[Closed] Petrol V Diesel

In the current " diesels are nasty " climate depending on wether your journey takes you into a city centre regularly I would vouch for a petrol engine ..as more city centres are set to ban diesel cars .

I also get the feeling that a diesel will depreciate in value a lot quicker ..I know you said that you were looking at a second hand diesel ..but the government are also doing their best to discourage new diesel sales with a £500 first year road tax ..its all a con designed to hit the motorist yet again !

There's a lot to it, but in pure fuel economy terms diesel is, like for like, better as long as you're not making short trips as they're not very efficient until they're warm.

Some people argue that they're not very good in stop-start traffic, but I personally don't think that's true - it's very short trips, sub 3 miles when they never warm up that is bad for economy, but equally they take a lot longer than petrols to get up to temp which could take a long time at low speeds.

If you're mostly driving out of residential roads then they're better.

If you're making lots of short trips then petrol is the way to do - my Wife drives about 9k miles a year, but she's a district nurse - 10-15 trips a day of less than a mile sometimes - diesel would be terrible.

The 'Diesel Tax' you mention in to tackle inner city emission issues and only effects older diesels at the moment, but there's a good chance that it will roll forward so when your 1 year old car is 15 years old it might be banned from some cities.

Diesel all the way. 16k a year? No brainer. You More likely to actually return close to stated mpg, too, and thank the ‘diesel is the Devil’ brigade for the more sensible prices that may be available on diesels these days.

diesel is, like for like, better as long as you’re not making short trips as they’re not very efficient until they’re warm.

I don't think they are less efficient than petrol in that situation - the problem is that it's bad for the engine to not get them warmed up.

Some people argue that they’re not very good in stop-start traffic, but I personally don’t think that’s true

Sadly it is.  When they're idling, the operating temperature isn't high enough to burn off all the particulates and the flow rate isn't enough to get them all out of the exhaust, thus they collect in the exhaust.  When you then set off they get ejected in a lump before being burned off.  This is another reason why DPFs get clogged on short journeys.

They are however much more fuel-efficient when idling.

I'd have thought that the burn would be good at idle, since the engine speed is low and the amount of fuel injected is so small.

Those are not brilliant consumption figures for a relatively modern car unless its a bit of a tank (read 4x4, big suv etc). At 16K a year I'd be inclined to look a little harder maybe.

Diesel 2nd hand prices might well drop off a cliff so I guess it depends if you run your cars into the ground or want/need some resell value. It will also be interesting to see if in the future the government decides to punish the drivers of older diesels (who they encouraged to buy them in the first place) with higher tax on older models.

At 16K a year I would imagine you will be doing enough miles to get it warm enough to keep it clean.

As an aside I was reading on another forum that Audi regional managers were called to a conference last week to be told that VAG are radically changing their manufacturing plans with a lot of current models being slashing in production (or halted completly) to make room for a huge production push on hybrids. Diesel cars will make a tiny fraction of their production from MY19 (manufacture year 2019, which goes on sale about November 2018). UK stock and reservable pre-production of most audi dealer bread and butter cars is already running out.

as more city centres are set to ban diesel cars .

Currently it's almost exclusively Euro 5 and earlier, some are only banning those at 4 or earlier. I don't think you've been able to buy a new Euro 5 car for 2 or 3 years. No one has manufactured one since 2014.

Only place i've heard of actively looking to specifically ban Diesel, including the Euro 6 cars is Copenhagen from the end of next year. But that *seems* to be no more than political point scoring/waffle that Boris would be proud of, there's been nothing more concrete than some soundbites and flyers/political manifesto. Everywhere else is talking about 5-6-7 years off. No where in the UK (yet).

On the other hand some cities are looking to ban ALL cars with fuel engines, but that's a whole new pile of excrement to deal with.

I’d have thought that the burn would be good at idle, since the engine speed is low and the amount of fuel injected is so small.

IIRC The burn is too slow at idle, so more particulates, and if you reduce the fuel content further, the engine stalls. Diesels prefer running at stable conditions e.g. steady torque and speed at the crankshaft. Any fluctuations or variations from the engines ideal conditions = more emissions from the combustion chamber, and more work from the after treatment system. Hence using them for motorway driving. And the push to 8+ ratio gearboxes.

The place to watch is the manufacturers they all have hold of all the currently planned, proposed and "pre-proposal" documentation from governments in markets where they sell cars. They then make the call on if it's worth making diesels anymore.

VW probably not a good example as they are still suffering fallout from the dieselgate scandal. But TBH, most other manufacturers are beginning to limit their exposure to diesel. Because the market has become rather volatile recently. Even in market segments where diesel makes sense!

Good.  I'd love a Passat GTE.

Some people argue that they’re not very good in stop-start traffic, but I personally don’t think that’s true – it’s very short trips, sub 3 miles when they never warm up that is bad for economy, but equally they take a lot longer than petrols to get up to temp which could take a long time at low speeds.

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If you’re making lots of short trips then petrol is the way to do – my Wife drives about 9k miles a year, but she’s a district nurse – 10-15 trips a day of less than a mile sometimes – diesel would be terrible.

Depends on the engine and how long she stops...

My 3L takes way more than 3 miles to warm up... I used to do a regular trip of about 30 miles and the cab heater didn't switch on (on the way) for a good 10 miles.. HOWEVER coming back after laving it in an open car park it was 1/2 mile to a mile ... because the engine was still warm.

I don’t think they are less efficient than petrol in that situation – the problem is that it’s bad for the engine to not get them warmed up.

Mine is terrible on consumption when cold and/or urban (both of which are linked for me)... 6-10 MPG vs 50+ MPG (indicated).

They are however much more fuel-efficient when idling.

I’d have thought that the burn would be good at idle, since the engine speed is low and the amount of fuel injected is so small.

Once warmed up .. but the same holds true for 70 mph, its just ticking over.

Ignoring the potential worry of city centre and residuals, it sounds like the diesel is the best bet for now.

I expect the petrol will be worth more if you sell it, but at £16k a year you'd probably save a reasonable amount on diesel - unless the government decides to, say, discourage diesel use with higher duty on diesel.

I would be surprised if a 175hp petrol was slower than a 150hp diesel - a lot of reviewers would say that in gear, the diesel might feel faster, but FFS if you want to go fast shift down a gear or two and rev the thing (not an option in a diesel, tbh becoming less effective in turbocharged petrol engines). If it's slower 0-60 I'd see if I could find the times for say 30-70 - it might just be that the petrol has an extra gear change at just the wrong time, it might be that the petrol is a bit peaky or has a crap gearbox or something too (i.e. the diesel might genuinely be the better engine to drive).

My money, I'd cycle half the distance and buy the petrol 🙂

Just drive them back to back. The diesel will feel horrible compared to new turbo petrol (which I presume is what you're looking at).  Unless I was doing spaceship mileage or couldn't get my car of choice in a petrol variant I'd be happy to pay a little extra for the nicer driving experience petrol offers.

We've just bought a petrol, for the first time in 20 years. It's the family run around and does about 10K a year, and I based the decision soley on depreciation. I figured in 3-4 yrs it will be worth more than the equivalent diesel.

I do similar mileage. Lots of motorway and long 100 mile+ trips and not much urban. I tried petrol and diesel engines of similar spec and ended up with the diesel. Mainly as (Dec last year) I got such a deal compared to the equivalent (ish) petrol. Mine's returning close to mf figures, but as ^^ above it's rubbish cold/short journeys.

I leased mine so if it's worth bog all in three years, fine they get it back and it doesn't cost me anything. I expect the next one I'll have is a hybrid.  I do like 600 miles to the tank, lots of torque and the super smooth power delivery. Still I was coming off a 1.2 petrol yeti and this is a 2.0D so not a great comparison!

We bought a petrol as our little car two years ago. It does 10k a year, lots of local runs, our default local journey car. It's also old school petrol, with no turbo, no DMF etc.

For the big car, that I use for work, we went diesel. Prices have fallen, mine was £9k against valuation and others for sale at £13-14k. It does 20k per year, most journeys are 10-100miles, daily. It still works economically for us.

So many miles!

Adjust your lifestyle, drive less, buy a stonking V8, profit. 😀

A friend of mine, a long time diesel fan, sold his newish Passat diesel, bought a Peugeot 106 (or whatever the tiny one is) and a Subaru Legacy Spec B for when his family needed more luggage space. The little car gets used around town and short trips, the Spec B for anything else. The Peugeot MPG balances out the Subaru GPM figure. 😉

So many miles! Adjust your lifestyle

If you can explain how mrs_oab gets to rural nursery schools on edge of Highlands without a car, I'm all ears.

If you can explain how I also get to schools all across Scotland and North England, often with a pile of kit with me that fills the boot, again I'm all ears.

If you can explain how we get five of us plus bikes or boats or boots to a moutain / forest / loch in Scotland, without taking two days public transport to get there, I'm all ears...

Matt_outandabout earlier today.

If you can explain how mrs_oab gets to rural nursery schools on edge of Highlands without a car, I’m all ears.

If you can explain how I also get to schools all across Scotland and North England, often with a pile of kit with me that fills the boot, again I’m all ears.

If you can explain how we get five of us plus bikes or boats or boots to a mountain / forest / loch in Scotland, without taking two days public transport to get there, I’m all ears…

If I chose to do all those things I'd be driving even further!

But I choose not to.

I chews the phat instead...

We have a 1.2 Fabia 110 Tsi petrol and a 2.0 Seat Leon 2.0 Tdi FR. They are both decent cars. The Fabia is plenty quick enough and with the Dsg box is great for short trips and urban driving. The diesel is superb for longer journeys faster more refined and better economy. If I was doing 16k a year it would still be diesel every time. Don’t believe the mpg fuel figures for some of these small turbo petrols. 38 mpg average for the Fabia 50 mpg for the Seat.