Story in the Mail today about the "myth" of the level of savings earned by using diesel vehicles:
tinyurl.com/co7hgc9
Any thoughts?
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Some truth in it, but anyone who doesn't bother doing the sums first must be able to afford it, and diesels come with other advantages, such as torque, low revving, sometimes quieter, lower CO2-based VED, can use red diesel at 77p/L and even up to £300 cheaper...
www.audi.co.uk/content/audi/new-cars/a8/a8/specifications.html
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You have to drive economical petrols in a very precise way to get the optimum economy whereas diesels that ive owned have been far less affected by driving style, though I still prefer a low thirst petrol myself even if they do lack torque.
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>>.... though I still prefer a low thirst petrol myself even if they do lack torque.>>
My 1.4 VW petrol TSi (168bhp, plus 177lb ft of torque virtually throughout the rev range) certainly doesn't lack for torque...:-) Also get up to 42-43mph depending just how hard I push it....
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>>Also get up to 42-43mph depending just how hard I push it....<<
43 mph. Those Golfs, not as fast as they used to be ;-)
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Maybe Stuart bought a manual by mistake. You have to select second yourself in those.
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>> Maybe Stuart bought a manual by mistake. You have to select second yourself in those.>>
No, it wasn't by mistake - I hate automatic cars...:-))) It's also a Jetta, not a Golf, but this is a test of the Golf with the same engine:
www.evo.co.uk/carreviews/evocarreviews/67063/volkswagen_golf_gt.html
In actual fact the 168bhp (170 PS) TSi unit in the Jetta was only around for a short time, being replaced by the 158bhp version, with performance etc not greatly affected. Hence there are very few around, especially the manual model, which meant I had to hunt for one for about three months.
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>> ............. and diesels come with other advantages, such as torque, ...........
It isn't the engine output torque (which is the figure always quoted) which matters, it's the torque at the driving wheels. When it comes to torque at the driving wheels, diesels lose the advantage of most (if not all) of their higher engine output torque by virtue of the higher gearing.
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>> When it comes to torque at the driving wheels,
>> diesels lose the advantage of most (if not all) of their higher engine output torque
>> by virtue of the higher gearing.
Have you driven a modern diesel, L'es?
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>> >> When it comes to torque at the driving wheels,
>> >> diesels lose the advantage of most (if not all) of their higher engine output
>> torque
>> >> by virtue of the higher gearing.
>>
>> Have you driven a modern diesel, L'es?
You seem to have ignored what I said. Most people aren't aware that it's torque at the driving wheels that matters. They just enthuse about the quoted engine output torque, and are blissfully unaware of the gearing factor.
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>> You seem to have ignored what I said. Most people aren't aware that it's torque
>> at the driving wheels that matters. They just enthuse about the quoted engine output torque,
>> and are blissfully unaware of the gearing factor.
Not at all. I just defy anyone to compare the rolling acceleration of an equivalent output petrol and diesel car, and state that the diesel has lost most of its advantage through gearing. In any accelerative situation involving crank speeds under 4000 RPM, a naturally aspirated petrol engined car wouldn't see which way an equivalent output turbodiesel went.
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>> In any accelerative situation involving crank speeds under 4000 RPM, a naturally
>> aspirated petrol engined car wouldn't see which way an equivalent output turbodiesel went.
I've never had any problem keeping up with a diesel version of my car. 0-60 mph times of most cars are usually very similar for diesel and petrol variants.
Last edited by: L'escargot on Thu 19 Jul 12 at 11:27
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You've asserted this so many times, l'Es, that it's a wonder it's not been immortalized among the stickies at the top of the screen. It's not my field, but doesn't any car need to achieve the same torque at the driving wheels for a given rate of acceleration? And, if so, isn't the higher gearing - and the more relaxed driving that goes with it - the benefit a diesel car can take from having higher torque from the engine?
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>> ............. it's a wonder it's not been immortalized
>> among the stickies at the top of the screen.
It should be. I'll have a word with the Moderators.
Last edited by: L'escargot on Wed 18 Jul 12 at 14:14
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>> You've asserted this so many times, l'Es, that it's a wonder it's not been immortalized
>> among the stickies at the top of the screen. It's not my field, but doesn't
>> any car need to achieve the same torque at the driving wheels for a given
>> rate of acceleration?
No. Half the torque at double the rpm will do the job. But that might also be your point.
The Outlander (2.3 tdi) trundling rpm is 1500. And it will accelerate quite briskly from there. Max torque is at 2000-3000, and is 380nm / 280 lbft. I don't think it's much less at 1500.
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>> No. Half the torque at double the rpm will do the job.
No. That will give the same power, but for acceleration the important factor is the torque at the driving wheels. Speed is irrelevant.
tinyurl.com/y9rukwk
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>> >> No. Half the torque at double the rpm will do the job.
>>
>> No. That will give the same power, but for acceleration the important factor is the
>> torque at the driving wheels. Speed is irrelevant.
>> tinyurl.com/y9rukwk
As you you well know, I was referring to crankshaft torque, not the torque at the driving wheels. By the time you get to the wheels of course the total torque has to be the same for the same acceleration.
You have already made the point that a diesel and a petrol with the same power output have similar maximum acceleration potential. I do not disagree. But I can get most of that changing up at 2200rpm, I don't have to keep it above 4000.
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>> >> ............. and diesels come with other advantages, such as torque, ...........
>>
>> It isn't the engine output torque (which is the figure always quoted) which matters, it's
>> the torque at the driving wheels. When it comes to torque at the driving wheels,
>> diesels lose the advantage of most (if not all) of their higher engine output torque
>> by virtue of the higher gearing.
All I can say is that's not my experience. Nearest like/like comparison I've had was 1.6petrol v 1.9 diesel BX. Although the petrol had a few more bhp the torque made the diesel mich more tractable in real world driving.
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>> It isn't the engine output torque (which is the figure always quoted) which matters, it's
>> the torque at the driving wheels. When it comes to torque at the driving wheels,
>> diesels lose the advantage of most (if not all) of their higher engine output torque
>> by virtue of the higher gearing.
Whilst that is strictly true it is largely irrelevant. At a given speed on two comparable cars the power at the wheels will be the same. The diesel will be producing more torque, as it is producing the power at lower revs. The quoted figure for cars is the peak torque and what this is indicating relevant to engines is that diesels produce more power at lower revs than equivalent power output petrol engines. This leads to a steeper power curve, and a larger gap between the delivered power on part throttle and the available power at WOT at a given engine speed. It is this factor that gives diesels superior in-gear acceleration, rather than just the 'torque'.
Of course there will always be people with strong views on both camps - I'm firmly at the black pumps still.
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At a glance it's telling us what we knew already; if you do around 10k miles pa and buy new a diesel may cost more, over several years, than petrol. Not clear if it takes account of higher residuals on diesels.
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If the pubic read this and move away from diesel then price premium in DERV models might reduce and pump price fall?
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The pubic !!? They wouldn't have the balls !
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It's not just the cost. I actually really enjoy driving a good diesel engine. They do something few "cooking" four pot petrol engines these days do, and that's make a car feel quick and effortless. I directly compared the E90 3 series in 318i and 318d guise, and the 318i wasn't even in the same league, despite an identical power output.
I am hoping the new direct injection turbo petrols can bring some of the sparkle back to petrol power which I think is sadly lacking in recent generations of four pot petrol units. Partly emissions legislation, and partly ever increasing kerbweights, I suspect.
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Over ten years and 130,000 miles I reckon my diesel Volvo has cost £6,000 less in fuel than its petrol equivalent (the one DP had) would have done. There was a difference in BIK tax in its first two years as a company car of maybe £700, and it's probably now worth £500 more than a petrol model. £7,200 in credit so far. Service intervals and costs are the same in either case.
On the debit side, it's had to have a new DMF and a new intercooler - components also present in the petrol engine but less likely to fail, apparently. That puts a £2,000 dent in my winnings, but still not nearly enough to make me wish I'd chosen petrol.
But then, if you run a car this long, cost of fuel overtakes depreciation as the largest item on the sheet. Buyers who take on a PCP every three years pay vastly more in interest and depreciation than they ever do for fuel.
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I find a 50/50 mix of virgins' blood and ass's milk, with a dash of Greencare washing-up liquid, as effective as anything thick, pink and sticky.
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>> Any thoughts?
>>
Yep, simplistic nonsense from the Daily Mail, who'd thought it?
e.g. who can compare the 1.6 tdci Fiesta with the underpowered 1.25? Surely they should have compared it with the 1.6 petrol.
They also haven't factored in re-sale values, which may or may not make up for the higher purchase cost in part or whole.
>> You have to drive economical petrols in a very precise way to get the optimum economy whereas diesels that ive owned have been far less affected by driving style
Agreed. My old Fiesta 1.25 would return less than 35 mpg if I drove it without a care. I had to drive in true mimser style to get anything near 40-45 mpg. Official combined of 47mpg.
My current Mondeo 2.0 tdci with auto will do 35-30mpg driving it like I stole it. Official combined 39mpg. No competition for me.
Last edited by: oilburner on Wed 18 Jul 12 at 14:39
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Turbodiesel vs Turbopetrol?
Green pump for me when it comes to driving enjoyment.
There's a reason N/A diesels aren't found in cars any more - you'd need 2.5 - 3 litres to shift an average saloon at a decent lick.
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>>Agreed. My old Fiesta 1.25 would return less than 35 mpg if I drove it without a care. I had to drive in true mimser style to get anything near 40-45 mpg. Official combined of 47mpg.<<
Indeed. I think it depends on whether your style matches the cars needs. Mine matches the Charade as I change up quite early anyway and I dont tend to feel the need to race away, I just let the speed build.
I find that because it lacks torque yet is high geared, it is more economical to keep it in a lower gear at higher revs on anything more than a moderate hill, so you maintain momentum at a small throttle opening, treating 5th as an overdrive.
Must be the right idea because in 2000 miles ive averaged 61 mpg against the 58.9 combined figure and that was before I discovered all the tyres had 8 psi less than they should :-/
Re Fiesta 1.25, Ive driven several generations of the Fiesta with that engine and its terribly underpowered in the later cars, has no guts at all so does require a heavy foot to maintain progress, though its atleast refined.
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The enemy of good mpg is driving in a way that requires you to use the brakes, and to drive at too high a speed (air resistance is the killer).
Revving past 3000rpm isn't too clever either but unless you're driving some soot-maker it's fun to rev.
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Let the powers be drop the price of petrol and diesel,we're overpaying as it is.
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>> Re Fiesta 1.25, Ive driven several generations of the Fiesta with that engine and its
>> terribly underpowered in the later cars, has no guts at all so does require a
>> heavy foot to maintain progress, though its atleast refined.
>>
As long as you stay below 60mph, after that point you find you need ear plugs! Had the same problem with a Focus 1.6 petrol too, very noisy at 70mph +. Interestingly, that gave almost identical fuel economy to the Fiesta 1.25 when driven in the same way..
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>>As long as you stay below 60mph, after that point you find you need ear plugs! <<
Yes I recall that from a 2010 version I drove - short top gear but still dog slow, horrid cars that ive never understood the appeal of.
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It's a shame. That engine was a peach in the (vastly lighter) mk4.
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The 1.4 engine was much better.
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>> The 1.4 engine was much better.
>>
Agreed. We had one on a P plate. Went like stink for what it was.
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>> Agreed. We had one on a P plate. Went like stink for what it was.>>
My youngest offspring had an S registered Fiesta with the 1.4. He was aiming for the 1.25, but I said test drive that first and then a 1.4....! He really loved that Ford.
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I read this with a bit of intrest due to my recent impulse car buy, I have a company car BMW 318d that does about 44mpg, my own car,( I like cars), was a leon cupra R on an 04, i recently swapped this for a 12 plate Leon 2.0 FR+ TSI DSG with 211 BHP, I got the car which was £23700 list for a little over £15k with 22 miles on the clock, when asking why its so cheap I get told no one wants a 2.0 turbo petrol auto anymore, well I did and so saved quite a bit, the equivelent diesel models are selling on 11 plates for £18k with 5k miles, the DSG in a petrol is more fuel efficiant than the manual petrol, it usually changes gear a 2.5 k revs and i see around 32mpg, not run in yet, but if you drive it a bit spirited expect that to be low 20's, point is that doing 4k miles a year in it, Ive saved quite a bit of cash, there were no deals on diesel models.
VW have cracked the auto myth too, problem is on a diesel DSG you get worse MPG, strange, Petrol for me all the way :-)
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Unless I've missed something I cant see where the Mail got its figures from.
In the case of the Sharan the combined figure for the petrol is 39.2 and the Diesel 50.4, but the mail quote 35.3 / 47.9. This meas they have used a difference of 12.6 mpg, but by VW's figures the difference is slightly less.
As others have said, the figures are skewed as they don't appear to take into account residual values and finance costs.
The comments below the article are funny - they all appear to be of the opinion that diesels are far more reliable than petrol engines.....................
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Isn't the original article's headline a bit misleading? It's well established that if you're doing 10k miles or less per annum then you'd do well to do your sums properly. having said that, it looks like Which have done their sums by the manufacturers quoted mpg. In my experience, a petrol is far less likely to achieve these figures than a Diseasel. Add in that I do nearer 20k a year and the article itself becomes, well, rubbish.
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>> .............. it looks like Which have done their sums by the manufacturers quoted
>> mpg. In my experience, a petrol is far less likely to achieve these figures than
>> a Diseasel.
I've always been able to equal, or better, the official combined figure in my petrol cars.
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>> I've always been able to equal, or better, the official combined figure in my petrol
>> cars.
>>
That's something I've always been able to say too, until I had the underpowered Fiesta. The only way I could ever even reach the official combined was to drive at exactly 60mph on the motorway, slipstreaming trucks - from a safe distance, before anyone asks...
Of my other 20 or so cars I've had, petrols have always required far more careful driving to get the magic combined figure, from the Avensis 1.8 to the C5 3.0 V6. Whereas with my diesels, I've been able to cane them around town and then drive normally (at least 70mph on the motorway) and still beat the official combined figure.
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Like oilburner and woodster self and Mrs F have always seen a larger real life gap between petrol and diesel.
3yrs ago my petrol Mondeo was doing around 30-33mpg on the 20ml daily "commute". My current C5 diesel took this straight up to 50-53mpg. Now I'm doing far less miles and many runs around 1-8mls the C5 still does 48mpg. I know the old Mondeo would have been around 28mpg with such use.
And then of course there's the driving pleasure of a diesel...
However mileage has dropped so much I am looking at petrols for the end of year swap.
Last edited by: Fenlander on Thu 19 Jul 12 at 10:06
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>>In any accelerative situation involving crank speeds under 4000 RPM, a naturally aspirated petrol engined car wouldn't see which way an equivalent output turbodiesel went.<<
It would. You just follow the smoke...
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Our 2004 Scenic didn't smoke at all, even when driven hard, and that was a Euro III engine with no DPF. All diesels since then (with the exception of the later VW PDs) are free of visible smoke if they are in good condition.
My 320d is a mile away from its combined figure, but a genuine 53 mpg (over 6800 miles) from an 'enthusiastically' driven 5 seat saloon that can hit 60 in 8 seconds and do 140 mph are figures way beyond the reach of any petrol powerplant that I am aware of. The fact I can get this without trying suggests 60 mpg would be perfectly possible if I were driving for economy.
I risk sounding a bit fanboyish with this, and other threads will show I have been critical of the car itself, but frankly there isn't a petrol engine on earth that gets close to it.
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0-60 mph times of most cars are usually very similar for diesel and petrol variants.
True but pretty much irrelevant. When did you last need to get from 0-60 as fast as possible? Occasionally joining a main road from a small junction, perhaps, but most acceleration is with the car already moving, and this is when a TD leaves an NA petrol wondering why there isn't even any smoke.
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>> ......... but most
>> acceleration is with the car already moving, and this is when a TD leaves an
>> NA petrol wondering why there isn't even any smoke.
>>
Like I said, I've never had any trouble keeping up with a diesel version of my car.
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Hat tip to DP for neatly pointing out the two sides to the nature of the modern diesel engine.
In this thread:
". . . genuine 53 mpg (over 6800 miles) from an 'enthusiastically' driven 5 seat saloon that can hit 60 in 8 seconds and do 140 mph are figures way beyond the reach of any petrol powerplant that I am aware of."
In a previous thread:
"It is ironic that the masterpiece of precision engineering and fuelling technology that is a modern diesel engine, relies on a Heath Robinson contraption that traps crap in a bin, and then throws an almighty strop if it isn't presented with the right conditions to start a chimney fire before it clogs up with soot. "
This is the main worry for me regarding diesel engines. They've got some pretty fancy plumbing that will have to get even fancier (and more fragile one suspects) in order to meet the ever more stringent legislation on emissions.
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>> This is the main worry for me regarding diesel engines. They've got some pretty fancy
>> plumbing that will have to get even fancier (and more fragile one suspects) in order
>> to meet the ever more stringent legislation on emissions.
>>
Yeah, true. For Euro 6 (comes in Sept 2014) there are no additional requirements for petrol engines, but diesels will have to tighten their belts further from 0.180 g/km NOx to 0.08, which is the same as a Euro 4 petrol!
HC+NOx will also have to fall from 0.23 to 0.17.
It's hard to get specific data on NOx levels from brochures (they tend to just state Euro level), but the V5 tells you, and for my car (from 2009) it states NOx of 0.216, so it wouldn't even make Euro 5 and is nowhere near Euro 6.
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>> Like I said, I've never had any trouble keeping up with a diesel version of
>> my car.
There isn't a diesel equivalent of your 2.0 petrol engine in the mk1 Focus. The most powerful diesel in the range gave away 200cc and over 20PS. The Ford / PSA joint venture hadn't kicked in at that point, so Ford diesels were average at best.
In sheer performance terms, the progress the diesel engine has made since the early-mid 2000's in any case is staggering.
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>> >> Like I said, I've never had any trouble keeping up with a diesel version
>> of my car.
>>
>> There isn't a diesel equivalent of your 2.0 petrol engine in the mk1 Focus.
Perhaps I should have said the nearest diesel equivalent..
>> The most powerful diesel in the range gave away 200cc and over 20PS.
If you want to be exact, the Ford Focus September 2002 brochure says .........
2.0i 16V Zetec ............... 1988 cc, 130 PS at 5500 rpm, 178 Nm at 4500 rpm
1.8 Duratorq TDCi .......... 1753 cc, 115 PS at 3800 rpm, 250 Nm at 1850 rpm
Last edited by: L'escargot on Fri 20 Jul 12 at 18:03
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My mistake. The same 2.0 petrol unit made 136 in the Mondeo. In any case my point stands. You have more power, you shouldn't struggle to keep up.
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0-60 is never flattering for diesels, as they almost all need two gearchanges to reach 60 mph due to the limited top end revs available.
The in-gear increments give the real clues to diesel performance. The old 318i was 1.5-2 seconds slower than the 318d (same 143PS) in all of the 20 mph acceleration increments between 30 and 100 mph.
As you say, WDB, the trick is to ask yourself how often you accelerate from, say 30-50 or 50-70 compared with how often you go from 0-60.
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Petrol is fine for the lightweight tasks, lawn mowers, motobikes and the like but once there's a bit of weight to move and some work to be done diesel is the way to go.
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My Lancer Estate could do with a 2 ltr T/D engine, but don't tell Zero I said that for gawds sake!
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Lets just say the Lancer engine is "relaxed", not "prone to excessive energy" or "overly energetic"
Smooth and quiet tho.
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>>Smooth and quiet tho<<
So much more so than the 1.8 DOHC lump in my Almera which became quite harsh at higher revs.
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>> Petrol is fine for the lightweight tasks, lawn mowers, motobikes and the like but once there's a bit of weight to move and some work to be done forced induction is the way to go
There, fixed.
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Certainly did Lygonos. Don't recall too many 42 tonne forced induction petrol HGVs, Zero's a bit quiet too, must be out hunting the lesser spotted petrol Deltic :-)
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Im other words, when refinement and noise don't matter, its time for diesel (modern car diesels excepted)
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True gmac - the WW2 tanks were naturally aspirated ;-)
en.wikipedia.org/wiki/King_Tiger
etc
Last edited by: Lygonos on Thu 19 Jul 12 at 23:18
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>> True gmac - the WW2 tanks were naturally aspirated ;-)
>>
>> en.wikipedia.org/wiki/King_Tiger
>>
>> etc
Ran on petrol IIRC.
Military vehicles always used to be petrol - probably better for logistics to have universal fuel.
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That's why BA commissioned diesel powered motor bikes at one time.
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>> True gmac - the WW2 tanks were naturally aspirated ;-)
>> en.wikipedia.org/wiki/King_Tiger
>> etc
Which was about the time the Navy took the decision to switch from petrol to diesel:
"The Deltic story began in 1943 when the British Admiralty set up a committee to develop a high-power, lightweight diesel engine for Motor Torpedo Boats.[1] Hitherto in the Royal Navy, such boats had been driven by petrol engines but this fuel is highly flammable, making them vulnerable to fire, and at a disadvantage compared with the German diesel-powered E-boats."
[1] D. K. Brown & George Moore (2003). Rebuilding the Royal Navy. Warship design since 1945. Chatham Publishing. ISBN 1-86176-222-4.
en.wikipedia.org/wiki/Napier_Deltic
Is there another application for petrol turbo other than cars ? I'm not aware of any bike manufacturers who do this as factory fit though there are specialist engineering companies and people with big hammers in sheds who have done this.
Last edited by: gmac on Fri 20 Jul 12 at 07:53
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>> I'm not aware of any bike manufacturers who do this as factory fit though there are specialist engineering companies and people with big hammers in sheds who have done this.
In case anyone has been living on Mars for the past 10 years, here's what is being referred to...
www.youtube.com/watch?v=3qecCf6fJG4
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>> Certainly did Lygonos. Don't recall too many 42 tonne forced induction petrol HGVs, Zero's a
>> bit quiet too, must be out hunting the lesser spotted petrol Deltic :-)
Well hopefully, if things work out, he will be filming Deltic D9009 Alycidon next week.
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Is Alycidon passed to run on NR metals?
If so where's she going - cannot drive yet or walk far but have chauffeuse!!
Last edited by: Bromptonaut on Fri 20 Jul 12 at 09:26
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Yup its on the main road, leaving kings cross at sparrow fart o'clock (latest I heard was 06:30) next wednesday hauling 13 Mk1s to Edinburgh, so thats probably the ECML.
When I get confirmed timings and route I will let you know. I will probably grab it somewhere between Potters Bar and St Neots.
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>> Yup its on the main road, leaving kings cross at sparrow fart o'clock (latest I
>> heard was 06:30) next wednesday hauling 13 Mk1s to Edinburgh, so thats probably the ECML.
>> When I get confirmed timings and route I will let you know. I will probably
>> grab it somewhere between Potters Bar and St Neots.
1Z55
KX 06:50
Sandy 07:23
Peterborough 08:02-08:04
Grantham 08:44
Newark North Gate 08:54
Retford 09:06
Doncaster 09:29-09:33
York 10:02-10:05
Darlington 10:50 (DML)
Durham 11:08-11:13
Newcastle 11:31-11:35
Morpeth 11:56
Berwick-Upon-Tweed 12:30
Dunbar 12:54-13:04
Edinburgh 13:40
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>> Yup its on the main road, leaving kings cross at sparrow fart o'clock (latest I
>> heard was 06:30) next wednesday hauling 13 Mk1s to Edinburgh, so thats probably the ECML.
I hope the video turns out OK. I trust you will get a good sound recording, hopefully on a hilly section so that the engine gets a workout.
Don't forget the sun lotion.
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This is a little gem from the Euro regulations for Euro 6:
"In addition to complying with the emission limits mentioned above, vehicle manufacturers must also ensure that devices fitted to control pollution are able to last for a distance of 160 000 km. In addition, conformity must be checked for a period of 5 years or over a distance of 100 000 km."
DPFs (and other emissions control hardware) will have to last to 100,000 miles or the manufacturer will be liable, if I read that rightly. Still "able to last" sounds quite vague.
Last edited by: oilburner on Thu 19 Jul 12 at 13:55
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A Which story saying the obvious, unusual. Surely everyone works out their mileage, and the car purchase premium, and hence the total cost of ownership. I suppose Toyota Prius owners don't.
Manufacturers are now putting a lot of effort into making petrol engines more efficient. The latest Ford Focus Ecoboost has a 1 liter 3 cylinder petrol engine and a combined fuel economy of 59mpg. There is a premium over the normal engine although you get a better 0-60mph time. My little VW Up, roughly a VW Polo, has an official combined figure of 63 mpg, and I get that. It seems that 2 cylinder engines are even more efficient, and they can throw in regenerative braking and other tricks.
I had a diesel VW Polo on loan. I hated the engine. When stationary it would twiddle its thumbs for an hour or two between you pressing the accelerator and the car moving, very disconcerting, unless I floored the accelerator. Nice at speed though, lots of welly.
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The EU has all but killed diesel through its regulations, making it too complex and too costly to be looked at long term, which is why manufacturers are now working hard on petrol engines.
Pity really it may mean the death of the diesel hybrid which was clearly an interesting and possibly fruitful path.
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>> The EU has all but killed diesel through its regulations, making it too complex and
>> too costly to be looked at long term, which is why manufacturers are now working
>> hard on petrol engines.
>>
It'll be interesting to see what the French come up with. They've had a preference for diesel since Adam was a lad. I don't have any figures for new car sales in France but it would be interesting to see if there was a pattern emerging of a shift.
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>> The EU has all but killed diesel through its regulations, making it too complex and
>> too costly to be looked at long term, which is why manufacturers are now working
>> hard on petrol engines.
>>
>> Pity really it may mean the death of the diesel hybrid which was clearly an
>> interesting and possibly fruitful path.
>>
>>
>>
And just as PSA have started bringing them to market.
I recall a while back VW announcing that they were not really sure how much more development could take place on Diesels, and as such were investing heavily in new petrol technology as it was easier to hit the emissions targets
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IMO diesels are nicer to drive, though!
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Have you driven a turbopetrol, Roger?
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>> Have you driven a turbopetrol, Roger?
>>
For me that could go one of two ways.
Drive something which was built from the outset to be a performance car for which there is no comparison and walk away converted or, drive one that is trying to be something bigger for which there is a comparison and walking away wishing there was an alternative measurement for emissions whereby a normally aspirated six could be retained over a forced four.
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>> For me that could go one of two ways.
>> Drive something which was built from the outset to be a performance car for which
>> there is no comparison and walk away converted or, drive one that is trying to
>> be something bigger for which there is a comparison and walking away wishing there was
>> an alternative measurement for emissions whereby a normally aspirated six could be retained over a
>> forced four.
Let's face it, if it wasn't for emissions regulations and the price of fuel, driving a big normally aspirated petrol engine would be a no brainer.
And if cars weren't so damn heavy these days you wouldn't need these torque monster diesels.
Last edited by: corax on Sat 21 Jul 12 at 12:16
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No end of people complaining about their 120/170hp 1.4 turbo petrols online.
Oh hang on, they all seem pretty happy with them.
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Sounds ideal to me. The petrol car can have a flat torque curve like the diesel, and lots more rpm as well if required. Best of both worlds.
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Only downside re. petrol is the inherent efficiency advantages enjoyed by compression ignition, and a fuel that is heavier/more energy dense.
Euro 5 and Euro 6 seem likely to put paid to those advantages by choking diesels further....
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Euro 5 doesn't appear to have done too much damage if Alfa Romeo's data is to be believed.
1.4 turbo petrol 170PS, 230Nm peak torque top speed 218kph; 0-100 kph 7.8 seconds vs the turbo diesels 170PS, 350Nm top speed 218kph; 0-100 7.9.
In gear acceleration is pretty even between the two (diesel being marginally quicker), even the emissions are pretty close 121g/km vs 119 but the diesel has a longer service interval ? That does surprise me, maybe all this filtering is actually doing some good extending the oil life of the heavy oil burner.
Last edited by: gmac on Sat 21 Jul 12 at 17:43
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My Shogun had 12.5k mile intervals for oil change compared to the older (same engine) 9k intervals - I think this was managed by having a bigger oil capacity (9.8 litres in the newer engines).
Maybe Alfa do similar?
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Possibly, Volvo jumped from 12k to 18k intervals on the S60 D5 (diesel) when they went from Euro 3 to Euro 4.
Whether that's down to cleaner oil or chasing the company car driver $ I don't know.
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>> Only downside re. petrol is the inherent efficiency advantages enjoyed by compression ignition, and a
>> fuel that is heavier/more energy dense.
I think it's the higher compression ratio that can be used with diesel that accounts for most of the efficiency advantage, though the fuel density helps the diesel mpg measurement.
I'm slightly bemused by the blurb on my Outlander which has the newish Mitsubishi 4N14 VVT diesel in it. They boast about the low (16.x) compression ratio which apparently makes it quieter; other things equal, it must make it less efficient.
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>> I'm slightly bemused by the blurb on my Outlander which has the newish Mitsubishi 4N14
>> VVT diesel in it. They boast about the low (16.x) compression ratio which apparently makes
>> it quieter; other things equal, it must make it less efficient.
I'm amazed by how quiet the Honda CTDi diesels are. I walked passed an idling Accord and it was like a slightly tappety petrol. Many owners complain about fuel economy, though some seem better than others. This engine also has a low compression ratio (16.7:1).
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High compression with diesels increases the NOx emissions I believe.
I think the forced induction makes up for some of the downside of lower compression efficiency.
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Eyeopener re diesels...? - Shiny
