Thread: Small diesel cars - Amazing fuel economy

For a period of about 12 months over 2011/12 through work I had a replacement car at intervals of between 2 and 6 weeks. Never had the same car more than once although I could have the same model allocated again. These ranged from a small Peugeot 206 through Clio, Golf, Astra, Vectra, Mondeo, Megane, BMW 3 series, Mercedes c Class, Audi A5 to a Peugeot 5008. These were all 4 cylinder and a mix of petrol and diesel - auto and manual. None were new all had between 5k and 50k on them before I got them.

Was doing about 600 to 800 miles a week mixture of motor way and city driving. What did strike me was that the petrols all achieved about 35 mpg and the diesels all did about 50 mpg. Did not seem to matter the size of the car or if manual or auto. The Peugeot 5008 achieved the best fuel economy despite being the biggest car.

Have found in my own car which is a diesel auto that the best economy is on the motor way at about 75 miles per hour. Go over 80 miles an hour and the fuel consumption goes up to a level similar to that seen at 60 miles per hour.

Originally Posted by MR LR

Bet you don't get the same smile as when I bury my foot and burn through 17L/100km in my Classic Rangie

My 2.0tdi scout will beat my 93 V8 rangie to 100km/h, will beat it to 200km/h (rangie won't get there) and has more torque while weighing a ton less. So I think it gives me a better smile.
Uses 1/4 of the fuel (V8 has some issues) and corners like a medium height 4wd car shouldn't.

I run about 6.5 litres/100km in the scout average (I have calibrated both the speedo and the fuel readout) with a bit under 6 on an open road trip.
I have done as low as 5.3 over 200km in holiday traffic.



This car is a VW golf with 4wd, a bigger boot, higher ground clearance, steel underbody protection, bigger wheels, different interior and different panels. It's also 6sp manual.
Yet it burns fractionally more fuel than my 4wd nissan diesel work-car. I think that's down to electrical load.

I have only one vehicle that isn't diesel. It's a V8 classic rangie and that engine (with it's auto box) are temporary residents at my place.

Originally Posted by 101 Ron

I used to own a Datsun 120 Y station wagon......1978 year model
Only Two valves per Cylinder push rod 1200c motor and a Carburettor.
It was fun to drive with only a 4 speed gearbox simple to fix , not that anything went wrong with it.
It was happy cruising at 100kph.
I never got anything worse than 40 MPG and that being a young bloke at the time.
One time I did a trip and drove the thing for economy and accurately recorded 60 mpg.
All done without electronics including points ignition.
The A12 Nissan motor even as a push rod motor was happy with revs with max torque at 4000rpm and max power at 6000rpm.
The above figures match the modern Diesels..........and using petrol.
We have advanced very little.
40 mpg equals......5.88 litres per 100
60mpg equals ...3.92 litres per 100km

Your figures don't work.
40mpg (UK) = 7 litres/100km.
60mpg (UK) = 4.7 litres/100km.

Fuel Economy Conversion (Online Units Converter)

As for why anyone would want a v8....
1994 falcon xr8 sprint, V8 manual, averaged 10-10.5L/100km
2002 vu commodore ute v6 auto averaged 10.5-11L/100km
2005 Bba falcon rtv ute, 4.0L 6 cylinder..... averages 12.8L/100km

and the worst part? The v8 gave the best fuel economy, but got driven harder.....

With technology comes weight...

My 1150kg Torana with one of these new little turbo diesels would be a hoot to drive, while only drinking bugger-all...

Am I onto something?

Originally Posted by Keithy P38

With technology comes weight...

My 1150kg Torana with one of these new little turbo diesels would be a hoot to drive, while only drinking bugger-all...

Am I onto something?

I'd like to put a small tdi diesel in a prius and see the fuel economy.
All those aero mods, tiny low-rolling-resistance tyres etc should make fantastic fuel economy with a real engine.

Originally Posted by DoubleChevron

You wouldn't know .... You'd only be able to see a rapidly receding view of the back of his head.

For a few months (before the baby was born a couple of years back) my wife has a Citroen C4 ... My mother bought the car new and it has only done 28,xxxkms. The bloody thing was so grunty it was hard not to run over all the traffic around you ( strangely the spec's on them don't read as very fast, or very powerful), but out of the now old technology 1.6 litre diesel it was pumping 260Nm of torque on overboost ( far more than the 3.5litre V8 in my classic). It used to average around 4.2L/100kms Pitty the suspension under it crappy.

That was replaced with a 2litre poogoe 407 sedan. This thing was an ex-company car out of melbourne. A 6spd manual gearbox meant it had only 42,000kms on it from new (even though it's '07 model). Other than riding like a bucket of ****, being so stuipidly low it's forever smashing it's nose into the ground and breaking **** underneath.... it hasn't been bad. It's bloody fast for something that weighs a staggeringly 1.7tons ... the little diesels in them are 340Nm on overboost (likely as much as the 4.2+ litre V8's fitted to the later Classics) yet return < 7.00L/100kms. I'd love to tear it's motor/6spd manual gearbox out and stick it into one of my old Citroens

Now australia has finally caught up with the diesel craze (that the rest of the world has driven for 20years), they are moving away from it back to tiny capacity high pressure injection turbo charged petrol motors.

My sister has just purchased a 900cc Renault Clio .... I couldn't imagine buying anything with such a tiny motor, but my old man test drove it and he reckons it's brilliant. I guess it's 300cc bigger than the motor in there 2cv though

seeya,
Shane L.

Sounds like your classic is rooted, according to Wikipedia my '83 had 280Nm when it was new, I have no doubt it still has close to this as it was rebuilt only 20,000kms ago, and it goes nearly as well as a slightly tired td5 (when you give it the stick).

My initial comment was not actually based on power or economy, in actual fact it's the exhaust note that sold me on a V8 as a weekend car, it sounds better than any diesel hatch! (Hang on, why are we comparing a 2 tonne 4WD to diesel hatchbacks that can't tow half as much, or go offroad?). My V8 weekend car makes me smile every time I open it up through the gears, and my XR6 Falcon with dual fuel is cheap to run and will flog up the highway better than any hatch on the way to UNI. I also wouldn't own a front wheel drive POS if someone payed me!

To sum up, my comment was about the sound of a V8 making up for the fuel use.

Cheers
Will

BTW: my range rover is manual, much faster than auto ones.

Originally Posted by MR LR

Sounds like your classic is rooted, according to Wikipedia my '83 had 280Nm when it was new, I have no doubt it still has close to this as it was rebuilt only 20,000kms ago, and it goes nearly as well as a slightly tired td5 (when you give it the stick).

My V8 put out 320Nm new. Still beaten in torque by my 2.0tdi.

Originally Posted by MR LR

(Hang on, why are we comparing a 2 tonne 4WD to diesel hatchbacks that can't tow half as much, or go offroad?).

My one can legally tow exactly half as much (1750kg) and does extremely well offroad.
[ame=http://www.youtube.com/watch?v=2hVqKz2EM3E]Лакированны� �̆ Off Road - YouTube[/ame]

Work often takes me around a mine-site. When it's wet and muddy I'll take the diesel work car over a rangerover.
Because the car has a flatter under-belly (it slides over mud better) and weighs a ton less it doesn't sink as much.
I haven't had it stuck offroad yet and it's been through some nasty bogs.

Originally Posted by MR LR

To sum up, my comment was about the sound of a V8 making up for the fuel use.

To sum up. You were trolling and suck at it.