[Closed] Would you buy a Diesel?

jimw

Bigdugsbaws, try an Audi 3.0 Tdi BiTurbo. I think you might be surprised at its flexibility and refinement.

Yeah that seems like a fair comparison for a 1.5ltr 3cylinder petrol. A £50,000 3.0 twin turbo. How about comparing the Mini Cooper [i]D[/i] with a 3.0 twin turbo petrol? Maybe the BMW M3 with 425 bhp and 410lbs ft of torque?

molgrips

All torque no action aren't they

No, not at all. Torque IS action, and in my car max power is 4,200 rpm so it keeps pulling to the red line.

Obvious troll is......

I can only assume that those who don't like how diesels drive have only driven crap manual diesels.

We've two diesels, a 190bhp Freelander 2 and a 315bhp 435d xDrive. Both auto.

The Freelander 2 replaced an old-style Freelander, it's almost twice the power yet uses the same amount of fuel, and been a high-spec its a very nice place to be.

Words can't describe how good the 435d is, and I've previously had lots of big-engine petrol cars including a 535i (V8), incredible performance (40-80 acceleration is stunning, perfect for the single carriageway A roads where I live) and averaging nearly 40mpg over it's lifetime.

b r - Member

I can only assume that those who don't like how diesels drive have only driven crap manual diesels.

Words can't describe how good the 435d is, and I've previously had lots of big-engine petrol cars including a 535i (V8), incredible performance (40-80 acceleration is stunning, perfect for the single carriageway A roads where I live) and averaging nearly 40mpg over it's lifetime.

So are you also suggesting that a near £50,000 3.0 6 cylinder twin turbo car is good? Are there any similar 3.0 6 cylinder twin turbo petrol cars costing about £50,000 you can compare it to? How does it compare?

I would assume the diesel gives better fuel economy? Is that really a major concern if you are running a 50k coupe?

one petrol 1600 in line 4 with an 8500rpm redline, sounded fantastic between 6500-8500 rpm but wouldn't pull the skin of a rice pudding below 2000 rpm. Gearing meant it was turning at 4000rpm at motorway speeds

That sounds awful to me, and there I think we have it. I very seldom see any need to go near the red line, I'm quite content to chug along with the revs as low as will get the job done. I can't summon up the antipathy towards a particular fuel some of you manage and I'm perfectly happy driving a petrol engined car but my Diesel suits me.

I would assume the diesel gives better fuel economy? Is that really a major concern if you are running a 50k coupe?

I don't have a a £50k coupe (or anywhere near it) but I do know I'm happier standing on a garage forecourt every 650 miles than every 500 and it's not just the money.

A lot of strong opinions on petrol and diesels depending on personal experience. But regarding the OP and the commuting distance, a diesel will just be getting up to operating temp when she gets to work. So economy won't be as high as manufacturer stats, esp if town or city driving. If all open country roads or motorway then the diesel may be a practical option.

[I]So are you also suggesting that a near £50,000 3.0 6 cylinder twin turbo car is good? Are there any similar 3.0 6 cylinder twin turbo petrol cars costing about £50,000 you can compare it to? How does it compare?

I would assume the diesel gives better fuel economy? Is that really a major concern if you are running a 50k coupe?
[/I]

As said previously I'd had large petrol engine cars, most did 22-25mpg so works out at a saving of over £100 per month. Yes we could've bought a cheaper car and saved more, but we didn't, so like-for-like saving Of £1200-1300 per annum.

And tbh with the exception of when the engine starts due to the auto stop/start you've no idea it's a diesel. And when accelerating, again no idea it's a diesel, just sounds like a large capacity powerful engine.

Whereas the Landie we have, is definitely a diesel 🙂

Petrol all day long in a Mini Cooper. We have a 59 plate Cooper with the 1600 NA 4 pot in it. Think it's 120 bhp or thereabouts. Cracking little motor. Petrol is much more refined in a little car, more finesse to it and they don't sound like a tractor. Nothing worse than a diesel motor being thrashed - bloke round the back of mine red lines his derv Audi most mornings and it's a nasty harsh sound.

Each to their own though. I've never owned a diesel, never plan to. I test drove a 335d xdrive F what's it and thought it was dull as dishwater.. mental fast but ultimately dull. I quite happily jumped back into my old 325i at the time knowing the diesel wasn't for me.

She's got an Aygo at the moment, 1 litre petrol, completely gutless. So either car will be good by comparison. Driving both on Saturday, so will make a decision based on the test drive. I haven't been completely put off the diesel by the debate.

b r

As said previously I'd had large petrol engine cars,

A 20 year old non turbo'd petrol engine in a bigger heavier body isn't really a valid comparison is it?

most did 22-25mpg so works out at a saving of over £100 per month.

Wouldn't the M4 depreciate less and therefor negate the fuel costs over a year?

And tbh with the exception of when the engine starts due to the auto stop/start you've no idea it's a diesel. And when accelerating, again no idea it's a diesel, just sounds like a large capacity powerful engine.

That's fine and I'm sure it's a great car but when we discuss general petrol vs general diesel engine characteristics let's discuss like for like at least.

[I]A 20 year old non turbo'd petrol engine in a bigger heavier body isn't really a valid comparison is it?[/I]

FWIW with BMW's there's barely 100kg between a 1 series and a 3 series if both with the same engine/gearbox.

The 435d is actually heavier than the 535i I had previously, xDrive doesn't help.

b r

The 435d is actually heavier than the 535i I had previously, xDrive doesn't help.

Holy shit.

8000 miles per year. the generally accepted break even for derv is 12000. that number can only go up given the £ + nox.

No, unless your wife does a lot of motorway, pottering around town in a diesel is no good for them. The filters get all blocked up, egr valves stick, they're just rubbish. Had a diesel zafira 2 litre, loads of power but it was poo. Of course I may have just been unlucky.

As long as it doesn't kill any cute domesticated animals.

People fine ****-em.

Just bought one but I'm doing a minimum of 15,000 a year and if my shoulder gets fixed I'll be driving to the Alps so maybe as much as 20,000 miles. Next time, 4 years time, I hope to buy a petrol as by then I'm hoping to be doing around 4,000 a year.

Diesel all the way, like early torque and how lazy can you drive them. 4 pot petrol engine sounds like screaming microwave when you rev them, V5 in line6 or V8 that's where it at with petrol engines. 4 pot diesel doesn't whine when you apply *Torque* and make progress. And MPG! I get 60mpg in an automatic E-class over 36k miles of mixed driving, hello?

I think with the mileage and use mentioned I'd go for the petrol Mini for the following reasons:

The petrol engine should be fine in short journeys - the diesel won't like lots of short slow journeys in traffic - it'll clog up the dpf and potentially end up costing you a lot of money to fix.

Your wife doesn't really do enough mileage to justify a diesel - although this arguement is a bit negated by the fact that both cas are a similar cost. Normally new like for like the diesel costs more.

The anti diesel sentiment in the press / in society - it sounds like there's going to be more and more pressure to phase out diesel cars (although at some point this is going to apply to petrol too - they don't exactly produce butterflies and kittens out the exhaust) and this is going to result in tax increases - probably on ved and fuel. Could also get diesel bans on city / town centres.

Diesels aren't the nicest things to listen to either when driving.

That mini must be Euro 5 compliant so will be worse on emissions Jan than the newest euro 6 engines so more likely to get caught up in town bans / tax rises.

I have actually just got a brand new diesel car, but it's a company car so I don't have to worry about depreciation and I'm likely to be doing well over 15k miles per year so cost wise it makes sense. Just bik could be a stinger. I actually prefer the way petrol cars drive - especially small revvy engines ones - I had a Suzuki swift sport a few years back and it was great fun to drive -except on the motorway when it was a loud revvy tin box.

I'll say it again just in case you missed it. You need to try the S. We've got a cooper S clubby. It's nice and nippy. With just 120bhp suspect it'll feel sluggish.

Nissan Leaf or any other electric car OP?

Drive them back to back. That's what we did and after driving the petrol, the diesel felt awful (despite being a newer car with similar bhp and loads more torque).

This.

I did the same & the handling between the two was markedly different - almost like two completely different cars. Probably due to the big, heavy oil burner stuck in the front of one of them.

Having had both petrol & diesel models of the same car now I am happy that I went with petrol this time & there seems to have been no real difference in overall running costs in the two years since I made the change.

I'm with lesgrandepotato if you are after something a bit sporty with some go. The Cooper is just a One with extra shiny bits really. The S gets going, although maybe not with the bigger wheels as they made the loan car we had a bit unforgiving and skittish, size down with taller sidewalls would probably offer more grip.

Sounds like petrol best suits your situation. We have gone back to petrol due to a drop in our annual mileage.

Anybody who has a choice and buys a diesel car right now is an idiot.

winston - Member
Anybody who has a choice and buys a diesel car right now is an idiot.

Anyone who has a brain and just blithely buys a car based on what people in the news and the government say is an idiot.

Like anything else, it requires thought as to your use.

No it really doesn't. Use is now immaterial. Diesels are very bad news. Obviously they always were but:

A few years ago people buying diesels could claim a number of mititgating factors in defence of being an idiot.

They didn't know how bad they were
They knew how bad they were but the economics of thier situation dictated a diesel
No alternatives
favourable tax treatment
etc etc

Now...all gone.

So idiot.

Depends.

I'm currently chugging around very happily in a diesel, which I've owned for 6 years and hoping to get at least another 5 out of. It handles well, has reasonable performance and does a solid 45 to the gallon unless either I'm sat in stationary traffic (which I avoid like the plague) or I'm driving continuously like a total knob.

My mileage has dropped massively now from when I first bought the car - I used to do 15-20k private miles per year, now it's down to 8k or below.

If the arse drops out the diesel car market and there are lots of nicely specced derv cars out there cheap (late model E91 330d anyone?), and if the demand for diesel drops, then I can see it getting cheaper again (OK, with more tax on), then it could still make sense.

For long cruising I do prefer the way a diesel drives - most of the time in the UK you need torque not power, and that's what they're good at. Also I'm not convinced that small cap. turbo petrol engines will last the course - too highly stressed. I can see a lot of woe once they're out of warranty period, and I'm the kind of guy who buys an 80 or 90k car and runs it to 180+k, then no thanks!

The basic thing is not to choose whether you buy petrol, diesel or even EV, but whether you should use a car or a more suitable means of transport (including walking!) for the job.

Also I'm not convinced that small cap. turbo petrol engines will last the course - too highly stressed

I have a feeling that such things are made possible by modern materials and engineering processes. After all, turbos aren't a new idea so such a concept will have been well known for ages, only now it's feasible. We'll see.

Oh dear, looks like turny things 101 is needed again.

molgrips - Member

No, not at all. Torque IS action

Torque has no component of time so it has nothing to do with speed or "action". For that you need [i]power[/i].

Think of it like this as an easy way to remember the difference: torque is the size of caravan you can tow, power is how quickly you can tow it (don't worry, there won't be a race).

As for petrol vs diesel, I'm firmly in the petrol camp. I did less than 4,000 miles in my last year of car ownership so outright mpg was less of a concern, though running costs of friend's diesels has been alarming (DPF,DMF etc).
Diesels sound awful (even the most auto-disinterested can tell when the taxi has arrived), are dirty and sooty, and I simply don't like their power delivery.
Never understood why some people are so averse to using the range of an engine, but then I'm used to tuned up Hondas that would happily and reliably rev through the roof and had gearboxes that were a joy to use.
If you don't like changing gear or using revs then of course an auto diesel makes sense, just not my cup of tea.

After all, turbos aren't a new idea

Nope, I've help change loads! 😉

I'm on the fence at the moment.

My current car is a 2.0l diesel with all wheel drive on demand, gets around 44mpg, not far shy of the official 47mpg. I do 20k miles a year but mostly on twisty country lanes so keeping it above 2000rpm for the half hour plus required to clear out the DPF is difficult. I've had it 2 years and it's already had one £800 DPF associated repair job

The 1.5T petrol equivalent latest model allegedly gets 46mpg so if I were to get one of those and got as close to the official figure as I do now, there wouldn't be much in it, and I wouldn't be worried about the next DPF repair bill. And I wouldn't be contributing as much to asthma and other diesel associated health problems . But I would be contributing more to climate change compared to a diesel

So there I am, undecided

Car - no. Our annual car mileage is low, so no point.
Van - there's barely any choice. Well, there is a petrol vw 2l tsi with 204ps/350Nm, that sounds fine, but it's as rare as hen's teeth in the uk.

Anybody who has a choice and buys a diesel car right now is an idiot.

Find me a petrol estate with 4WD, good rear legroom behind a 6ft+ driver, >600L of boot space that is relatively quick yet does >40mpg in the real world.

That's why I ended up with a diesel. I hope it will last until electric is an option with the 500 mile + range I need.

Yep vans are the problem. We have a long wheelbase hightop transit for business and there is absolutely nothing we can swap it for. There is one EV van coming to market but its range is not great and it can't tow enough for us.

oldbloke

Find me a petrol estate with 4WD, good rear legroom behind a 6ft+ driver, >600L of boot space that is relatively quick yet does >40mpg in the real world.

Skoda Superb Estate, 280 TSI Sportline 4x4.

@oldbloke

Tesla Model S has 900 litres of cargo space and 4wd!

Why do you need 500 miles of range? Do you often drive that far without a single break?

Skoda Superb Estate, 280 TSI Sportline 4x4.

Funny thing is that the next gen petrols will mostly sound like diesels anyway (multistage direct injection and/or some sort of compression ignition) they'll also be laggy (need turbos on small engines to move heavy cars. Cars aren't going to get light any time soon.) they'll also tend to have lower maximum engine speeds thanks to all the stuff they need to make them powerful and less noisy.

Basically like a diesel.

They'll also have DMFs (many do already) and GPFs (instead of DPFs) and active exhausts and variable geometry turbos.

All things to go wrong.

Oh joy.

Tesla Model S has 900 litres of cargo space and 4wd!

Why do you need 500 miles of range? Do you often drive that far without a single break?

oldbloke

Looked at it originally. But I said realworld 40mpg. Combined official doesn't even get there!

A minor detail. It has a bigger boot than your stated requirement, you'll be a long time dead.

Think of it like this as an easy way to remember the difference: torque is the size of caravan you can tow, power is how quickly you can tow it

Not a very good explanation.

What you feel in the back of your chair is forward force. This comes from the torque at the wheel. That's it. Power is this force multiplied by how fast that wheel is turning.

Think back to your bike - if you are standing on the pedals really hard whilst applying the brakes, you are creating a lot of torque but no power at all. As you heave off the line you are putting in huge torque but not all that much power because you are not doing many rpm.

Now, in the context of motor vehicles, people quote engine torque and engine power, but these don't mean a lot because it's the wheels that make you go, and there's a gearbox in between. Because the car can move, torque is intrinsically linked with power. Torque will make the car move forward so the engine needs to keep applying torque as the wheel turns, which is generating power.

So torque is the instant push, and power is the sustained push. You cannot have one without the other.

As far as statistics go, the number quoted tells you the engine RPM that delivers peak torque, which affects how it feels when you drive. A diesel engine with more torque at say 2,000rpm will be generating more power at that same RPM. The BHP figure quoted is the maximum power, and this is higher for petrols simply because they can rev higher. Because we are talking about piston engines, we can say that in a diesel there is more force per bang; but a petrol engine can deliver more bangs per minute *at maximum*.

So if you drive around at high engine speeds, a petrol will feel nice and fast, but unless you are ragging your car all the time it won't. This is what people mean when they talk about 'torquey' engines - how much power there is at lower revs.

But we are just talking about engine speed here. It's important to remember that there is a gearbox in between the engine and the wheels and it's the wheel speed that is related to the car speed. So an engine with more torque at a lower engine speed can be made to feel the same as an engine with less torque but at a higher engine speed, by using a higher gear ratio. Therefore the only thing that actually matters is the shape of the torque curve.

If you had a diesel with a red line of 4krpm and a petrol with a red line of 6krpm, the torque curve was the same, max power was the same, and the diesel had higher gears, you'd get basically the same performance and they'd feel the same.

The fact they don't is that the torque curve is different. But not as different as they used to be in the days of PD engines.

Oh dear, looks like turny things 101 is needed again

I have a degree in Physics, but this is actually a-level stuff.

Yes if the economics worked in my favour.
My driving is rural and so are the fuel stations. Diesel every where, not always petrol. No urban driving so I reckon the pollution effects are less and I also believe that we should be hammering the leisure use of fossil fuels as a more effective way of saving the planet. Holiday flights and driving T5's to trail centres.
Where have the emotithingies gone?

@oldbloke - I agree electric isn't really there yet. Perhaps if we hadn't been dragged off down a decade long cul de sac by the fossil fuel diesel lobby and misguided govt policy the we might have been.

TBH its the OP's type of driving that really needs to be targeted first. Urban and suburban small cars doing short distances in populated area's and busy motorway traffic are killing people far faster and can be substituted by EV and petrol hybrids more easily than rural traffic.

molgrips

Not a very good explanation.

What you feel....
Think back to your bike.....
Now, in the context of motor vehicles.....
So torque is .....
As far as statistics go..

Did everyone else see this coming 😆

So if you drive around at high engine speeds, a petrol will feel nice and fast, but unless you are ragging your car all the time it won't. This is what people mean when they talk about 'torquey' engines - how much power there is at lower revs.

Are you considering all petrol engines there molgrips? Or are you just doing the usual thing of comparing a small normally aspirated petrol engine to turbo charged diesel?

I was comparing NA petrol to TD yes, I didn't go on to talk about TP because it was a long post.

But the point I was trying to make was the relationship between power and toruqe in practical terms, and also that power *delivery* i.e. the torque curve are what's important, rather than the engine RPM at red line.

[i]Also I'm not convinced that small cap. turbo petrol engines will last the course - too highly stressed[/I]

I've run motorbikes past 50k, my Kawasaki was 130bhp from a 900cc and revved to 12000rpm - engine was solid.

Very rare for a 4 cylinder bike engine to fail (except not maintained etc).

I can't see why anyone doing less than 50 miles a day and considering a Mini wouldn't have an EV instead as long as they have off street parking.

The sooner they put an electric engine in these lifestyle type cars the better. Fiat 500 is another prime example - they even built an electric version for Europe for a couple of years......madness