Diesel MPG - all its cracked up to be?

My only experiance of Diesel is a 1.5 106 belonging to an Ex! Slowest car evar but good MPG!

Diesels: You're doing it wrong!

Certainly those chrysler (PT Cruiser?) ones aren't the most efficient.

We get an average of 55mpg from our Picasso, which is the 2.0 HDi as found in loads of other PSA bilge. That's quite a decent figure, I reckon, especially as Mrs Pog has a history of ragging the knackers off cars (though she is getting betterer). That's a figure from the onboard cleverness, not some half-arsed calcualtion on the back fof an envelope by the way (though I expect someone will be along in a minute to tell us how they get 900mpg from a 5.0 petrol V8 or something ) The old Focus rarely dipped below 50mpg either, and that was a clattery old direct injection tractor engine, not a super common-rail....

Probably boils down to how it's used, short trip? Up & down hill? Stop-start traffic? Never going to be great! From where we live you essentially have to get on t' motorway to go anywhere, so it's a 1 mile tootle to the A1, then open the taps up to 70 and cruise.... Might have something to do with it...

In my eyes diesel is a bit of a false economy for me, or at least it is right now.

My old Vectra, while a fantastic car, only achieved 40-45mpg. Now I know that seems good, but when you look at the difference in cost between derv and petrol right now, and add in the fact that a decent petrol engine will do 35-40mpg without batting an eyelid it makes you question the reasons behind buying a derv motor, at least an older one anyway.

The onyl diesel that I have been truly blown away by is my Mum and Stepdads 2007 Astra TDi Sport. My Stepdad has had a Diesel Technologies chip fitted and I don't car what anyone say, it works. He's calculated that from a full tank with over an approx 50/50 split of motorway and town driving it has achieved 50mpg with ease. It's quite the machine. But, again, does a £15k car that does 50mpg better a £2500 petrol that gains 3-35mpg, in terms of real world economy?

It's a real swings and roundabouts thing I guess, and it's all down to the mental justification of the car owner. For me, a person who finds £2000 cars to be the stuff of dreams, diesels are the wrong way to go. But, if you're going to spend a lot (anything more than £2000 lol) on a car, than I guess it might change.

That, or I'm just talking curse word like usual! Still, you might extract something useful from my ramblings!

Chris

Modern diesels, I'm not convinced by.
My old-skool diesel citroen C15 van however, NEVER gives worse than 52 real-world MPG no matter how its driven - and often substantially better. My personal record was 61mpg from a full tank, driving very economically. However, it has the weight, structural integrity and interior comforts of a chinese takeaway carton.
I think modern diesels are potentially capable of decent mpg in perfect driving conditions - conditions you are unlikely to ever find on the roads. Excessive weight due to large sizes, safety systems, comforts, soundproofing, electrically opertated ashtrays etc make it impossible to achieve the quoted figures in normal use.
If I were in the market for a modern and had the choice between the two fuels, Id run petrol every time. The cost per litre difference often makes the diesel poorer value, plus the petrol has the option of LPG conversion at a later date.

some interesting feedback. Are those quoting figures quoting

1. figures calculalted from filling up and then returning to the same location to refuel and checking the mileage?

2. trusting the display on the dash?

3. estimating based on the fact its 10 miles to work and I put X amount of fuel in a week

just curious.

I would say this is accurate. It's easy to take a light petrol car, take it easy, and get good fuel economy out of it; and compare it to a curse word diesel that's being ragged about. There are lots of other diesel cars that are built for torque, and not for FE specifically. Petrol cars are definitely getting better at fuel consumption, and diesels are getting faster, but if you still take a car with a diesel engine designed with economy first and foremost, you're going to find it very hard to run a petrol car cheaper.

I talk about this all too often on retro rides, but I've got figures of ~85mpg out of my peugeot 106 diesel before, without going mad "hypermiling". I use the fill up, and check the odo' method. I typically get around 500 miles for £40.

I'm comparing a full size family car from 1993 with a diesel "estate car" from 2003. And the Alfa was brand new (5000 KM on the clock). Neither were ragged round in. If you've driven a bus you'll know how a PT Crusier drives. Not something you "rag". Its only rated at 40 MPG by Chrysler anyway. I haven't checked what Alfa reckon for the 159 but it never went above 100 KM/h and was mostly in "relaxed" driving, and a bit of Autostrada.

if you can get much more out of the PT Cruiser than I can I'd love to see how.

I was warned off the 2.4 Petrol, apparently you'll be hit with some huge car tax on it next year as well.

I don't know if my experience counts, as generally I only ever drive crusty old nails......

When I had The Scrote (now-departed but fondly-remembered 1989 Escort L) its 1297cc Valencia petrol lump and 5-speed meant that it did anywhere between 48 and 52mpg on the daily grind, slightly more than that if I literally sat at 56mph slipstreaming artics. The worst I ever had was 42mpg and that was on a flat-out blast to Santa Pod and back. It was hellishly slow though.

My 205 has the venerable old 1769cc non-turbo diesel which surprisingly is much quicker accelerating than the Escort was, even if the top end's about the same. The owners manual quotes 71mpg at a steady 56mph, but in reality I've not managed anywhere near that, 62mpg being the best I've managed. Having said that even thrashing it mercilessly (I managed the Master Brewer bypass at Hillingdon on the A40 to my house...92 miles..in 1 hr and 4 minutes on the way home from the RR Ace Cafe Meet back in July) I've never managed to get it above 48mpg. About 55 is the norm.

So I gain about 5 miles on each gallon of fuel which is a 10% saving, offset by diesel being about 8% more expensive.....and I pay £100 a yr more to tax it.

It's pennies, really.