Audi dealer query

Ultrasonic

motorguy wrote: »

Actually that autoblog link - theres a press release at the bottom and the figures were validated by two AA patrolmen who followed the car the entire time

http://green.autoblog.com/2010/10/04/passat-bluemotion-enters-record-books-running-1-527-miles-withou/

"The Passat BlueMotion's fuel tank was drained before the record breaking journey and filled with 77.25 litres of standard forecourt diesel, resulting in an overall fuel consumption of 89.83 miles per gallon. This substantially exceeds the Passat BlueMotion's official combined figure of 64.2 mpg."

So as you can see, a very capable car.

I don't doubt it's a capable car . But bear in mind this is an mpg figure for a 45 mph average speed trip. My car would give fairly exciting economy for a long cruise at that speed (though not 90 mpg!).

motorguy

Ultrasonic wrote: »

And that I believe. But it's very different to the 75.8 mpg etc in the quote.

Its very easy to get a high mpg figure on one journey. On "average" driving it'll even out with lower miles round town work.

To average 62 mpg over the course of a tank of fuel its not unreasonable to believe that some journies were significantly more than 62mpg and others were significantly less.

Ultrasonic wrote: »

I've done 64 mpg plus trips with a similar engine (BKC vs I guess ALH?), my best being 65.9 mpg (all brim-to-brim). This is mostly driving at 60 mph indicated (~57 mph on satnav) in hot weather.

Are you saying then that, assuming you reset the trip computer before you started, that your car was reading over 80 mpg for the entire fill - which i assume it must have if its 25% out?

Ultrasonic wrote: »

I have heard of others being as bad, I assume it's a question of how it was calibrated (or not!) when installed. The distances recorded on the trip computer are right by the way (agreeing with satnav/Google maps). I have a Scangauge II that I've calibrated to be correct to within about 0.5%, and interestingly the difference between its readings and my trip computer isn't a simple scaling factor, so the trip computer is possibly wrong in quite a complicated way . I'm sure mine is an extreme example, but it does make me sceptical of exceptionally high indicated mpg figures in other cars.

I think overall you have to work on a tank full of fuel, not comparing single journeys to a brim to brim calculation. When i've reset the trip when the car has been filled to the brim and then done a brim to brim calc then i've found the trip to be little more than a couple of mpg out.

For the record, I was driving an old Fiat Marea 1.9 JTD there for a couple of months and it was averaging 54mpg brim to brim (it didnt have a trip computer to compare to) but if something as old and worn out as that could get me 54mpg, it doesnt seem that proposterous that a new high efficiency car is going to trump that significantly.

motorguy

Ultrasonic wrote: »

I don't doubt it's a capable car . But bear in mind this is an mpg figure for a 45 mph average speed trip. My car would give fairly exciting economy for a long cruise at that speed (though not 90 mpg!).

Oh aye. Definitely not saying its "real world" but i posted it to demonstrate its capability.

Hoof_Hearted

Prothet_of_Doom wrote: »

Whilst distance selling regulations will protect your deposit, if you decide the car isn't for you, I would personally tell them that if they want you to consider buying the car, you need to be able to view it without paying a deposit.

They probably don't actually own it, and are getting it off another dealer.

Conclusion : Tell them to "Do one"

Stop getting on the point. How dare you chip into this argument!

Ultrasonic

motorguy wrote: »

Are you saying then that, assuming you reset the trip computer before you started, that your car was reading over 80 mpg for the entire fill - which i assume it must have if its 25% out?

Yes. 79.7 mpg indicated for a distance of 462.3 miles (I keep a very detailed spreadsheet...). This is not full tank range of course, but that was when I refilled. But trust me, the trip computer in my car really is terrible for estimating mpg!

For the record, I was driving an old Fiat Marea 1.9 JTD there for a couple of months and it was averaging 54mpg brim to brim (it didnt have a trip computer to compare to) but if something as old and worn out as that could get me 54mpg, it doesnt seem that proposterous that a new high efficiency car is going to trump that significantly.

Not preposterous no, but there is a huge amount of evidence that the claimed performance of modern cars is increasingly out of sync with real world performance, and that actually modern cars aren't that much better than old ones.

motorguy

Ultrasonic wrote: »

Yes. 79.7 mpg indicated for a distance of 462.3 miles (I keep a very detailed spreadsheet...). This is not full tank range of course, but that was when I refilled.

Bloody hell! :eek:

Ultrasonic wrote: »

Not preposterous no, but there is a huge amount of evidence that the claimed performance of modern cars is increasingly out of sync with real world performance, and that actually modern cars aren't that much better than old ones.

Yes, i would be inclined to agree. Economy figures are skewed more towards longer journeys than most of us do on average. Also, the economy figures are gleaned in test conditions, not how any of us really drive. Even to give a simple example. On todays run to work over 43 miles i averaged 75.5 mpg (according to the trip) however yesterday i was running a little late and averaged 62mpg - same run, same time of the day, but driven with a little less care for economy.

BUT ultimately as can be seen by that verified Passat world record run, modern cars are capable of exceedingly high mpg if driven in a certain way. How much a car falls short of that in the "real world" will depend predominantly on the length of journeys and the ability to keep consistent steady speeds. I guess its a sliding scale in that sense. If someone had the same car and were doing short around town work, then they might only be getting 40mpg.

And yes cars probably arent typically much more economical. I guess because cars are so much heavier because of extra safety features and strengthening, extra 'features', performance stiffling emissions controls such as DPF's, etc, etc.

anotherbaldrick

Ultrasonic wrote: »

Not preposterous no, but there is a huge amount of evidence that the claimed performance of modern cars is increasingly out of sync with real world performance, and that actually modern cars aren't that much better than old ones.

What planet are you on ? not so many years back I was driving medium sized family cars and when they brought in cat converters they were all struggling to do 30 mpg, now my SUV is doing 54 average (and that is proved by checking full to empty figures)see previous post.

Ultrasonic

anotherbaldrick wrote: »

What planet are you on ? not so many years back I was driving medium sized family cars and when they brought in cat converters they were all struggling to do 30 mpg, now my SUV is doing 54 average (and that is proved by checking full to empty figures)see previous post.

I used to believe as you do that there had been dramatic improvements in fuel economy. On another forum I had it pointed out to me that if you compare the fuel economy of vehicles fitted with engines offering comparable power the differences aren't that great - certainly nothing like the getting on for 100% improvement you're suggesting above. I did try to find evidence to the contrary, but couldn't. We're talking more like 10% improvement, up to maybe 20% for extreme examples.

anotherbaldrick

Ultrasonic wrote: »

I used to believe as you do that there had been dramatic improvements in fuel economy. On another forum I had it pointed out to me that if you compare the fuel economy of vehicles fitted with engines offering comparable power the differences aren't that great - certainly nothing like the getting on for 100% improvement you're suggesting above. I did try to find evidence to the contrary, but couldn't. We're talking more like 10% improvement.

I believe in the vast improvements in fuel economy because I used to have to fill up every 10 days on average. Now I only fill up once every 3 weeks. (same mileage)

Ultrasonic

anotherbaldrick wrote: »

I believe in the vast improvements in fuel economy because I used to have to fill up every 10 days on average. Now I only fill up once every 3 weeks.

Is your fuel tank bigger? If the engines don't offer similar performance it is also not a fair comparison.

This is wildly off-topic and I'm about to head off on holiday for a bit so I won't debate this further for now.