Is diesel a dead end as a technology?

[300bhp/ton]

NoelWatson said:

heebeegeetee said:

willhollin said:

Why would anyone in their right mind buy a diesel in the first place.

'Cos they're better at the ordinary stuff, ie 95% of the time.

Does that ordinary stuff including pulling briskly away from a junction into moving traffic? I was unable to do this in the auto diseaseal I was recently in. There was a good 2 seconds of turbo lag.

Sorry, but that's total bks and rubbish unless the car you where in had some major issues, ie not working correctly.

A diesel turbo suffers no more lag than a petrol turbo, possible less as turbo's and diesels suit each other due to the rpm ranges they operate in.

[NoelWatson]

300bhp/ton said:

NoelWatson said:

heebeegeetee said:

willhollin said:

Why would anyone in their right mind buy a diesel in the first place.

'Cos they're better at the ordinary stuff, ie 95% of the time.

Does that ordinary stuff including pulling briskly away from a junction into moving traffic? I was unable to do this in the auto diseaseal I was recently in. There was a good 2 seconds of turbo lag.

Sorry, but that's total bks and rubbish unless the car you where in had some major issues, ie not working correctly.

A diesel turbo suffers no more lag than a petrol turbo, possible less as turbo's and diesels suit each other due to the rpm ranges they operate in.

Maybe there was something wrong with it, but as I said, it was pretty new. Alternatively, perhaps I am used to decent N/A petrols that actually produce power when requested, and not seconds later.

[Deva Link]

NoelWatson said:

Welshbeef said:

That auto merc your talking about they always start in second gear solution for sharp get aways you slip it into sport. However if a 350cdi pulling away in 2nd is causing you problems which still does 0-60mph in sub7seconds how on earth do people cope with slower than 7second cars really what about those with sub11seconds.. They can never escape that roundabout in fact they probably avoid it.

If that's not the case there is something wrong with the car.

Christ my wifes 84bhp 1.8ltr petrol Volvo 16yrs which has less than that by now has never had issues exiting the roundabouts. The mondy st 2.2 tdci again never an issue manual and likewise the 330d auto is a piece of cake to exit.

So either that was a broken car or carpet jammed under the throttle pedel

Welshbeef said:

solution for sharp get aways you slip it into sport

I'm sure I tried this. Still slug slow off the line

They don't start in 2nd in E mode anymore - the car always starts in 1st. In theory it should be sharper in Sport but it doesn't seem to work in practice. The Merc forums are full of complaints from E350CDi owners.

[300bhp/ton]

NoelWatson said:

300bhp/ton said:

NoelWatson said:

heebeegeetee said:

willhollin said:

Why would anyone in their right mind buy a diesel in the first place.

'Cos they're better at the ordinary stuff, ie 95% of the time.

Does that ordinary stuff including pulling briskly away from a junction into moving traffic? I was unable to do this in the auto diseaseal I was recently in. There was a good 2 seconds of turbo lag.

Sorry, but that's total bks and rubbish unless the car you where in had some major issues, ie not working correctly.

A diesel turbo suffers no more lag than a petrol turbo, possible less as turbo's and diesels suit each other due to the rpm ranges they operate in.

Maybe there was something wrong with it, but as I said, it was pretty new. Alternatively, perhaps I am used to decent N/A petrols that actually produce power when requested, and not seconds later.

Actually, just read the other replies after your post and was going to delete mine.....

I've not been in one of those, but it does sound wrong, suspect it's some dodgy factory setup or something. Certainly isn't 100% the result of it being a TD though.

I do know a low of cars with high torque outputs are limited in lower gears to prevent damage to the gearbox. Maybe this car would suffer this if they didn't deliberately make it limp off the line.

[300bhp/ton]

entwisi said:

SWMBOs Astra Diesel auto is hopeless at pulling out. another with 2 seconds of nowt by which time you have your foot flat and it eventually goes from nowt to scalded cat. 2 seconds later its after 2nd and you lose all drive again for a second.

I've a Honda CDTI although manual. first gear is too low so you can't get away too quickly as you are diving for 2nd with hardly any speed on the clock. 2nds not bad though but I dont fancy lunching the clutch with 2nd gear set offs too often. As such it doesnt get any of the traffic light stick I gave all my previous LPG'd stuff. It has been reliable so far ( 150K, 5.5 YO, still on original clutch) and is cheap to service ( 32 quid oil and filter at National for Castrol Edge, 10 quid air filter from motor factors, quick lube and check. It goes into local back street garage every 36K for the fuel filter and gearbox oil as I can't be arsed faffing with all the pipe work and its just much easier on a 4 post than me crawling underneath.)

Is derv the future? not for me, its doing a job here and now but I can't see mey next car being diesel. having said that I can't see it being a DMF equipped either. It seems we peaked at reliablity vs complexity in about 1995 so I shall be mostly looking to stay there-ish. Either that or old skoool Merc W123, proper Saab, or classic with a few modern touches.

I know it's not always easy for people to accept. But the issues you cite above, are they not more an example of poor development and a poorly designed car?

Diesel engines really require very different gearing to petrol ones. Get it wrong or scrip on final drive ratio's and it'll affect how they drive. Also this modern craze for as many gears as possible seems just wrong with a diesel IMO.

I'd much rather have 4 or 5 gears with a tall final drive if you have a grunty diesel. This will mean good terminal speed in gear and a broad speed range per gear. As a real world example I really didn't get on with the TDV6 Discovery 3 diesel manual I drove. 6 gears was far too many and you where always, and I mean always changing gear. By contrast a much slower less powerful tweaked Tdi in a Disco 1 with a 5 speed manual is much more pleasant to drive as you can use the gears far more sensibly.

[heebeegeetee]

entwisi said:

SWMBOs Astra Diesel auto is hopeless at pulling out. another with 2 seconds of nowt by which time you have your foot flat and it eventually goes from nowt to scalded cat. 2 seconds later its after 2nd and you lose all drive again for a second.

I'm really surprised to hear this - this is 2 diesel autos apparently suffering drive-ability issues.

If the car is an auto, as the revs increase to spool the torque converter up it should spool the turbo too, so there shouldn't be any lag.

Our tow VAG products have been absolutely fine, and a far as I'm concerend i've never suffered any lag or brick-wall rev governors or anything, the car is just in the right gear at the right time, or if it isn't it gets into it really quite quickly with our dsg.

Our mundane Leon is brilliant at pulling out into gaps, fwd scrabble not withstanding if i've been injudicious with the throttle. As i said, you really can make good progress without exceeding 2,500 rpm and there really is little point in exceeding 3k rpm. I find I can get around with sparing use of the throttle, I find it very impressive. Really good overtaker too, and easily does 500+ miles on a tank. All the attributes I'm looking for in a daily driver, in other words.

(Not being the car's regular driver though, I really struggle with the over-servoed brake pedal, and the Golf we tried at the same time when buying was much worse).

[300bhp/ton]

heebeegeetee said:

entwisi said:

SWMBOs Astra Diesel auto is hopeless at pulling out. another with 2 seconds of nowt by which time you have your foot flat and it eventually goes from nowt to scalded cat. 2 seconds later its after 2nd and you lose all drive again for a second.

I'm really surprised to hear this - this is 2 diesel autos apparently suffering drive-ability issues.

If the car is an auto, as the revs increase to spool the torque converter up it should spool the turbo too, so there shouldn't be any lag.

Not too sure on that.

Most stock TC's stall at 1100-1200rpm. Even with a modern TD unit that is out of the boost threshold.

And also a turbo won't really boost without load on the engine. Sure the TC provides some load, but not a lot. Hence why if you have a boost gauge it'll hardly move if you rev the engine while not in gear. No load = low exhaust gas flow rate = low turbo impeller speed = low or no boost.

[unpc]

heebeegeetee said:

unpc said:

Ships and Trucks! The black stuff should be used for ships and trucks only IMO. As said earlier Euro 6 will effectively kill off diesels for small cars as the cost will be prohibitive. The complexity of modern diesels will be their death knell, without even getting started on the DSG time bomb.

No, you've got it the wrong way round - Toys and Lawnmowers! That's all petrol is good for. No point in having it in anything else.

So Euro six is going to kill diesel now. I was told it was Euro 1,2,3,4 and 5. In fact I've been reading since the 1980's that diesel is all but dead.

Maybe it will die one day but we do need diesel for all sorts of things - getting work done, basically - so it will never go away entirely.

Then I guess i'll have to go back to some petrol jobby that won't move unless I'm revving its tits off or doing sub-30mpg.

I didn't say it will kill Diesels but it might get prohibitively expensive for small cars.

[heebeegeetee]

300bhp/ton said:

heebeegeetee said:

entwisi said:

SWMBOs Astra Diesel auto is hopeless at pulling out. another with 2 seconds of nowt by which time you have your foot flat and it eventually goes from nowt to scalded cat. 2 seconds later its after 2nd and you lose all drive again for a second.

I'm really surprised to hear this - this is 2 diesel autos apparently suffering drive-ability issues.

If the car is an auto, as the revs increase to spool the torque converter up it should spool the turbo too, so there shouldn't be any lag.

Not too sure on that.

Most stock TC's stall at 1100-1200rpm. Even with a modern TD unit that is out of the boost threshold.

And also a turbo won't really boost without load on the engine. Sure the TC provides some load, but not a lot. Hence why if you have a boost gauge it'll hardly move if you rev the engine while not in gear. No load = low exhaust gas flow rate = low turbo impeller speed = low or no boost.

I agree with what you say, but the no-load time is very short and i'm assuming the turbo has spun to a faster speed before it really spins up and produces boost.

In fairness i'm going by assumptions because I've never suffered any turbo lag issues at all on the 2 autos we've had. I've driven a couple of the types of crappy diesels out there, an elderly vauxhall and a Mondeo respectively, whereby there is proper lag, surge, brick-wall rev governor, really very painfull, but in comparison my auto diesels have suffered nothing remotely like any of that.

The Leon may well have a variable vane turbo, I don't know (I really don't take much interest in the daily drivers ). All I know is it that it sets off at a fair lick right from the movement of the throttle pedal.

(Relatively speaking of course, not claiming it's a hot hatch or owt, but it really is a complete doddle to drive).

[Deva Link]

heebeegeetee said:

I'm really surprised to hear this - this is 2 diesel autos apparently suffering drive-ability issues.

If the car is an auto, as the revs increase to spool the torque converter up it should spool the turbo too, so there shouldn't be any lag.

About 5yrs ago I had a Mondeo TDCi auto on test from Ford for a week (via our fleet leasing company).

The lag both from standstill and from over-run to drive was just ridiculous.

The only way to pull onto fast roundabouts was to hold it on the footbrake and spool the engine up and then let go of the brake at which point it would surge forwards and you were glad it was an auto as you needed to have both hands free to cling on to the wheel!

If, say, you saw a gap on the approach to a roundabout, you still had to stop as you couldn't rely on it picking up drive quickly enough to get you into the gap.

[NoelWatson]

Deva Link said:

The only way to pull onto fast roundabouts was to hold it on the footbrake and spool the engine up and then let go of the brake

I was tempted by this method but it seemed slightly uncouth

[entwisi]

300bhp/ton said:

I know it's not always easy for people to accept. But the issues you cite above, are they not more an example of poor development and a poorly designed car?

Diesel engines really require very different gearing to petrol ones. Get it wrong or scrip on final drive ratio's and it'll affect how they drive. Also this modern craze for as many gears as possible seems just wrong with a diesel IMO.

I'd much rather have 4 or 5 gears with a tall final drive if you have a grunty diesel. This will mean good terminal speed in gear and a broad speed range per gear. As a real world example I really didn't get on with the TDV6 Discovery 3 diesel manual I drove. 6 gears was far too many and you where always, and I mean always changing gear. By contrast a much slower less powerful tweaked Tdi in a Disco 1 with a 5 speed manual is much more pleasant to drive as you can use the gears far more sensibly.

I'd agree. The astra is abysmal design. Huge Blind spots( an interior mirror so large I can't see people stood on a kerb waiting to cross if I'm turning left, B post so thick my motorcycles induced 'lifesavers' are greeted with nothing but an eyeful of nothing.) even driven gently you struggle to top 40mpg, paint as soft as butter, uncomfortable seats, a tailgate my wife ( 5'4 ) struggles to reach when fully open are a few of the niggles. I've not even mentioned the crap P11D rating

The Honda low 1st aside is actually very good. no issues with blind spots, a smooth engine, tall 5th gear ( 2K = 70 ) eleccy tailgate ( gimmick till you have kids then you realise just how useful, plus when your car is as dirty as mine it stops you getting mucky hands! ), paints soft again but I'll forgive it that. even driven like a loon I can't get below 42 mpg.

We have no choice on SWMBOs as its company provided with no option. I'm just hoping her next one will be teh new shape as its meant to be a much better engine and better on the tax front as well.

[redgriff500]

Deva Link said:

heebeegeetee said:

I'm really surprised to hear this - this is 2 diesel autos apparently suffering drive-ability issues.

If the car is an auto, as the revs increase to spool the torque converter up it should spool the turbo too, so there shouldn't be any lag.

About 5yrs ago I had a Mondeo TDCi auto on test from Ford for a week (via our fleet leasing company).

The lag both from standstill and from over-run to drive was just ridiculous.

I think you will find its to do with the Auto gearbox NOT the engine / turbo.

I work with an Auto box guru and when I complained about my wife's A6 response he said it was due to it not having a torque converter.

When the XC90 was slow off the line he said he could cure that, something about a inbuilt delay after coming off the brake pedal.

Its like the stupid 'clutch delay valves' on manual BMW's its there to either protect the car from hooning or to give added 'comfort' but it is annoying to real drivers.