Motoring Discussion > Petrol V Diesel Buying / Selling
Thread Author: Skip Replies: 68

 Petrol V Diesel - Skip
Some advice please guys. My Ceed will be 2 years old in a couple of months time when it will be changed and i have started to think about it's replacement.

I have never owned a diesel car, but am wondering if it might be time to change. I drive about 14,000 miles a year, about 90% of which are on motorways/dual carriageways. Given that i will be looking a similar sized car the diesel option seems to be about a grand more than the petrol plus the extra 4/5p per litre difference in the cost of the fuel, am i going to recover this in the 2 years that i will keep the car ?

The only dissapointing aspect of the Ceed has been its overall fuel consumption, it has always covered 39mpg since it was new, i admit that i do drive "enthusiastically", but since the recent price increases in fuel prices i have tried sticking to 60MPH and changing gear at about 1000 fewer revs for the last 4 tanks of petrol and the comsumption has only improved by about 2MPG. I guess that i shouldn't have been so tight and paid the extra for the 1.6 engine rather than the 1.4 !

Andy
 Petrol V Diesel - Dave_
>> changing gear at about 1000 fewer revs

That's quite a big drop, does it suggest you're changing up at 4,500 now instead of 5,500?

You'd find a diesel would just about cover its extra cost over two years/14,000 miles p.a., the decider should be whether you like driving one or not. They call for a completely different driving style which, I fear, you may not find to your liking.
 Petrol V Diesel - movilogo
>> My Ceed will be 2 years old in a couple of months time when it will be changed

Why do you want to change cars after just 2 years?? Is it a company car?

For just 14k miles/year, diesel may be just the borderline.

I have a 1.6 auto petrol Cee'd and I get around 35-39 MPG.

 Petrol V Diesel - Skip
"Why do you want to change cars after just 2 years?? Is it a company car?"

No it is my own, i know that buying a new car every 2 years is a great way to lose money but it is really my only extravagence these days. The mortgage is paid off, i dont smoke, & hardly ever go out drinking (i am not really all that sad !), and having a new car is something i enjoy having.

The 1.4 engine in the Cee'd is a cracking little (109BHP) unit and unfortunately it really encourages to rev the nuts off of it - yes, i know you don't have to, but it is so easy to get up to about 4500/5000 revs before you realise it !

Andy

 Petrol V Diesel - Statistical Outlier
Andy, I'm afraid this will sound hostile, but I'm really just very curious so please take it for the genuine question that it is. What is is about a new car that you like so much?

From what you say, the car is an extravagance, bought mainly for your own pleasure, and I guess you're losing 3-4k a year in depreciation? In those circumstances, with that much spare cash to spend, and for my own enjoyment on a reasonably modest mileage, I would be buying a 2 year old Focus ST, Honda Civic Type R or other 'fun' car, or at least something a bit larger and/or faster and/or more luxurious.

A brand new Korean shopping trolley, fine cars though they undoubtedly are, seems a surprisingly sensible and sedate choice, one that I would perhaps have expected from someone wanting to take advantage of the long warranty and low running costs over an extended period of time.

I don't have any problem with your changing just because you want to by the way, I'm just interested in why you want to, and why that sort of car?
 Petrol V Diesel - spamcan61
>> Given that i will be looking a similar sized car the diesel option
>> seems to be about a grand more than the petrol plus the extra 4/5p per
>> litre difference in the cost of the fuel, am i going to recover this in
>> the 2 years that i will keep the car ?
>>
Depends totally on what real world economy you'd achieve with the diesel.
 Petrol V Diesel - movilogo
Think of diesel as a lifestyle choice. With your 14k mileage, don't make too many calculation as when to break even compared to a similar petrol car etc. Just enjoy more torque, less trips to fuel pump etc.

 Petrol V Diesel - Old Navy
My diesel Ceed estate averages 43mpg around town and 50mpg at at motorway speeds on cruise control. Dropping the cruise speed to 60 puts the consumption down to 55mpg, (lots of NSL single carriageway roads in Scotland).

I am not too fussed about the fuel cost, I prefer the way a diesel drives, and it does need a different technique to a petrol car.
Last edited by: Old Navy on Thu 20 Jan 11 at 14:21
 Petrol V Diesel - TheManWithNoName
AndyP - driving a diesel does not constitute any large change to driving style so don't be put off by that comment. It's not like your changing from a push bike to a traction engine!
 Petrol V Diesel - Old Navy
I only said different technique, I have heard petrol drivers revving diesels to screaming point, making a lot of noise for little progress. Torque is alien to some.
Last edited by: Old Navy on Thu 20 Jan 11 at 14:36
 Petrol V Diesel - Old Navy
I would add that the Ceed 1.6 diesel is the quietest, and most refined diesel that I have driven in 20odd years of diesel cars, but I have not owned a luxobarge.
Last edited by: Old Navy on Thu 20 Jan 11 at 14:57
 Petrol V Diesel - RattleandSmoke
I didn't even know it was a diesel until you told me, sounded like a torquey petrol rather than an oil burner.
Last edited by: RattleandSmoke on Thu 20 Jan 11 at 14:58
 Petrol V Diesel - RattleandSmoke
It depends what you're used to. I am only used to little petrol engines so I am very used to changing gears constantly and reving the pants of engines. I actually like it as it keeps me busy.

I would find having a lot of torque quite hard to get used to.

14k is not too bad, anything less than that then a diesel is not worth it as the modern filters cause too many problems with low milleages.

I suspect on a larger such as a Cee'd (I know it is not a large car, but it is by current standards) a diesel would be easier to tell than the petrol one.
 Petrol V Diesel - Bigtee
Stick to petrol as two years worth of driving at 14k a year is not worth the bother of the extra 1k and extra fuel of a diesel.

Now if your doing 3 years worth or like me keeping mine 8 years to get your money out of it buy the diesel.

 Petrol V Diesel - madf
If you think the extra £1k purchase costs dispapear when you come to sell it...they won't.

And diesel cars tend to be easier to sell secondhand due to the perceived benefits..

(For a comparison, look at secondhand prices for the same spec diesel vs petrol cars...)..

And VED tends to be lower.

The debate is presented in simple terms - it ain't. It's not complex.. just more issues to consider.
 Petrol V Diesel - WillDeBeest
I think the cost difference is too close to call. If the diesel would genuinely achieve 50mpg against 39mpg for the petrol then, at today's fuel prices it would be up by a couple of hundred after 28,000 miles. But it would take only a slight change in any of the variables to overturn that.

So the best advice to Andy is to choose the one he prefers. Or, if he really wants to save money, to keep the one he has.
 Petrol V Diesel - NortonES2
The "cost per mile" figures over 3 years for most vehicles seem to be very similar, assuming the costs include the major item, depreciation. Depreciation is left out in many "comparisons" especially by petrolhead journalists who get a taste for large capacity petrol engines they couldn't afford themselves! So, as WDB says, buy the version you prefer.
 Petrol V Diesel - Old Navy
>> So, as WDB says, buy the version you prefer.
>>

I agree, when I become a shopping trolley user in my old age it will still be a diesel, I prefer them.
 Petrol V Diesel - corax
>> I only said different technique, I have heard petrol drivers revving diesels to screaming point,
>> making a lot of noise for little progress. Torque is alien to some.

Ironically that would probably be better than mimsing around at low revs and blocking up the engine with crud.
 Petrol V Diesel - Old Navy
>> Ironically that would probably be better than mimsing around at low revs and blocking up
>> the engine with crud.
>>

I assure you mine gets plenty of exercise. :-)

Its all down to when and how, I was thinking about the people who hit the rev limiter during the traffic light GP.
Last edited by: Old Navy on Thu 20 Jan 11 at 16:09
 Petrol V Diesel - DP
I gave the Golf some exercise last night. Worked late, and enjoyed relatively light traffic as a result, so gave it some proper beans for a while.

The cloud of cack in the headlights of the cars behind initially was almost embarrassing! :-) A good few acceleration runs in the lower gears on full 'throttle' from 1800 RPM through to the governor to exercise the VNT mechanism on the turbo, and a couple of miles of "making progress" on the motorway, with more spells at full power (but not for long, officer)

It COMPLETELY ruined my average mpg this tankful, but it does tend to feel snappier after such treatment. :-)

I try to do this at least once every couple of weeks, if I can.

 Petrol V Diesel - Old Navy
>>>> It COMPLETELY ruined my average mpg this tankful, but it does tend to feel snappier
>> after such treatment. :-)

An "Italian tune up" does them the world of good, and will probably improve your fuel consumption until it gets sooted up again by mimsing (traffic). Worth it for the fun even if it doesn't.
Last edited by: Old Navy on Thu 20 Jan 11 at 17:08
 Petrol V Diesel - nyx2k
i have to drive 4 miles to the youngests school daily and the last 1mile is a fast dual carriage way with a difficult entry, the only way on safely is to match the traffic speed, usually 70mph.
the slipway is short so the 1.6psa diesel engine gets a 30sec tune up 2 times a day.
 Petrol V Diesel - Old Navy
>> i have to drive 4 miles to the youngests school daily and the last 1mile
>> is a fast dual carriage way with a difficult entry, the only way on safely
>> is to match the traffic speed, usually 70mph.
>> the slipway is short so the 1.6psa diesel engine gets a 30sec tune up 2
>> times a day.
>>

When it's cold, OUCH.
 Petrol V Diesel - corax
>> I assure you mine gets plenty of exercise. :-)

Not getting at you ON :)

There's a young guy at work, 20, who floors his Fiesta ST TDCi out of the car park every afternoon, and drives everywhere with foot to the floor. I've never seen any visible smoke when I'm behind him, though he does get through front tyres quite regularly.
 Petrol V Diesel - Old Navy
>> Not getting at you ON :)
>>
>> There's a young guy at work, 20, who floors his Fiesta ST TDCi out of
>> the car park every afternoon, and drives everywhere with foot to the floor. I've never
>> seen any visible smoke when I'm behind him, though he does get through front tyres
>> quite regularly.
>>
No problem, I am too thick (skinned) to take offence. :-)

It makes you wonder about the common rail doom merchants, diesels are tough and are designed to work hard (when warm).
 Petrol V Diesel - Skoda
>> i admit that i do drive "enthusiastically"

Avoid a diseasal then :-P

In a low gear:
*squeeze throttle* ... 2k rpm later ... it's all over, time to change gear

In a high gear:
*squeeze throttle* ... wait ... wait ... GO! ... 2k rpm later ... i have to change gear again!?

I am in no way biased and this is a completely fair and objective review of all diseasals :-)
 Petrol V Diesel - NortonES2
Very similar to a RR of not so old. No need for Honda levels of rpm to get going.
 Petrol V Diesel - DP
>> In a high gear:
>> *squeeze throttle* ... wait ... wait ... GO! ... 2k rpm later ... i have
>> to change gear again!?

....but I'm now doing a ton ten and am about to hit that lane hogger straight up the chuff ;-)
 Petrol V Diesel - Fenlander
>>>In a low gear: *squeeze throttle* ... 2k rpm later ... it's all over, time to change gear In a high gear: *squeeze throttle* ... wait ... wait ... GO! ... 2k rpm later ... i have to change gear again!?

Hmmm... more like put the diesel in the right gear and whoosh away from (or past) that pesky petrol car so he's a dot in the mirror.

 Petrol V Diesel - Skoda
They tease you with a surge of torque then they go and run out of puff wayyy too soon and the funs all over :-( Good for a quick squirt but if you need any more, better get stirring.

The Renault Clio 200 Cup, might be cheaper than a Ceed. That's the complete opposite of a diseasal, i think the redline's up about 7500rpm.
 Petrol V Diesel - Old Navy
Glad you know the difference between a boy racer and fast unobtrusive progress, Skoda. Or maybe not, you obviously don't know much about diesels.
Last edited by: Old Navy on Thu 20 Jan 11 at 21:15
 Petrol V Diesel - diddy1234
Thing is, if you build the revs too much in each gear it leaves nothing in the next gear.

Alot of petrol heads who drive Diesels miss the point of driving using the torque and not the revs.

I find changing up between 2.5k or 3k rpm then just rows past other cars without much effort as the next gear up has the turbo already spooled up and at the right revs (around 2k rpm)
 Petrol V Diesel - Boxsterboy
Methinks Skoda hasn't driven a diesel for a very long time. Or simply doesn't know how to drive one.
 Petrol V Diesel - Skoda
The diseasal apologists are out in force tonight :-)
 Petrol V Diesel - Old Navy
>> The diseasal apologists are out in force tonight :-)
>>
>>

We don't need to apologise for your obvious lack of knowledge of the subject. :-)
 Petrol V Diesel - Skoda
Haha in a past life I uttered the words 'I will never buy anything other than diesel cars' after a run of 3 of them.

I've since been cured!
 Petrol V Diesel - Old Navy
>> I've since been cured!
>>

It's not our fault you bought crap ones.
 Petrol V Diesel - Skoda
Hmmm, that kind of writes off 2 of the supposedly better ones!

The one in the middle was a vauxhall, it was crap (but the most economical)
 Petrol V Diesel - John H
>> Avoid a diseasal then :-P

>> That's the complete opposite of a diseasal,

>> The diseasal apologists are out in force tonight :-)

Skoda - What is diseasal ?
Last edited by: John H on Thu 20 Jan 11 at 22:24
 Petrol V Diesel - Skoda
It's a shorthand way of writing acetaldehyde, butadiene, formaldehyde, among other disease inducing, artery blocking pollutants.

 Petrol V Diesel - L'escargot
>> It's a shorthand way of writing ............

I thought that shorthand used symbols instead of letters.
 Petrol V Diesel - Clk Sec
Shorthand outlines.
 Petrol V Diesel - Old Sock
For a level playing field, shouldn't we be comparing the driving characteristics of a normally-aspirated diesel with its similarly-fueled petrol equivalent (of identical capacity)?

The power delivery of a turbocharged petrol engine can be very similar to that of a (turbocharged) diesel.
 Petrol V Diesel - Statistical Outlier
OS, you're absolutely right. Turbo'd cars are very similar in many ways, the difference is that a diesel gives you all that power / torque without the fuel consumption becoming horrendous.

All massive generalisations obviously, and the gap in both price, performance and economy has narrowed significantly recently.

The shortage of revs issue is overblown by those that haven't driven a modern diesel though. My Honda is useful between 1500 and 4500 rpm, and I can feel the petrol advocates recoiling at the low redline. However, consider for a second.

If I just relabelled the rev counter, that could also be represented as useable range of 2000 to 5980 rpm, which is actually pretty much what my last petrol would useably do. In other words, pretty much the same % increase of speed is available in the useable range of revs. It's not quite the same as a screaming 8.5k vtec, but then I've always found the very high revving stuff to be irritating and tiring to drive on a daily basis, exactly the opposite of the characteristics I want for day to day driving. And generally I find that the diesel has more power available more of the time than my NA petrol.

And so we come round to the start. A large NA 6 or 8 cylinder petrol is probably ideal in terms of instant power delivery and flexibility. Assuming that most of us don't want to pay the sort of running costs that would entail, I personally think that a turbo diesel offers the best real world compromise for day to day driving.
 Petrol V Diesel - WillDeBeest
>For a level playing field, shouldn't we be comparing the driving characteristics of a normally-aspirated diesel...?

In general, fair point, but in this specific case the original question was about the relative merits of turbo-diesel and NA petrol engines in the same car. Don't know much about the Ceed but I don't suppose it offers the other two combinations.
 Petrol V Diesel - Skoda
>> For a level playing field, shouldn't we be comparing

Well the OP was talking about 4 pot petrol vs. 4 pot Turbo charged diseasal so it'd be unfair for me to say a v8 petrol would be the best choice :-) (but we all know the score there really...!)

>> The power delivery of a turbocharged petrol engine can be very similar to that of a (turbocharged) diesel.

Well, my daily driver is a turbo petrol. You get the surge of TD torque, but it doesn't run out of puff until the red line at 7k rpm. Put any comparable diseasal TD next to it and it'll fall behind after 3k of revs while the diseasal guy stirs the 'box.

To that end, i'd be inclined to say they're not similar, but in favour of the turbo petrol

I digress...
 Petrol V Diesel - Iffy
...and it'll fall behind after 3k of revs while the diseasal guy stirs the 'box...

Not necessarily, the diesel guy has a great deal more torque, so diesels need fewer gear changes, not more.

My 2.0ltr diesel Focus has six forward gears, as does the 2.0ltr petrol.

 Petrol V Diesel - Skoda
>> so diesels need fewer gear changes, not more.

Not really iffy, the diesel is closer ratio than the petrol up to 3rd gear, then it's longer ratios than the petrol.

It wont be able to put the torque down in first gear, 2nd it'll get a move on, 3rd will be useless because the driver's held on to 2nd to use the power, 4th will be too high a ratio for rapid acceleration of the kind the petrol driver will experience in the power band - he's just changed into the power band in 3rd at this point in the hypothetical side by side.
 Petrol V Diesel - Iffy
...Not really iffy...

Skoda, as others have said, I don't think you've driven a modern turbo diesel.

I'm not saying they are better, but on the road - not paper - they are faster than a normally aspirated petrol of equivalent capacity.

On the negative side, diesels are more expensive and heavier, which means the diesel variant will feel less agile.

Much is made of the fuel consumption, but the differences there are not as much as they were, and diesel is always a few pence more per litre.

You sound like a keen driver, prepared to keep your car on the boil, so a turbo petrol may work for you.

But there's no reason a turbo diesel cannot be driven keenly, it just requires a slightly different driving technique.

 Petrol V Diesel - Skoda
I've not lived with a modern turbo diesel, last common rail TD i owned was an '04 1.3 Corsa CDTi, which is quite a bit smaller than the diesel engines talked about in this thread.

In terms of driving though, I had a C30 diesel (cant remember which engine, 1.8? It had stop / start if that narrows it down) on hire last year and we racked up a few miles travelling from one side of Poland to the other.

Diesel was a candidate when i was choosing a new car last year. The BMW 318d and the Octavia Vrs are both modern common rail turbo diesels.

But they pale into insignificance next to the turbo petrol TSi engine, which i'd contest is always "on the boil". Have a look at that torque graph :-)

For what it's worth, i agree that for mainly motorway driving the 318d is marginally better than the 320i, but it just doesn't have the oomph to live with it for a while, and i couldn't afford a 6 pot petrol.
 Petrol V Diesel - WillDeBeest
>They tease you with a surge of torque then they go and run out of puff wayyy too soon and the fun,s all over...Good for a quick squirt but if you need any more, better get stirring.


Rubbish. Either of our (turbo) diesels will pull in third from about 10mph, then strongly from 20 to over 80. I often block-shift the Verso from third to fifth (and occasionally even sixth) after booting it out of a short sliproad. If that's Skoda's idea of 'stirring', it ain't mine.
 Petrol V Diesel - L'escargot
There's more to consider than fuel consumption and driving characteristics. In general people either like diesels or they hate them. Hire a diesel for a week or so to find out their disadvantages.
 Petrol V Diesel - tyro
"In general people either like diesels or they hate them."

. . . or aren't bothered.

I remember the first time I was given a diesel as a hire car - a Vauxhall Corsa about 10 years ago. My first inclination was to say "But I don't know how to drive a diesel." I drove it around for two weeks, and didn't honestly notice it being any different from a petrol car.

I am, obviously, a person with little sensitivity. OK - I've hired several diesels since then, and have noticed a bit of a difference, but not much. To be honest, I found that there was more variation between one diesel car and another than there was between diesel and petrol cars.

I have just bought my first diesel. However, had the dealer had the equivalent petrol model in stock instead of a diesel, I'd have quite happily bought that instead.
 Petrol V Diesel - Skoda
Just to be clear, my anti diseasal goading is at least partly tongue in cheek. If it has an engine and wheels in a box then it's automatically good in my eyes. Turbo diseasal, NA petrol, battery powered... It's just the degree to which it's "good".

I'm conflicted on diseasal. Ignoring the whole problem that oil will run out, which is better to live with?

The new 2.0 TD lump from BMW which arrived in the 5 and has just made it into some versions of the 3 series, that is undeniably a seriously cool engine. 180+bhp (it can't fairly be accused of running out of puff) while being able to return 60mpg is not to be sniffed at.

It comes down to torque delivery. TD gives you it all from early down the rev range, it lends itself to and encourages what i'd describe as almost a lazy type of driving. It is well suited to (boring) motorway runs, especially in traffic. As noted above, you'll find it eager to give with no effort on the drivers part in those conditions. Where a petrol would need to drop a cog.

The equiv petrol will have a different delivery altogether. When you're out on the twisties having fun, the closer ratio 'box will enable you to keep it in the power band more of the time. I'd describe it as an enthusiastic delivery.

Which goes back to my original post in response to the OP. He enjoys enthusiastic driving occasionally, it's hard to make a diseasal do that. It's much more suited to, as ON put it, "unobtrusive progress".

Also known as mimsing, doddling, getting in the way, and polluting* ;-)

* what, you didn't expect me to agree did you :-P
Last edited by: Skoda on Fri 21 Jan 11 at 11:15
 Petrol V Diesel - hobby
Its spelt "diesel" Skoda! < roll eyes >

Re all this talk about revs and gear changes is academic in the real world... I can't remember when I've ever had to to a racing start up to 60 unless I was doing just that, racing, so how many gear changes I have to do to get there is not even relevant!

Re turbo petrol, I assume you have one of the VAG TSi engines... I have heard that the turbo quality is similar to a diesel rather than old-style turbo petrol, but as yet they are not as economical... if they ever become as good for mpg as a diesel then I'll switch, until then I see no need...

Last edited by: hobby on Fri 21 Jan 11 at 11:37
 Petrol V Diesel - Skoda
>> I can't remember when I've ever had to

Sounds like a diseasal mimser talking* ;-)

*i jest!

The TD does lend itself to "lazy" driving, the OP said he enjoys enthusiastic. I contest diseasal is not a match for enthusiastic driving.

If the OP wanted "wafting" - which i take to mean getting a shift on but in a laid back non-exerted kind of way, TD would be the one to go for.

If he wants the fun which comes from a measured, increasing release of torque over a long enjoyable rev range, petrol's the job.

There's a reason the equivelant diesel will be left seconds behind the petrol on a track. Those peak torque figures mean nothing if they're not usable effectively. No points for wafting round a track :-)
 Petrol V Diesel - Skoda
>> There's a reason the equivelant diesel will be left seconds behind the petrol on a track.

I've just opened myself up to the BTCC victory :-) I'll pre-empt that point...

If we say the gearbox in the petrol Focus is a refinement of a road going design gearbox, refined to keep the car in the power band easier, but generally the ratios are laid out with the same idea.

On the same scale, the diesel Leon's gearbox bares absolutely no resemblence to any diesel gearbox on offer on a forecourt in the UK, never mind "tweaked" or "refined" version of the road going ratios.
 Petrol V Diesel - RichardW
"Hire a diesel for a week or so to find out their disadvantages."

Driven 300k miles or so since 1998 in TD motors, and I'm still trying to find any disadvantages. But then we have agreed to disagree on that in the past L'esc!
 Petrol V Diesel - Woodster
Skoda making a lot of sense there - the last 1000-1500 revs in a good petrol engine is - I'm trying to find the right words here - supremely adjustable - perfect for having fun in the bends. But you can go just as fast round those same bends in a decent Diesel, you just do it lower down the rev range and it's equally adjustable. You can still pour in the power, you just don't do it close to the red line. I'm with RichardW, I can't see the disadvantages of Diesel. If we'd all grown up with Diesel engines, that would have been even further refined by now, then someone came along with a new-fangled petrol engine, we'd be having a different argument. It's taken some time for really good petrol's to be available, but there are some seriously good ones now that prove you can have torque as well as power from moderate capacity, alas not the economy.
 Petrol V Diesel - Snakey
I've had several diesels in a row and have now gone back to a small petrol (1.4)

I miss the torquey surge of a diesel on the motorway.

I like the fact my petrol warms up in 2 miles instead of 30

I like the simple maintenance of my petrol (no DMF,DPF etc)

I liked the 50mpg plus of my diesel

I like the revvy nature of a petrol around town

I liked the easy cruising nature of a diesel on the motorway

I liked visiting the pumps less with a diesel

I liked paying less for the petrol car in the first place

So for my next car I will get a diesel. No, make that petrol. Or maybe diesel. Errmmm
 Petrol V Diesel - paulb
I've always liked diesels but the sort of driving I do now (mainly 12-mile round trip to station and back) means that this will be the last I have - can't see a DPF liking that sort of use much.

Next will either be smallish-capacity forced-induction petrol (Fabia vRS estate keeps catching my eye) or a used 330i or similar. For less than 100 miles a week the mpg (or lack of) will not be much of a concern.
 Petrol V Diesel - corax
Good post Snakey. There are pro's and con's to either type of engine. I just drove a friends Mondeo 2 litre petrol today. It was OK, but nothing special. After all the praise bestowed on the chassis by the reviewers I was disappointed*. And the engine really needed revving to make any progress. I couldn't help thinking if the TDCi engine would improve it.

* but then I've been spoilt by a tweaked BMW chassis and straight six engine
 Petrol V Diesel - DP
We have a turbo diesel and turbo petrol version of the same car (mk4 Golf) in our household. There is 100cc difference in capacity, and there is 20 bhp difference in power, in favour of the petrol engine.

The turbo petrol is a very flexible unit which delivers 220NM of torque at 2000 RPM. It has a 20 bhp advantage over the diesel, and a redline set 2000 RPM higher. This means it feels lively and punchy at day to day revs, but it can't match the diesel which makes 310NM of torque at a similar 1900 RPM peak. Even if we had the higher tuned (180 bhp) petrol engine, it would still fall short of the diesel's torque figure by 70 NM.

Only when you get above 4000 RPM and the diesel has had enough, does the petrol pull out any advantage at all, as it keeps making more and more power right up to its 5700 RPM peak, plus a still useful amount a few hundred RPM later too. The diesel has really had enough by 4000 RPM, and the final 500 to the redline requires a complete lack of mechanical sympathy.

The petrol is faster outright, no question about it. But the diesel feels far quicker at day to day revs, simply because it is. Nearly a third more twisting effort to play with.

The diesel's big limitation is its soft throttle response (compared to the petrol) and its limited rev range. The petrol's big limitation is that you need to use almost all the revs to get the best out of it. So which is best depends on which limitation applies in your daily driving.

Apart from noise and vibration, one area where the petrol does win is in its response. I have always thought you can feel the difference in output control methods between petrol and diesel. With a petrol engine you are throttling its air supply, and to rev / accelerate, you are effectively removing the restriction which always makes it feel keener than the diesel. That's probably psychological on my part though.

Oh, and I've just filled the diesel up in the last half hour, and despite heinous traffic and a mad blast home two days ago using all the power and revs, it's averaged a genuine 47 mpg. The petrol in similar circumstances would be lucky to hit 30.
Last edited by: DP on Fri 21 Jan 11 at 13:26
 Petrol V Diesel - Clk Sec
I had always thought that diesels were a sluggish alternative to a decent petrol car until I hired a VW Passat turbo a few years ago. It was certainly one of the liveliest cars I have ever driven.

For my rather low mileage, though, it's petrol for me.
Last edited by: Clk Sec on Fri 21 Jan 11 at 13:28
 Petrol V Diesel - Skoda
>> The petrol in similar circumstances would be lucky to hit 30.

Yeah, diesel has petrol licked in economy stakes, there are positive signs that Petrol economy is improving (eventually!).

The Octavia 2.0TSi official extra urban is 47.9mpg (yeah right! :-) and combined 37.7mpg. For a 200bhp petrol that's going the right way, but needs to improve further.

I managed 42.5mpg brim to brim one time, and the 4 tanks leading up to that were all over 37mpg -- i'd started each one on the idea that i'd not exercise the turbo, but i failed half way through each tank before scoring a proper run :-)

 Petrol V Diesel - hobby
On a run at about 60 or so and no hard driving I expect it'll get 48 Skoda!
 Petrol V Diesel - Old Navy
I gave up and went to bed last night when Skoda shot himself in the foot by admitting he had used three diesels in succession.

If he bought them himself he is not the petrolhead he makes himself out to be.

If they were company freebes he didnt refuse to use them, same conclusion.

He is on a wind up.
 Petrol V Diesel - Skoda
Ahhh virtual pint to you ON. I've admitted before that I wasn't interested in cars as anything other than a tool until I got my 7er. I had done some 4x4 offroad training before then but that was it.

And the bar mans been instructed to put one for John H on my tab too once he's given one of his trademark caustic replies to my justification of the diseasal moniker.
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