Omega Owners Forum
Chat Area => General Car Chat => Topic started by: tunnie on 03 May 2010, 18:49:43
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
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Thank you Tunnie. VERY interesting post ! Honestly.
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Tunnie lad you join my growing list of "Human Sleeping Tablets" ;D
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
That is surprising, tunnie! :o I would have expected at least a noticeable increase in mpg? Still, in your case it's a plus point! ;D :y
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i thought it was interesting that fuel economy at 80mph is same as 65mph....
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Thank you Tunnie. VERY interesting post ! Honestly.
LPG conversion users will be interested ;)
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i thought it was interesting that fuel economy at 80mph is same as 65mph....
I have noticed this before being honest.... I think it must be momentum ::)
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i thought it was interesting that fuel economy at 80mph is same as 65mph....
I have noticed this before being honest.... I think it must be momentum ::)
Revs were much lower, 2.7k ish, compared to 3.2k, so on a long motorway run, i would have expected it to be better.
There are some long hills, its 90% motorway, so would think it would be better. It did not 'feel' right, felt it giving more power on hills, usually at 80 just blasts up.
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Tunnie lad you join my growing list of "Human Sleeping Tablets" ;D
;D ;D
I must admit, as soon as I saw Tunnie and LPG I thought not again ;D ;D ;D
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Did a little test on last tank of LPG.....
You need to test it over more than one tank, as LPG fills are not that consistent. Pumps are temperature compensated so if the temperature is different one fillup might not give you the same range as the next.
I tend to take the view that it's cheap therefore MPG doesn't interest me. Let the V6 growl away. :y
Kevin
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
Tunnie , honestly I dont think this calculation reflects correct values..
the force you must spend increases proportional with your speed squared in a fluid , called drag..
check drag at high velocity..
http://en.wikipedia.org/wiki/Drag_(physics)
I guess some extra factors that Kevin mentioned mislead you..
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
Tunnie , honestly I dont think this calculation reflects correct values..
the force you must spend increases proportional with your speed squared in a fluid , called drag..
check drag at high velocity..
http://en.wikipedia.org/wiki/Drag_(physics)
I guess some extra factors that Kevin mentioned mislead you..
Have been using same LPG pump, but i did notice same on petrol before, that there is very little difference in mpg at 65 vs 80.
If i push it to 90, it drops a lot, but 80 car just feels 'right' at that speed
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
Tunnie , honestly I dont think this calculation reflects correct values..
the force you must spend increases proportional with your speed squared in a fluid , called drag..
check drag at high velocity..
http://en.wikipedia.org/wiki/Drag_(physics)
I guess some extra factors that Kevin mentioned mislead you..
Have been using same LPG pump, but i did notice same on petrol before, that there is very little difference in mpg at 65 vs 80.
If i push it to 90, it drops a lot, but 80 car just feels 'right' at that speed
this 'right' feeling is more like I feel 'better' at higher speeds ;D :-X
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
Tunnie , honestly I dont think this calculation reflects correct values..
the force you must spend increases proportional with your speed squared in a fluid , called drag..
check drag at high velocity..
http://en.wikipedia.org/wiki/Drag_(physics)
I guess some extra factors that Kevin mentioned mislead you..
Drag is the major factor when cruising at motorway speed but I think the Omega is geared to hold the engine at the most efficient RPM when doing 80+ mph.
I do seem to get better MPG if I let the speed drift up in to that range....
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I notice on our 2.6 that the mpg difference between 60mph and 75mph is minimal, so normally cruise at that higher speed
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Did a little test on last tank of LPG, set cruise bang on 65mph instead of the usual 80, over the course of 300 miles? Got almost exactly same mpg as i usually do, and pence per mile was 10.5 instead of 10.6.
Glad there is no saving as i was bored doing 65, and it was taking ages to get places ;D
Back to usual cruise speeds 8-)
Tunnie , honestly I dont think this calculation reflects correct values..
the force you must spend increases proportional with your speed squared in a fluid , called drag..
check drag at high velocity..
http://en.wikipedia.org/wiki/Drag_(physics)
I guess some extra factors that Kevin mentioned mislead you..
Drag is the major factor when cruising at motorway speed but I think the Omega is geared to hold the engine at the most efficient RPM when doing 80+ mph.
I do seem to get better MPG if I let the speed drift up in to that range....
there are also other factors that can effect mpg..that I didnt mention..
air lift which can drop the friction coefficient between the tires and road..
but increasing revs at a fixed gear wont help imo as
you need more fuel at a fix time slice and energy losses on the engine increase with increasing temperature proportional to revs increase which also at high speeds wont be negligible..
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but increasing revs at a fixed gear wont help imo as
you need more fuel at a fix time slice and energy losses on the engine increase with increasing temperature proportional to revs increase which also at high speeds wont be negligible..
The 4 pots have all the torque high up in the rev range to squeeze the power out and a fixed induction system unlike the V6s multirams so it's possible that they are more efficient at higher revs where they're "on cam".
I find the Westfield the same. You might just as well go for it on a motorway run because MPG doesn't start to drop until plenty over the speed limit. Comes on cam at about 3500 RPM / 80 in 5th.
Kevin
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but increasing revs at a fixed gear wont help imo as
you need more fuel at a fix time slice and energy losses on the engine increase with increasing temperature proportional to revs increase which also at high speeds wont be negligible..
The 4 pots have all the torque high up in the rev range to squeeze the power out and a fixed induction system unlike the V6s multirams so it's possible that they are more efficient at higher revs where they're "on cam".
I find the Westfield the same. You might just as well go for it on a motorway run because MPG doesn't start to drop until plenty over the speed limit. Comes on cam at about 3500 RPM / 80 in 5th.
Kevin
imo for a real measurement road traffic, distance, geograpy , wind and gear changes through the travel must all be fix which is really really hard to apply ..
And Westfield's profile is so different than a miggy as the drag is really minimized :-/
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And Westfield's profile is so different than a miggy as the drag is really minimized :-/
On the Omega, it is. ;) A Westfield has the aerodynamic properties of a small post office once you get close to 3 figure speeds. ;)
The Omega's Cd is around 0.30 IIRC. Westfield? More like 0.70, so I'm told. ;D
Kevin
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And Westfield's profile is so different than a miggy as the drag is really minimized :-/
On the Omega, it is. ;) A Westfield has the aerodynamic properties of a small post office once you get close to 3 figure speeds. ;)
The Omega's Cd is around 0.30 IIRC. Westfield? More like 0.70, so I'm told. ;D
Kevin
Pretty good on the Miggy
Body
Aerodynamic drag co-efficients:
Saloon - Cd 0.29
Estate - Cd 0.32
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And Westfield's profile is so different than a miggy as the drag is really minimized :-/
On the Omega, it is. ;) A Westfield has the aerodynamic properties of a small post office once you get close to 3 figure speeds. ;)
The Omega's Cd is around 0.30 IIRC. Westfield? More like 0.70, so I'm told. ;D
Kevin
:o :o whaaat ..
I'm shocked.. :-?
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:o :o whaaat ..
I'm shocked.. :-?
That's what happens when the wheels, suspension, exhaust, occupants are exposed rather than covered in bodywork.
Improves a lot if you remove the windscreen but not a very wife-friendly modification. ;D
The frontal area is a lot smaller than an Omega's, so it's not as bad as it may seem, but they do hit a brick wall at 3 figure speeds. I reckon to match the top speed of a V6 Omega you'd need over 300 BHP.
Acceleration from rest is a different matter, of course. ;)
Kevin