Petrol or diesel?

Dickyboy – Member

^^^ this – plans in central london for a low emissions zone starting 2020 covering the congestion zone, will add an extra £12 per day for trips into the centre for all but the latest diesels but petrols since about 2007 are already compliant.

To put that into perspective, if I worked in the congestion zone and drove in every weekday it’d cost me more or less the same as I save on tax, insurance and fuel with my diesel over the nearest petrol equivalent.

Last car Auto,2.5 petrol averages 35 mpg. Replacement 6 speed manual,2.0 Turbodiesel averages 53 mpg. This is in hilly Lake District,had it been a flatter area I would have bought 1.4/1.6 Turbodiesel or eco 1.0 petrol. Extra engine capacity great on the climbs…. . Happy I chose the diesel,but it felt odd the first time as the fuel is a few pence a litre more!. 🙂

BrickMan – Member
I guess the rule would be, use it for city driving, short journeys, not many motorway trips. Petrol Petrol Petrol. they are so much cleaner (in an urban environment) and cost effective in this use.
But if you spend most of your life on A roads + motorway with little city/town driving then diesel diesel diesel!

Absolutely this. We only do about 10k miles a year between both cars* as we walk most places, but have a 1.2 petrol for round town, and a 2l diesel for longer journeys.

* yes having two cars is an extravagance.

Thats especially true now where all (?) diesels have a DPF which does not like short journeys.

Diesel:

-ve: poison your fellow citizens with fine particles and Nox (particle filters don’t work), fails to start in ski resort at below -20°C, stinks, narrow power band, more servicing, more MOTs (in France), more big bills sooner… .

+ve: might work out a bit cheaper if you do a high mileage, perhaps a little quieter on the motorway.

Petrol:

-ve: slightly higher revs on the motorway, slightly more expensive to run for high mileage users.

+ve: cheaper to buy, nicer to drive, starts first time every time even when it’s cold, warms up faster so the heater works

Diesel is cheaper in France but despite that Autoplus found that when they calculated the number of kms you had to do in a diesel to make it cheaper than the equivalent petrol some diesels would never save you money.

You didn’t mention CO2, Edukator. Although it’s not as simple as it seems…

Ive been looking at a new Octavia vrs, tried the diesel, Ive had a D5 V70 for the past 7 years, and it was ok. £30 road tax and £300 or so more than the petrol. I then tried a Golt GTI, same engine etc, miles better to drive than the diesel, slightly less torque but starts lower and has a much wider rev range 😀 a proper smile on my face 😀 so up to press I`m having the petrol vrs 😀 12k miles pa and the extra few hundred quid a year is worth it for the driving enjoyment 😀 😀
30-35k a year would be diesel unless someone else was paying for my fuel

sbob – Member

TheArtistFormerlyKnownAsSTR – Member

I love diesels and the torque they deliver.

If you don’t like having to change gear, why not drive an auto?

Genuine question.

Firstly, I’ve no idea why you asked that question

Secondly, I do drive an auto

” fails to start in ski resort at below -20°C”

Funny the russians and crazy canauks manage it, there are tricks to it.

My lr which is diesel and chip fat 50/50 started – albe it reluctantly at -28

The Russians never turn off their engines and if they do have a heater under them.

Quite possible that Ed is supplied with warm weather diesel in nice warm central France, which is unsuitable for frigid ski resorts. All Russian diesel would have more cold weather additives in it, one would think.

Same as the canukes. – plug in block heater too- even for the petrols.

So rather than your blanket statement its just that the folks that take their fairweather diesels to the skimresorts dont think forward

It’s quite clear that many of those slating modern 3 cylinder, small, turbo engines have never driven one. Go test drive the 125psi Focus version back to back with the diesel then come back and report.

125psi

Compressed air engine? 😉

Power? Blah, blah, blah…

Means a lot less than people like to believe, if we’re looking at usefulness it’s torque we should be looking at. Quite frankly I wouldn’t want any less torque than I already have given the hills I drive over which a 3cyl doesn’t deliver. Wouldn’t fancy doing the milage I do with one either, I’ve already put 100k on in the space of 5.5 years and accepted that we’ll only be parting when it’s knackered. I’m guessing that would come sooner with a highly strung petrol being ragged day in day out.

The 1.0 ecoboost does look quite favourable on torque on paper.

125ft lbs from 1400-4500rpm on paper and the 125bhp has a 148ft lb torque boost for 30 seconds on turbo over boost.

The 1.2tce didnt

It had 107ft lbs at 3000 rpm and anything below 2500 it really suffered bad.

3 cylinder engines are inherently more torquey than 4 cylinders for similar size engines.

Hence a small three cylinder with a turbo for torque is the latest craze on the engine block…

It’s quite clear that many of those slating modern 3 cylinder, small, turbo engines have never driven one. Go test drive the 125psi Focus version back to back with the diesel then come back and report.

I have. It was ok around town but numb on the open roads.

3 cylinder engines are inherently more torquey than 4 cylinders for similar size engines.

True since the displacement is shared amongst less cylinders and stroke length my be comparitively increased as well however that means each cylinder is consequently working harder. Hence my misgivings about long term durability.

TR – I’m kicking out about 162ft/lb just now, not earth shattering by any stretch but still wouldn’t want any less – with more than just the driver you can feel the difference.

TheArtistFormerlyKnownAsSTR – Member

Firstly, I’ve no idea why you asked that question

😆

I’ve probably jumped the gun on assuming why you like diesels from your post I quoted.
As torque doesn’t get you anywhere quickly, I had assumed you liked diesels because you don’t have to “work” the engine, as many people don’t.
I personally don’t mind, hence why I can happily live with a gutless auto petrol car which I may have to nail from time to time.

Sorry little car! 😳

Edit: just checked, and I’m rocking 78ft lbs! 8)

OP if I was doing 35k miles a year it’d be diesel, a auto and great seats. 15k a year and its a big petrol, manual and noisy 😀

squirrelking
True since the displacement is shared amongst less cylinders and stroke length my be comparitively increased as well however that means each cylinder is consequently working harder. Hence my misgivings about long term durability.

Understandable. It remains to be seen how durable they are, my wife, sister in law and my sister have all had small engine motors give up the ghost around the 100k mark. That being said the 3 banger in a focus is so small it looks like you could lift it out on your own (obviously I couldn’t) so replacing the engine may not be a massive undertaking.

my wife, sister in law and my sister have all had small engine motors give up the ghost around the 100k mark.

I’m interested to know exactly what failed on them.

I’d be surprised if there was any problem intrinsict to small engine size – perhaps the bottom of the range cheapest option types are simply underbuilt to save money – which the turbo-ed 120bhp etc ones ought not to be.

Ive been looking at a new Octavia vrs, tried the diesel,…petrol miles better to drive than the diesel, slightly less torque but starts lower and has a much wider rev range a proper smile on my face so up to press I`m having the petrol vas … worth it for the driving enjoyment … 30-35k a year would be diesel unless someone else was paying for my fuel

This.

I test drove both diesel and petrols when replacing my Alfa, I just couldn’t get on with 4 cylinder diesels, they all sounded like vans and had stupidly short power bands. More cylinders improve things but then the mpg savings start drop off. The only diesel I was tempted by was a 330/335d touring and couldn’t find one with sensible milage.

I ended up in a petrol VRS estate, far nicer to drive than the diesel variant, 260bhp, does 30+ mpg on the commute, sensible tax band (in comparison to bigger engined, NA petrols) and you can brim it for £50 at the current prices!

I ended up in a petrol VRS estate, far nicer to drive than the diesel variant, 260bhp, does 30+ mpg on the commute, sensible tax band (in comparison to bigger engined, NA petrols) and you can brim it for £50 at the current prices!

I think I have the same engine in a different car.

I drove the petrol and diesel equivalents. From my research @32-35mpg average on the petrol v @42-45 mpg on the diesel.

Diesel would save me approx £325 a year on 15,000 miles. Diesel was £1,200 more to buy, so it would actually costing me more to run the diesel for the first 4 years!

Got to the first set of traffic lights in the diesel and the noise made me sad. Bought the petrol.

Just back from a 510 mile motorway round trip…on one 60 litre tank of petrol. Considering that it’s a moderately powerful petrol engine in quite a heavy estate, I’m more than happy with this!

Ahh Torque

One of the most quoted and least understood aspects of cars.

What you feel when you drive isn’t engine torque, its wheel torque and wheel torque is easily changed by selecting a different gear (or you auto box kicking down if your so inclined)

When people say the like torquey engines what they really mean is they like engines that have acceptable power at lower rpm

Anyway 30k miles a year buy the diesel

molgrips

I’m interested to know exactly what failed on them.

Clio and a Yaris with big end failure. And the wife’s clio threw a rod if I recall correctly .

A rod? When was this? 1980?

molgrips – Member

A rod? When was this? 1980?

Nah, it was about 6 or 7 years ago. The engine instantly developed a fairly terminal sounding engine knock, followed by reluctance to turn over. My mechanic is a fairly thorough, curious sort and that was his diagnosis. I’ve never known him to be wrong so that was good enough for me. No doubt there must have been contributing factors, but that’ll be case with any failure.

I do circa 25k a year and am going back to petrol – I’ve had fours years of diesel power and have hated it. The fuel stinks, the pumps are always covered in it, the power band is horrible, the noise is horrible etc.

Not totally sure what I’ll get yet because it depends on what is available on my car list (as the lease priced fluctuate cars come and go). Something from VAG with the 1.4 TFSi engine is high on the list as is the new MINI (that little three cylinder engine is a peach). The latter is a bit selfish because it’s small, but there is lots of room in the front and it now has proper seats (better than the Golf that I sat in the other week).

In my case, I’m not expecting to get the claimed economy but if I can get high 40’s it won’t cost me more to run tham mt current diesel that scrapes 51 at best (it doesn’t get ragged and sits at 70 or so for most of it’s life).

In the case of the OP, I think it would depend on what petrols you were looking at. Not all petrols are noisey, revvy things. Our 330 is pretty relaxed on the motorway – 2400ropm or so at 75. Things like the MINI seem pretty relaxed too.

I guess at that kind of mileage deisel will be a bit cheaper to run, but I’d still struggle to look past petrol.

After having diesels for the past dozen or so years for doing a 100 mile a day round trip commute I aging bought a diesel again last year although I don’t do the commute anymore. More by accident than design and sometime I wish I’d gone for the petrol version with a couple of extra cylinders. But having notched up over 400 miles at the weekend its averaged moved up to 36 MPG so not too bad I guess. And to be honest I didn’t really notice the lack of speed compared to the more desirable petrol model.

For your mileage stick with a diesel. Oh and someone mentioned them not warming up, the auxiliary heater kicks in and solves that problem.

What you feel when you drive isn’t engine torque, its wheel torque and wheel torque is easily changed by selecting a different gear (or you auto box kicking down if your so inclined)

Of course it’s wheel torque, just as power isn’t shaft power. But it’s still dependant on engine power/torque in the first place. Personally I like being able to go up the hilly bits and around their corners without dropping a gear when the engine runs out of steam.

Nah, it was about 6 or 7 years ago.

Surprised that engine didn’t have OHC..?

I find it amazing that people moan about the power bands and noise. FFS talk about picky.

The power band thing is rubbish as the gears are higher so if you don’t look at the numbers on the tach you’d never know. Engine torque isn’t the issue, it’s wheel torque.

Our 330 is pretty relaxed on the motorway

Of course it is, but it’s hardly comparable in terms of economy!

Molgrips – I think he meant con rod rather than push rod 😉

You want your torque curve to be as flat as possible to ensure consistent power delivery, something diesels do better than petrol. If you like to over use your gears you might as well just buy a Honda.

I dunno, I think that’s totally a matter of taste. Like, my dad has a 1.6 petrol focus, which makes 110bhp for about 1/10ths of a second at its peak power, but seems to be mostly propelled by the gearstick. I hate it… Rubbish around town, rubbish on the motorway, super mega rubbish on twisty roads. But you don’t have to look far to find people who like all that- revvy engines are more involving, balancing revs and gears is a skill etc.

Same reason I chose a v-twin over an inline 4.

Northwind my engine revs upto 7,000 (red starts at 6,500). I love it. You have to be good at utilising and riding the torque on a diesel. Thats key not the ‘oh no the powers now gone’ like some people say but I LOVE hearing the revs on a petrol. 😀

I find it amazing that people moan about the power bands and noise. FFS talk about picky.

The power band thing is rubbish as the gears are higher.

Not picky, it’s called priorities. Yours are obviously different to mine that is all.

Petrol vs diesel VRS – the petrol was a far nicer car, I’m happy take a hit on mpg in exchange for car that, to me, is a more pleasant drive.

The “power band thing” isn’t rubbish in this case either with the diesel having about half the power band of the petrol going through the same box. Fine if you’re sitting on motorways all your life but a daily A and B road commute, I’ll take the petrol.

jamesfts – Member
The “power band thing” isn’t rubbish in this case either with the diesel having about half the power band of the petrol going through the same box.

The petrol and diesel are unlikely to have the same gearbox….gear ratios suited to diesel would be rubbish in a petrol & vice versa….

squirrelking – Member

You want your torque curve to be as flat as possible to ensure consistent power delivery

No I don’t!

If you like to over use your gears you might as well just buy a Honda.

If you’re too old to enjoy the pleasure of Honda’s manual gearboxes then just buy an auto, Grandad!

Get an auto Micra like mine; no gears for you to worry about but as a CVT you can still rev it furiously for no reason like pensioners love to.

glad you called it SK – i was thinking do molgrips pistons float around in thin air on hopes and dreams !

“The “power band thing” isn’t rubbish in this case either with the diesel having about half the power band of the petrol going through the same box. Fine if you’re sitting on motorways all your life but a daily A and B road commute”

petrol fair makes the road come alive. I like bimbling along in my diesal OAP mobile – i minimise my driving anyway as i hate driving on the road with other road users cause mostly they are coonts up here – bruneep im looking at you.

Just ask a fireman which type he’d like to be in when it crashes and the fuel tank splits….