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Modern diesels - what's the point? - Dave N
I've been running my 3 litre CR auto D-Max for nearly 3K miles now, and I get about 29mpg running around, dropping to 25 when I tow 3 tons.

My old '93 Landcruiser 4.2TD auto does around 25mpg, dropping to 22 towing 3 tons.

So considering the LC is 15 years old, has a 6 cylinder engine, permanent 4wd, old style auto, 600kg heavier, bigger tyres, and is less aerodynamic, why does it not use much more fuel? It's also got more torque lower in the rev range, and is much smoother and quieter that the Isuzu. So what have I actually gained?

It looks to me like I've gained nothing at all, except a super complicated engine that's unlikely to run for 200K miles without issue (like the LC). And when it does go wrong, it will probably take the garage a month (and numerous attempts) to fix, and require a second mortgage to pay for it. If CO2 is a direct result of fuel consumption, they'd have been better off putting the old LC engine in the new Isuzu, and I'd had had better power, fuel economy, and reliability.
Modern diesels - what's the point? - oilrag
Its all for the benefit of the motorists following behind who are breathing in the exhaust plume. ;) Having said that, there is a wind from China blowing this way today..........

Edited by oilrag on 27/04/2008 at 09:24

Modern diesels - what's the point? - gordonbennet
Dave, I'll report similar to you, my old and trusty swb landcruiser '93 3.0td 130k (2 tons exact) would return 25 mpg running round, it was whisper quiet, under acceleration you really could ony hear the turbo whistling gently.

Our 3.0 d4d hilux, '07 (2 tons incl hardtop) does 30 mpg with swmbo driving reasonably briskly, its virtually the same engine, but obviously now cr and noisier for it, yes its slightly faster.

TBH i don't think the new vehicle is any better at all on fuel, the big difference's between the two is that the hilux is very high geared 2000rpm at 70 whereas the old lc would be doing nearly 3600 at the same speed, both are rwd normally with 4WD selectable, the hilux is also the best aerodynamically in its class, so where is the benefit of all this modern technology?

I'll also bore you with my opinion that real truck consumption figures are no better than 25 years ago...'84 cummins engine 38+ tons 1200 (approx, memory) lbs ft of torque normal cruising speed 70mph (and would maintain constantly) and 7 to 7.5 mpg.
'06 swedish vehicle same weights (but it does weigh 22 tons empty) similar power figures (ignoring bhp as its irrelevent on a truck) but in fact the new vehicle lacks any grunt at all, normal cruising speed 54 mph (when you can get to it) and 7 to 7.5 mpg.
Again big difference between the two was gearing '84 truck 1100 rpm at 70, '07 truck 1900 rpm at a pattern emerging.
My non engineering opinion only, and no doubt on paper and test beds the new technology wins hands down, not so sure in working practice though.

Probably emissions are better as you say Oilrag, but i rememeber how amazed the mot tester was every time i had the old lc mot'd, as the emisions were very small for the size of vehicle, no smoke at all but still very low speed torque, and we all know they don't often go together (how many have been behind a modern cr diesel car and watched incredulous at the amount of black smoke that gets left in its wake under hard acceleration, real world as against testing perfection).

Sorry to have waffled so much again.
Modern diesels - what's the point? - madf
1995 Peugoet 106 diesel.. no catalyst no aircon 50mpg.
2003 Yaris diesel - cat and aircon 57mpg
Both driven same routes etc.

Plus Yaris is about 100kg heavier...
Modern diesels - what's the point? - RaineMan

Sadly these comments seem to apply to petrol engines as well. I ran a Vauxhall Carlton for many years and it's fuel consumption was about 28 mpg around town, 35 mpg in mixed motoring and upto 45 mpg on a long run. The Omega that followed it is a real gas guzzler by comparision. The equivalent figures are 21-22 mpg, 28 mpg and 35 mpg. In both cases the emissions are fine. I suspect the problem is a) the Omega is heavier, b) the Omega is higher geared, c) the Omega seems to have sacrificed a flat torque curve for a peakier one to gain a few more BHP and d) the Carlton did not have a catalytic convertor.
Modern diesels - what's the point? - Pendlebury
>>>Having said that, there is a wind from China blowing this way today.......... <<<

I know it's shocking - what the Chinese are doing to our planet. How dare they think they can live a standard of living similar to what we have been doing for many years now. Don't they realise that unless they all live like peasants then our planet is doomed. How dare they. They should realise that UK and US households can only run 2 cars per household if they travel around on foot or horse and cart.
I love being British because we never do anything to harm the environment. I mean we have had North Sea oil for years now and we have hardly used any of it.
Countries like China should do as we say and not as we do and then the world would be a much better place.
I'm with you oilrag - keep these developing nations down so we can live a different life to them - if we don't people could accuse us of being hypocrtitcal.
Modern diesels - what's the point? - boxsterboy
Dave N, 29 mpg v 25 mpg may not sound much better, but it is 16% better, and the new engine has much tougher emissions hurdles to jump over.
Modern diesels - what's the point? - MikeTorque
Modern diesel engines are more fuel efficient and a lot cleaner than older versions. The efficiency is sometimes offset by additional size and/or weight due to crash protection, safety features plus additional features.

In general the less weight of a vehicle the more mpg its potential assuming other factors are equal, as the Seat Ibiza 1.4TDI DPF demonstrates :

Urban (mpg) 57.6
Extra urban (mpg) 88.3
Combined (mpg) 74.3
CO2 (g/km) 99
Modern diesels - what's the point? - Dave N
Dave N 29 mpg v 25 mpg may not sound much better but it is
16% better and the new engine has much tougher emissions hurdles to jump over.

That's true, but the old truck weighs over 20% more. It seems like economy is suffering to improve the emissions. So maybe it would be better to actually use less fuel, hence less emissions. Not to mention the enviroment cost of all the electronic doodads, reduced service life, and more noise (externally). And then all the (possible) replacement parts needed to see it through the next 200K miles and 15 years. There's an enviromental cost to everything, and not just what comes out of the tailpipe, if indeed any of it makes any difference at all anyway.

I was just thinking that instead of spending £20K on a new truck, I would have been better off spending £20K completely renovating the old one, and ended up with something much better, even if it uses a little more fuel.
Modern diesels - what's the point? - movilogo
Whenever a new model comes to the market, consumers are made to believe that unless they ride on the latest model, they won't look cool. So, they buy the latest model and then next year, another model is out and last year's model is termed as "obsolete" so that public can be enticed to buy the new one.

And the cycle continues.

Old cars were made to last.
New cars are made to last too but only till CEO of the manufacturer leaves for fatter pay.


Value my car