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I've driven only two diesels: an Audi A4 several years ago and just recently a Rover 220. I recall that the A4 was very torquey low down in the rev range and was surprised to find that it was only upwards of 2500--3000 that the Rover provided much punch. Do diesel engines vary that much or might the Rover need attention?
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Roger,
Many turbo diesels only get shifting from 2200rpm. People not used to them often complain of the narrow power band. Say 2500 - 4000rpm, when the noise kicks in.
I don't know the Rover well (as it isn't made by Citroen) but it sounds about right.
David
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Roger, test drive the new common rail diesels of VW or Peugeot or BMW, for a totally different diesel experience to the old oil burners you describe. I drove the BMW 530d for a year - the accleration was stunning particularly when overtaking but also very quick from standing start. I lost count of the number of people who said " you'd never know it was a diesel"
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Roger,
I have to agree, sort of, with David, except that I would put the point at which they start to kick in a bit lower @ about 1800 rpm with the real peak @ 2200. Much above 3500 you are wasting fuel and just making a lot of noise. It does vary from model to model, eg the current Rover 75 with the detuned BMW engine is as flat as a f*rt at low revs. The car absolutely cries out for an autobox, yet the GM Ecotec pulls acceptably from not a lot above 1100rpm.
There really is no substitute IMHO for being picky, driving as many examples as you sensibly can of a model you are interested in but not familar with, and you will just know when you have got a decent one.
You say you have only driven two diesels but not how far. I guess not too many miles. It takes time to adjust, even from an atmo to a turbo. First diesel I drove was a Sierra Estate with that diabolical ex Peugeot 2.3 engine and it took me all the way from N England out to the Nurburgring (and a not very quick lap round Spa) before I really got the hang of it and realised that I had to relax, stop revving the nuts off it and use the torque. Oh the ignorance of youth.
Rover 220SDi was the most powerful diesel in its day so in principle it has to be reasonably quick, look up the spec/handbook see at what rpm it produces the max torque and try driving it keeping revs around there +/- 500 rpm or so. It will take a lot more than a blast round the block to suss it out.
Cheers,
S
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Although the power band is narrower on a diesel than a petrol, what you need to look at is the ratio between the bottom and top of the band, which in both cases is about 2:1. But at lower revs in the case of a diesel.
In the case of petrol the band will say be between about 2,250 revs to 4,500 revs. In the case of the diesel from say 1,800 revs to 3,600 revs. In both cases you will double your speed if you go through that band when you change up a gear.
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I agree with Brian. I currently drive one of the last of the Carlton turbo diesels.
Power band between 1800 and 3600 rpm. Keep in that band and it performs well.
Has anyone any experience of the 2.5 Omega fitted with the BMW diesel?
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I just drove a petrol engined car for the first time in five years and had the opposite problem. Where was the power when I needed it at 30mph in fifth? Somewhere down in third gear. I was changing up gears so early the pre-stall vibration made the poor thing sound more like a diesel than a modern diesel.
Chris
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I've got a Saab 9-3 diesel, never had a diesel before, but am convinced by them. I've covered 50,000 miles in just over two years on a mix of roads varying from long continental motorway journeys to twisty single track roads. Before I bought it, I tried a 1999 Passat demonstrator with the old 110bhp engine & that felt flat as a pancake at low revs, with the Saab feeling much more lively. Motorways are a pleasure, as normal cruising speeds put you right at the bottom of the max torque & you can really squirt by the sluggards when necessary!
The only thing I would point out is that, although in the UK under normal driving conditions I don't really notice the narrow torque band (max is between 1900-3000), it really makes a hell of a difference in Austria!! Up & down the mountains it has to be kept on the boil and it clobbers fuel consumption - I remember spending 3-4 miles grinding behind a heavy lorry up a steep hill/mountain, and watched the overall fuel consumption drop from 47 to 42 mpg over that short period. So it does depend to some extent on where you live & subsequent driving conditions - I'd expect to notice the torque band more anywhere in the UK with hilly terrain.
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Stuart wrote
> "It does vary from model to model, eg the current Rover 75 with the detuned BMW engine is as flat as a fart at low revs. The car absolutely cries out for an autobox" - the Rover 75 is now out in diesel-auto form and is, as you quite rightly say, a real dream to drive - the autobox is really suited to this engine. I took one to Basingstoke recently and really enjoyed driving it - averaging 45 mpg during the run. The 75 diesel with a manual 'box does indeed feel a little 'breathless' but seems at home on the motorway at speed. See my earlier thoughts ref TuningBox - there is one available for this model - it should provide the extra 'buzz' required
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