Not quite sure why I've been scribbling on the back of an envelope. Maybe it's because I've been crunching work related numbers all day. Three year business plan. As usual a work of fiction based upon assumptions of the unknown but there it is done anyway.
No, the thing I've been scribbling on my scrap stationary is a wee analysis of the fuel costs of a fictitious petrol car and an equally imaginary diesel one. No account is taken of the other factors which might lead to choosing one over the other, this is just about fuel cost.
Following assumptions were made -
Petrol car gets 30 mpg
Diesel car gets 40 mpg
Petrol costs £1.30 a litre
Diesel costs £1.40 a litre
Both cars are driven for 10,000 miles a year
Now here's the interesting bit...
It costs £1600 a year to put fuel in the diesel car ( 16p a mile )
It costs £2000 a year to put fuel in the petrol car ( 20p a mile )
It costs £4.38 a day for fuel in the diesel ( assuming equal daily usage 7/7 )
It costs £5.47 a day for fuel in the petrol
The difference is £1.10 a day or about 3 cigarettes, or a half pint of beer, or half a takeaway sandwich, or half a Starbucks coffee.
Granted, it's £400 quid a year which sounds scarier but it does sort of make you think. Well it amused me for a few minutes.
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You would also have to factor in the higher price that the diesel car cost to buy(usually £1000 more) and suddenly petrol and diesel cars are very similar in 3 year costs to run.
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But the higher capital cost will largely be recouped when you sell. Also remember that £400 a year requires you to earn around £650 a year before tax.
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I know the figures do come out close unless you are doing monster mileages but in my case going from Mondeo III petrol to new C5 diesel has taken me from 32mpg to 52mpg... and overall I drive the C5 faster than the Mondeo as I don't have to worry about saving fuel.
Only have to add my preference for a diesel engine and it's an easy choice.
On 15k personal use I save £1000/yr.
Last edited by: Fenlander on Wed 11 May 11 at 19:46
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All valid points, but here's where it gets really weird in our household. Currently we both have Qashqais. Mine is a 2.0 diesel auto 4wd which gets 36 mpg. Her's is a 1.6 petrol manual 2wd and it gets 42 mpg. So assuming the above model the diesel one costs 18p a mile to fuel and the petrol one costs 14p a mile to fuel. Or...£400 a year less than the diesel one.
Anyway my envelope's full now...
:-)
Last edited by: Humph D'Bout on Wed 11 May 11 at 19:47
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My pad has plenty of room but I have to stop for curry & chips and a beer... plus a balti pie for pudding.
The weird bit in our household is that Mrs F is only getting 52mpg from her diesel C3 because she canes it everywhere. So we go out somewhere with a choice of drastically different cars that cost the same to fuel for a trip.
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Did you factor in the difference in VED costs though, wouldn't be fair to do so unless on a like for like basis.
Our C2 VTS for example, petrol version would be band G at £165, whereas our Diesel is band C at £30.
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My diesel £245, her petrol £155. I know it's not a fair comparison of course.
Edit, oh and the petrol one is a lower insurance group too...
:-)
Last edited by: Humph D'Bout on Wed 11 May 11 at 20:38
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>> My diesel £245, her petrol £155. I know it's not a fair comparison of course.
No it's not, your company car is the all singing all dancing version with big bhp, what would the same size/power/transmission Diesel version be i wonder.
Just shows though, you have to research a lot before you sign on the dotted line, something so many buyers fail to do...or test drive the things either.
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>> My diesel £245, >>
That's the problem, it is an inefficient diesel, it should be nearer £120 per year.
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>> You would also have to factor in the higher price that the diesel car cost
>> to buy(usually £1000 more) and suddenly petrol and diesel cars are very similar in 3
>> year costs to run.
>>
I've never understood this argument.
If I spend 10k on a car, it doesn't matter if it's a petrol or a diesel model. It still cost 10k.
If you approach a car purchase with a specific figure to spend, then you should always buy a diesel if fuel costs are your main consideration.
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>> I've never understood this argument.
>>
>> If I spend 10k on a car, it doesn't matter if it's a petrol or
>> a diesel model. It still cost 10k.
>>
>> If you approach a car purchase with a specific figure to spend, then you should
>> always buy a diesel if fuel costs are your main consideration.
I've never understood this argument. If you approach a car purchase witha specific car in mind, e.g. you want a 4 year old Mondeo with 100k on the clock, then you should always buy a petrol if overall costa are your main consideration. ;)
I've honestly never understood the mentality that says "I need to spend 10k on a car." Rather than "I need an estate car and am prepared to go 4 years old and 100k, what's the cheapest car I can get away with?"
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But MM, the cheapest car you can get away with would cost you 50 quid. You can just keep going down. Reductio ad absurdum.
So, if you want something half decent, and the least you're going to spend on a car is, say, 10k (we all usually have a max and min figure in mind), you're open minded on which specific model you'll buy, and fuel costs are your main concern, then you'd never choose a petrol car.
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I started with a maximum budget, a list of "must have" requirements, and then set out to find the youngest car with the least number of miles, the intention being to achieve the maximum number of years/miles use from my budget or less.
I cant find a hole with that approach
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>> I cant find a hole with that approach
Is there a danger you end up with a big limo which is cheap to buy because it's expensive to run?
EDIT I guess such a car wouldn't fit your 'must haves'
Last edited by: Focus on Thu 12 May 11 at 11:12
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>> I cant find a hole with that approach
>>
You are not considering the running costs during those maximum number of years/miles.
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which is the least variable component between cars.
The largest variable is repair costs, and reliability and running costs was one of the pre requisites,.
Last edited by: Zero on Thu 12 May 11 at 11:21
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>>
>>
>> I've honestly never understood the mentality that says "I need to spend 10k on a
>> car." Rather than "I need an estate car and am prepared to go 4 years
>> old and 100k, what's the cheapest car I can get away with?"
>>
That's certainly my approach.
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Yes, and when you've found your car, there will be a diesel car of a different model next to it on the forecourt for the same price, which will cost you less to run.
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it wont be the same price, it will be dearer.
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It will be, because it's a different model.
Last edited by: Alanović on Thu 12 May 11 at 11:56
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then it probably wont fit your buying criteria.
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Using the above criteria from Mapmaker of 4 yrs old max, 100k max, estate car:
Lancer petrol:
tinyurl.com/436k2fk
Astra diesel:
tinyurl.com/5tc7chk
If you're interested in fuel costs above all else, you'll buy the Astra. It's actually the cheaper of the two.
Last edited by: Alanović on Thu 12 May 11 at 12:07
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One of them fails my primary buying requirements as I clearly outlined above.
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I didn't mention yours. Just using Mapmaker's example.
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Factor in electric cars and public metro transport and you get:
tinyurl.com/657yaef
a link to cars.com and a metro run in Detroit between a Nissan Leaf, Chevy Volt, Toyota Prius, new Ford Focus auto and a diesel-electric series hybrid train.
Last edited by: gmac on Wed 11 May 11 at 21:33
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One thing that we can be sure of is that fuel prices will rise long-term. From April 2010 to April 2011, according to the AA, Petrol prices rose by 12.9% and diesel by 16.8%.
The average price for Petrol in April 2011 was 1.36 per litre, and diesel 1.42 per litre.
My own planning was based on doing 17k miles per year and keeping the car approximately for 7 years or 119k miles. Over the course of this period, assuming trends continue, the average price of petrol would be 1.85 (8.40/gall), and diesel 1.97(8.94/gall).
Petrol car gets 33 mpg and uses £30,290 of fuel over the period.
Diesel car gets 41 mpg and uses £25,948 of fuel over the period.
Net saving for diesel = £4,242.
Of course there are other costs such as purchase price, depreciation, tax, servicing and insurance to take into consideration, as well as personal preferences as to the characteristics of diesel and petrol engines.
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>> Petrol car gets 33 mpg and uses £30,290 of fuel over the period.
>> Diesel car gets 41 mpg and uses £25,948 of fuel over the period.
It's not till someone puts those stark totals down that you realise, with horror, just how much you might have spent and will continue to spend over the years on transport, trying not to work out how much of that would have been tax...which had already been taxed, so to speak.
This car lark really is a mugs game.
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It really depends how the car is going to be used and so many other factors. For me petrol works out far cheaper than a diesel but as I do only do 4500 miles a year it is easy to see why. Modern diesels don't like low mileages either where as petrols can cope a lot better.
My car costs me a fortune, but in real terms it is still less than £1 a mile, and while public transport is cheaper it is impracticable for my job, I simply could not work as much. £1 a mile is still far cheaper than a taxi.
Last edited by: RattleandSmoke on Wed 11 May 11 at 22:53
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Using a similar B-O-E calculation method to Humph, I reckon I'm saving £385 a year, or 31%, in fuel costs in the Mondeo vs the Escort. VED is £55 cheaper, but insurance is £180 more (although for better cover). Add in the more expensive (16" vs 14") tyres and the whole-ownership cost is likely to come out around the same overall, just in a bigger, smarter, more reliable car.
If the retail cost of diesel has risen by 16.8% in 12 months and continues to do so, my cost-per-mile next year in the Mondeo will match last year's figure in the Escort. Gone are the days of a tenner getting you 100 miles...
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Thats a sum on the high side of motoring tho.
for me I would get 40mpg petrol, 84,000 miles over 7 years, so thats just a mere £17.6k
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I've worked out my total motoring costs per year is slightly under £3k. That includes servicing, petrol, £100 for silly bits, insurance etc. So it would be probably about 80p per mile.
Now I am planning to pay most my insurance by cash this year, which will save me a fortune in interest costs.
Now I am lucky that I can claim tax back on a lot of my car costs so that makes it a lot cheaper in reality.
I know somebody who buys a brand new Toyota Prius every couple of years, so he basically some how pays no tax, because you can claim 100% capital allowances in the first year on that car.
Last edited by: RattleandSmoke on Wed 11 May 11 at 23:03
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>> I've worked out my total motoring costs per year is slightly under £3k
Using the same criteria, mine is £1996 excluding purchase to cover 10k miles, so 20p per mile.
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There is two main reasons for that though
1) I assume you bought the car out right, do you need to pay any of that money back? If so that has to be factored into the cost.
2) Your insurance is probably cheaper than mine, although I suspect there won't be a massive difference.
Now if I had the £6400 cash my cost per mile would be a lot lower but I would still have to factor in the purchase price.
I think at the very least you need to work out how much your car in terms of its purchase price will cost you per year if you estimate how long the car will last. In my dads case the cost is £200 a year.
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Assume 5 years to depreciate from £2800 to nowt = £560 per year. Still a cheap motor, and in reality it will never be worth completely nothing.
Just renewed insurance at £473 for the year in the end - £23 already paid and £50 x11 months.
The Skoda taxi was 36p/mile to run in 2001-4, but firstly it was brand new and secondly the insurance cost 2 grand.
Last edited by: Dave_TDCi on Wed 11 May 11 at 23:21
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including depreciation, insurance servicing, road tax petrol, mine is currently 29p per mile.
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I am not going to include depreciation as it a PCP so it isn't really relevant yet but on my figures I have worked out its actually 66p per mile but I am tired but I simply divided £3000 by 4500 miles.
Once I've paid the loan off the cost will nearly halve.
Last edited by: RattleandSmoke on Wed 11 May 11 at 23:37
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Actually diesel and petrol are now closer and around £138.9 and £143.9 and a decent diesel car will do 50+mpg, at least 15mpg more than the equivilent petrol car. I.e diesel costs 3 or 4% more though a diesel car will do 40% more miles per gallon.
Last edited by: Cheddar on Thu 12 May 11 at 08:41
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I'm pretty close to that Cheddar.... Xantia 2.0HDi gives 45mpg average. I would expect the 2.0 petrol euiqvalent to give about 30mpg. Diesel car cost around £1500 more than the petrol, but I've done 70k in 3.5 years so used about 7,000 litresn of diesel. Petrol would have used about 10600 litres. Take av diesel price of £1.20 and petrol at £1.15 and I've saved £2290 - taking out the inital price differential (not to mention that I could probably flog the diesel estate for about £750, whereas I would have to weigh in the petrol!).
We're running at about 30p / mile for both our (diesel!) cars, but are covering between them in excess of 30k miles. I prefer not to multiply those two numbers together....
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>>I know somebody who buys a brand new Toyota Prius every couple of years, so he
>>basically some how pays no tax, because you can claim 100% capital allowances in the
>>first year on that car.
What a pointless, ignorant and misleading statement. Sorry Rattle, but that's complete rubbish - or rather, he's lying to you.
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We filled up with petrol yesterday and it was €1.53 for a litre. Diesel was cheaper at €1.38. This was a few miles south of San Gimignano.
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Diesel fuel economy has not generally improved over the past 10 years, whereas the latest petrol engines are closing the gap (especially small turbo-petrols).
Would be interesting to compare something like an Octavia running the 1.6 TD and the 1.2 TSi in real world economy.
Doubt the "40% more miles with diesel" would apply.
Petrol can't be as efficient as diesel thermodynamically, and diesel weighs 10% more per litre than petrol and thus has more 'calories' per litre (maybe should be sold by the kg since thermal expansion won't alter the quantity per cost that way?) giving an inbuilt advantage for diesel but the gap is likely to close somewhat I think.
The future is turbocharged, whether petrol or diesel.
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>> The future is turbocharged, whether petrol or diesel.
>>
Aye, well if that's the case then manufacturers had better make sure that turbochargers are reliable, then.
[Walks off wearing a large frown, and muttering inaudibly to himself]
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>> >> The future is turbocharged, whether petrol or diesel.
>> >>
>> Aye, well if that's the case then manufacturers had better make sure that turbochargers are
>> reliable, then.
And that the engine bearings, etc will reliably stand the higher loads that they would have to endure compared with a non-turbo engine of the same size.
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>> Petrol can't be as efficient as diesel thermodynamically, and diesel weighs 10% more per litre
>> than petrol and thus has more 'calories' per litre .............
But the calorific value (on a weight basis) of diesel is 9% less than for petrol. www.aidfueloils.co.uk/common/fueloils.htm#top
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The water vapour goes out the exhaust pipe in an internal combustion engine, this energy is not recovered.
en.wikipedia.org/wiki/Fuel_efficiency#Energy_content_of_fuel
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>>compare something like an Octavia running the 1.6 TD and the 1.2 TSi in real world economy.
Funny you should say that. If you're happy to slum it with the Fabia running the 1.6TD and 1.2 TSi in real world economy then try this link:
www.telegraph.co.uk/motoring/green-motoring/8461146/Petrol-versus-diesel-economy-challenge.html
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For a brand new car, today, I would almost certainly go petrol. These new direct injected petrol turbos like the VAG TSI and Ford EcoBoost would seem to offer the best of both worlds, or close to.
The diesel argument has also taken a huge kick in the spuds with the advent of this Euro IV / DPF nonsense, which ruins fuel economy, and adds another expensive, failure prone component to the mix. I would personally want nothing to do with a DPF equipped diesel if it was my own money. A car should not dictate to me what kind of journeys I can do in it.
For someone buying a 3-5 year old car (Euro III diesel vs traditional indirect injection, normally aspirated petrol), I suspect the diesel argument is stronger, and the petrol's weaker. The old Euro III diesels were the pinnacle of diesel engine development in my opinion.
I'm delighted with my 8 year old Euro III diesel. All the grunt of anything of comparable size today with proper 50 mpg diesel fuel economy, and it won't throw an expensive strop if I decide to pootle it around town for a few weeks at a time.
Last edited by: DP on Thu 12 May 11 at 21:01
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I think something very similar, DP. My old Euro-III diesel (Volvo) outscores our newer Euro-IV one (Toyota) on every count - and the Toyota manages Euro-IV without a DPF. Favouring big cars as I do, I'd probably still want one diesel, but when the Volvo does have to go it'll give way to something smaller and petrol-powered for my daily M4 trundle.
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Agree about the Euro IV drawbacks. My Honda is marvellous in many ways, but its fuel economy is not good. The engine is very petrol-y in terms of being quiet and tractable over wide revs, but on last weekend's run to the Lakes, half loaded, 80 mph cruise both ways on the M6 except in traffic, and climate on, plus about 40 miles pootling around the Lake District, I got about 35-36 mpg. That's not brilliant, even if it is a big, heavy, powerful car.
Last edited by: Statistical Outlier on Fri 13 May 11 at 08:48
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>> I got about 35-36 mpg. That's not
>> brilliant, even if it is a big, heavy, powerful car.
>>
A petrol car that has any chance of getting near on the economy would be less powerful and harder work on that kind of trip.
A petrol car that matches the diesel flexibility etc would do 10mpg less at best.
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>> >> I got about 35-36 mpg. That's not
>> >> brilliant, even if it is a big, heavy, powerful car.
>> A petrol car that has any chance of getting near on the economy would be
>> less powerful and harder work on that kind of trip.
>>
>> A petrol car that matches the diesel flexibility etc would do 10mpg less at best.
skoda.co.uk/GBR/newcars/octaviaestate/Pages/default.aspx
:-)
Easy! Assuming 74mph cruise with enough junk in the boot for a weekend away, and a 200 mile trip up some motorways, some A roads... i'm doing just such a trip tonight. I expect 38mpg real with 39.5 on the trip computer.
If i were to drive for economy i reckon i could do 43mpg over the trip.
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>>
>> Easy! Assuming 74mph cruise with enough junk in the boot for a weekend away, and
>> a 200 mile trip up some motorways, some A roads... i'm doing just such a
>> trip tonight. I expect 38mpg real with 39.5 on the trip computer.
>>
>> If i were to drive for economy i reckon i could do 43mpg over the
>> trip.
>>
Was about to say the same; my A4 cab is not exactly a light car, and it has the 200PS 2.0T petrol engine which, even with the manual 6 speed 'box, isn't exactly hard work on long trips, and can show a clean pair of heels to the equivalent diesel ;-) And it's also more pleasing on the ear with the roof down...
On longer journeys getting 500 miles out of 60 litres is easy (37.5mpg) without any adjustments to driving style. I have often topped 600 miles on an 120kph cruise down through France.
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>> my A4 cab is not exactly a light car, and it has the 200PS 2.0T petrol engine
They are outstanding engines, very very good. Leaves me wondering what the next version of this engine will be like (expect further improved fuel economy, it'll be able to run in compression ignition mode under light loads, slated for 2015).
>> I expect 38mpg real with 39.5 on the trip computer.
367 miles (odo / trip computer), filling up with just under quarter tank left (45.35 litres) = 36.8mpg.
Thinking about it, I doubt the 170bhp diesel version of my car would have given any better figures if driven to keep pace, although maybe not a strictly fair comparison since i loaded on the stage 1 remap.
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One of the guys here running an Insignia CDTi SRi 160 reckons his running average (calculated rather than computer readout) over 26,000 miles is 32.4 mpg. That's with about 70% motorway use and 30% urban.
This is not progress.
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Could be shockingly inept driving, of course - or something wrong with the car. Does he have previous figures for comparison?
We typically get 40-43 mpg from the Euro IV Verso, and 45-48 from the Volvo.
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>> One of the guys here running an Insignia CDTi SRi 160 reckons his running average
>> (calculated rather than computer readout) over 26,000 miles is 32.4 mpg.
Without such detailed numbers over a long period, my 1999 1.8 Vectra managed 44 on motorways if cruising at no more than 70, and generally managed about 35-38 with a mix of motorway and other use.
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To be fair my Honda normally does about 41 with no effort to conserve fuel. If I make an effort it rises to 47, but life is too short and my free time too lacking to do that all the time.
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It could be poor driving, I don't know.
I can't get the Golf down to 32, no matter what I do with it. I've never averaged less than 40 mpg over a tankful. I suppose repeated, sustained 100+ mph speeds might do it, but this is impossible in the South East in rush hour. I know the Golf is lighter, but my brother-in-law used to see high 40's to low 50's in his identically engined Passat.
My "no effort" figure is about 48, and in extreme mimsing, can drag it into the low 60's. Average tends to hover somewhere around 52-53 mpg. Tends to depend on how badly the M3 is playing up over a week. I fully expect this tankful to be well down into the 40's as it's been a car park most of the week, followed by booting it on the clear bits to make up time. Not a good combination.
I still know it's going to be comfortably over 40 mpg though. The computer suggests 48.1, but it's normally about 10% optimistic.
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Those are impressive figures, DP. Which engine do you have in your car? It wouldn't be the much recommended 1.9 PD, by any chance?
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>> Those are impressive figures, DP. Which engine do you have in your car? It wouldn't
>> be the much recommended 1.9 PD, by any chance?
1.9 PD 130PS (ASZ engine)
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>> The difference is £1.10 a day or about 3 cigarettes, or a half pint of
>> beer,
If buying a diesel car gets me beer at £2.20 a pint, then it is well worth going diesel. I pay almost £3 a pint.
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The thing that can decimate your diesel savings is a repair bill for an injector, EGR valve, DMF, DPF etc.
One of those goes and you've got a massive bill would could easily ruin 3 years of saving over the petrol. Of course petrol engines can have bills as well but on those particular items they're not so much of an issue.
So I suppose it also depends on whether you have a warranty.
I've had 3 diesels in a row and will probably go for a petrol next - as new as possible
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My next car, a Passat Cc 170PS diesel, is said to easily get 50mpg from it.done say they easily get 800 miles from a tank and done a lot more. I'll have to post later in October when I get it.if I average 50mpg I will be pleased.
The hills in the Fiat Panda 1.2 makes me remember why I like turbo petrol and diesel engines.
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Interesting but with the Diesels now you have such nasties as DPFs that can block and need to be replaced every 4-5 years,complicated injection systems and variable turbos. Also using Volkswagen as an example their 122 1.4 TSI engines are chain cam against the Diesels belt. I'd definately chose a modern turbo petrol over a Diesel now: flexible enough, wider power band, smoother and crucially probably more reliable. I have a PD 130 TDI (original Fabia VRS )at mo and aim to run that into the ground anyway so not anti Diesel.
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Been cruising up and down to Middlesbrough (c 260m each way) for work for the past two weeks. Well, twice each way. Each time I've had a dream journey, rarely having to knock off the cruise control, and at a steady (shade under) indicated 80, with a little local driving once there.
Been pleased to get 30.9 mpg overall in my 2.5 T petrol Mondeo. I could probably squeeze a bit more out of it by doing a steady 70 but then it would increase journey times.
The Mondeo will be going later this year, for something more economical!!!
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...Each time I've had a dream journey...
Welcome to the wide open motoring spaces of the North East.
But don't tell all those parked on the M25 - we don't want them here cluttering up the place.
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>> ...Each time I've had a dream journey...
>>
>> Welcome to the wide open motoring spaces of the North East.
>>
>> But don't tell all those parked on the M25 - we don't want them here
>> cluttering up the place.
However, if he is driving 260 miles from Middlesbrough, his driving is obviously not all conducted in the North East.
It's clearly the wide open spaces of the South East....
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Well in my experience it's the Midlands that is likely to catch me out in the autumn - from about Birmingham upwards, although I have less experience of the M1 than the M6 in that region.
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Now here's a thing..Petrol v Diesel costs - Videodoctor
