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#1
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Spa trip 41 mpg! :-)
Only Leamington Spa! Drove down on Friday for a overnight stay at my dads. it's the first time I've done motorway journey and remembered to do proper Economy check 272 miles £39.70 of lpg at 63.9p.
most of the time I tried between 70-80 on the speedo (apart from the 50 road works). And a bit of town driving I think 50 mpg equivalent may be possible with all motorway and not using cruse control. I've also been trying to find out if the car has a sweet spot where it's most efficient, by setting the cruse at different speed for 10min and reset the mpg average in the DIS here are my results 60mph average 29.6 mpg 70mph average 27.3 mpg 80mph. average. 26.5 mpg I've only tried it once, but not on the same route! so I need to try it a lot more. Anybody else tried this? Cheers dave
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2002 S8 silver with black half leather 2000 d2 S8 in Racing green pearl, RS4 manual gearbox, 2003 A4 avant TDi 1997 Volvo V40 2.0T 1992 Mazda eunos v spec 1976 Reliant Kitten 1965 Porsche 911 Last edited by awolfinsheepsclothes; 25th May 2013 at 09:36 PM. |
#2
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Quote:
Air resistance is insignificant at speeds below 20mph and you would want to keep car in as high as possible gear for better economy. You need about 40 mph to drive in fifth on D2 so you would most likely get best economy somewhere in 20-40mph range.
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Currently 8less 2011 Q7 S Line 3.0TDI, 2016 Tesla Model S 90D 8 history: 2006 A8 Sport 4.2TDI quattro SOLD, 1997 S8, reached end of life with gearbox failure |
#3
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But is it simple?
Has a D2 got a speed it's happy cruse at in sensible speed on the motorway between 50-90 where it doesn't cost the earth. Fuel economy at steady speeds with selected vehicles was studied in 2010. The most recent study indicates greater fuel efficiency at higher speeds than earlier studies; for example, some vehicles achieve better mileage at 65 mph (105 km/h) rather than at 45 mph (72 km/h), although not their best economy, such as the 1994 Oldsmobile Cutlass, which has its best economy at 55 miles per hour (89 km/h) (29.1 mpg-US (8.08 L/100 km)), and gets 2 mpg better economy at 65 mph (105 km/h) than at 45 mph (72 km/h) (25 mpg-US (9.4 L/100 km) vs 23 mpg-US (10 L/100 km)). The proportion of driving on high speed roadways varies from 4% in Ireland to 41% in Netherlands. When the National Maximum Speed Law's 55 mph (89 km/h) speed limit was mandated, there were complaints that fuel economy could decrease instead of increase. The 1997 Toyota Celica got 1 mpg better fuel-efficiency at 65 mph (105 km/h) than it did at 45 mph (72 km/h) (43.5 mpg-US (5.41 L/100 km) vs 42.5 mpg-US (5.53 L/100 km)), although almost 5 mpg better at 60 mph (97 km/h) than at 65 mph (105 km/h) (48.4 mpg-US (4.86 L/100 km) vs 43.5 mpg-US (5.41 L/100 km)), and its best economy (52.6 mpg-US (4.47 L/100 km)) at only 25 mph (40 km/h). Other vehicles tested had from 1.4 to 20.2% better fuel-efficiency at 55 mph (89 km/h) vs. 65 mph (105 km/h). Their best economy was reached at speeds of 25 to 55 mph (40 to 89 km/h) Officials hoped that the 55 mph limit, This was partly based on a belief that cars achieve maximum efficiency between 40 and 50 mph (64 and 80 km/h) and that trucks and buses were most efficient at 55 mph (89 km/h).
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2002 S8 silver with black half leather 2000 d2 S8 in Racing green pearl, RS4 manual gearbox, 2003 A4 avant TDi 1997 Volvo V40 2.0T 1992 Mazda eunos v spec 1976 Reliant Kitten 1965 Porsche 911 |
#4
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I don't know where you got those figures from.
Maybe we should ask Mythbusters to test it. It's basic physics - higher speed has higher losses in friction and air and rolling resistance and they increase exponentially with speed. If you drive in top gear the slower you drive the better efficiency is down to the lowest rpm that engine is happy to with which would be around 1200rpm on A8 and 1500rpm on S8. The question is can you get better economy if you drive in lower gear as losses to drive engine and ancillaries remain the same even if air and rolling resistance drops. Please try and report back, I am sure it will be below 50mph and most likely 20-40mph range.
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Currently 8less 2011 Q7 S Line 3.0TDI, 2016 Tesla Model S 90D 8 history: 2006 A8 Sport 4.2TDI quattro SOLD, 1997 S8, reached end of life with gearbox failure |
#5
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In my PF S8 it seemed to make little difference at speeds from about 45 to 80mph.
My FL changes into 5th at lower speeds, but given the different engine I don't know what rev range is the most efficient. Haven't driven it far enough to get a good feel on economy at different speeds but overall it's about 10% better. That may be due to a fair bit of 40mph driving where the PF would usually insist on 4th (even after I recoded the box) but FL is happy in 5th.
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.). 2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one! Finally: gone, but not forgotten..... 1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors. e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later) 1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer. And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850! |
#6
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Wikipedia!
No need for mythbusters you have a 8 outside you can test it yourself! You might even save some money! Mine doesn't get into top gear until 40mph,so I'd expect it so be above 40mph but I'm not driving at such low speeds on the motorway 60 is low enough! but my engine is happy to pull from about 1100rpm In fourth gear but won't go below 1400 in fifth as it changes into fourth. Cheers Dave
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2002 S8 silver with black half leather 2000 d2 S8 in Racing green pearl, RS4 manual gearbox, 2003 A4 avant TDi 1997 Volvo V40 2.0T 1992 Mazda eunos v spec 1976 Reliant Kitten 1965 Porsche 911 Last edited by awolfinsheepsclothes; 26th May 2013 at 11:20 PM. |
#7
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Ok so please go carefully on me because i'm only a counrty bumbkin and i are i little bit fik but my reckoning is,
29.6mpg is 6.5 miles per liter, 26.5mpg is 5.8 miles per liter over a 90 liter tank thats a wopping 63 miles, so at 29.6 just over 2 liters a massive £3 in your pocket. It's just not worth worrying about, a 4.2 V8 has never been know for it's economy. I've owned my 8 for a few years now and thrown a little over 80k miles on it and i've worked out that you can drive it pretty much however you like on UK roads and it really makes not difference much at all, when the tank is empty you have to fill it.
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1996 A8 4.2 QS. Bose, Solar roof, um...um... rally sport towbar. Now gone to a new home as the Traders 8. Bright yellow bus o love. |
#8
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'Only' Leamington Spa, cheeky. I was born, raised and have lived here every year of my life. Hope you had a good visit.
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2009 Audi RS 6 Saloon V10 - 420mm Ceramics, Keyless, Soft Close, Adaptive Cruise, Glass Sunroof, Blinds, Twin Pane & UV, Freeview & DAB, High Beam Assist, MTM bits, Audi Exclusive Bits, MRC, Milltek, GYEF1 ASY2's, Bluetooth streaming music to AMI mod - 753 PS/1021 NM 2016 Audi S3 Saloon, Sepang, S-Tronic - B&O, Tech Pack etc... Company Car 1995 Audi A8 4.2 V8 quattro Sport - Bose, Solar, Blinds |
#9
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Yes it was really good thanks its a really nice place I would recommended it to anyone. I had a good meal at the star and garter and the moorings. And a good walk round :-)
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2002 S8 silver with black half leather 2000 d2 S8 in Racing green pearl, RS4 manual gearbox, 2003 A4 avant TDi 1997 Volvo V40 2.0T 1992 Mazda eunos v spec 1976 Reliant Kitten 1965 Porsche 911 |
#10
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Both regular hangouts of mine, there are loads of others, too.
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2009 Audi RS 6 Saloon V10 - 420mm Ceramics, Keyless, Soft Close, Adaptive Cruise, Glass Sunroof, Blinds, Twin Pane & UV, Freeview & DAB, High Beam Assist, MTM bits, Audi Exclusive Bits, MRC, Milltek, GYEF1 ASY2's, Bluetooth streaming music to AMI mod - 753 PS/1021 NM 2016 Audi S3 Saloon, Sepang, S-Tronic - B&O, Tech Pack etc... Company Car 1995 Audi A8 4.2 V8 quattro Sport - Bose, Solar, Blinds |
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