Why diesels?

My daily round trip is nearly 50 miles hence the beat-up but reliable old diesel... (that doesn't include the kids' taxi runs which can add as much again)

Aprt from the fact I don't have to worry about it getting trashed in the school carpark, the other attraction for me of having old cars is that I can afford more of 'em, so I always have a choice of ride!

He only has a slight dislike of diesels compared to mine.

I've driven hundreds of the bloody things, and so far found about two that I'd class as "tolerable" which are the Xantia TD and the Merc 270CDi.

The Golf PD motor I thought was awful, the BMW 530d (new shape) was laggy as hell and sounded 'orrible, the TDCi 130 Mondeo went well - provided you rowed it along with the gearlever.

The Xantia was a decent family car - the suspension counteracted the weight of Dr D's Evil invention, and the Merc E270CDi was nice enough, although it still did the shudder when you switched it off. Hardly fitting for a luxury car having it shudder and vibrate.

Petrol with LPG for the cheapskates is the answer. Environmentally better than diesel, nicer engines, nicer cars, nicer world.

The only reason for diesels is if you're skint enough to have to run them on veg oil / kerosene. Then there's an excuse.

With the latest Diesels, you know..ones from manufacturers managing quiet refinement, more hp/cc, torque/cc and mpg from diesel than petrol (like BMW), the question must be 'why buy petrol cars (over

Even 4 years ago I bought my diesel for its performance not its economy - an Alfa Romeo 156 2.4JTD. 5 Years ago these were 130hp, now they're 175hp but the same mpg!! 200hp has been announced for the next model next year and certain versions of that engine are planned for

Petrol for performance, and refinement, even the best diesels aren't there yet.

BMW 535d is best bhp/l, 272 bhp from a 3.0 twin turbo. Of course there's plenty of 2.0 turbo petrol cars making 280bhp.

even VW's V10 diesel only makes 320bhp. BMW's V10 petrol makes 500 without a turbocharger.

Is the Merc 270CDi a 5-pot or V6? I ask, as I'm assuming it's a 2.7 litre lump, and the Sprinter 316CDi has a 2.7 5-potter.

Too laggy/peaky? Would I be right in thinking that the 90/110bhp older style TDIs are a better bet than the 115/130bhp PD engines, from a driveability POV?

Indeed, it's because they can't rev, and due to the nature of diesel combustion, they never will be able to rev much past about 4500rpm. I think. Can someone who knows explain the physics behind that?

Yes, but that's because they rev about 60% or so higher. All people can do with diesel engines is increase the torque available in their limited powerband (up to around 4500rpm generally) and after that, changing up is the only option. I'm pretty sure a similar sized turbodiesel will produce a reasonable amount more torque at revs within this range than even a similar size turbo petrol - certainly below 3000 or so rpm.

In news:BO36f.6977$ snipped-for-privacy@newsfe6-win.ntli.net, AstraVanMan decided to enlighten our sheltered souls with a rant as follows

It's the amount of time diesel takes to burn that limits the RPM range.

Petrol + spark = boom

Diesel is much more awkward to set fire to!

In news:cK36f.6968$ snipped-for-privacy@newsfe6-win.ntli.net, AstraVanMan decided to enlighten our sheltered souls with a rant as follows

Tis a 5 pot.

Laggy *and* peaky, much in the style of every modern diesel. Loads of torque occasionally, but bugger all most of the time.

Except that you're not comparing like with like engines - cc and manufacturer (from your selection, for example):

BMW 535d 2993cc 272hp 560Nm 0-62 in 6.5s Top speed 155mph 35.3mpg BMW 530i 2996cc 258hp 300Nm 0-62 in 6.5s Top speed 155mph 32.1mpg

Meanwhile, back on planet earth 'Joe Public' (who doesn't buy many extreme cars) will be much more likely to be considering things like this:

BMW 320d 1995cc 163hp 340Nm 0-62 in 8.3s Top speed 140 mph 49.6mpg BMW 320i 1995cc 150hp 200Nm 0-62 in 9.0s Top speed 137 mph 38.2 mpg

(tops speeds are limited to 155, mpg is combined, all official BMW figures today)

Do you see where I'm coming from yet?

Yes, but you're forgetting the fact that the diesels have a turbocharger. Add a turbocharger to the petrol and the performance argument goes out of the window, and there is very little difference between the n/a petrol and turbo petrol in terms of economy. On the flip side, it's often a *lot* easier to get close to the manufacturer's published "combined economy" figures in a diesel than a petrol, due to diesels being a lot more efficient at idle, and on shorter journeys from cold, compared to petrols. Then there's the cost thing, diesels cost more, and especially if you're buying new, you need to be doing a fair few miles to make up the extra purchase price in fuel savings. Though with increased demand, the difference is less than it used to be.

Anyway, I'm taking bets on how long this thread's going to last. Get your bets in now (well define the point for measuring as the number of posts according to google at midnight on Hallowe'en night (31st October for the ignorant)), to snipped-for-privacy@whataloadofbollocks.co.uk.

In message , Zathras writes

You missed a couple of things off:

BMW 530iSE £32645 BMW 535dSE £37335

BMW 320d £23225 BMW 320i £21390

BMW 540iSE £36985 306bhp 390Nm 0-62 in 6.2s Top speed 155 mph 25.7mpg

BMW 325iSE £25525 218bhp 250Nm 0-62 in 7.0s Top speed 152 mph 33.6mpg

The message from "AstraVanMan" contains these words:

Ah, the joys of an automatic. I have a little box which takes care of all that tedious rowing stuff for me. The only time this month I've pushed the pedal all the way down is towing a Laguna up a 1:7 hill.

No I'm not. The above is what this manufacturer offers - it's no use in a real world comparison to say to BMW 'Can I have a normally aspirated 320d' - because they don't exist. You have to draw the line somewhere.

In which case, why do manufacturers (Saab being a notable exception) not routinely turbo all their petrol engines?

Not many I'd bet. BMW have nicely fallen into line with my arguments and provided some proof too! I'm not sure if many will want to waste time arguing against actual documented realty with their opinions.

Umm, you do realise you're posting on usenet, don't you?

cheers, clive

That's not the argument I'm making though. There are too many variables not related to engine performance like the trim specification and the price the manufacturer sets. I would expect the quicker faster car to be more expensive even if the underlying costs weren't.

Probably goes to show why the 535d was so designated and not as a

As I said, performance/price is not an accurate measure of performance as price can be anything. Even so, a 320d isn't going to be that far behind a 325i in normal road conditions.

I don't dispute your argument..it's just that it's not the one I was attempting to make.

Ha Ha.. That's it PC off..down too the pub!!!! :-)

In message , Zathras writes

Cost & simplicity, market, fashion and the availability of other ways of getting more power. Some markets don't need the power, some people prefer a naturally aspirated engine in a performance car and get that either through more displacement or higher revs.

They do with a lot of them, as do Volvo and VAG. And they're very popular, for a good reason.

That's never stopped people before.

Yes, but comparing like with like, the diesels are more expensive than equivalently performing petrol counterparts. It's because they're better in a lot of ways. Just as a penthouse apartment goes for more money than one the size of a shoebox.

Ironically, putting the 325i in there proves nothing, as it's more expensive than the 320d! Maybe the 323i isn't, but I'm not too sure what the difference is between the 323i and the 325i.