Are modern dervs rubbish?

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Deanxm
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Are modern dervs rubbish?

Post by Deanxm »

..............Im starting to think that they are after getting my new van :roll:
but what do you lot think? modern dervs are certainly much quieter and smoother but are they more trouble than they are worth?
My New van (ok its five yers old) has been causing trouble in the last two weeks since picking it up with an Injector failure, wiring faults, 3 derv leaks, and now it is back in the garage with another orange light of doom and what looks to me to be to be head gasket failure, not a good sign for a vehicle with only 40k on the clock..............

D
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spider
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Post by spider »

The main problem I see with them (although yes they are more powerful and more efficient as well as quieter)

They are only as reliable as a petrol engine (if that) due to the mass of electronics needed to keep them running.

A mechanical diesel (XUD etc) does not require much (any really) in the way of electronics to keep it going.

Not that new engines are unreliable, just that their reliability is reduced to that of a petrol engine effectively, at least in my opinion anyway. I said this around 1999 too when the first DI engines started to appear.
Sl4yer
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Post by Sl4yer »

The way I think about an XUD, once it's running there's nothing to stop it, as long as there is fuel in the tank. Barring a mechanical failure of course, which the modern engines are probably still as prone to.

The modern breed rely on the electronics to make them go, and the slightest fault will cause problems. Saying that, engine electronics have come a long way (both in complexity AND reliability) since the early 1990s when they became commonplace, so hopefully the lessons learned on the petrol engines will have been incorporated into the diesel setups.

I personally don't always find modern diesels smoother or quieter than the XUD, although economy is amazingly impressive. But although I haven't driven one, the Beemer 335D which does 0-60 in well under 7 seconds and 155mph limited top speed, and can also return 40MPG, would seem to be a good way forward! :D

James
XantiaMan
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Post by XantiaMan »

335d, limited to 155mph, 0-60 in 6.1 seconds means most cars left standing at the lights once 428lb ft kicks in. Nice bit of kit.
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DickieG
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Post by DickieG »

XantiaMan wrote:335d, limited to 155mph, 0-60 in 6.1 seconds means most cars left standing at the lights once 428lb ft kicks in. Nice bit of kit.
They sound nice too.
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Post by KP »

All the ones I have driven, TDCi, TDi PD's.... just seem to have no torque low down at all compared to the old XUD's i've had :( and then the lag on some of them...

Oh and compared to my experience they all stall far too easily :( old XUD's as long as the handbrake wasn't on you could drop the clutch and it would chug but still go, new ones just stall and die :(
Deanxm
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Post by Deanxm »

Yes this is what ive found, they still dont rev but have no torque at all at idle either now, they dont feel as solid as an old XUD or any other proper dervs.
Then of course you have frap filters and the like now.................i have to say im not really that impressed with them and im not on about the bad experience of this one vehicle either.

D
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DickieG
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Post by DickieG »

I can't believe the comments above re the low down torque of a modern diesel engine compared with an XUD, I thought XUD's invented turbo lag especially whenever pulling out of a junction, flat as a pancake until 2,000 rev's then all over by 4,500. As for modern diesels stalling I'm also lost on that one as they have ECU's that maintain the idle speed, strange, very strange :?
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myglaren
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Post by myglaren »

I find mine easy to stall where the Xantia and BX were just about impossible.
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Post by Citroenmad »

I agree with Richard, if anything the modern range of diesels improve low down torque. After all, thats what a diesel is all about, not revs.

I really like the HDi engines, the 2.0 110s pull almost evenly through the whole rev range, and they are still pulling at 4500-5000RPM. There is a lot of pull low down, and it never really gets into a lull of torque at low revs, its very flexable.

The 2.1TD isnt at all like that, torque low down is low and you must be in the mid band of the rev ranege to get the best, too low or too many revs and the power is not there. Which is where the HDi scores. The HDi is an easier car to drive for this reason and provides more pull more of the time.

I find VAG group TDi PD engines excellent in terms of the kick which comes in with the turbo. You get a real sense of the power. TDis always have a noticable kick as the turbo comes in, HDis have a much more smooth power delivery and usually rev more freely.

The later 16v HDis, 1.6 and 2.0 138 are much of the same as my above comments on my 2.0HDi 8v 110. The 138 is easier to stall though. On the whole i find diesels very hard to stall, infact i cant remember doing so. All of the modern diesels ive driven will happily pull away with no accelerator use at all, which makes parking and town driving much easier. I find the T2.1TD requires some gas or it seems unhappy at parking with just the clutch.

The 2.1TD does feel like a hardly old lump, it is much more old school with the short useful rev range and smoke on start up and heavy acceleration after slow cruising. The only time i see the HDis smoke is a bit of mist in headlaps of following cars as i floor it. However, the 2.1TD in the Xm estate is exactly the same for performance when going for it and delivers only slightly less fuel economy than the HDi 110s.

I dont like the Ford diesels one bit though, mainly because their own engines are quite an old design and they are not always reliable. The TDDi engines seem very unrefined, smokey and un-economical. The later TDCi FORD engines are similar and i was dissapointed with the one i drove. Ford now use the PSA diesels in most cars and that must say something. I will say that the later 16v HDi engine were designed with Ford and are not soley PSA engines.

In terms of reliability on the whole, you get good and bad modern diesels. Ive said before but in my opinion the 1.9DCi Renault lump must be among the worst. Excellent engine when it works, but it often goes wrong and badly. TDis engines are quite hardy and HDis tend to give reasonably little faults but offer great driveability and economy.

Electrics are a problem of modern diesels, however high pressure pumps and injectors, eco credential adding features such as FAP filters and stop start features, etc are all going to the add to the potential problem list.

While i do value older style and more simple diesels for their reliability and ease of owenership, i also value modern diesels which usually offer more performance, refinement, economy and drivability, albeit with the risk of the occasional problem, which, with HDis at least, is usually electrically related.

In some ways modern diesels are easier to own, longer service intervals and much longer cambelt change times for one thing.

Ive no doubt that my HDi lump will never let me down, but i fear it will be the electrics on the car which might cause a problem.
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Post by Sl4yer »

Citroenmad wrote:I find VAG group TDi PD engines excellent in terms of the kick which comes in with the turbo. You get a real sense of the power.
I used to have a Leon FR TDi (150hp). Great engine, good car really. That engine would be perfect for an Activa - as much torque as the 225hp petrol turbo! Sounded like a tractor when cold though, hence my earlier comment about modern diesels not being smoother than the XUD. :D

James
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Post by citroenesque »

Are modern dervs rubbish?

Yes, they are.

Old dervs are at least simple.
Citroenmad
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Post by Citroenmad »

Sl4yer wrote:
Citroenmad wrote:I find VAG group TDi PD engines excellent in terms of the kick which comes in with the turbo. You get a real sense of the power.
I used to have a Leon FR TDi (150hp). Great engine, good car really. That engine would be perfect for an Activa - as much torque as the 225hp petrol turbo! Sounded like a tractor when cold though, hence my earlier comment about modern diesels not being smoother than the XUD. :D

James
Ture, however the 1.9TDi does rather date back a fair way nd its certainly not the most modern in terms of refinement.

We have had a few TDis, they have been fantastic engines never a problem.

Im very much a diesel person and unless its something interesting, a V6 or turbo, i can't ever see me owning a petrol car again :)
Deanxm
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Post by Deanxm »

well as a comparison my previous van was an R reg transit, a 2.5 turbo and it clattered like a transit so you can understand i dont miss the noise, it done 24mpg and would max out at 85mph, the 2.5 DCI of the Renault just feels like a nasp petrol engine that wont rev above 3800rpm with no low down torque and it does 26 mpg it would do above 85 but not now its all racked and full of tools so i fail to see the improvement here, in a car fine as when both vans are unloaded the renault flys but both carrying the same weight there is nothing in it so where is the improvement???????? as far as a van goes i want a truck that will do the job day in day out and this dci engine wont (by the looks of things anyway) i mean a head gasket failure and bad mechanical knocking on a 40k one owner frsh vehicle thats 5 years old :? my merc van covered 340k with no problems, the transit went to car heaven with 170k isle of wight miles on the clock and in 5 years (ok it was on its 3rd gearbox) but the engine never had anything other than a turbo...............
Everyone i talk to curses their new trucks, be it Vauxhall, renault, Mitsubuishi, mazda, the only ones that seem ok (and it pains me to say this) is ford but then quality isnt high on the list and those daft DM flywheels seem to bite the dust pretty damn quick, maybe this van has tainted my opinion i dont know but so far common rail dervs have not impressed.
Sl4yer
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Post by Sl4yer »

Citroenmad wrote:Im very much a diesel person and unless its something interesting, a V6 or turbo, i can't ever see me owning a petrol car again :)
I said that once, but Activas only come in petrol over here. :D

The Leon had a split personality. You could tootle along gently with great economy and smoothness (once warm). But press on and keep the revs up and it really came alive. Makes me quite want one again, although the thought of driving along a bumpy road after 3 hours driving (and needing a toilet break) might put me off.

The 1.6 HDi in the C3 should, in theory, perform identically to the XUD turbo (same output, very similar torque, pulling a very similar weight car). But it just doesn't work like that somehow! It's just a bit....soulless. I suppose some of it is down to the chassis - the C3 doesn't compare to the Volcane in terms of handling - but I'm sure the XUD pulled better from lower down, and sounded better too.
Of course, it's all down to personal opinion at the end of the day.

James