Fuel efficient driving.

skiddlydiddly

Some people(not Wig) still changing the example I gave to suit them.Like I said, an extra bit of speed would get you past and still avoid the car coming towards you and the car pulling out.I never mentioned any speeds.

If people want to coast along saving fuel then maybe the fact that the extra wear on your clutch/flywheel and gearbox will most likely offset any savings on fuel might make you think twice.Using the clutch more is going to wear it more quickly, no getting away from that.

You're still going to be burning fuel(albeit less)coasting or the engine wouldn't turn over, so the savings just don't seem worth it to me.

myhooose

skiddlydiddly wrote: »

Some people(not Wig) still changing the example I gave to suit them.Like I said, an extra bit of speed would get you past and still avoid the car coming towards you and the car pulling out.I never mentioned any speeds.

If people want to coast along saving fuel then maybe the fact that the extra wear on your clutch/flywheel and gearbox will most likely offset any savings on fuel might make you think twice.Using the clutch more is going to wear it more quickly, no getting away from that.

You're still going to be burning fuel(albeit less)coasting or the engine wouldn't turn over, so the savings just don't seem worth it to me.

I had some advanced driving lesson a long time ago (I don't consider myself an advanced driver). The instructor made the point; whats more expensive to replace, a set of brake pads or a clutch?

Inactive

myhooose wrote: »

I had some advanced driving lesson a long time ago (I don't consider myself an advanced driver). The instructor made the point; whats more expensive to replace, a set of brake pads or a clutch?

Indeed.

Gears are for going, brakes are for stopping.

Harry_Flashman

DirectDebacle wrote: »

Frontal Protection System.

Ah thanks for that - a chrome bull bar looks so much better though than these plastic things that some folk use

Wig

Except that the clutch bearing argument holds no water, whenever I replace a clutch I replace the bearing aswell (it's stupid not to do this). And I have never had a bearing fail before the clutch wears out. People stand on the clutch at traffic lights all the time it's not just when coasting. Bearings are designed to long outlast the clutch pads.

Mankysteve

skiddlydiddly wrote: »

Some people(not Wig) still changing the example I gave to suit them.Like I said, an extra bit of speed would get you past and still avoid the car coming towards you and the car pulling out.I never mentioned any speeds.
.

No you wont. You end up having a crash with something as I've pointed out. If there driving a idiot/didn't see you but now checked there mirror and seen you about to go into there behind there going to accelerator away at high rate.

You've got to swerve across the road probably change a gear then accurate faster than they are then swerve back into your lane not a chance buddy.

almillar

skiddlydiddly is getting wound up into his/her own example. When I stated that I coast, I said when safe to do so. Perhaps coasting when you see a car waiting to pull out isn't the right time, doesn't mean you can't coast at other times.

cyclonebri1

fred7777 wrote: »

There have been several articles in the motoring press recently recommending max throttle at low revs then changing up at around 1500 in a diesel and 2000rpm for a petrol car. This ties up with wikipedia:
"modern diesels being able to reach an efficiency of about 40% in the engine speed range of idle to about 1,800 rpm. Beyond this speed, efficiency begins to decline due to air pumping losses within the engine.would seem to tie up with the fact that most modern diesels achieve a max efficiency of 40% at around"
http://en.wikipedia.org/wiki/Engine_efficiency

I seem to get improved results driving around town doing this.


You will have to prove it to convince me. The kinetic energy put into the vehicle is the same for each example but the engine will be requires to produce twice the force to accelerate in half the time. Your example only works out if the engine efficiency doesn't vary with power output or rpm.


Unfortunately engine efficiency maps are not enough. This link shows fuel economy versus speed for a selection of vehicles tested. http://en.wikipedia.org/wiki/File:Fuel_economy_vs_speed_1997.png

It shows there is no hard and fast rule which can be applied to all vehicles.


Agreed, no argument there


Agreed


No coasting with the engine not running gives the best fuel efficiency. I believe hybrids do this safely.
In normal cars it is better to run with the engine on in gear and either no throttle or just enough to maintain speed than to coast. I have tried each approach to some long descending dual carriage ways near me and coasting shows a higher fuel consumption.


The AA website has some good advice covering almost everything that has been on this thread so far:
http://www.theaa.com/motoring_advice/fuels-and-environment/drive-smart.html

Without the background that's exactly what I've found, but max throttle still "feels" excessive

cyclonebri1

fred7777 wrote: »

Surely in a discussion on fuel economy it's perfectly sensible to compare a more efficient vehicle with a "normal" vehicle.

Not if there are safety factors involved which mat not understand;)

cyclonebri1

skiddlydiddly wrote: »

Some people(not Wig) still changing the example I gave to suit them.Like I said, an extra bit of speed would get you past and still avoid the car coming towards you and the car pulling out.I never mentioned any speeds.

If people want to coast along saving fuel then maybe the fact that the extra wear on your clutch/flywheel and gearbox will most likely offset any savings on fuel might make you think twice.Using the clutch more is going to wear it more quickly, no getting away from that.

You're still going to be burning fuel(albeit less)coasting or the engine wouldn't turn over, so the savings just don't seem worth it to me.

Sorry mate, but you still don't get the issue. If there is time to consider pulling out, getting in the correct gear, avoiding the car in front and avoiding the oncoming car, (after checking for any), and then checking behind to ensure someone hasn't pulled out to avoid the possible collision you are about to be involved in, then there is time to stop