4-Cylinder Petrol or 6-Cylinder Diesel

4-Cylinder Petrol or 6-Cylinder Diesel

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Discussion

Chris Hinds

Original Poster:

337 posts

106 months

Saturday 27th April 2013
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Given that last year more than half the cars sold new in the UK were Diesel and if you search Autotrader for cars under 3 years old you get a roughly 50/50 split, what about a debate rarely seen. Should you take the 4-cylinder turbo petrol or the 6-cylinder turbo diesel? It's almost as default as an MX-5 to suggest a mapped 335d as a car of choice and nobody could deny they are good cars but ultimately it is still a Diesel. For the last three years I've lived with a 3.0TDI and it's a great car but you can still tell it's diesel and however good the sound proofing that rattle is still there at times (of course at others it's blissfully quiet and it sounds great working hard).

So let's say you walk into a BMW showroom. You want a 3-series, one that's quicker than the standard 320d. You're mulling over a 328i or 330d... both automatic since you can't have a manual 330d. By the time you add auto there's about £2700 difference with the 328i cheaper. Petrol costs you £150 more in tax over 3 years, leaving £2550 for extra fuel. Sure the 330d could well be a little faster (much of the advantage probably negated by the auto box) but the 328i weighs 185kg less over the front wheels...

Of course in this case the two are closely matched and I know there are other examples where the figures stack up the other way, but as a company car or a private purchase I wonder how many people are defaulting to "Diesel is the answer" without thinking it through.

What do you think?

MJK 24

5,312 posts

177 months

Saturday 27th April 2013
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The diesel engine surely doesn't add 185kg of extra weight over the front wheels? I could understand it being 100kg heavier, but not 185 surely?

Your sums make the petrol look attractive. I'm assuming maintenance of the petrol will be cheaper but no doubt depreciation higher. If it was to be a very long term proposition, the petrol may make financial sense.

Pablo68

910 posts

76 months

Saturday 27th April 2013
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Petrol every time for me. Unless I am buying a load lugger work horse that will do 50k miles per year. Or a tractor.

Fort Jefferson

8,182 posts

163 months

Saturday 27th April 2013
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Unless you're buying a new car with a warranty, get a petrol. The cost of making diesels go fast is obscene.

Fastdruid

5,839 posts

93 months

Saturday 27th April 2013
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All depends on mileage and if it's personal or for work. Tragically if it's a company car you almost have no choice, got to be diesel. If you do 15k then it's a choice and 10k or under then petrol all the way.
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Pistom

2,980 posts

100 months

Saturday 27th April 2013
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Fort Jefferson said:
Unless you're buying a new car with a warranty, get a petrol. The cost of making diesels go fast is obscene.
Could you put some facts and figures to that statement?

It's the low nd torque that attracts me to diesels.

I'm currently looking for a snotter to do 15k miles a year in, the petrol option is much cheaper to buy but th torque nd general manners of a modern diesel do attract.

My cars in the recent years have been petrol.

Fastdruid

5,839 posts

93 months

Saturday 27th April 2013
quotequote all
Low end torque at the expense of top end torque. My petrol has the same torque as the equivalent diesel in the range, except the torque spread is twice as wide and starts lower! Diesel power is in such a narrow band that you really need a lot of ratios and ideally an auto box. The torque is great but it's so short a duration that you need to permanently be changing gears if anything other than constant speed cruising is what you want.

Heathwood

1,842 posts

143 months

Saturday 27th April 2013
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The thing that bothers me is depreciation/resale of a petrol engined car due to people's blinkered obsession with diesels.

Most people don't need a diesel; it simply doesn't make sense. However, with many models it feel like it would be financial suicide to choose the petrol. Perhaps the more efficient modern petrol turbo models will change people's views.

clockworks

2,685 posts

86 months

Saturday 27th April 2013
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Never quite got this "narrow torque band" statement regarding modern diesels. All the TDs that I've driven have had plenty of torque from below 2000 rpm to over 4500rpm. That's half of the usable rev range. Most NA petrols that I've driven are flat below 3000rpm or so. Same result - torque over half the rev range.

surveyor

13,492 posts

125 months

Saturday 27th April 2013
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Fort Jefferson said:
Unless you're buying a new car with a warranty, get a petrol. The cost of making diesels go fast is obscene.
I'm in a bad mood, so please allow for directness.

Complete and utter cock.

Fittster

18,146 posts

154 months

Saturday 27th April 2013
quotequote all
Chris Hinds said:
Given that last year more than half the cars sold new in the UK were Diesel and if you search Autotrader for cars under 3 years old you get a roughly 50/50 split, what about a debate rarely seen.
I'd like to know how the split breaks down. Once you start looking at saloons (e.g. 3 series) I'd be shocked if the majority aren't bought by company car drivers. These buyers are incentivised by the tax system to buy diesel models. When these cars turn up on the second hand market finding petrol models is difficult because so few were sold in the first place. So as a buyer you can be far more picky when choosing a diesel over a petrol model.

Do used diesels still command a premium over petrols? The supply of used diesels is now so great it might have driven down their prices.

philmots

4,491 posts

201 months

Saturday 27th April 2013
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Agree.. But the 328 may come without metallic paint etc which brings the price even closer.

I like diesels but I prefer petrol turbos. I drive a 335d I'd of had an I but the bork factor was higher.

When I get into an F30 I'd like to have a 328i or 335i but I doubt there will be many about to choose from.!


RobM77

32,125 posts

175 months

Saturday 27th April 2013
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Personally I'd test drive both and buy the one I preferred. Life's too short to make yourself miserable over a few hundred quid a year. For me that meant buying the diesel, but for others (the majority according to a recent thread) that might mean the petrol.

Fittster

18,146 posts

154 months

Saturday 27th April 2013
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Doing a quick search on autotrader. If I set a three year age filter and there are 1090 BMW 320d v 188 320i. Most of the petrols are coupes, only 70 are 4 doors.

It's hard to do like for like comparisons on price but it doesn't seem like there's much in it between petrol and diesels when buying secondhand.

billzeebub

3,806 posts

140 months

Saturday 27th April 2013
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Petrol

CDP

5,662 posts

195 months

Saturday 27th April 2013
quotequote all
surveyor said:
Fort Jefferson said:
Unless you're buying a new car with a warranty, get a petrol. The cost of making diesels go fast is obscene.
I'm in a bad mood, so please allow for directness.

Complete and utter cock.
Injectors at £500 per go (I know somebody who needed all four)
DMF - what £900?
DPF
Fuel pump at £1500
BMW Swirl flags (quote of £6K on a £5K BMW - needless to say it was scrapped)
Turbos

Everybody I know running a modern diesel has had issues of this sort. The economics just aren't stacked in their favour these days.

Apparently the later BMW 530 petrol can easily beat 30mpg and is officially 37 combined which can't be a lot worse than the diesel.

Fittster

18,146 posts

154 months

Saturday 27th April 2013
quotequote all
CDP said:
Everybody I know running a modern diesel has had issues of this sort. The economics just aren't stacked in their favour these days.
Everyone? I know people who haven't had problems,

The economics stack up for the original buyers (they have the warranty and the tax breaks). The logic is less compelling for used buyers.

CDP

5,662 posts

195 months

Saturday 27th April 2013
quotequote all
Fittster said:
CDP said:
Everybody I know running a modern diesel has had issues of this sort. The economics just aren't stacked in their favour these days.
Everyone? I know people who haven't had problems,

The economics stack up for the original buyers (they have the warranty and the tax breaks). The logic is less compelling for used buyers.
Pretty much. I'm trying to think of anybody I know who hasn't had big diesel bills as they've got older. Then again I know people with serious issues on new(ish) petrol Audis too. Stretchy cam chains, gearbox ECU, Haldex drive.

Leasing a new diesel makes some sense as the costs seem low but one bill can wipe out 50,000 miles of savings and maybe more. With the extra cost of a diesel requiring maybe 80,000 to pay back it's quite a gamble.

littleredrooster

3,933 posts

137 months

Saturday 27th April 2013
quotequote all
CDP said:
Injectors at £500 per go (I know somebody who needed all four)
DMF - what £900?
DPF
Fuel pump at £1500
BMW Swirl flags (quote of £6K on a £5K BMW - needless to say it was scrapped)
Turbos

Everybody I know running a modern diesel has had issues of this sort...
Tosh. 400,000 miles in 12 years running secondhand DI diesels and I've had none of that. Pug, Citroen, 2 Skodas, BM and Jag all trouble-free; there's tempting fate!

Sorry - just remembered - the Citroen's lift pump lost pressure gradually and cost me £48 for a new one.

Now, the wife's various petrol cars over the same years have been considerably more expensive; coil packs, crank sensors, cam sensors, seized spark plugs...

E38Ross

22,411 posts

153 months

Saturday 27th April 2013
quotequote all
Pistom said:
It's the low nd torque that attracts me to turbo charged engines.
edited that for you