Fuel economy - anyone beating the official figures?
Discussion
I'd also call a portion of wishful thinking, as there is no way on God's earth a 335i matches an Aygo's MPG at 75mph.
I used to own a C1 and did a lot of motorway miles in it. I couldn't do it below 50mpg unless I chose to pedal to the floor at all times (which on that meant you're at 85+).
Now having an auto 140 petrol, a more economical car than the 335, it does nowhere near the MPG of the C1 at steady motorway speeds.
I'd seriously question, all other things being equal, a 1500kg 3000cc petrol needing the same (or less) energy than an 800kg, 1000cc petrol to do 75mph? There would have to be an enormous disparity between gearing and or aerodynamic efficiency in the heavier car's favour.
Either that, or you complete your physics using man maths.
I used to own a C1 and did a lot of motorway miles in it. I couldn't do it below 50mpg unless I chose to pedal to the floor at all times (which on that meant you're at 85+).
Now having an auto 140 petrol, a more economical car than the 335, it does nowhere near the MPG of the C1 at steady motorway speeds.
I'd seriously question, all other things being equal, a 1500kg 3000cc petrol needing the same (or less) energy than an 800kg, 1000cc petrol to do 75mph? There would have to be an enormous disparity between gearing and or aerodynamic efficiency in the heavier car's favour.
Either that, or you complete your physics using man maths.
The official fuel economy test simulates a short-ish commute home from work, with lots of time spent crawling at slow speed, lots of time spent stationary and at the end there's a short bit of dual-carriageway type driving. All electrics switched off (radio, lights, wipers, aircon, demisters).
Approximate amount of time spent at various speeds:
Stationary: 15%.
Speeds up to 30mph: 50%.
30-40mph: 15%.
40-50mph: 5%
50-60mph: 5%.
60-70mph: 5%
70-80mph: 5%.
So the test flatters cars which are optimised for being stationary and pootling around at town speeds. That flatters cars with small engines and cars with stop-start systems. It punishes cars with large engines, cars without stop-start and autos with slushboxes that tend to be wasteful when idling and when not locked-up for cruising.
If you drive without lead boots and spend a lot of time cruising at fairly steady speeds between about 35-55mph you may well match or exceed official figures, especially if you have a large-engined slushbox without stop-start.
Approximate amount of time spent at various speeds:
Stationary: 15%.
Speeds up to 30mph: 50%.
30-40mph: 15%.
40-50mph: 5%
50-60mph: 5%.
60-70mph: 5%
70-80mph: 5%.
So the test flatters cars which are optimised for being stationary and pootling around at town speeds. That flatters cars with small engines and cars with stop-start systems. It punishes cars with large engines, cars without stop-start and autos with slushboxes that tend to be wasteful when idling and when not locked-up for cruising.
If you drive without lead boots and spend a lot of time cruising at fairly steady speeds between about 35-55mph you may well match or exceed official figures, especially if you have a large-engined slushbox without stop-start.
Ron99 said:
The official fuel economy test simulates a short-ish commute home from work, with lots of time spent crawling at slow speed, lots of time spent stationary and at the end there's a short bit of dual-carriageway type driving. All electrics switched off (radio, lights, wipers, aircon, demisters).
Approximate amount of time spent at various speeds:
Stationary: 15%.
Speeds up to 30mph: 50%.
30-40mph: 15%.
40-50mph: 5%
50-60mph: 5%.
60-70mph: 5%
70-80mph: 5%.
So the test flatters cars which are optimised for being stationary and pootling around at town speeds. That flatters cars with small engines and cars with stop-start systems. It punishes cars with large engines, cars without stop-start and autos with slushboxes that tend to be wasteful when idling and when not locked-up for cruising.
If you drive without lead boots and spend a lot of time cruising at fairly steady speeds between about 35-55mph you may well match or exceed official figures, especially if you have a large-engined slushbox without stop-start.
Yeah, started to arrive at this conclusion from reading through the various posts and from my own experience.Approximate amount of time spent at various speeds:
Stationary: 15%.
Speeds up to 30mph: 50%.
30-40mph: 15%.
40-50mph: 5%
50-60mph: 5%.
60-70mph: 5%
70-80mph: 5%.
So the test flatters cars which are optimised for being stationary and pootling around at town speeds. That flatters cars with small engines and cars with stop-start systems. It punishes cars with large engines, cars without stop-start and autos with slushboxes that tend to be wasteful when idling and when not locked-up for cruising.
If you drive without lead boots and spend a lot of time cruising at fairly steady speeds between about 35-55mph you may well match or exceed official figures, especially if you have a large-engined slushbox without stop-start.
Ron99 said:
The official fuel economy test simulates a short-ish commute home from work, with lots of time spent crawling at slow speed, lots of time spent stationary and at the end there's a short bit of dual-carriageway type driving. All electrics switched off (radio, lights, wipers, aircon, demisters).
Approximate amount of time spent at various speeds:
Stationary: 15%.
Speeds up to 30mph: 50%.
30-40mph: 15%.
40-50mph: 5%
50-60mph: 5%.
60-70mph: 5%
70-80mph: 5%.
So the test flatters cars which are optimised for being stationary and pootling around at town speeds. That flatters cars with small engines and cars with stop-start systems. It punishes cars with large engines, cars without stop-start and autos with slushboxes that tend to be wasteful when idling and when not locked-up for cruising.
If you drive without lead boots and spend a lot of time cruising at fairly steady speeds between about 35-55mph you may well match or exceed official figures, especially if you have a large-engined slushbox without stop-start.
I assume that is for the average / combined figure? What about urban and extra urban?Approximate amount of time spent at various speeds:
Stationary: 15%.
Speeds up to 30mph: 50%.
30-40mph: 15%.
40-50mph: 5%
50-60mph: 5%.
60-70mph: 5%
70-80mph: 5%.
So the test flatters cars which are optimised for being stationary and pootling around at town speeds. That flatters cars with small engines and cars with stop-start systems. It punishes cars with large engines, cars without stop-start and autos with slushboxes that tend to be wasteful when idling and when not locked-up for cruising.
If you drive without lead boots and spend a lot of time cruising at fairly steady speeds between about 35-55mph you may well match or exceed official figures, especially if you have a large-engined slushbox without stop-start.
Mr2Mike said:
Then it's broken. An Aygo will not drop to 31mpg at a steady 75mph unless you are driving into hurricane type headwinds.
Haha, maybe it was 85mph. My point was, you need to buy a car that is designed to do the type of driving you do. Ignore the test figures, take them out and do the journeys you do. It was crap on the motorway for mpg, it also bounced all over the place.
As a city car it was great, but I don't live in the city.
Just checked fuelly for a 2000/10 aygo.
309,000 miles average of 42mpg.
http://www.fuelly.com/car/toyota/aygo/2009
I bet it isn't doing any more than 31/32mpg at 85mph.
309,000 miles average of 42mpg.
http://www.fuelly.com/car/toyota/aygo/2009
I bet it isn't doing any more than 31/32mpg at 85mph.
No 
Claimed 34 mpg average on the X5, have averaged 20-26mpg on this. Full tank claims 635 miles on a long run on the motorway, £100 to fill up.
Claimed 33mpg average on the XC90, seen 26-27 average. Full tank claims 550 miles from £75 fill up. Much better on fuel, however is veeeery slow.
Claimed 34 mpg average on the X5, have averaged 20-26mpg on this. Full tank claims 635 miles on a long run on the motorway, £100 to fill up.
Claimed 33mpg average on the XC90, seen 26-27 average. Full tank claims 550 miles from £75 fill up. Much better on fuel, however is veeeery slow.
The only time I've ever exceeded official figures was on a long overnight run from Liverpool to Brighton. We were in a brand new at the time 2010 Skoda Superb, with the old 1.9 PD/TD engine (103 BHP) and five speed manual box. It was the Greenline edition, optimised for economy with lowered suspension, extra undertrays for aero, shutters for the front grille, low rolling resistance tyres, lower weight etc. The car had an official NEDC rating of 58mpg extra-urban and 50mpg combined.
We tucked up our lad in the back at about 2am, and then headed out. We live just down the road from the motorway on-slip, so we basically started the engine and hit the motorway at a steady 55mph, then turned on cruise control. We covered 240ish miles of mostly deserted motorway, occasionally accelerating up to 70/80 to break the boredom and then back down to 50/55 for roadworks/economy. I'd chosen to go overnight because we had no time pressure (visiting family for a week), and the roads would have been - and were - basically empty until we hit London around the time the world started to wake up.
As we neared our destination my wife snapped a pic between my arms, hence crap quality, but as you can see I comfortably exceeded the book figure and then some.
By the time we arrived in Brighton, I rolled into a Shell and brimmed it again. The OBC by that time had gone up since the pic was taken, and said 78.something mpg. The brim-to-brim calculation came out at a true 74mpg, versus the book extra-urban figure of 58mpg. You can't argue with that really, even if it was a long and boring journey - especially not for a bloody massive great thing like a Superb.
These days I have a much nicer 2.0 TSI 220ps that never reaches book figures; mostly because I drive it everywhere in manual mode and enjoy wringing its neck.
When I do have to use a motorway, my speeds certainly never start with a 5 any more unless I'm in a (rarely encountered) SPECS zone. Life's too short. That said it still returns mid 30s around town and mid 40s on a motorway, which isn't bad at all for a big petrol car.
We tucked up our lad in the back at about 2am, and then headed out. We live just down the road from the motorway on-slip, so we basically started the engine and hit the motorway at a steady 55mph, then turned on cruise control. We covered 240ish miles of mostly deserted motorway, occasionally accelerating up to 70/80 to break the boredom and then back down to 50/55 for roadworks/economy. I'd chosen to go overnight because we had no time pressure (visiting family for a week), and the roads would have been - and were - basically empty until we hit London around the time the world started to wake up.
As we neared our destination my wife snapped a pic between my arms, hence crap quality, but as you can see I comfortably exceeded the book figure and then some.
By the time we arrived in Brighton, I rolled into a Shell and brimmed it again. The OBC by that time had gone up since the pic was taken, and said 78.something mpg. The brim-to-brim calculation came out at a true 74mpg, versus the book extra-urban figure of 58mpg. You can't argue with that really, even if it was a long and boring journey - especially not for a bloody massive great thing like a Superb.
These days I have a much nicer 2.0 TSI 220ps that never reaches book figures; mostly because I drive it everywhere in manual mode and enjoy wringing its neck.
When I do have to use a motorway, my speeds certainly never start with a 5 any more unless I'm in a (rarely encountered) SPECS zone. Life's too short. That said it still returns mid 30s around town and mid 40s on a motorway, which isn't bad at all for a big petrol car.Done some calculations on the last couple of tanks of fuel in my Mx5 (NB2 vvt), I'm beating the manufacturer figures fairly consistently. From a 50/50 city & rural commute I'm getting 33mpg, from a 50/50 rural and motorway run I got 37mpg. I drive it as it is intended though, gets its kneck wrung right out to redline on a regular basis and a 100k mile engine.
Manufacturer mpg is 32mpg combined.
Manufacturer mpg is 32mpg combined.
Strudul said:
I assume that is for the average / combined figure? What about urban and extra urban?
Approximate time, Urban:Stationary: 25%
Up to 10mph: 25%
10-20mph: 25%
20-30mph: 25%
Approximate time, Extra-urban:
Up to 30mph: 10%
30-40mph: 25%
40-50mph: 25%
50-60mph: 10%
60-70mph: 15%
70-80mph: 15%
For the combined mpg figure, approximately two-thirds of the total time is 'urban' and one-third 'extra-urban'.
Also please note that most of the time I am blocked from posting on these boards so if I don't reply in a timely manner it's probably because I'm a newbie and I keep getting this message:
'.....The forums are currently not accepting posts from new members.
This is due to persistent abuse earlier today.
The forums are likely to stay in this mode for some hours.
We apologise for the inconvenience and hope you'll return later.....'
Edited by Ron99 on Tuesday 11th July 09:44
janesmith1950 said:
I'd also call a portion of wishful thinking, as there is no way on God's earth a 335i matches an Aygo's MPG at 75mph.
I used to own a C1 and did a lot of motorway miles in it. I couldn't do it below 50mpg unless I chose to pedal to the floor at all times (which on that meant you're at 85+).
Now having an auto 140 petrol, a more economical car than the 335, it does nowhere near the MPG of the C1 at steady motorway speeds.
I'd seriously question, all other things being equal, a 1500kg 3000cc petrol needing the same (or less) energy than an 800kg, 1000cc petrol to do 75mph? There would have to be an enormous disparity between gearing and or aerodynamic efficiency in the heavier car's favour.
Either that, or you complete your physics using man maths.
Agreed, SMWBO has a 107 and it would do more way more than 31mpg at 75, id estimate mid-40's maybe more.I used to own a C1 and did a lot of motorway miles in it. I couldn't do it below 50mpg unless I chose to pedal to the floor at all times (which on that meant you're at 85+).
Now having an auto 140 petrol, a more economical car than the 335, it does nowhere near the MPG of the C1 at steady motorway speeds.
I'd seriously question, all other things being equal, a 1500kg 3000cc petrol needing the same (or less) energy than an 800kg, 1000cc petrol to do 75mph? There would have to be an enormous disparity between gearing and or aerodynamic efficiency in the heavier car's favour.
Either that, or you complete your physics using man maths.
The only time i was able to get close to the extra urban figure of 68.9 was on a full tank of mainly 60mph motorway driving, got 68.8 worked out.
Having said that....it never gets near its combined figure of 61.4 in general driving, last tank was 52mpg and it's often gone into the 40's. Hardly a guzzler though.
Willy Nilly said:
2011 Jazz 1.4 ES, can't remember the fishal figures, but...
filled up yesterday morning and have now done 47.2 miles around town with 8 engine starts, so several short trips. The dash says 62.2mpg. There may have been tail backs.....
Very impressive!filled up yesterday morning and have now done 47.2 miles around town with 8 engine starts, so several short trips. The dash says 62.2mpg. There may have been tail backs.....
Although my Civic 1.8 OBC over-reads by 3-5mpg. Said i was getting 43.4mpg on the last full tank. Worked it out and it was 38.6. Not too chuffed...
I saw 38 mpg in my M3 on the trip computer on the way home on the M25, light traffic and speed between 7* & 8* mph.
Even though I doubt the trip computer is actually correct its quiet impressive.
Although I suspect that it was either due to someone kindly removing my passenger side wing mirror the previous evening...
Even though I doubt the trip computer is actually correct its quiet impressive.
Although I suspect that it was either due to someone kindly removing my passenger side wing mirror the previous evening...
M1C said:
Agreed, SMWBO has a 107 and it would do more way more than 31mpg at 75, id estimate mid-40's maybe more.
.
We have Vauxhall's equivalent as a shopping trolley, a Viva. .
It gives 50mpg on long 75mph runs and similar mpg when used for commuting in rush hour although my wife tends to always be too hot or too cold so the heated seats, heated steering wheel or aircon is always on which knocks 5mpg off when she uses it compared to when I use it.
It's most economical at 30-40mph and can give 70mpg on clear roads cruising at those speeds (country lanes, urban roads at night etc).
Official figures are U=50mpg, Ex-U=70mpg, C=61mpg.
With small cars (and to some extent cars with small engines) their mpg and acceleration tend to suffer a lot more than large cars if there are lots of electrics running or lots of people/luggage on board. The official mpg tests are conducted with just the driver, with no electrics running.
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