fall in motorway speeds, or my imagination?
Discussion
Most folk on the M6 in Cumbria pressing on much more than normal actually I thought the other day. Lane 3 certainly 95+ territory!
By and large though I find (up here at least) the spread of speed has become much less. A lot of people in the 75-80 bracket who prob were doing 85 before. It's a nightmare because everyone gets bunched up much more.
By and large though I find (up here at least) the spread of speed has become much less. A lot of people in the 75-80 bracket who prob were doing 85 before. It's a nightmare because everyone gets bunched up much more.
XDA said:
sharpfocus said:
Aren't cars more efficient at constant throttle than constant speed? I find this cruise control mightier-than-thou obsession slightly OCD at best.
I don't use cruise control for fuel efficiency reasons, I use it out of laziness and to maintain a clean licence... I agree about the constant throttle thing, and using momentum, best learned with a 1.0 Micra on Highland roads!
s?munroman said:
XDA said:
sharpfocus said:
Aren't cars more efficient at constant throttle than constant speed? I find this cruise control mightier-than-thou obsession slightly OCD at best.
I don't use cruise control for fuel efficiency reasons, I use it out of laziness and to maintain a clean licence... I agree about the constant throttle thing, and using momentum, best learned with a 1.0 Micra on Highland roads!
Streaky
Knock_knock said:
IIRC, above 65mph the wind resistance becomes the greatest factor in fuel consumption, and increases exponentially above this.
Which I think explains why a 1.2 Corsa with 80bph can manage 100mph, but you need a 1000bhp Veyron to go 250mph (and not the 200bph which multiplication would suggest).
KK
I am pretty sure the Americans went for 56 mph (or was it 55?) as this was the magic figure which gave most engines the best mpg possible. That limit was introduced solely to deal with the fuel crisis....it just took decades to get rid of.Which I think explains why a 1.2 Corsa with 80bph can manage 100mph, but you need a 1000bhp Veyron to go 250mph (and not the 200bph which multiplication would suggest).
KK
Although yes, that did hard back to the time when 110mph was considered a very high top speed for a car, so maybe the most economical speed is different now.
(Isn't it at maximum torque in 5th gear?)
munroman said:
XDA said:
sharpfocus said:
Aren't cars more efficient at constant throttle than constant speed? I find this cruise control mightier-than-thou obsession slightly OCD at best.
I don't use cruise control for fuel efficiency reasons, I use it out of laziness and to maintain a clean licence... I agree about the constant throttle thing, and using momentum, best learned with a 1.0 Micra on Highland roads!
I use the cruise to avoid letting the speed creep up, for enforcement reasons. However I managed a record mpg in last night's saunter from the midlands - London. Over 57 mpg average, most of the journey using cruise control.
And it is possible to disengage/vary the speed easily to accomodate other drivers' speeding/slowing, just in the past I've tended towards applying a burst of speed to pass them. It's a different technique that needs to be perfected.
shuvitupya said:
Another annoying thing is when I use cruise control and people overtake with 1mph difference like the truck drivers do, and then slow down in front of me, so I need to overtake them to mantain my cruise control set speed.
This is where radar cruise (which was getting roundly slated on another thread) makes perfect sense. Heavy traffic where it's speeding up and slowing down - set the cruise to, say, 65, tuck in behind somebody and then you can sit and watch a dvd, read the paper etc. Maintains a set distance, brakes when they brake, accelerates when they do, slams on the brakes when they do or if someone pulls into the gap etc. Fantastic in SPECS controlled roadworks.
?jondude said:
....
Although yes, that did hard back to the time when 110mph was considered a very high top speed for a car, so maybe the most economical speed is different now.
(Isn't it at maximum torque in 5th gear?)
Nope, else I'd be driving at 7500rpm in 5th (so around 140 mph or so) for "best" economy Although yes, that did hard back to the time when 110mph was considered a very high top speed for a car, so maybe the most economical speed is different now.
(Isn't it at maximum torque in 5th gear?)
Best mpg is normally attained at low revs but not so low the engine labours, typically this will be around one third of max revs I would guess, maybe a little lower.
I dont really do enough miles to worry about fuel consumption.
I dont see a stark difference in how many miles i get out of a tank between completing a journey having done 80 - 90mph the whole way or if i had been doing 60 - 70mph.
It is quite frustrating now when i do use a motorway when the MPG Marathon runners refuse to move. Maybe turning the wheel very sligtly to the left to get into L1 or 2 from L3 causes a 0.01% drop on the average MPG.
I dont see a stark difference in how many miles i get out of a tank between completing a journey having done 80 - 90mph the whole way or if i had been doing 60 - 70mph.
It is quite frustrating now when i do use a motorway when the MPG Marathon runners refuse to move. Maybe turning the wheel very sligtly to the left to get into L1 or 2 from L3 causes a 0.01% drop on the average MPG.
Yep, I remember dicing with the trucks back then when I was driving at 55. In the end I gave up because my nerves got fried. I had to concentrate so hard on what all the trucks I could see (even half a mile up the road) were doing to make sure I didn't have to mash the brakes at any point.
When driving a van for a band in Germany, I always ask them how fast they want to go; curiously they always prefer the extra hour in bed to saving fuel...
When driving a van for a band in Germany, I always ask them how fast they want to go; curiously they always prefer the extra hour in bed to saving fuel...
Dracoro said:
jondude said:
....
Although yes, that did hard back to the time when 110mph was considered a very high top speed for a car, so maybe the most economical speed is different now.
(Isn't it at maximum torque in 5th gear?)
Nope, else I'd be driving at 7500rpm in 5th (so around 140 mph or so) for "best" economy Although yes, that did hard back to the time when 110mph was considered a very high top speed for a car, so maybe the most economical speed is different now.
(Isn't it at maximum torque in 5th gear?)
Yes, and I don't think the police would buy my maths there as an excuse! Ahh, everything is relevant.
I noticed around here speeds increased slightly as cameras shut down, and journeys became not so long. Isn't that what it is 'supposed' to be about: keeping the traffic moving?
Now with the jump in price of fuel, some do seem to be trundling, but it won't last. Increases are just a bit madder this time in rip-off Britain, so it's the shock factor.
Friend who moved to Aussie just told me they've seen big increase in fuel prices.
Ha ha. ...to 80p a litre.
We're still the mugs!
I noticed around here speeds increased slightly as cameras shut down, and journeys became not so long. Isn't that what it is 'supposed' to be about: keeping the traffic moving?
Now with the jump in price of fuel, some do seem to be trundling, but it won't last. Increases are just a bit madder this time in rip-off Britain, so it's the shock factor.
Friend who moved to Aussie just told me they've seen big increase in fuel prices.
Ha ha. ...to 80p a litre.
We're still the mugs!
jondude said:
Knock_knock said:
IIRC, above 65mph the wind resistance becomes the greatest factor in fuel consumption, and increases exponentially above this.
Which I think explains why a 1.2 Corsa with 80bph can manage 100mph, but you need a 1000bhp Veyron to go 250mph (and not the 200bph which multiplication would suggest).
KK
I am pretty sure the Americans went for 56 mph (or was it 55?) as this was the magic figure which gave most engines the best mpg possible. That limit was introduced solely to deal with the fuel crisis....it just took decades to get rid of.Which I think explains why a 1.2 Corsa with 80bph can manage 100mph, but you need a 1000bhp Veyron to go 250mph (and not the 200bph which multiplication would suggest).
KK
Streaky
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