Petrol / Diesel differences....

[Buttons76]

apart from the blantantly obvious of course!

I am open to owning either but there are 2 major things for consideration:


how does the MPG differ between the 2 in the real world - i dont beleive what car salesmen tell me full stop!
And then there's the residual value to take in to account.....
diesels always seem to hold their value better but is this true with the A4 also?
I dont notice a big difference in price at present but is this because the cars i am looking at are relatively new still? ('11, '60 and '61 looked at so far)

As i said, im keen to hear opinions from the real world!

[theskyfox]

Um..just a few thoughts....

-Diesel is generally lower road tax/lower insurance

-As a rough guide, to get an idea of the real MPG take the Combined cycle figures and knock off 10mpg and it should be about right. Figures in the book are from the rolling roads which don't take into account things like tyre friction and air resistance.

-Things like gearbox type and driving style will affect MPG heavily. Manuals use less fuel than autos, if you take quattro as an option you will lose about 5 MPG.

-Don't consider diesel if you are doing very low mileage, you will lose any benefits as you only get the decent MPGs when the car is fully warmed up (This can take a long time to happen). Constant stop-start driving can screw things
like the Diesel particulate filter (which all diesel cars 2008+ will have).

-The bigger diesels (e.g. 3.0TDi) are superb performance and the newer ones have a quicker 0-60 time than their petrol equivalents, but of course..the MPG gain only becomes "relative" in these engine sizes.

-Although they have a higher initial cost, you get some back in resale value. Try selling big engined petrol cars these days...their appeal is falling.

-Most fuel efficient will be something like a Front wheel drive, manual 2.0TDi in the range. Last time I looked the lowest was 140bhp, but there might be more with lower BHP that give more MPG now...

-From personal experience, I was buying a 3.0TDi. I spent a whole year looking for a used one..and actually found it worked out better value to haggle on a new car and get a good finance deal
since the value on the used ones was only actually about a £3-4000 difference (which was nothing considering you could choose all options new and have the full 3 year warranty).

-Andrew

[Buttons76]

Andrew,

Thank you for your reply, some real good points there.
I currently have (don't shoot me down!) a BMW 330d - it is a great car to be honest, 240bhp and a consistent 39mpg (if you choose to believe on board computer).
The car is getting on now, 55 plate and 120k, so it's time for a change and I fancy an Audi.

Yes... I have considered the 3.0tdi but they seem hard to find second hand and carry pretty hefty price tags new (in my opinion of course).
In a nutshell, I would like something to return mpg in the region of what I'm used to.
My wife will also be using the car so a smaller engine appeals in that respect too.

There are 3 variants I am considering....
A 143bhp TDi, a 170bhp TDi and the 2.0T petrol (as this looks quite respectable on paper but small enough to please my concern of wife!)

Again, the second hand market isnt flooded with 170bhp so that just leaves the 143 and 2.0T really.
I'd expect the 143 to be quite boring but return good MPG - however, the 2.0t would give a slightly wider smile..... :biglaugh:

I just need to weigh up if the width of the smile is enough bearing in mind the MPG!

Residual value.... I agree that diesels tend tend to be better but even so with the small engines? (im classing 2litre as small for this example)

hope this makes sense. Decisions decisions!

[John140]

For what its worth, my A4 TDI 143 does about 48 Mpg at high 70's MPH on the motorway. On nice warm days maybe 50 Mpg if you stay below 80.

In the current bout of hideously cold weather however I struggle to get into the 40's until I have done a good few miles from a cold start. Mind you it has been between -2c and -8c every morning for the last week. The new CR engine isnt much if any more economical than my old PD 140 BHP, but it is way more smooth quiet and flexible than the old engine.

[J_B204]

My quattro tdi 170 manual has returned an average of around 45 mgp over 8500 miles.

Mostly motorway miles and easy on the right foot too.

I'm happy with that considering the low mileage. Will say that pick up is great but won't necessarily compare with your 330d.

Agree that there are few on the market though.

On the 2.0t petrol, think they're easier to find but you may be shocked with the real life mpg when compared to your current car, that said very tidy performance and cheaper.

Given the performance of your current car and the fact you look to be after something that'll be keep the juices flowing you may find the 143 disappointing.

I personally think the performance of the 143 to be pretty good BUT I'm not comparing to a 330d!!

My recommendation....

Test drive, test drive, test drive!

Only you know what performance you are willing to accept vs cost etc

Sent from my LT15i using Tapatalk

[Buttons76]

Totally agree - I have spoilt myself with the 330d and replacing it like-for like is out of budget.
I also agree with test driving,.... I am borrowing a 143bhp TDi for the day from my local Audi *******.
It's a lovely looking car with a good spec list but only a good drive will tell me if I could live with it.

I don't know what it is about the 2.0T petrol but I am strangely attracted to it!
Strange as my last 3 cars have been diesel.... (B7 1.9tdi, modeo (!) TDi and the BMW).

I'll be honest, I haven't noticed much price difference between diesel and petrol on the forecourts.... maybe that's my first mistake! ;)

[theskyfox]

I wouldn't shoot you down for having a BMW. I think their engines are better than Audis in that they seem to be able to extract more BHP whilst giving more MPG. The main thing that lets them down for me is the rear-wheel drive, and the fact that you literally have to shell out a bomb for every optional extra.

You're definatley going to notice a drop in power from anything less than the 240bhp...the real equivalent would be the 3.0tdi. Best bet would be like these guys have said..get out there and test drive a few. You're definatley doing the right thing, research is the key thing. Let us know what you choose in the end!

-Andrew

[sparker3000]

Interesting thread. I personally think petrol cars are getting more attractive. One reason is that Diesel is 9p more per litre. Or at least it is where I am.

Also when speccing up my new A4 which is on order I had the choice of:

1. 3.0 TDI quattro, s-tronic. Combined mpg is 47.6 and 0-60 is 6.1

2. 2.0 TFSI quattro, s-tronic. Combined mpg is 39.8 and 0-60 is 6.6

I worked out that on roughly 10,000 miles per year the diesel is around £250 more per year cheaper on fuel. And half a second quicker. But the petrol is nicer to drive.

But, and wait for it, the diesel is £4000 more expensive!

It was a no brainer for me and I ordered the petrol.

[theskyfox]

You've kinda hit it in a nutshell there though. You just said...you were comparing the 2.0T and 3.0Tdi. Why didn't you look at the 3.0 Petrol? :P

-Andrew

[sparker3000]

Why didn't you look at the 3.0 Petrol? :P

I wish!

I did test drive an S4 which was just awesome, gave me goose bumps it was so quick. My heart said yes but my bank balance said no :(

[John140]

I don't know what it is about the 2.0T petrol but I am strangely attracted to it!
Strange as my last 3 cars have been diesel.... (B7 1.9tdi, modeo (!) TDi and the BMW).

I'll be honest, I haven't noticed much price difference between diesel and petrol on the forecourts.... maybe that's my first mistake! ;)

I had a 2.0T as a loan car a while ago, compared to my TDI 143 it was drinking me out of house and home !!
The real world MPG is far worse than the advertised figures, even though I understand you have to give these a wide latitude.

[J_B204]

Interesting thread. I personally think petrol cars are getting more attractive. One reason is that Diesel is 9p more per litre. Or at least it is where I am.

Also when speccing up my new A4 which is on order I had the choice of:

1. 3.0 TDI quattro, s-tronic. Combined mpg is 47.6 and 0-60 is 6.1

2. 2.0 TFSI quattro, s-tronic. Combined mpg is 39.8 and 0-60 is 6.6

I worked out that on roughly 10,000 miles per year the diesel is around £250 more per year cheaper on fuel. And half a second quicker. But the petrol is nicer to drive.

But, and wait for it, the diesel is £4000 more expensive!

It was a no brainer for me and I ordered the petrol.

Absolutely spot on - did the same calculations for me and it was the diesel that worked out best (intending to own for quite a while) - also wanted the quattro.

Comparing Petrol vs Diesel on just performance and mpg alone misses out the point that diesels are more expensive and diesel is a lot more at the pumps.

First off I sat down and worked out how long I wanted to own the car (which has always changed but I had to have a starting point).

Added cost of car, mpg adjusted for difference in cost of petrol vs diesel, then factored in purchase price and car tax difference, finally having a quick look at insurance prices.

After all that I had a comparative set of figures for cars ranging from the 1.8T up to the 3.0 TDI quattro - finally settled on the 2.0TDI quattro...getting the SE Technik instead of the S-Line as I favoured the equipment over the styling.

Easy enough if you are **** about these things as I am!!!!

[ScottyUK]

But, and wait for it, the diesel is £4000 more expensive!

When I ordered mine the 3.0TDI was only £850 cheaper than the S4. I'd bet the S4's residuals easily cover that difference.

I decided I didn't need that performance so I spent a load on options on a 2.0T instead.

[satsu]

1. 3.0 TDI quattro, s-tronic. Combined mpg is 47.6 and 0-60 is 6.1

2. 2.0 TFSI quattro, s-tronic. Combined mpg is 39.8 and 0-60 is 6.6

I worked out that on roughly 10,000 miles per year the diesel is around £250 more per year cheaper on fuel. And half a second quicker. But the petrol is nicer to drive.



Beware of the figures! The 3.0TDI might only be half a second quicker on paper (partly due to that extra gearchange - grrr!) but in real-world driving it's much faster thanks to that mountain of torque. Conversely while you can get close to the theoretical mpg in warm weather on longer trips (I typically average 42-44 true mpg) short trips in cold weather are a killer (25-30mpg!).

I'm very happy with the 3.0TDI; it suits the sort of driving I do and I'll probably get another one next time round. Mind you, everyone here is spot on - fire up an excel spreadsheet, do your sums carefully and test drive, test drive, test drive. :-)

[Buttons76]

thanks for all the replies, It's been good reading feedback from real people :D

For the record, I still haven't decided 100% what to get but I will bear in mind everything I've read recently when looking.

Thanks :D

[SunnyBard]

I currently have a BMW 330d - it is a great car to be honest, 240bhp and a consistent 39mpg (if you choose to believe on board computer).

Yes... I have considered the 3.0tdi but they seem hard to find second hand and carry pretty hefty price tags new (in my opinion of course).
In a nutshell, I would like something to return mpg in the region of what I'm used to.


I've had my 3.0TDI for nearly a year, for the first 5-6 months I put every mile and every diesel receipt into spritmonitor and it worked out at a true 33mpg (trip computer generally claimed about 3mpg higher) that does include a few tanks full where I was trying to be good, but I bought the car to enjoy and the majority of the miles I don't have fuel economy as my primary aim :D about 75:25 motorway:town driving at a guess.

[albion80]

all i can add is that as an owner of a 2.0 tdi 143 auto for 2 months now (after owning a 2.0 fsi for 4 years) - youre only really gonna see the benefits if you're doing motorway miles in my humble and limited experience.. everything else is merely swings and roundabouts and down to what you prefer driving around in

[ScottyUK]

it worked out at a true 33mpg (trip computer generally claimed about 3mpg higher)

If you have or have access to VCDS you can tweak the DIS to show your corrected figure ;)

[SunnyBard]

If you have or have access to VCDS you can tweak the DIS to show your corrected figure ;)

Yes I knew that, but never seem to build up enough reasons to make buying one seem attractive (if they were fifty quid I'd have one!)

Just had a look back at my spritmonitor data, and the highest true mpg over a full tank was 38, and in general the trip computer tended to exagerate more, the more you tried to be economical ... i.e. it helped you fool yourself.

[ScottyUK]

Yes I knew that, but never seem to build up enough reasons to make buying one seem attractive (if they were fifty quid I'd have one!)
Well if you're ever in Essex/North London .... ;)

[J_B204]

Did a 500 mile return journey starting with a full tank ( filled until full followed by one more squirt!)

Other driving took the total to 560 with range saying 35 miles left.

Filled up - put 55 litres in.

So by my calculations...

About 10 miles per litre... Therefore 45 mpg - display said 48 but...

I had 9 litres left in the tank which meant more than 35 miles left, in fact more like 90 which would have meant around 640 miles on a tank which means 10 miles per litre which means 45 mpg...

So 45 mpg for a 170 tdi quattro in sub zero temp with only 9500 on the clock... I'm happy with that ...

Oh and I will admit I was easy on the right foot...

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[markp306]

2.0 TFSI quattro, s-tronic. Combined mpg is 39.8 and 0-60 is 6.6 ................ It was a no brainer for me and I ordered the petrol.

OK, so the maths works, but what are you actually averaging (just out of interest)?
I can concur with the previous responses. 50+ is no problem if sticking at 70mph, but dropping to mid 40's for another 10mph or so. A mixture of dual carriageway and A roads yesterday saw 47mpg on the DIS.

I notice the imminent version of the 1.8T (170PS) looks econmical with a claimed 49mpg combined. Not bad!

[sparker3000]

OK, so the maths works, but what are you actually averaging (just out of interest)?
I can concur with the previous responses. 50+ is no problem if sticking at 70mph, but dropping to mid 40's for another 10mph or so. A mixture of dual carriageway and A roads yesterday saw 47mpg on the DIS.

I notice the imminent version of the 1.8T (170PS) looks econmical with a claimed 49mpg combined. Not bad!

Will let you know when I get it (-:

[John140]

Yes I knew that, but never seem to build up enough reasons to make buying one seem attractive (if they were fifty quid I'd have one!) .

I'm surprised the chinese havent copied the system yet on Ebay for less than £50 they must be slipping !

[SunnyBard]

I'm surprised the chinese havent copied the system yet on Ebay for less than £50 they must be slipping !

Well, I think they have ... but ...

a) If I can't get free/open source software, and I don't like the price of the commercial offerings, I go without rather than reach for the tricorn hat

b) Talking about dodgy s/w is frowned on vwaf.

[cornwallman]

Interesting thread. I personally think petrol cars are getting more attractive. One reason is that Diesel is 9p more per litre. Or at least it is where I am.

Also when speccing up my new A4 which is on order I had the choice of:

1. 3.0 TDI quattro, s-tronic. Combined mpg is 47.6 and 0-60 is 6.1

2. 2.0 TFSI quattro, s-tronic. Combined mpg is 39.8 and 0-60 is 6.6

I worked out that on roughly 10,000 miles per year the diesel is around £250 more per year cheaper on fuel. And half a second quicker. But the petrol is nicer to drive.

But, and wait for it, the diesel is £4000 more expensive!

It was a no brainer for me and I ordered the petrol.

Did the same calculations as you, comparing a 2.0 TDI170 Quattro with a 2.0TFSI Quattro, using MPG figures from http://www.honestjohn.co.uk/RealMpg/Results?manufacturer=audi

Not sure how reliable, but came to £300-350 pa difference on 12,000 pa.

One thing not mentioned is maintenance differences between petrol and diesel, looking at the Audi service schedule, it looks like the Petrol goes twice as long before a service, and Petrols have cam belts at 120k, not 60k on a diesel, plus differences with filter changes , set against new plugs at 40k I think in a petrol.

[Buttons76]

That's very interesting, hadn't looked at it from that angle.
Thing is, is 39.8 realistic with the petrol?

I had a 136bhp diesel for a morning last week and its average mpg in time I had it (96miles) was 35.9 - not too impressive bearing in mind how gutless it was..... :(
One theory I had was that as it was lacking power, in my opinion, I was driving it harder than I would a bigger output engine and thus using more fuel - false economy.

I currently have 3.0tdi that I drive like I stole and get circa 39!
I'm thinking that upping my budget will be cheaper in long run than - how's about that for some strange logic?! ;)

[ScottyUK]

You'll definitely get closer to the diesel mpg than you will the petrol mpg. Just take a look at my sig! hehehe

These calculations are very personal and depend massively on the mileage you do and how you drive. I think many people would argue against the comment "but the petrol is nicer to drive."

The will of course be a premium to be paid for a faster car and the 3.0TDI is a lot quicker in the real world i.e. over taking etc rather than 0-60.

If I was paying the extra £4k then I'd spend a fraction more and get an S4! The residual would probably cover the cost difference.

[Geordie Amanda]

A few months ago I drove a 330D which has roughly the same sort of power etc that my A4 3.0tdi has. To be honest, I thought it was slightly nicer to drive (don't shout), but of course having recently been in the snow again, the A4 is light years ahead in that sense. The 330D seems slightly more economical too btw but I average around 41-43 mpg mainly, as I drive mostly motorways.

As for performance a friend of mine with a TTS recently exclaimed he thought the performance of his and my car, were roughly similar -his having more 'top end bite' and mine having more 'shove'- and that for the first time in his life he would consider a diesel when the time comes to change. This guy is a petrol head nutter too, so I guess the 3.0tdi can gain no higher praise really :)

[Buttons76]

having recently been in the snow again, the A4 is light years ahead in that sense :)

I can't argue there, the 330d is the worst car I have EVER had when snow around :zx11:

[SunnyBard]

it looks like the Petrol goes twice as long before a service

My diesel on variable servicing is 19200 between services, I can't see the petrol being 38400, as for the belt changes I can't remember what they are, you could well be right on those.

[Simo_UK]

Hi All,

As it happens, I'm in the market for an A4 Avant and have been considering the 2.0TFSI Quattro and the...wait for it.....3.2 V6 FSI Quattro.

Does anyoe have any experience of the V6? And any idea on true fuel economy? <gulp>!

:o)

[J_B204]

My diesel on variable servicing is 19200 between services, I can't see the petrol being 38400, as for the belt changes I can't remember what they are, you could well be right on those.

I understand that servicing for either fuel type is the same distance/time - i.e. approx 19000 miles or 2 yrs whichever comes first if you are on 'long life servicing' - fixed interval is 10000 miles or 1 yr whichever comes first and is supposed to be better for those who do lower mileages (again valid for either petrol or diesel). It is approximate I think as the computer actually calculates it in km and then converts it to miles.

The max distance/time is also dependent on driving style as the on board sensors will reduce the miles to service if driven particularly hard.

I'm approaching 10k miles with over 9k left until the first service.

[cornwallman]

Thanks J_B204, my VW tdi DPF was on the fixed servicing schedule at 10k intervals, where as the petrol Audi was on 20k, I tried to get the VW changed to Long life but they said no, now I understand why..

[theskyfox]

Really don't understand why anyone would want to do an oil service more than a year apart. The oil degrades, and the oil picks up all the dirt from the exhaust and engine. In the first few thousand miles you tend to find all sorts of rubbish in your oil including iron filings. Ditch it every year and keep your engine purring :).

-Andrew

[OVI82]

Finally someone who talks sense.And I bet you these people have never done an oil change themselves or seen an engine wrecked by oil sludge.

[J_B204]

Thanks J_B204, my VW tdi DPF was on the fixed servicing schedule at 10k intervals, where as the petrol Audi was on 20k, I tried to get the VW changed to Long life but they said no, now I understand why..

Interesting as my father in law (with a golf mk6) has been told that you can switch between services as long as you do it at a scheduled service. I.e. You are on fixed 10000 mile service, and are ready for your 20000 mile service there is nothing to stop you from asking to have the car changed to a long life service - you'll just have to pay the higher rate.

The main difference between the two types of service is the type of oil that is used IIRC.

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[J_B204]

Finally someone who talks sense.And I bet you these people have never done an oil change themselves or seen an engine wrecked by oil sludge.

In fairness we are only taking about cars that are at maximum a few years old. Whilst I agree that changing oil every year is better for the engine, we don't change air filters, brake pads, pollen filters, etc etc every year and yet replacing those every year would be beneficial.

I've only owned 2 cars (a Passat and my current car ) with long life servicing and neither had an issue.

Theskyfox actually said that oil should be replaced every year - for higher mileage cars they could easily hit the 18/19000 mile limit in that time so wouldn't benefit from yearly servicing. Equally someone who only does 5000 miles per year will easily go to the 24 months maximum and yet only get to 10000 miles.

Imho modern engines with modern synthetic oils are designed to cope with high mileages using longer life service schedules. If they weren't you'd find forums like these plastered with posts bemoaning the long life service schedules and in my short time on this forum I haven't seen a single post like that!

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[skymaster]

Really don't understand why anyone would want to do an oil service more than a year apart. The oil degrades, and the oil picks up all the dirt from the exhaust and engine. In the first few thousand miles you tend to find all sorts of rubbish in your oil including iron filings. Ditch it every year and keep your engine purring :).

-Andrew
I couldn't agree more. It's crazy how long some cars go without an oil change. Whats worse is how Audi seem to have begun 'servicing' cars and not changing the oil!!!!! My car has just under 30k on the clock in 3.5 years, It's got three stamps in the book. I rang the servicing dealers to check which service was carried out each time. One of them was an 'inspection only' service where the oil stayed in the car... and it seems it's never had a new air filter either! Are the dealers trying to make more work for themselves later on when these engines go south?

[skymaster]

Imho modern engines with modern synthetic oils are designed to cope with high mileages using longer life service schedules. If they weren't you'd find forums like these plastered with posts bemoaning the long life service schedules and in my short time on this forum I haven't seen a single post like that!

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I have been on the forums for a while, and believe me, there are plenty of posts with people moaning about this, and also moaning about serious engine issues later on in the cars life. I have even found that if you develop a good rapport with the guys in the dealerships even they will admit that longlife service schedules are no good.

[theskyfox]

This should probably be in a new thread actually...but the other thing that tends to be a worrying new trend is this modern fad changing your oil by sucking it out through the dipstick..so you sit thinking, how is the sludge at the bottom of the sump ever going to come out????

-Andrew

[thescouselander]

This should probably be in a new thread actually...but the other thing that tends to be a worrying new trend is this modern fad changing your oil by sucking it out through the dipstick..so you sit thinking, how is the sludge at the bottom of the sump ever going to come out????

-Andrew

If your oil has gone sludgy you're already in trouble as this shouldn't happen if you've used the correct stuff.

[OVI82]

My oil hasn't gone sludgy.And that's because I don't wait 2 years or 20000 miles for an oil change.And I allways service it myself(A4 b7).Curentlly looking at buying the new(to me)b8 shape,and I'm putt off by the fact that the ones I've seen so far only have 2 or at best 3 stamps in the service book(with about 60.000 miles on the clock).

[Simo_UK]

I've been using "Crisp and Dry" for my engine oil and have never had any issues....other than a desire to eat a lot of chips, and the subsequent 3 stone weight gain. Engine is running fine though! Does that help?

;o)

[drmartin]

This should probably be in a new thread actually...but the other thing that tends to be a worrying new trend is this modern fad changing your oil by sucking it out through the dipstick..so you sit thinking, how is the sludge at the bottom of the sump ever going to come out????

-Andrew

Thats an old trick so nothing new there. If you have contamination in the oil then there are bigger issues to deal with!

M

[skymaster]

I think some dealers use the 'suck the oil out' technique so that they can be 100% sure of no sump bung problems. If they strip the thread putting it back in... or don't do it up tight enough (both happened a few times when I worked at a dealers) it was always a world of pain...

[JimC64]

Apologies to OP as this seems to have turned into an oil change thread, but as I'm here I may as well add my 2c worth.

I've been driving deisels for 25 years or more now, had many many cars, all diesel in my time as a sales rep / area sales manager. I've travelled well over 1 Million miles in these past 20 years averaging 50k - 60k miles per year.
I was on longlife servicing probably before a lot of you guys knew about it tbh.
I'm not a mechanic so I can only tell you my first hand experience of these cars in their lifetime.

Istarted with a Peugeot 309GLD but they were mostly Ford Mondeos 1.8d, 2.0 Tdci and 2.2 Tdci, Vauxhall Vectra 2.2d, SAAB 93 1.9Tid and Audi A6 amongst others and all of them from new. They all went back or were sold to guys in the company after 3 years with approx 160k miles on them.
The first Peugeot had 196k miles on it after 3 years and barely missed a beat with no engine trouble to report.

Some of the cars in the later years used longlife servicing and I never ever had an issue, I did however do a lot of motorway miles and not so much stop start.

Currently my A6 has 90k miles on her and runs sweet as a nut......the first 2-3 years my driving style changed a little and down to around 20k miles per year still on longlife up to 60k - 70k miles or so. My driving habits changed dramatically so I went to fixed life servicing and am now at 90k miles