RE: NEDC mpg tests don't lie: Tell Me I'm Wrong
Discussion
RoverP6B said:
My 520i Touring nominally weighs 1680kg and puts out a mere 155ftlb. It'll keep up with traffic quite happily. Yes, I tend to rev the b
ks off it, so it only gets about 26mpg, but so what?
rev the bks off it, so it only gets about 26mpg, but so what?ks off it and keeping up with traffic happily are not compatible IMOIf it needs thrashed, it'working too hard
BiggestVern said:
...The promised 74.3mpg is likely to nearer 40, my BMW 330d averages closer to 50mpg in normal driving, & 50+mpg on a run without ever making me wish for more performance.
...
Fuelly data doesn't back your claim up. A 1.5 DCi Quashquai (equivalent-ish) records 5.7L/100km (49.6mpg) and the 330d data gives 6.6L/100km (42.8mpg). That's nearly 14% better fuel consumption, not to mention the "nearer to 40" is actually "closer to 50mpg" and vice versa for the BMW....
If you use the EUDC data as an estimate of the real-world "ultimate" fuel consumption potential of the two cars, then the BMW at 4.3L/100km is still 19% thirstier than the Quashqai at 3.6L/100km.
Downsizing is all about improving the fuel consumption potential, but if you rag it around like a race car, they will all drink - usually in some proportion to their maximum power
To achieve good real-world fuel consumption, it's all about keeping high average speeds but with low speed variation. A gasoline vehicle will give its best fuel consumption around the 50mph area, whereas a diesel will be more likely optimum around 40mph. On the open road at motorway speeds, vehicle drag plays a huge part, so MPVs and heavy, large-tyred vehicles will all suffer compared to smaller cars on skinnies, but the fuel consumption will be nowhere near their ultimate best.
Edited by AER on Saturday 24th October 07:15
Bladedancer said:
No it doesn't. The fact someone is driving poorly does not mean they will have an accident. Why would it?
Because a crash is usually a fairly good indication that somebody was driving badly.Bladedancer said:
If you don't know what I'm talking about let me list it for you:
1) Lights. People in UK have NO idea how to use lights on their car. Indicators? What's that? Driving on fog lights, parking lights on no lights at all in the dark is common (like 6am today).
2) Tailgating - so common I've become indifferent to it.
3) Blocking intersections. This one is driving me up the wall. People will block your way across an intersection and think nothing of it. No consideration for their fellow road users.
4) Cutting corners and keeping in lane. 1st one common, the other appears to be a dying art. Like just this morning. Car in front of me started on the left lane (there are 3), got onto the roundabout, cut 2 lanes getting to the right one, then left the roundabout on the middle lane. What kind of driving is that?
5) Non economical driving. People in UK don't drive at their own pace. They have to tailgate. Say I'm doing 70 on M-way and I'll pull into slower lane. 4 times out of 5 person behind me will speed up, get to tailgating range of the car in front and slam the brakes. WHAT IS THE POINT?
6) Racing. There's s person doing 35 in 40 zone and I can drive behind him all day and he'll keep 35. If I overtake him he will speed up to 40 just to be spiteful.
7) As I call them perma-speed types. They will do 40 in 30 zone. They will also do 40 in 60 zone.
8) The "I just realized I need this exit" type. That's the person who despite seeing all the markers and signs describing what the next Mway exit is, only realized that (s)he needs it 200 yards before the exit itself. And cuts 4 lanes of M25 in heavy traffic. While breaking from 80. Lovely.
9) Lastly - not knowing who has priority. Many times people forced priority on me, especially on roundabouts, and seem oblivious to the fact they did that.
All of this and probably a few other things I've forgotten makes me say driving standards in UK are poor.
They do all of that everywhere else you know, but much worse and that's why their accident rates are often much worse. Using the link posted above I see the Belgians are just about precisely twice as bad as we are, for no apparent reason such as climate or terrain etc. 1) Lights. People in UK have NO idea how to use lights on their car. Indicators? What's that? Driving on fog lights, parking lights on no lights at all in the dark is common (like 6am today).
2) Tailgating - so common I've become indifferent to it.
3) Blocking intersections. This one is driving me up the wall. People will block your way across an intersection and think nothing of it. No consideration for their fellow road users.
4) Cutting corners and keeping in lane. 1st one common, the other appears to be a dying art. Like just this morning. Car in front of me started on the left lane (there are 3), got onto the roundabout, cut 2 lanes getting to the right one, then left the roundabout on the middle lane. What kind of driving is that?
5) Non economical driving. People in UK don't drive at their own pace. They have to tailgate. Say I'm doing 70 on M-way and I'll pull into slower lane. 4 times out of 5 person behind me will speed up, get to tailgating range of the car in front and slam the brakes. WHAT IS THE POINT?
6) Racing. There's s person doing 35 in 40 zone and I can drive behind him all day and he'll keep 35. If I overtake him he will speed up to 40 just to be spiteful.
7) As I call them perma-speed types. They will do 40 in 30 zone. They will also do 40 in 60 zone.
8) The "I just realized I need this exit" type. That's the person who despite seeing all the markers and signs describing what the next Mway exit is, only realized that (s)he needs it 200 yards before the exit itself. And cuts 4 lanes of M25 in heavy traffic. While breaking from 80. Lovely.
9) Lastly - not knowing who has priority. Many times people forced priority on me, especially on roundabouts, and seem oblivious to the fact they did that.
All of this and probably a few other things I've forgotten makes me say driving standards in UK are poor.
What's wrong with introducing an additional test at 70MPH, similar to the 56 but at our motorway speeds? OK, first flaw is that it'll have to be in Km, rounded, so 110Km/h.
I see another problem with it and that's aero. As James May once said, air is like blancmange and gets considerably harder to displace as speed increases. How'd they test that cost effectively, anyone's guess.
I just think that having one additional controlled repeatable test at sensible speeds would give Joe Public a better idea. Up the speed to 120Km/h for even more separation from 90Km/h. It would certainly be informative for me.
What do ya think?
I see another problem with it and that's aero. As James May once said, air is like blancmange and gets considerably harder to displace as speed increases. How'd they test that cost effectively, anyone's guess.
I just think that having one additional controlled repeatable test at sensible speeds would give Joe Public a better idea. Up the speed to 120Km/h for even more separation from 90Km/h. It would certainly be informative for me.
What do ya think?
ChesterUK said:
What's wrong with introducing an additional test at 70MPH, similar to the 56 but at our motorway speeds? OK, first flaw is that it'll have to be in Km, rounded, so 110Km/h.
I see another problem with it and that's aero. As James May once said, air is like blancmange and gets considerably harder to displace as speed increases. How'd they test that cost effectively, anyone's guess.
I just think that having one additional controlled repeatable test at sensible speeds would give Joe Public a better idea. Up the speed to 120Km/h for even more separation from 90Km/h. It would certainly be informative for me.
What do ya think?
My personal idea would be a weighted average constructed from a bunch of individual tests, something like constant mpg at 20,30,40,50,60 and 70mph then acceleration (at for example full throttle, 3/4 throttle, 1/2 throttle and 1/4 throttle) and deceleration with some idling. Could give the individual figures as well as the constructed figure(s) which would both give an more realistic idea of how a car will perform on the motorway (at least at legal speeds!) and give far more representative figure(s) for comparisons.I see another problem with it and that's aero. As James May once said, air is like blancmange and gets considerably harder to displace as speed increases. How'd they test that cost effectively, anyone's guess.
I just think that having one additional controlled repeatable test at sensible speeds would give Joe Public a better idea. Up the speed to 120Km/h for even more separation from 90Km/h. It would certainly be informative for me.
What do ya think?
skyrover said:
rev the bks off it and keeping up with traffic happily are not compatible IMO
If it needs thrashed, it's working too hard
Not really, it's perfectly happy below 3000rpm around town, but A-road acceleration tends to call for higher revs, and the engine thrives on it. It feels like it's got a hang sight more to give when the rev limiter cuts in at about 6700rpm, but the hollow lifters are a weak point, need a set of solid lifters & cams from Shrick to get more revs. I've also got a 535i auto which is the definition of lazy barge, but the 520i is more fun...ks off it and keeping up with traffic happily are not compatible IMOIf it needs thrashed, it's working too hard
ChesterUK said:
What's wrong with introducing an additional test at 70MPH, similar to the 56 but at our motorway speeds? OK, first flaw is that it'll have to be in Km, rounded, so 110Km/h.
I see another problem with it and that's aero. As James May once said, air is like blancmange and gets considerably harder to displace as speed increases. How'd they test that cost effectively, anyone's guess.
I just think that having one additional controlled repeatable test at sensible speeds would give Joe Public a better idea. Up the speed to 120Km/h for even more separation from 90Km/h. It would certainly be informative for me.
What do ya think?
Aerodynamic drag is taken into account with the current test. There's no reason different test speeds would change that. I see another problem with it and that's aero. As James May once said, air is like blancmange and gets considerably harder to displace as speed increases. How'd they test that cost effectively, anyone's guess.
I just think that having one additional controlled repeatable test at sensible speeds would give Joe Public a better idea. Up the speed to 120Km/h for even more separation from 90Km/h. It would certainly be informative for me.
What do ya think?
RoverP6B said:
skyrover said:
rev the bks off it and keeping up with traffic happily are not compatible IMO
If it needs thrashed, it's working too hard
Not really, it's perfectly happy below 3000rpm around town, but A-road acceleration tends to call for higher revs, and the engine thrives on it. It feels like it's got a hang sight more to give when the rev limiter cuts in at about 6700rpm, but the hollow lifters are a weak point, need a set of solid lifters & cams from Shrick to get more revs. I've also got a 535i auto which is the definition of lazy barge, but the 520i is more fun...ks off it and keeping up with traffic happily are not compatible IMOIf it needs thrashed, it's working too hard
texr2000 said:
Want there a big thing about the new BMW i8 struggling to meet the official quoted over 100MPG, with some owners getting sub 50MPG.
Isnt this a prime example of the tests not being true to life?
Unfortunately, the average man in the street isn't very good at understanding the difference between efficiency and consumption!Isnt this a prime example of the tests not being true to life?
Ie you could have a 100% efficient car, and it would still use a lot of fuel if it's producing 300bhp, compared to the roughly 30bhp needed for the drive cycle....
On a different subject entirely but sort of related..... I think the Huracan used in the photo for the purpose of this discussion looks great in the metallic grey. It definitely shows off the styling in a far better light, and good old polished alloys... always look classier than black. To these eyes anyway!
texr2000 said:
Want there a big thing about the new BMW i8 struggling to meet the official quoted over 100MPG, with some owners getting sub 50MPG.
Isnt this a prime example of the tests not being true to life?
I can tell you the i8 most definitely did not do 100MPG when I drove it last weekend Isnt this a prime example of the tests not being true to life?
But that has everything to do with how I drove it and to some extent, how it was designed to be driven.
A car is only ever as economical as the weight of your right foot.
The point of the test is to indicate the MPG a car _can_ achieve, not what it will achieve in any and all conditions.
Most i8 owners don't poodle around so it's no surprise they get relatively poor MPG returns.
But if you were to drive the car in full electric mode and utilized the various energy recovery systems as effectively as possible, then I have no doubt it would do 100MPG.
Similarly, if you were to drive a Prius like a hooligan, you'd get incredibly poor MPG as well.
But since Prius owners usually don't drive flat out, you don't hear them complain as much.
Draexin said:
But since Prius owners usually don't drive flat out, you don't hear them complain as much.
A fair chunk of Priuses that I see are being driven with little or no regard to fuel economy, often flat out in the outside lane of the M40 etc. I'd be surprised if they weren't using just as much fuel as a boggo 1.6 Focus when driven like that.Makes me wonder why they bought one in the first place, but I guess company cars etc.
MonkeySpanker said:
RoverP6B said:
Can't recall what the gearing is except that 5th is 1:1, but it's quick enough for the real world. A 530i would be nice though.
5th gear is usually an 'overdrive' gear so wouldn't or shouldn't be 1:1.Gassing Station | General Gassing | Top of Page | What's New | My Stuff