d is a bit rough when cold but once warm it isn't too bad. From inside it sounds just like the petrol 6. It does produce 282 bhp so I can forgive it something. I also sampled the V6 diesel fitted to the VW Toerag. Knocked around in it for a few days while the Bentley was in for a service and found it to be almost silent and quite punchy. Not too economical mind. For me, aural appeal is more important than economy - even with high mileage. I need to enjoy a car and when doing high miles it is even more important to me to have something pleasing to listen too as I'm in the car all the time. I've yet to hear a good 4cyl diesel, though I'm looking forward to trying the Scooby Derv.

 

[A210AMG]

Hello

I agree the tank size for LPG is an issue but cars such as mine you can have a 70L underslug tank (although you probably get around 60L in it full), the other method to keep your boot space is a donut tank in the spare but these are around 45L (my dad had this in a C200 and the range was 200 Miles)


I think now you may fine LPG easier to obtain? as most garages have them and if you know the local farms and industrial estates you can often buy it much cheaper.

Horses for courses but petrol power and £28 for me to do 200 miles instead of £60 is good. Cost of kits and quality of the kits are better than they were also.

Agree with the noise issue, my dad has a 2003 320cdi Estate and while it does go well, round town or starting up it IS noisey, still amazed nothing can be done to make them sound better?

 

[stumpy]

Hello

I agree the tank size for LPG is an issue but cars such as mine you can have a 70L underslug tank (although you probably get around 60L in it full), the other method to keep your boot space is a donut tank in the spare but these are around 45L (my dad had this in a C200 and the range was 200 Miles)


I think now you may fine LPG easier to obtain? as most garages have them and if you know the local farms and industrial estates you can often buy it much cheaper.

Horses for courses but petrol power and £28 for me to do 200 miles instead of £60 is good. Cost of kits and quality of the kits are better than they were also.

Agree with the noise issue, my dad has a 2003 320cdi Estate and while it does go well, round town or starting up it IS noisey, still amazed nothing can be done to make them sound better?

The RRS V8d sounds just like a proper V8 from the exhaust, but up front it is still chuntering away like a bag of spanners

 

[hawk20]

What a range of views -perhaps as one would expect.
Just on the facts side:
a) Price: diesels are nowadays often NOT dearer than petrol cars to buy. Check out the E class and others.
b) Economy: once you have a diesel that gives similar grunt to petrol (e.g in the A class the 200cdi has almost identical performance to the 2 litre petrol and in the E class the 320cdi has the same performance as the 350 petrol) you will find that 'typically' the diesel will have a combined economy figure showing 20-25% more mpg.
c) Fuel cost. Most of the time petrol and diesel are 1-2p apart per litre (that is 1% to 2% dearer for diesel). But you get 20-25% more mpg. Recently the gap has widened to 5-6p per litre (but it is still only 5% more than petrol and you get 20-25% more mpg so still quids in).
d) Noise. If you buy an old diesel it is noisy especially when cold. But under way even the old ones are barely audible in a Merc until pressed hard. But try a state of the art diesel like the 3 litre V6 in the E320cdi or S320cdi or the new C 320cdi and it is a revelation. Even at rest it is as quiet as a petrol. No diesel 'clatter' at all. Amazing. And under way, it is just as quiet too. The diesel in my A class may only be 2 litres but it pulls a remarkable 40 mph per thousand revs. So at 80 it is only doing 2,000 revs and you can't hear it. I tried the petrol -no difference except the petrol is working harder as it has a lot less torque.

Even the old S class 220 series that I had was virtually silent at 70/80 doing 35 per thousand revs. The new S is even quieter.


So here's my take on petrol v diesel:
Same cost to buy -approx.
Diesel worth more on resale.
Diesel cuts fuel bills by 15 to 20% plus
New diesels are amazingly quiet and once under way no difference in noise level.
The more performance you want, the more you need diesel. Seems odd compared with the past but now true. a) the 3 litre diesels are just as fast as 3.5 litre petrols and b) the depreciation on big petrols is now horrific.
For me, diesels are nicer to drive nowadays as they have so much low down grunt and they do the business very well indeed but at low, stress free revs. Always power on tap at whatever revs and in whatever gear. So more relaxing on long journeys.

And as for pollution, diesels emit less CO2 per unit of grunt, and are in lower VED bands; and next year's Bluetec diesels will be like breathing fresh air.

 

[verytalldave]

Its the compression ratio of about 20:1 that produces the distinctive diesel engine sound and barring having an engine made of about 6" thick cast iron all round to help absorb some of the knocking, will always make THAT noise. Its true more modern diesels are quieter, but thats mainly because their compression ratio is slightly lower than 20 years ago. So a little less noise. Some car makers are developing quite effective active noise suppression systems for within the cars cabin, but of course, that wont affect the man in the street. He will still hear the taxi go past, even if you as the driver or passenger dont.

Line me up a mix of 20 cars on tickover. 10 petrol and 10 diesel, and I will pick out which is which 100% every time.

Enough said.....................

 

[rf065]

Line me up a mix of 20 cars on tickover. 10 petrol and 10 diesel, and I will pick out which is which 100% every time.

Enough said.....................

And from the same line up, I will pick out the 10 that can get 50+mpg

Russ

 

[hawk20]

Its the compression ratio of about 20:1 that produces the distinctive diesel engine sound and barring having an engine made of about 6" thick cast iron all round to help absorb some of the knocking, will always make THAT noise. Its true more modern diesels are quieter, but thats mainly because their compression ratio is slightly lower than 20 years ago. So a little less noise. Some car makers are developing quite effective active noise suppression systems for within the cars cabin, but of course, that wont affect the man in the street. He will still hear the taxi go past, even if you as the driver or passenger dont.

Line me up a mix of 20 cars on tickover. 10 petrol and 10 diesel, and I will pick out which is which 100% every time.

Enough said.....................

Don't let's descend into debating points on this. I would have said just what you have posted only 1 year ago. But then I was lent the new S320cdi for a few weeks. I tell you if you try it, it will open your eyes. And it is not sound deadening. Stand next to one with the engine riunning and you will swear it is not diesel. No clatter at all. None. Then open the bonnet as I was asked to at a get together because all were so amazed. And still there is no clatter. Smooth, silky, incredibly silent.

With the A class, you have some diesel sound at rest especially when cold. I like it. And why care about it? as soon as it is moving you don't hear it. You just notice that you are doing 50mpg

 

[stumpy]

The diesel car may well be silent from inside at a motorway cruise, but when you accelerate you hear the noise. And that's the thing for me, it's not always a 'nice' noise. I like to have the roof and windows open when I'm driving and that lets the racket in. I was in Devon at the weekend and diesel was 12p more than UL. The 500 was doing 29 average on the way there which pleased me for such a car. That included the full NASCAR snarl when leaving the A303 roundabouts

 

[verytalldave]

Don't let's descend into debating points on this. I would have said just what you have posted only 1 year ago. But then I was lent the new S320cdi for a few weeks. I tell you if you try it, it will open your eyes. And it is not sound deadening. Stand next to one with the engine riunning and you will swear it is not diesel. No clatter at all. None. Then open the bonnet as I was asked to at a get together because all were so amazed. And still there is no clatter. Smooth, silky, incredibly silent.

With the A class, you have some diesel sound at rest especially when cold. I like it. And why care about it? as soon as it is moving you don't hear it. You just notice that you are doing 50mpg

Its only all a matter of opinion anyway. Nothing to get worked up about. We all have out own agenda and criteria to meet, and thats all there is to it.
I am always open to have my mind changed, so maybe you are right.

 

[hawk20]

The diesel car may well be silent from inside at a motorway cruise, but when you accelerate you hear the noise. And that's the thing for me, it's not always a 'nice' noise. I like to have the roof and windows open when I'm driving and that lets the racket in. I was in Devon at the weekend and diesel was 12p more than UL. The 500 was doing 29 average on the way there which pleased me for such a car. That included the full NASCAR snarl when leaving the A303 roundabouts

Stumpy, let's agree the V8 snarl has few equals. But it is going to be a thing of the past for most people. £25 per day for Londoners and massive depreciation wherever you are. But lovely while it is allowed and you can afford.

But get one thing right. IF you try out the new S320cdi you will not hear what you have described. (It won't be the gorgeous V8 snarl) but you will be amazed, as I was, at what a smooth refined sound it does make. Same engine in the ML320cdi I imagine. And the four litre diesel V8 is tasty too.

 

[hawk20]

Its only all a matter of opinion anyway. Nothing to get worked up about. We all have out own agenda and criteria to meet, and thats all there is to it.
I am always open to have my mind changed, so maybe you are right.

I agree. All I am saying is the new diesels need to be tried to be believed. And I used to hate diesels and be a confirmed petrolhead.