Petrol/diesel maths

Chunkylover

Im just doing a bit of maths to see which I would be better off doing, the mpgs Im using are purely hypothetical so can someone correct any mistakes im making with my maths

My yearly commute is 17000 miles
Petrol
MPG 40
Cost of petrol 1.23 p/l or 5.54 p/g
Cost of petrol for the year €2354

Diesel
MPG 52
Cost of diesel 1.13p/l or 5.08 p/g
Cost of diesel for the year €1599

So If Im keeping the car for, say, 2 years Id be spending €1510 less using diesel or €1510 more to spend on a diesel (looks like they go for a few more euro than their petrol versions)

Are the figures Im looking at realistic, also are the mpgs realistic for a family car e.g focus salon/citreon picasso

Cheers

Alanstrainor

40mpg would seem pretty optimistic in the likes of a focus etc. And the mpg will depend on the type of driving you do. Motorway driving giving the best MPG. An equivalent diesel will be more expensive than a petrol.

bazz26

17k miles per year is not diesel mileage to be honest imo. The only justification for diesel with that mileage is if you are buying 08 or newer to avail of the cheaper road tax and keeping it for many years to make the premium back on the purchase price of the diesel car over a petrol one.

245

You also need to take depreciation into account and, for the sake of argument, the likely depreciation of the brand that you're buying. You might find that a diesel Fiat depreciates more heavily than a petrol Toyota and a Focus class car will most likely depreciate a bit less than a Mondeo. Also, servicing costs for some brands are quite steep (VW and Peugeot for example) although its not a major isue with your mileage and you can always use an independent. You also need to bear in mind that modern diesels can be really expensive to fix if they go wrong - dual mass flywheels, particulate filters and anything to do with common rail systems will wipe out any diesel savings and then some.

Whether petrol or diesel, you can make major savings by working on improving the efficiency of your driving style and ensuring that your car is properly maintained. You could also consider importing an 'unloved' secondhand car from the UK - for instance the Toyota Avensis seems to depreciate more heavily there than here and if you buy one with a full dealer service history and save a couple of grand over the equivalent here then you've saved a good bit up front.

flamegrill

On servicing most new diesels have 30k KM service intervals or 2 years. I think most petrols are every 10KM still (though I don't know for sure).

The 30k KM service on a diesel is generally just an oil change aswell so I don't see where the expense is coming in?

testicle

flamegrill wrote: »

On servicing most new diesels have 30k KM service intervals or 2 years. I think most petrols are every 10KM still (though I don't know for sure).

The 30k KM service on a diesel is generally just an oil change aswell so I don't see where the expense is coming in?

Go back and read that again.

Petrols were never every 10,000 km either.

245

flamegrill wrote: »

On servicing most new diesels have 30k KM service intervals or 2 years. I think most petrols are every 10KM still (though I don't know for sure).

The 30k KM service on a diesel is generally just an oil change aswell so I don't see where the expense is coming in?

Sevicing for VW & Peugeot models - petrol & diesel - is steep in comparison with, say Ford or Toyota - I didn't specify just diesel.

Also, a lot of people are starting to think that 30k km service intervals are too long for the modern turbo diesel and are used by manufacturers to appeal to fleet buyers who are just concerned about running costs during the lifetime of the lease. Turbo failure outside of warranty/lease period is of less concern to both parties. Manufacturers don't always get it right....

GTE

bazz26 wrote: »

17k miles per year is not diesel mileage to be honest imo..

I have never understood or really heard about diesels not being worth it under a certain mileage.

Can someone explain this diesel mileage thing to me? Is it service costs that make petrol better under a certain level?

Thanks
bbk

Absurdum

Get the car you like most and can afford

/thread

Darwin

Yep, set a budget, stick to it and get what you want be it petrol or diesel.

Gumbo

bbk wrote: »

I have never understood or really heard about diesels not being worth it under a certain mileage.

Can someone explain this diesel mileage thing to me? Is it service costs that make petrol better under a certain level?

Thanks
bbk

its because the price of a 2.0 petrol car will be alot cheaper than the 2.0d version of the same car ie. BMW 520i Vs BMW 520d.

the 520d will be 3k more approx so you need to be doing a certain mileage over a given time to make up the 3k difference in savings you could of made by buying the petrol version.

GTE

kceire wrote: »

its because the price of a 2.0 petrol car will be alot cheaper than the 2.0d version of the same car ie. BMW 520i Vs BMW 520d.

the 520d will be 3k more approx so you need to be doing a certain mileage over a given time to make up the 3k difference in savings you could of made by buying the petrol version.

Thanks for that. The price difference is simply because the diesels are in such high demand right now compared to petrols?

flamegrill

flamegrill wrote: »

On servicing most new diesels have 30k KM service intervals or 2 years. I think most petrols are every 10KM still (though I don't know for sure).

The 30k KM service on a diesel is generally just an oil change aswell so I don't see where the expense is coming in?

Petrol service every 10K km
Regardless what any manufacturer says 30K km is too long to leave oil in a diesel.

Gumbo

bbk wrote: »

Thanks for that. The price difference is simply because the diesels are in such high demand right now compared to petrols?

maybe? and also due to their low motor tax if 2008 or newer and also the price of petrol.

There is fanatastic value out there with 2nd hand petrol cars, everyone seems to want a diesel these days, a friend bought a diesel Accord for about €2500 more than he could have gotten a petrol one for, he barely does 10 000 miles a year. Looney carry on.

sean1141

a peugeot 307 or 607 hdi 1.6 will give you very good mpg and older than 08 will have small tax due to its 1.6. not the nicest looking car imo but the newer ones are trouble free...

mickdw

RoverJames wrote: »

There is fanatastic value out there with 2nd hand petrol cars, everyone seems to want a diesel these days, a friend bought a diesel Accord for about €2500 more than he could have gotten a petrol one for, he barely does 10 000 miles a year. Looney carry on.

His diesel will still be cheaper to run for those 10k miles and he will get majority of the extra purchase outlay back come resale.

746watts

I drive a 08 Yaris Diesel 1.4 turbo.
77mpg at 60kmph, 63mpg at 100kmph, 59mpg at 120kmph.
Oil and filter change every 15,000kms, air filter and fuel filter change every 60,000kms. 78,000kms on the clock from new in 1 year & 5 months. Changed pads at 76,000kms with 6mm of brake material left (new pads have 11.4mm).
Fab car , was €17,500 new in 08. Road tax class A = €104
Worth considering ...............

stimpson

I recently ordered a new 2.0 diesel Avensis. Difference in cost compared to a 1.6 petrol?? €400

And it's a second quicker to 60! Diesel FTW

GTE

746watts wrote: »

I drive a 08 Yaris Diesel 1.4 turbo.
77mpg at 60kmph, 63mpg at 100kmph, 59mpg at 120kmph.
Oil and filter change every 15,000kms, air filter and fuel filter change every 60,000kms. 78,000kms on the clock from new in 1 year & 5 months. Changed pads at 76,000kms with 6mm of brake material left (new pads have 11.4mm).
Fab car , was €17,500 new in 08. Road tax class A = €104
Worth considering ...............

Now thats a good car. A little Toyota.

mickdw

mickdw wrote: »

His diesel will still be cheaper to run for those 10k miles and he will get majority of the extra purchase outlay back come resale.

- it won't be much cheaper to run than the petrol model, his road tax is also about a fiver a week more

- I doubt he will see anywhere near €2500 more for this than a petrol one is 3 years time. It was an 04 he bought.

biggus

Fuel prices are only going to go one way and thats up Petrol or Diesel

johndaman66

OP I don't think you are taking all factors into account. Firstly it will depend on whether you intend to buy a car registered before 1st of July 2008 or after this date. If pre 1st of July, 2008 more often than not you would be paying higher motor tax on the equivalent diesel than its petrol counterpart. I am thinking in terms of your typical family car...avensis, passat, vectra, laguna, octavia etc. For the most part in Ireland used cars in this category would be 1.6 litre petrol (whether or not you feel a 1.6 litre engine in car of such size makes sense as many don't fact of the matter remains that such will be the case in the used car market) or 1.9/ 2.0 litre diesel. Now if you factor your annual road tax for the petrol versus the diesel I think realistically you would be talking quite a few months before you recoup this cost through your savings in fuel. Motor tax being 137/ 169 EUR more for the examples I outline.

I drive a 1.6 petrol vectra and cover circa 400 miles a week or 21/ 22k miles per annum. My fuel bill is around 45 EUR per week. I might be well of the mark for that matter but realistically I don't think I'd be doing it for anything a hell of a lot less than 40 quid a week in a 2.0 diesel vectra, maybe 35 EUR but I reckon that would be optomistic. As such it could be up to 30 weeks before I claw back the extra cost of motor tax in my fuel bills. The less mileage you are doing is obviously going to mean the longer it will take to make this saving in a diesel.

Plus also the fact that modern advanced diesels can quite often give serious trouble and things that go wrong in them such as dual mass flywheels/ particle filters/ turbos can be very very expensive to repair...such problems could potentially put you out thousands and thousands. I'm not saying petrols don't give trouble or aren't expensive to repair if they do... Moreso that more often than not you would be possibly be more unlucky with a modern diesel. Will you get anything near your initial extra outlay for the diesel back come resale time? Depends on make and model quite a lot definately don't expect to do so.

Sorry for the long winded post and getting rather pedantic in my figures but think I had to do so to get point across! If you are going for a post July 2008 car though more often than not your motor tax may be less in the equivalent diesel...depends on make/ model. Obviously a lot will ultimately depend on the make/ model you intend to go for OP but don't just assume you will be quids in by buying a diesel.:)

johndaman66

Also forgot to mention to you OP do check first if your insurance is going to be bumped up if you change to a higer capacity diesel car. I think this depends a lot on the insurance company. I found in the past that some companies would charge higher premiums on higher capacity diesel models than their petrol counterparts even though bhp figures for the diesel would be the same or less than the petrol.

sean1141

johndaman66 wrote: »

Also forgot to mention to you OP do check first if your insurance is going to be bumped up if you change to a higer capacity diesel car. I think this depends a lot on the insurance company. I found in the past that some companies would charge higher premiums on higher capacity diesel models than their petrol counterparts even though bhp figures for the diesel would be the same or less than the petrol.

my insurance on a 1.9 tdi(150bhp) is 650. for 300 more i can insure a 8.3l dodge viper srt-10 coupe!!! and they wont quote me on any subaru impreza sti/wrx or a lancer evo etc!!! I'm 26!

a 1.6 passat wont be anywhere near as fuel efficient as say the 130/140bhp tdi aslo it will lack the power of the tdi when it comes to overtaking etc

fuel wise i get about 650 miles out of a tank of diesel and i dont have the lightest foot!! and i do a lot of back road driving so i never get to cruise along. on a motorway trip at a constant 120k/ph i got a return of about 62mpg i would recomend a diesel over a petrol anyday but thats me!

i think it would be a lot easier to sell on a diesel in 3 years time than a petrol the way things are going. plus if you plan to run it till it dies you will get a lot more driving out of a diesel. maybe a petrol would be a better option if you planned to change every year but i would still rather the diesel!

johndaman66

I do suppose it quite often boils down to a matter of personal preference too Sean1141. I do know some people will drive nothing but a diesel. I do have a couple of friends who live in and work with me in Limerick city area. They would be doing 10,000 miles per annum or less and there is no way in the world they could justify driving a diesel on them grounds. Some people learned to drive in diesels and thats just their preference ever since. More people might do a lot of towing or carrying havy weight and hence their choice in diesel. More people think you can't beat a diesel, great economy with a diesel/ great yoke etc or they like their friends one and thats the reason for their choice:eek:

I'd personally rather the relative smoothness of a petrol engine but granted I have never drove a very modern diesel and my first car being a diesel and giving more trouble than it was worth was probably enough to put me off diesels for life. Just on the point you make on diesels having better overtaking power...I accept your point but quite often I think the benefits of this advantage is negligible given the general driving conditons in this country. More often than not I tend to find that you are only as fast as the red lights in front of you....even if overtaking. I do a 70 mile round trip commute on a daily basis and for a large stint of that journey overtaking is a no no regardless of whether you are driving a petrol or diesel....I'm sure such would depend on the roads you tend to use but having said that I do find the 1.6 vectra while not a rocket is generally pretty adequate for overtaking:)

nationalgeo

Get something with a 1.4 hdi engine.

€104 tax a year. Service intervals of 20,000 kms. Most new toyotas are very cheap to service. Friend just bought a 1.0 yaris and they have the 3 year plan with fixed price services costing year 1 €110, y2 €110, and y3 €140.

Thats very cheap tax, cheap insurance and cheap servicing for 3 years.

80 mpg or higher if you drive it correctly.
60 mpg in city driving

rugbyman

there have been diesel versus petrol debates for years,
but nobody on Boards ever comes out with what is often heard in the pub,

it has to be diesel,
" sure where can you get green petrol"

Rugbyman

zziplex

Some dealers seem to be offering silly money for petrol trade-ins or wont take petrol in at all. I just switched from a 1.3 petrol to a 1.4 diesel and running costs are so much cheaper for me anyway. I do about 25000mls a year mixed driving.

sean1141

johndaman66 wrote: »

I do suppose it quite often boils down to a matter of personal preference too Sean1141. I do know some people will drive nothing but a diesel. I do have a couple of friends who live in and work with me in Limerick city area. They would be doing 10,000 miles per annum or less and there is no way in the world they could justify driving a diesel on them grounds. Some people learned to drive in diesels and thats just their preference ever since. More people might do a lot of towing or carrying havy weight and hence their choice in diesel. More people think you can't beat a diesel, great economy with a diesel/ great yoke etc or they like their friends one and thats the reason for their choice:eek:

I'd personally rather the relative smoothness of a petrol engine but granted I have never drove a very modern diesel and my first car being a diesel and giving more trouble than it was worth was probably enough to put me off diesels for life. Just on the point you make on diesels having better overtaking power...I accept your point but quite often I think the benefits of this advantage is negligible given the general driving conditons in this country. More often than not I tend to find that you are only as fast as the red lights in front of you....even if overtaking. I do a 70 mile round trip commute on a daily basis and for a large stint of that journey overtaking is a no no regardless of whether you are driving a petrol or diesel....I'm sure such would depend on the roads you tend to use but having said that I do find the 1.6 vectra while not a rocket is generally pretty adequate for overtaking:)

ill be the first to agree with you about the differance between a modern diesel and older ones. my first diesel was a 98 toyota avensis. it was a very comrortable car but was loud and dead. my brothers old peugeot was a disaster for power and noise but it never let him down. compared to these my 130tdi bora was a dream to drive. a little loud when starting up but when running at 60mph at about 2000rpm was very quiet. i drove a honda accord for a day and my god was it quiet for a derv. i urge you to try one and i bet you will then relate to what im saying.
being stuck behind lorries often here due to new motor way construction and having to over take if you want to progress i would much rather the diesel than any petrol i have driven. 1.4 or 1.6 just dont have the get up and go of any tdi i have driven. not that i drive like a madman but its nice knowing the bit of power is there when wanted. all depends on your driving style i guess.
i know diesel is not for everyone. i haven driven a mix of both old and modern petrols and diesel and i just prefer diesel. my running costs for my 1.6 seat leon compared to my tdi bora for 1 year was about the same. same milage/roads etc both basicly the same car. 25k miles. tax on diesel is more expencive but fuel costs are a lot less.

im basing my recomndation of going for a diesel on my experience of driving both petrol and diesel cars over the last 7 years. maybe the op drives in different conditions to me such as in a city or large town or on busy roads. i often drive the 20 miles to work each morning without seeing another car!!
OP just go for what you want. the costs of running an average famliy sallon be it petrol or diesel are marginal it just boils down to personal taste. both will needed to be serviced, need new tyres etc and only if your lucky will you get one that never has to go to a garage!!!
my advice pick a car you like. drive both petrol and diesel and see which you rather then buy it!

quarryman

How has the thread got this far without anyone asking what the red i on the TDi means?

Eoin

I've been working out the figures as well as my commute has changed in the last month or so.

I have an automatic 2.5 petrol car, and I am getting just under 30MPG for a 40 mile round trip every day.

I've calculated that a 1.9/2.0 diesel doing an average of 45MPG (would probably get more on my commute) would be about €1,200 less a year to run. This is purely based on fuel and motor tax, it does not include servicing or any other factors.

If I could switch to a nice diesel car for 2K or less, then I'd think about it, but as my car's resale value has been absolutely hammered over the last 18 months, that's not going to happen.

Chunkylover

Thanks for all the help

Just to clear up a few things, unless I win the lotto tonight, I wont be buying anything near new, realistically, bout 4 or 5k to spend
My commute will be from arklow to bray, bout 35m each way, bout 1/2 dual carrage, the other normally ends up being stuck behind a tractor/auld one
At the moment,in a 01 almera, Im going from finglas to bray and that is costing me about €45/50 a week (tbh am not 100% sure what im spending)
Am to old to have a heavy foot so i tend to take it handy and am not to pushed on acceleration/top speed of the car

johndaman66

rugbyman wrote: »

there have been diesel versus petrol debates for years,
but nobody on Boards ever comes out with what is often heard in the pub,

it has to be diesel,
" sure where can you get green petrol"

Rugbyman

Ha ha. Best to keep that talk in the pub I reckon. I do know a neighbour of mine was caught using green diesel in his car and he was fined 1,000 punts and put of the road for a year. That was a good few years back. I know that a few chaps around here driving Landcruiser's and the like were apparently putting 2 fuel tanks into them The seemingly proper fuel tank contained the road diesel. It seems customs/ guards are getting smart to it though as they are now testing the fuel entering the engine.

I'd say if your bragging about using green diesel down the pub be careful who your bragging to and who is nearby:rolleyes:

stimpson

Chunkylover wrote: »

Thanks for all the help

Just to clear up a few things, unless I win the lotto tonight, I wont be buying anything near new, realistically, bout 4 or 5k to spend

I'd recommend a Honda Jazz for that money. It's petrol, but gets about 50mpg (if you don't have a heavy right foot). Tax would be around 300 notes and cheap to insure. And because it's a Honda it should run forever.

galwaytt

flamegrill wrote: »

The 30k KM service on a diesel is generally just an oil change aswell so I don't see where the expense is coming in?

If you drive a diesel, and only service it every 30k kms, you deserve every bit of trouble you get. And you will get it. I wouldn't go 1km past 10k kms in a modern diesel without a basic service anymore. (learn't the hard way..)

245 wrote: »

Also, a lot of people are starting to think that 30k km service intervals are too long for the modern turbo diesel and are used by manufacturers to appeal to fleet buyers who are just concerned about running costs during the lifetime of the lease. Turbo failure outside of warranty/lease period is of less concern to both parties. Manufacturers don't always get it right....

+1

OP - diesels are more expensive to service, and are heavier, too (cue: might require shocks and drop links a bit sooner, too..............)

JHMEG

stimpson wrote: »

I'd recommend a Honda Jazz for that money. It's petrol, but gets about 50mpg

I had one for a few months. On a trip it'd do 4.5l/100km, which is 62mpg in old money. Great load lugger too.

traco

Chunkylover wrote: »

Thanks for all the help

Just to clear up a few things, unless I win the lotto tonight, I wont be buying anything near new, realistically, bout 4 or 5k to spend
My commute will be from arklow to bray, bout 35m each way, bout 1/2 dual carrage, the other normally ends up being stuck behind a tractor/auld one
At the moment,in a 01 almera, Im going from finglas to bray and that is costing me about €45/50 a week (tbh am not 100% sure what im spending)
Am to old to have a heavy foot so i tend to take it handy and am not to pushed on acceleration/top speed of the car

Very Broing 98 Passat 110bhp estate. Malahide to Naas - 5 days a week. approx €55 to fill and last two weeks, 60 odd mile round trip. As its M50 / N7 is sitting in traffic and matching speed of surrounding traffic but even if you push it on or are sitting in traffic the variance is minimal in fuel consumption. If you have stop go traffic the diesel will run away in mpg figures from the petrol - motorway, carriageway figures would be closer.

Unless you fancy very sporty driving then for eveyday sloogging I hate to say it but diesel makes sense and it is boring. Petrol only wins in performance cars where you want to keep weight down for better balance, higher bhp, rev range, gear ratios etc. When I buy petrol again it will be another performance car as the p1ssrat is a let down from my previous M3 but then I get my petrol speed thrills on two wheels now.

Eoin

JHMEG wrote: »

I had one for a few months. On a trip it'd do 4.5l/100km, which is 62mpg in old money. Great load lugger too.

That's very impressive fuel economy.

traco wrote: »

Unless you fancy very sporty driving then for eveyday sloogging I hate to say it but diesel makes sense and it is boring.

The diesel Passat is boring, or all diesel cars are boring?

traco

eoin wrote: »

That's very impressive fuel economy.
The diesel Passat is boring, or all diesel cars are boring?

Boring was probaly not the right word - I suppose predicable, capable etc. We also have a 225bhp 3l diesel and while its quick its still not exciting in my book but if you want to cover huge miles, UK, continent with family and luggage then its a brilliant machine for the job. Fill it every 1000kms and arrive completly relaxed, unstressed and not tired. So by boring I mean its not something that gets your heart racing, its not going to be edgey or require concentration to drive it nor is it something you would track. They are however all excellent transportation, roomy, safe and comfortable.

Personally I think most all modern cars are boring, all of them are very quite, comfortable, effcient etc but that makes them comfortable to travel in. An equivalent size diesel will have more torque than the same size petrol and give you a bigger "shove" in the back so may feel faster than its petrol brother.

Anyway back to teh topic - Servicing costs are low aprt from timing belt every 70k miles. Otherwise I do the oil and filter change myself which if done regularly will help the engine last forever. Taking it to a garage a diesel will be cheaper as labour costs are lower and regular serice parts changed are less. Main difference is the lack of spark plugs to be changed - everything else is similar. As for turbos, intercoolers, sensors etc many of the modern high bhp petrol cars have these also or have other items which could fail and also be expensive. Don't get tied up on these what ifs. Look at the regular service costs and also timing belts changes if applicable when you are comparing running costs.

Fuel will be your biggest saving, forget the quoted figures as if you are in an urban environment and unless you have a Pruis you will not attain the urban mpg figures in a petrol and the diesel will remain closer to the quoted mpg. On the open road the quoted figures will be more accurate.

The Passat was bought as a workhorse, now has 150k miles on it and touch wood its running great. I am a high mileage driver and as a tool for a job I would not buy another petrol car for family use again, my next petrol will be a sports car.

At the moment I have sort of decided what the next relacement will be for the VW. Plan is to keep it till 2012 and then, funds permitting, import a 2l TDi Superb estate from the UK as I will be buying used and I don't see anything out there in terms of space / value for money etc that would be a better buy in 2/3 years. Unless of course I buy a garage queen and aim for 300k miles on the VW. Always wanted an E30 M3 or 968 for some sunday fun.:rolleyes:

So, if its efficient everyday transport you want I think its hard to better diesel, some people hate them some people love them. For me its the best choice for my needs, boring is not a bad thing in my book for an everyday commute when you want something that just gets on with the job. Maybe I'm getting soft in my old age??

Best of luck with whichever you buy.

sean1141

galwaytt wrote: »

If you drive a diesel, and only service it every 30k kms, you deserve every bit of trouble you get. And you will get it. I wouldn't go 1km past 10k kms in a modern diesel without a basic service anymore. (learn't the hard way..)


+1

OP - diesels are more expensive to service, and are heavier, too (cue: might require shocks and drop links a bit sooner, too..............)

take for example a vw bora. 1.6 v 1.9tdi 130bhp
front shocks and springs are smaller and weaker in the 1.6 so they will wear every bit as quick as the diesel.
service
petrol
every 10k oil and filter
every 40k spark plugs and air filter
every 60k timing belt + water pump

diesel
10k oil and filter
40k fuel filter + air filter
every 60k timing belt + water pump

so pretty much the same in terms of costs. i have driven both petrol and diesel so i know

OP you should be able to pick up a nice tidy tdi bora for what your looking to spend. they are less troublesum than the passats as they dont have the alu front linkage that the passts suffer from. also being a bit lighter you will get a few more mpg from them. but the passat would have a small bit more comfort!

maidhc

I would surmise as follows:

If buying new/nearly new, get a diesel.

If buying secondhand, get a petrol.