Couple of questions

thehappybutterfly

I'm quite an impatient driver and hate being "held up" behind someone driving below the speed limit. Im not agressive but I do change lanes a lot, undoubtedly using a lot of fuel. My hubby, damn him!, annoys the hell out of me because whenever he has the car he manages to squeeze another few points on the mpg! He's a very careful driver! However, we've just bought a Suzuki GV 2l, a big step up from the 1.6 Astra so Im going to have to run it more economically. Thanks to the thorough explanations on this thread, I know how to do so. Despite my hubby's 20 years of nagging!

Joe_Horner

Do make an effort to change those little points, Butterfly

One curious thing is, if you're doing (say) 50mph in a 60 limit right on someoone's bumper, then it feels like you're being held up a lot more than if you drop back and do the same speed with a 50 yard gap.

No doubt there are psychologists out there who could explain that, all I know is that it works! If I had to guess, I'd suggest it's related to whatever it is tat makes people subconciously speed up slightly when you pass them on dual carriageways. We've all had it - you come up fairly fast behind someone, overtake, then as you pull back in they seem to be glued to your bumper for half a mile or so because they've almost matched your speed. Then they suddenly start falling back again as their concious brain kicks in and they slow down.

Just leaving a bigger gap (you're still doing the same speed, so it doesn't slow you down at all) helps to break that "urge to keep up / get ahead", gives you time to react without braking (saving fuel, tyre wear etc), and you will find it more relaxing once you settle into it!

facade

Personally, I find that leaving a bigger gap simply encourages chancers to pull out in front of me, causing me to have to brake rather than hit them, then they belch out huge clouds of black diesel/chipfat smoke so I have to put the aircon on and use recirculate as well, wasting even more fuel :mad:

I do tend to leave a reasonable gap anyway, to give me a chance to swerve round the craters in the road as soon as the car in front is bouncing over them (always leave enough gap in queues to get around the car in front when they stall and cannot start again, also gives you time to play tunes on the horn and make sweeping motions forwards with your arms when they roll back towards you on hills )


On a constructive note, learn the 'bus routes, so you are ready to go smoothly around a 'bus when it stops for 15 minutes without stopping, rather than drive on its back bumper, and then act surprised that it has stopped, and force everyone to wait whilst you have to do a 90 degree turn needing the whole of the other side of the road to be clear to get round it.:o

Ultrasonic

Richard53 wrote: »

I have heard it said that on a clear road (e.g. a dual carriageway) it's better to accelerate briskly up to your cruising speed...

As you probably know, there is sound basics for this (re. BSFC) but a downside of faster acceleration is increased tyre wear. I tried high load acceleration for about 6 months and saw marginal improvement in mpg at best (most of the time you aren't accelerating so it will never have a huge effect), but front tyre wear also appeared to be increased, so I have stopped do this now. This also presumably reduces strain on the gearbox etc.

So I now accelerate 'normally' - not hard but also not super slow.

The OP mentioned a dual carriageway. Here the speed at which you drive is the big factor in mpg. Drive slower and it goes up. Obviously there are limitations based on safety and annoying other road users, but sticking to 60 mph is IMHO generally a good compromise (as this is faster than HGVs).

The other basic factor that I don't think has been mentioned is choice of gear. Generally for better mpg you want to be in the highest gear you can be at which your car is still happy, but have a look at your car's manual which probably has a guide as to what rpm it is appropriate to change up.

Ultrasonic

Joe_Horner wrote: »

Just leaving a bigger gap (you're still doing the same speed, so it doesn't slow you down at all) helps to break that "urge to keep up / get ahead", gives you time to react without braking (saving fuel, tyre wear etc), and you will find it more relaxing once you settle into it!

There also might be the benefit that the driver in front could speed up as a result of you dropping back. Standard advanced driving advice is to slow down if there is another vehicle sitting too close behind, to give more time to react to hazards rather than having to brake hard and risking the tailgater run into the back of your car. This is what I do.

Richard53

Ultrasonic wrote: »

As you probably know, there is sound basics for this (re. BSFC) but a downside of faster acceleration is increased tyre wear. I tried high load acceleration for about 6 months and saw marginal improvement in mpg at best (most of the time you aren't accelerating so it will never have a huge effect), but front tyre wear also appeared to be increased, so I have stopped do this now. This also presumably reduces strain on the gearbox etc.

I was meaning getting up to speed smartly (as opposed to the outdated advice to use as little throttle as possible while accelerating). The idea is that you spend a small amount of time with higher consumption (brisk acceleration) but the payoff is a longer period when the engine is cruising and at its most efficient. But the maths behind this must be horrendously complicated, so it's all down to trying different things and seeing what works. For me, smart acceleration (not caning it, ho ho), a moderate cruising speed, choosing a gear that keeps the engine in its sweet spot (not always the highest gear) and planning ahead to brake as little as possible, have given me some very good mpg figures.

And then sometimes I rag it, just for fun. Yolo, and all that