Tips for driving more efficiently?

iltisman

These guys are really into eco driving but some of their ideas will upset the "think about the children brigade".

http://ecomodder.com/forum/

cepheus

Driving at the optimum engine, driveline and tyre temperatures will impove fuel economy over shorter journeys. Try to use one car rather than two in the family if you have the option, so it is usually at least partly warmed up when you start it.

Of course sharing trips is even better but this is nothing to nothing to do with driving style or engineering!

For longer trips on the motorway having an aerodynamic Diesel car is more important than driving style.

forgotmyname

grizzly1911 wrote: »

If you use Motorways and Dual carriageways keep the speed "down".

Doing 80 v 70 makes a big difference, as despite the 6th gear, you are actually having to counter the effects of drag.

Don't over rev the engine, change up when the car can carry the next gear easily. Most diesels for instance don't need to go past 2000 and will often trundle around in traffic, or cruise on light throttle at a lot less.

I had an OBD reader plugged in at the time, I could have been more scientific and repeated the tests over and over but the 7% difference was good enough for me. And obviously not a slight mismatch.

Also its strange BUT at 80mph in 6th gear my economy gets better and better according to the trip computer.
I think 80 matches the peak torque in 6th or clearly has enough torque for that speed/gear ration.

Diesel mondeo 6 speed. The fact i am having to push the throttle down further must mean ideally 40mph in 5th needs slightly more torque than it gives at lighter throttle openings.

Shame i cannot read the cruise control throttle usage, I could then repeat the tests 100%.

Ultrasonic

forgotmyname wrote: »

Best economy = around the peak torque figure.

I always get confused by this one.

My car (Skoda Octavia 1.9TDi) definitely gives better fuel economy at 30 mph in 5th rather than 3rd, but I'd be much closer peak torque in 3rd. (Here I'm judging economy based on both what is indicated by the trip computer and what I can feel I'm doing with my right foot.) If I'm ACCELERATING from 30 mph then I'd be in third, but for a steady 30 mph (on a flat road) 5th defintely seems best for economy.

funkycoldribena

Fold the back seats down-creates less air resistance.

grizzly1911

forgotmyname wrote: »

I had an OBD reader plugged in at the time, I could have been more scientific and repeated the tests over and over but the 7% difference was good enough for me. And obviously not a slight mismatch.

Also its strange BUT at 80mph in 6th gear my economy gets better and better according to the trip computer.
I think 80 matches the peak torque in 6th or clearly has enough torque for that speed/gear ration.

Diesel mondeo 6 speed. The fact i am having to push the throttle down further must mean ideally 40mph in 5th needs slightly more torque than it gives at lighter throttle openings.

Shame i cannot read the cruise control throttle usage, I could then repeat the tests 100%.

I have 6 speed Avensis TD. I must Admit I tend to change up at no more than 2K most of the time and 80 = around 2100.

Since reading s few of these threads I have been dropping down to 5th/staying in 5thto see if it makes much difference. I find it difficult to judge unless loaded or going uphill as it seems to have more than adequate torque for what I want. It is quite happy to pull from just over 1K.

As you say 80 seems to be the tipping point when economy seems to start tailing off.

reeac

forgotmyname wrote: »

6th gear at 50mph in my car gives worse fuel consumption than changing down to 5th.

40mph in 4th = 11% throttle travel.

40mph in 5th = 18% throttle travel,

So in the higher gear im actually pushing the throttle down more and putting more fuel in to compensate for the lack of torque in the higher gear.

Thing is you wont notice, As it will easily pull less than 40mph in 5th.

Best economy = around the peak torque figure.

Agreed that you need more throttle in the higher gear but the engine will be turning more slowly and hence breathing in less fuel per minute and also "pumping losses" [work expended in sucking in air] will be less. I think that the accepted wisdom is to err on the side of low revs. but not to the extent that the engine judders.

Norman_Castle

To save fuel I only drive downhill.

Throbbe

funkycoldribena wrote: »

Fold the back seats down-creates less air resistance.

Improves handling by lowering the CofG too.

ironlady2022

Thanks for everyone's advice. I've been trying 5th gear and 6th gear at 50mph as there is a 7mile road to work at 50mph. Think if it is a long stretch, 6th gear is ok but slowing down means changing gear when cars build up.