3.0TDI does 43mpg at average of 70mph on a long run, but I give it beans on back roads and it does under 20mpg, same as GTR which has 320BHP more. Same journey time, not really using the petrol hard, using the diesel very hard indeed. The diesel car weighs 100kg more than the petrol. Petrol is port injection, diesel is direct injection.

I bought the diesel because of availability, depreciation, as a cruiser. It fulfils that, but interesting just how low the economy can go.

 

I'm sure I read somewhere that the diesel engine economy advantage is on part-throttle and full throttle openings are just as bad as the equivalent petrol engine.

 

Yes, thought it was a well known fact that diesel economy drops off a cliff as you approach max revs/throttle

 

I dunno how accurate it is but on my derv Bimmer as soon as you plant the throttle, the mpg dial drops off said cliff

 

I just didn't think it would be so bad!

 

Your findings are pretty accurate John, oddly enough I spent all day yesterday tweaking EDC16 C35 on an M57 TU2 for fuel economy. There are great improvements to be had under part load but nothing at all under hard use.

 

Ended up here in the real world, pretty good for a two ton 3 litre derv...





But if you start using all of its 600ftlb then it's not a great deal better than a turbocharged petrol engine as AFR's drop done closer to those of a comparable high efficiency petrol engine.

 

I noticed this too. I picked up a Leon FR 170bhp diesel on Wednesday night with a 1/4 tank of fuel. Obviously i've been "testing" it on straights and twists and the low fuel light popped on lastnight saying i've 15miles left in it !

I hope the novelty of me raggin it about wears off and the MPG evens out or it wont be any better than the Impreza (though economy wasnt my reason for buying it , it would be nice if i saved a bit)

 

Diesel mpg is overrated.
Our petrol car (320bhp) is better than our diesel (180bhp) van ;£)

 

Finally I've been saying that they don't make sense for ages.

 

It's probably the turbo what's done it!

 

My 530d fuel consumption goes up when I floor it but its no where near as thirsty as my Impreza then again its no where near as fast

 

Wow, really interesting!

 

I've got an A3 Quattro hatch with the 2.0 diesel. It's quite an enjoyable machine to chuck down country lanes.

I agree that if you spank it the fuel economy can be quite poor but I think we're missing the point.

You can drive a diesel flexibly in a higher gear and exploit the torque band whilst still making rapid progress. Sure you won't keep up with the Impreza in front of you but it will make for impressive mpg for the speed you are going.

 

I don't think you can exploit the torque as my 530d has about 530lbs since a remap and it pants, I put my foot down in any gear and its errr I think I'm accelerating but thing pass by soo slow

It would be a nice car for someone coming from say a 1ltr car but anything sporty and I don't think anyone would be impressed

 

530lbft? ****. My 330D is 369lbft as standard so for a remap that's a massive increase!

 

Imo the only real advantage to a diesel is good mpg at high speed motorway cruising. Too narrow of a band to actually buy one imo. Maybe a few years ago before they bumped the price of diesel up but nowadays petrol motors often work out just as economical.

 

Its not very quick though, although I noticed a big difference in pickup after I started using shell Ultimate diesel

 

diesels dont rev so its impossible to drive them fast like a petrol. they encourage you to drive lazy

 

I think they encourage you to plan ahead, I spent a fair amount of time in diesel company cars, most of it thrashing the knackers off them. Ultimately unless your doing huge milage there is no advantage, and even then it's a bit of a toss up between the two.

When I came to buy my own new company car I ended up buying a Blob WRX instead of a Volvo D5, reason being the Volvo was £4.5k more than the WRX, a damned sight quicker, better looking, as well as AWD and I figured it would take an awful lot of diesel to make up the £4.5k's difference in price tag.

Looking back i'm not so sure it was such a good choice because I became addicted to Imprezas.

 

I think you need to try a diesel designed for performance from the ground up and not to ferry reps around. You will be surprised.

 

Mine is not GTR fast, but in any reasonable comparison is decent, and is rather amusing to drive fast. It smoothly revs to 5000 RPM, sounds interesting and achieves a 0-60 of 6.0. The twin/triple turbo 6 or 8 cylinder Germans diesels are brisk.

 

Have a mk 4 PD tdi 150 golf with a map which has taken it to about 180ish, and the economy when abusing it is poor at best lol

 

The one reason I opted for a 330D over the 335D was the extra turbo. The extra power would've been great but I wanted some kind of mpg gain on a run over looking at the petrol ones. That said I can't remember the 0-60 etc for mine. Likes to spin the rears though, which could become expensive tom foolery

 

I can't get mine to spin the wheels, in the wet, full throttle first or second gear, lots of lock on. It just grips. For a winter car/cruiser I'm quite happy, but it is fun to fling around too.

 

Whats wrong with LPG, me personally i couldn't careless about mpg, but saying that i don't have to drive miles, but if i did i'd just get an LPG conversion, you can get them for around £700 fitted my local charges £1500 which is a rip off.

But £700 would be less than extra money cost to buy a diesel

 

Factor in the depreciation of a diesel car and not wanting a second aftermarket fuel injection system and I can quite see why LPG has not taken off. I found it very difficult to find a good selection of petrol cars too.

 

Why can you see why LPG has not taken off?

Its half the price of petrol, only slightly less efficient than petrol

 

John's listed three reasons above!

 

You like your Panzerwagens.