trashbat wrote:I've been experimenting this week, and going for the highest gear possible at steady speeds; so 30mph can be in fifth. Obviously this means unresponsive throttle and is in some ways akin to coasting.
The result was a nearly 10% economy gain, measured over a tank and at the pump. An average of 29.4 up to 32.2 mpg.
I think I applied it reasonably and appropriately, and although it was not optimum in terms of control, I don't think it always mattered. I wouldn't try it on a test though.
It got me thinking about how, along the lines of adapting your drive to make progress, you might pursue fuel saving as the aim. Obvious maybe, but there we are.
What do you guys regarding flexibility, especially for economy? Where are your boundaries?
7db wrote:If you want fuel economy, don't use the brakes, and cruise below 50mph. Gear doesn't make a huge amount of difference.
GJD wrote:trashbat wrote:I think I applied it reasonably and appropriately, and although it was not optimum in terms of control, I don't think it always mattered. I wouldn't try it on a test though.
I think my boundary might be described by the bit of your post I've highlighted. If your sub-optimal control did not always matter, doesn't that imply that sometimes it did matter - i.e. you had less control than you perhaps should have had?
GJD wrote:Not having the control when you don't need it is one thing, but I've found when I've tried driving in a higher gear with fuel economy in mind that it can make me subconsciously accept higher speeds than I ought to when driving around and through hazards - there's not as much variation in speed as there should be.
Recently I've been trying to make myself more readily prepared to use a lower gear in 30s. Between hazards that aren't too far apart, even if I will get up to 30 between them I might stay in a lower gear up to 30 and back down again. If I have got up towards 30 and gone up a gear, I'm trying to be more decisive about changing down if the next hazard demands it. I'm trying to think more "will the lower gear cope with this one - if so, then use it" rather than "can I get away with the higher gear for this one". In my car that means I'm usually in 2nd or 3rd in a 30. That's been driven by a desire for better control around hazards, irrespective of factors like progress or fuel economy which, for me personally, are secondary.
trashbat wrote:I probably should have written 'always matters' rather than in the past tense. I only used it when I felt the situations warranted it; e.g. a straight 30mph road with no obstructions ahead. I think being able to perform unplanned acceleration to mitigate trouble is valuable in certain contexts, but I find it hard to identify where that'd apply in an urban 30.
trashbat wrote:I've been experimenting this week, and going for the highest gear possible at steady speeds; so 30mph can be in fifth. Obviously this means unresponsive throttle and is in some ways akin to coasting.
The result was a nearly 10% economy gain, measured over a tank and at the pump. An average of 29.4 up to 32.2 mpg.
I think I applied it reasonably and appropriately, and although it was not optimum in terms of control, I don't think it always mattered. I wouldn't try it on a test though.
It got me thinking about how, along the lines of adapting your drive to make progress, you might pursue fuel saving as the aim. Obvious maybe, but there we are.
What do you guys regarding flexibility, especially for economy? Where are your boundaries?
zadocbrown wrote:How certain are you that this was a fair test? What proportion of this gain in economy might be down to other factors? I don't know.
zadocbrown wrote:Looking at the general approach behind your experiment.... Personally I think it's illogical to buy a poky car then drive like a grandad to get a few more mpg. You'd be better off getting a more economical car and driving it normally.
Which ones are more likely to be ski bores?WhoseGeneration wrote:However, that being said, as I commented in another thread, mpg bores are the new bhp bores.
GJD wrote:trashbat wrote:I probably should have written 'always matters' rather than in the past tense. I only used it when I felt the situations warranted it; e.g. a straight 30mph road with no obstructions ahead. I think being able to perform unplanned acceleration to mitigate trouble is valuable in certain contexts, but I find it hard to identify where that'd apply in an urban 30.
I can't think of an example off the top of my head either. But the control a lower gear gives you isn't just the ability to accelerate. I don't have my copy of Roadcraft to hand to quote, but it talks about the accelerator being a control you can use to slow the car down as well as speed it up. As I descend through the rev range, I find that the ability to reduce speed with the accelerator drops off more than/earlier than the ability to increase speed with it.
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