Petrol vs Diesel

[stoakseya4]

Ok so hear me out...

Why do people drive diesels?

1. There are those that think they are being environmentally sensitive as the emissions are less, and therefore less harmful.

2. There are those that drive alot of miles each year (18k +) so driving a diesel is actually financially the more sensible option, so long as it's not in a large diesel engine (2.0 max), as you need to be getting 40+mpg to make this work.

3. And there are those that think that as they are getting a better MPG figure and therefore more miles per tank, it must be cheaper than running a petrol car, which is completely wrong, due to the extra base cost of buying the fuel.

If you do c10k miles per year the actual difference between a diesel at c43mpg and a petrol car at c30mpg is only about £1 per day cheaper (on the current difference between petrol and diesel ~ 12p/ltr). Does that sort of difference make it worthwhile? I don't think so.



What's the long term scenario? Diesel costs more to produce so the liklihood is that it'll always cost more than petrol. Both diesel and petrol engines are (as you would expect) becoming ever more increasingly technologically advanced so, emissions and fuel efficiency should always be improving. The recent introduction of twin turbo's will help even more on both petrol and diesel motors.

I would imagine most people fall in Category 3 above.

What's the future for high performance petrol cars getting c15-20mpg, like our S4/RS4/S6/RS6/S8 & R8 models ? Soon it will come down to those that don't really do a great deal of mileage therefore it doesn't cost a massive amount, and those that have so much disposable income that they just don't care. Are we going to see those models all be given performance diesel engines so as to keep the S and RS marquee alive, as in the new R8 V12 diesel (but maybe a tuned 3.0 unit)?

Opinions ??

NB
This is meant as a semi-serious discussion, so please treat it as such...

 

[FactionOne]

Just to stick my tuppence in...

My own car is an A4 1.9TDI. I bought it because I was doing space-miles, and that does make it a bit more economical... The other thing is that I'd only really be looking at a car with a 1.6 or 1.8 N/A Petrol in as an alternative in terms of insurance/running costs... So the diesel burner is pocket-friendlier when running a lot of miles, but even if I wasn't, there are other advantages... Firstly it pulls like a train compared to a 1.6 or 1.8 N/A Petrol, which wouldn't pull you out of bed. In the right gear at the right moment the TDI pulls waaaaay better than the others would/do. The other thing is that the diesel is quite happy to take serious punishment... It's only ever needed fuel, a bit of oil, and tyres really. The petrol A3 I was driving needed considerably more upkeep when doing heavy miles.

My works car at the moment is a hire-car, and is a 1.6 N/A Petrol Focus, alright it's a small engine, but it's a clever twin-cam 16V zetec effort... The car I would normally be driving is a 1.9TDI Passat. Again, the Passats pull like a train by comparison. The Focus has a smidge of power between about 4,200rpm and 5,000rpm - and even burying the pedal in the carpet in that band I've got no chance of keeping up with one of the Passats. They just feel a lot more of a competent vehicle power wise. The fuel advantage is also in their favour, and again maintenance is lighter. Put it this way... This Focus is going to need a fair bit of TLC when the hire company get it back ()

If I didn't have an SP50 on my licence I'd have chopped the A4 in for something smaller with a turbocharged petrol engine; because I don't do any serious mileage in it any longer, and I don't doubt that in the right petrol car there's more fun to be had, but if you're looking down the bottom end of the petrol spectrum, a similar-level diesel always seems to be a much more pleasing drive...

Regards,

Rob.

 

[FactionOne]

Erm I think that the best answer is ...


I'll get back to you on that one...I'm too hyper to respond a sincere response to this.

Regards,

Rob.

 

[lil_coz]

Yes a diesel costs more to buy, but you selling it on means that you'll get more than a petrol so that kind of cancels that one out. You've also got to look at lower insurance for an oil burner.

I went for the dirty stuff because I do a lot of motorway miles so it made sense to get a diesel. Not to mention its effortless to drive on motorways because of the amount of torque. Its also A LOT more economical than an equivilant powered petrol. You show me a 200bhp/325 lbs/ft of torque petrol that'll do 45-50mpg and I'll happily change back. I'm not knocking petrols at all... just a diesel made sense for me and I love my car to bits. If I had to make the decision again I wouldn't change a thing!

Coss

 

[stoakseya4]

lil coz - you've hit the nail on the head really. You can't get an equivalent petrol car to a diesel in terms of power/torwue because the engines are completely different? And they'll never do 45-50mpg.

My point is, unless you do serious miles the cost difference between say a 2.0tdi 170 and a 2.0TFSI (both FWD) is only going to be c£1/day.

People's perception of diesel economy doesn't really stack up when you do the maths...

However, I would hole-heartedly agree with FactionOne's point, comparing a 1.9tdi and a 1.6 petrol, there really is no choice at all - tdi all the way.

I have both a 1.9tdi (130) and a 1.8T (190), both remapped, and can see the differences between them. The tdi is the wife's car and she doesn;t do a great amount of driving but think's she's better off with the diesel over the 1.8T because she's getting almost 600miles between fill-ups, compared to my 350-400...

Bye bye...

 

[Nickynibbles]

I've gone from a 3.0 A4 to a 698cc turbo charged Smart Roadster which does nearly 60mpg and is a total blast to drive! Its not the fastest thing on the planet by any stretch of the imagination & there's only room for 3 tesco carrier bags so it does have its downfalls! The alternative I looked at was a 1.9TDi but decided against due to the increasing costs of diesel over petrol. I know someone who bought a 1.8T 190 sline and did an lpg conversion for pretty much the same money as a similar 1.9TDi would of cost to buy alone! he does 30k miles per year & even though the lpg does slightly worse mpg than when on petrol, the much lower cost to buy means its more economical in £/mile than a 1.9TDi.

I can see small capacity single & twin turbo engines being the way of the future to give the necessary power to move 1.5 tonnes of metal and improve mpg further! This way they will be more efficient when driven conservatively and more cost effective than a larger n/a engine. Imagine a B9 chassis A4 with a 1.2 twin turbo engine spooling to 8000 rpm! That sort of engine would be capable of 200bhp easily at peak power, but if you were off boost at 65-70mph cruising along you'd be getting 50mpg easily i reckon!

 

[AndyMac]

I'd think it was pretty obvious that unless you do above average miles then diesel doesn't stack up. Nothing to do with the cost of the fuel or the residuals, just purely to make the additional economy worth it you have to be doing a decent amount of miles.
When did diesel start costing more to produce than petrol?
It always used to be cheaper or the same as unleaded at the pumps and that's been the case for the last 20 years. It's only since it's taken over as the number one fuel in the UK that it has strangely become more expensive than unleaded. Economies of scale would suggest if the demand is higher it should get even cheaper, not more expensive. Funny that isn't it?

 

[quattrojames]

Imagine a B9 chassis A4 with a 1.2 twin turbo engine spooling to 8000 rpm! That sort of engine would be capable of 200bhp easily at peak power, but if you were off boost at 65-70mph cruising along you'd be getting 50mpg easily i reckon!

You would want to debadge it tho' lol

Seriously I agree with the driveability of diesels - I love the slug of torque from 2000rpm on ..... The equivalent bhp to my 2.5TDi would be a 1.8T (190 bhp are they?) which if I drove it as hard and fast as I drive mine would achieve considerably less mpg than i do (I imagine??). I agree the cost of diesel fuel will largely offset that, but even saving £1/day is £365 a year, (a week in the sun?)! I like 6 cylinder engines for their smoothness over 4 cylinders, but a 3.0 A4 would have hit me even harder on fuel, hence the 2.5TDi

 

[AndyMac]

When some people won't even pay 50p a day for decent TV, £1 a day is quite a lot.

 

[g60jet]

I had a Leon 1.9 TDI FR, i just got the A4 Avant quattro 2.0TFSi and i did a check between the TDI version and petrol version and the cost of the Fuel was 1p difference per mile @10k per year on Audi's figures. i figured that Diesel will continue to rise faster than petrol per litre. So i went back to the petrol.
Yes it more to insure, yes its more to tax, but petrol cars are cheaper to start with.

So consider this
a TDI costing £20k and a Petrol costing £18k on a like for like spec bar the engine, both depreciate at the same percentage rate, which one looses more money.
Answer the Diesel.
say the cars depreciate at 5% per year
at the end of year 1 the TDi would be worth £19000 a drop of 1k
the Petrol at the end of year 1 would be worth £17100 a drop of only £900 thats a fair bit back toward the car tax or insurance.

 

[AndyMac]

But the diesel won't depreciate at the same rate as the petrol - thats the whole point! Durrrhhh!

 

[g60jet]

But the diesel won't depreciate at the same rate as the petrol - thats the whole point! Durrrhhh!

thats what the sales men have you believe but they do.
for example
I lost 6k in the 3 years i owned my tdi FR, and the petrol FRs on the market when i sold it had lost the same amount from the list price new when i worked it out as a percentage.

 

[lil_coz]

I'm sorry... but if your basing your losses on a Seat then thats where all your calculations have gone wrong. A Seat will depreciate like a stone compared to an Audi. Diesels will hold onto their value better as well as they are still being bought everywhere. You look at Audi's sales and the TDI's are selling like hot cakes! Every model out, Audi are saying that the TDI variants will sell the most.

 

[bigdom71]

Ok so hear me out...

Diesel costs more to produce so the liklihood is that it'll always cost more than petrol.
NB
This is meant as a semi-serious discussion, so please treat it as such...

Diesel is a by-product of Petroleum production, it gives them something to do with it; it costs them F*ck all to produce. There are a couple of reasons to the cost differences.

1. The UK always lagged behind europe in the 90's in converting to Derv, so the oil companies shut down some processing plants.

2. The UK government 'loads' diesel with tax - one is due to the supposed link to asthma (after they got people buying them) and now they come with DPF filters. The other is simply that as diesel is the number one fuel sold now, with cars doing more MPG Gordon/Darling recieve less money from us in tax!

3. If you remove the 'tax' we have the second cheapest diesel in Europe.

If i didn't do 40k a year, i would have Petrol, however something with a minimum of 6 cylinders - you got to go big to get the same mid-range. My combined fuel bill is over £500 a month as it is, if i drove Petrol it would be at least £900 a month.

If i wouldn't do a set of tyres every month, i would ride the Blackbird to work and take the hit on the reduced fuel consumption over the 1.9tdi. Now i just take the car allowance and run a 'disposal' car over a period of a few years. And leave the toys for the weekend.

I remember those sunny days, driving the old cossie with two banks of injectors, sucking premium unleaded in single figures, how times have changed.

 

[g60jet]

Thing is with Audi TDI's the market is flooded with them on the second hand market so that makes the prices come down as there are so many to choose from.

 

[g60jet]

If i didn't do 40k a year, i would have Petrol, however something with a minimum of 6 cylinders - you got to go big to get the same mid-range. My combined fuel bill is over £500 a month as it is, if i drove Petrol it would be at least £900 a month.

£500 thats 384 liters of Diesel (based on 129.9p/l)
£900 is 769 liters of Petrol (based on 116.9p/l)
(prices from the lowest stations near my postcode on petrolprices.com

you'd need be doing Half the MPG of the Diesel for it to cost you that.

 

[bigdom71]

The current car, Standard 1.9 130 B6 does 50 Mpg.

Say for argument sake a 530i will if i'm lucky return 25mpg (on a manual) My commute involves a lot of sitting around on various motorways including all the worst bits on the M25. My mate sees only 22 on a 523i auto.

As for the litres thats about right, thats why i always hit the bonus points calculator on the Shell air miles card!

 

[g60jet]

The current car, Standard 1.9 130 B6 does 50 Mpg.

Say for argument sake a 530i will if i'm lucky return 25mpg (on a manual) My commute involves a lot of sitting around on various motorways including all the worst bits on the M25. My mate sees only 22 on a 523i auto.

As for the litres thats about right, thats why i always hit the bonus points calculator on the Shell air miles card!

yeah but you cant compare a 1.9tdi with a 3l or 2.3l petrol, i bet if you drove the BMW in the same style as you drive the B6 you'd get more than 25mpg you have'd to have a heavy right foot to my way of thinking, or are BMW's that bad.

Trouble is there are so many ways to compare petrol and diesel

How do you match them like for like, MPG, BHP, PS, KW ?

for example a B7 2.0l TFSI is 147kw, the same in a TDI is a 3.0l give or take 3KW but loads more torque.???????????

I'll give you this though you berry your foot in a petrol and you can almost see the gauge move, but its not that bad in a diesel due to the torque a TDI produces.

 

[Ess_Three]

For me, it's simple...firstly:
A 1.9 TDI making 150ish BHP and 250ish lb-ft, and driven like a hooligan still returns 40+ MPG...nearer 50 MPH when you drive more sedately.
A similar powered petrol engined car will give 20+ MPG when driven hard...and maybe mid 30s when driven like you are driving your gran to church.
BTW, I have both...so know how the figures stack up.

Secondly:
As a complete petrolhead and hater of all things diesel...they are just 'better' to scoot about in when it's your everyday car.
You can be as lazy as you like, very few gearchanges, loads or torque...both easy and relaxing.


Despite rising fuel costs...diesels being dearer to buy etc...I'd still choose one as my 'normal' everyday car.

 

[g60jet]

For me, it's simple...firstly:
A 1.9 TDI making 150ish BHP and 250ish lb-ft, and driven like a hooligan still returns 40+ MPG...nearer 50 MPH when you drive more sedately.
A similar powered petrol engined car will give 20+ MPG when driven hard...and maybe mid 30s when driven like you are driving your gran to church.
BTW, I have both...so know how the figures stack up.

If i drove my old Leon FR TDI 150 like a Hooligan i could get it down to 18mpg on the MFA. I'd average 42MPG on a mixed run inc town and motorway on a normal run, not try to save fuel or drive fast. on the motorway i could get it upto 50mpg. It depends on the roads types, and how quick you floor it.

The only thin i miss about my tdi is the lazy driving style and torque, but its a different driving style that you need to adapt to for each engine imho.

 

[lil_coz]

If i drove my old Leon FR TDI 150 like a Hooligan i could get it down to 18mpg on the MFA.

Thats **** poor if you ask me. I gave my car a proper leathering the other day. Dunstable to Daventry and my foot was flat to the floor the WHOLE way! There were some country lanes involved too and I treated them like a rally stage. You know what I averaged in my car (200bhp quattro)? 32mpg. Thats the lowest I've ever seen it.

 

[g60jet]

Thats **** poor if you ask me. I gave my car a proper leathering the other day. Dunstable to Daventry and my foot was flat to the floor the WHOLE way! There were some country lanes involved too and I treated them like a rally stage. You know what I averaged in my car (200bhp quattro)? 32mpg. Thats the lowest I've ever seen it.

Yeah but the 18mpg wasn't the average, that was the instant measurement. I should of said that.

32mpg sounds about right for an average enthusiastic run in a normal TDI and good for a quattro to my way of thinking

 

[g60jet]

bigdom71 How many miles are you getting from a full tank, assuming you fill the tank normally and don't press the breather value in inside the filler neck?

 

[john_cook]

Dont forget that earlier this year Diesel was not so much more expensive than petrol, only a few pence, so it was more even more economical then even if not doing as many as 20,000 miles per year.

Now the difference is as much as 12-15p a litre between petrol and diesel its looking like a less sensible proposition, unless you are doing lots of miles. Is unfair the price of diesel has gone up so much more relative to petrol, both are overpriced of course.

 

[Dubplate]

If i had a choice and wasnt covering as many miles as i am i would stick to a petrol variant but as this isnt the case its diesel all the way, 40mpg is the worst ive seen in my BMW td after very hard hack and the best ive had is 60.1mpg.. I never had the S3 anywhere near the 40mpg mark....

 

[AndyMac]

Yeah but the 18mpg wasn't the average, that was the instant measurement. I should of said that.

The instant reading on the DIS means absolutely nothing, I've had it reading 200mpg in my 2.8Q, going downhill in neutral.

 

[benr]

The instant reading on the DIS means absolutely nothing, I've had it reading 200mpg in my 2.8Q, going downhill in neutral.

Agreed i have no idea why this feature is even on the dis.

On a decent run i average 60-79mpg but on a hard run average about 45-50mpg in a 1.9tdi. and i would definatly go for a tdi any day due to the torque and £100 tax and cheap insurance and they seem to go on forever.

I wouldnt buy a car new anyway so the extra cost from petrol/diesel model wouldnt make much difference.

Personal preference but i beleve there is a snobbery about it.

 

[quattrojames]

Agreed i have no idea why this feature is even on the dis..

Although you cannot get a representative reading from it, I think it's purpose is to highlight just how much fuel you are actually using (or not) at any given moment in any gear depending how hard you are accelerating. it's quite interesting if you use it as it was intended!

 

[AndyMac]

But it doesn't, it gives a very false reading. If you want to know fuel consumption at a particular moment in time then zero the average reading.

 

[buckas]

3. And there are those that think that as they are getting a better MPG figure and therefore more miles per tank, it must be cheaper than running a petrol car, which is completely wrong, due to the extra base cost of buying the fuel.

they're not, super/v-power is the same as diesel near me. maybe ordinary unleaded is cheaper, but i wouldn't run my car on 95ron

 

[bigdom71]

bigdom71 How many miles are you getting from a full tank, assuming you fill the tank normally and don't press the breather value in inside the filler neck?

I can quite easily get over 700 miles out of it, with room to spare. My commute is 144 miles per day, so i fill up generally every 4th as the Diesel is cheaper at home. Working out manual tank to tank it ranges between 47-54mpg.

With regards to the Petrol engine, i know you cannot compare like for like, however for 'everyday' use, you require torque between 30-80mph, this is where a diesel will wipe the ar$e of a similar sized petrol, and you require a large petrol engine to have that everyday flexibility. I can't be bothered revving the nuts of stuff just going to and from work!

In addition, i'm sticking approx 40k on this car for probably 2-3 years. I bought it last November FSH with 83K on it. It's now got 111k on the clock. Diesels are made to do mileage, small petrols aren't.

In the past i've had two cossies, UR Quattro, Alpina E30 B6 & E39 B10, E38 740i, 67' split screen camper with Porsche lump to name a few. Trust me, they all suck petrol sitting in traffic.

For the weekend i have a Blackbird, not the ultimate sports bike, although good for a large kid like myself. Soon i'll be out looking for a new 4 wheel toy, as i've just sold the Noble M12 as someone made me an offer at Le Mans 24hr i couldn't refuse.

 

[quattrojames]

But it doesn't, it gives a very false reading. If you want to know fuel consumption at a particular moment in time then zero the average reading.

Please can you explain how that is more accurate than the 'spot' consumption figure from the DIS?

 

[g60jet]

I can quite easily get over 700 miles out of it, with room to spare. My commute is 144 miles per day, so i fill up generally every 4th as the Diesel is cheaper at home. Working out manual tank to tank it ranges between 47-54mpg.

Basically you should be filling with about 60l of Derv a time then
and on a derv price of £1.329 per liter thats 11p per mile

using petrol at £119.9
I do 450 per miles on my town run to work, thats 15p a miles. but on the motorway my tank range goes to nearer 500. thats 14.3 per mile

I bet if i didnt have a quattro that would be a range of maybe 550miles at 13p per mile may be less.

so if Diesel continues to rise at the present rate petrol and Diesel will be costing the same per mile on fuel alone.

 

[bigdom71]

Basically you should be filling with about 60l of
so if Diesel continues to rise at the present rate petrol and Diesel will be costing the same per mile on fuel alone.

True, however when i bought it 7 months ago, the gap between them was just a couple of pence a litre. The issue is rip-off Britain, and if there's a way to screw the motorist, someone will!

Even working with the Gap at 3.3p working on your calculations, i'm still better off by £1320 over the year based on the assumption i will rack up 40k.

Looking at todays receipt - 48L (£62.88 - £130.9L) mileage 604 - i make this 10.4ppm. At 132.9 it's 10.56ppm.

Based on your car and calculations

450/119.9/60 = 15.9ppm
500/119.9/60 = 14.3ppm

This then makes 5.5ppm difference on your 450 tank, or 3.9ppm on your 500 mile tank. Or a saving between £1560-£2200 pa @ 40k miles. Which i'm sure your agree is enough for a 'free' holiday.

As i mentioned, this car is just to commute in, take the miles and be thrown away - why would i waste money just to get to and from work? I'm fortunate enough to have a toy, although soon to be toys again for the weekend.

Now the really Good news, i've found someone in the past day who will supply me with B100 (i haven't the time or the inclination to make it), and this is going to cost me 85p a litre even with the duty!

Thats the great thing about the 1.9tdi over the new 2.0tdi, it runs bio fuel as standard, i'll just need to change the fuel filter after 1K miles, although it will need doing anyway at the next service.

So i will be able to drop it to back under 7ppm! Now that is a right touch.

 

[g60jet]

True, however when i bought it 7 months ago, the gap between them was just a couple of pence a litre. The issue is rip-off Britain, and if there's a way to screw the motorist, someone will!

Even working with the Gap at 3.3p working on your calculations, i'm still better off by £1320 over the year based on the assumption i will rack up 40k.

Looking at todays receipt - 48L (£62.88 - £130.9L) mileage 604 - i make this 10.4ppm. At 132.9 it's 10.56ppm.

Based on your car and calculations

450/119.9/60 = 15.9ppm
500/119.9/60 = 14.3ppm

This then makes 5.5ppm difference on your 450 tank, or 3.9ppm on your 500 mile tank. Or a saving between £1560-£2200 pa @ 40k miles. Which i'm sure your agree is enough for a 'free' holiday.

As i mentioned, this car is just to commute in, take the miles and be thrown away - why would i waste money just to get to and from work? I'm fortunate enough to have a toy, although soon to be toys again for the weekend.

Now the really Good news, i've found someone in the past day who will supply me with B100 (i haven't the time or the inclination to make it), and this is going to cost me 85p a litre even with the duty!

Thats the great thing about the 1.9tdi over the new 2.0tdi, it runs bio fuel as standard, i'll just need to change the fuel filter after 1K miles, although it will need doing anyway at the next service.

So i will be able to drop it to back under 7ppm! Now that is a right touch.

Thing is your doing 4 times the miles of most "average " drivers, therefore base it on 10k a year and its only £330, you'd need to keep the car at least 4 years to get back the cost of the Diesel Engined car on some cars. (if you did 10k at year using yours and my figures). This is why I think diesel for the every day run to work or around 10k a year is no longer viable as it was three years ago when diesel was dirt cheap. It only costs me £70 a year more to insure the petrol over my old leon, and its about 5 or so insurance groups higher, maybe more. Then throw in the car tax at £100 extra. thats £500 a year saving if you had a diesel. so you need to have the car about 2.5 year to make the saving now but the fact is Diesel is going up faster than petrol.

Thats why i feel Diesel for the likes of me is no longer a viable option moving forward from now on for the average motorist.

Now Bio-Diesel, Brilliant and a great idea, but my other half used to run her PD100 TDI on certain well known supermarket fuel which has a percentage of Bio-Diesel, and its sooted up the turbo. I need to take the thing off a clean it at some point. I'd make sure you've not got a variable vain turbo before running Bio Diesel, but thats just my opinion. Now there is no way i can prove it, but my local VAG specialist has seen it loads of times and its always the same story.

And remember mine is a quattro so I think the difference will be a less for a non quattro petrol, or a quattro TDI.

I think the question still remains, how long before the TDI doing 50 odd to the gallon is no longer viable for the motorway muncher?

For me with the petrol I feel I've made a choice that isnt going to cost or save me anything over the old leon given the change in commute. whats is costing me is the quattro version, but having driven the TDI 130, S-line B7 and the Petrol Quattro S-Line B7 its a cost I am happy to live with even if i do have to change all four tyres at once. One thing im not going to miss about the old Diesel is having to do about 5 miles before you get any heat in the winter, but maybe that was a Seat thing with a naff heating system.

 

[AndyMac]

40mpg from a 2.0TQ? My god does the turbo and/or quattro system ever get used?
I think the point here is that you can rag the pants off a 1.9TDi and still get 40mpg. If you want to drive everywhere like a granny to achieve the same in a petrol then I'd question why have a 2TQ in the first place.

 

[g60jet]

40mpg from a 2.0TQ? My god does the turbo and/or quattro system ever get used?
I think the point here is that you can rag the pants off a 1.9TDi and still get 40mpg. If you want to drive everywhere like a granny to achieve the same in a petrol then I'd question why have a 2TQ in the first place.

40mpg is a motorway figure as i said, theres no way you can get that on my town/country lane commute to work. Ask my missus how i drive, she'll tell you I'm in no way a granny driver. Even she loves how much better the quattro feel and handles.

 

[AndyMac]

She told me last night you drive like a granny!

 

[g60jet]

She told me last night you drive like a granny!

Now now thats a bit personal................










tell your boyfriend to stop asking me out.

 

[neil.c]

I think that current prices would suggest that inflated diesel prices are helping to keep the price of unleaded down.

Our 89 MKII Golf GTi 8V used to do 50 mpg on my weekly motorway commute, our later (heavier) MKIII GTi 16v used to acheive 45mpg, our S3 acheives 38 mpg, and our 911 acheives 31mpg, all aceptable figures and all better drives than most oil burners. I drive an Astra diesel company car Monday to Friday which averages between 47 and 52 mpg and I would drive any one of the above at the weekend in preference to the oil burner.