What is better for econnomy?

[R1 Indy]

After working out ive spent 360 quid on fuel over the last month, i need to reduce this as i can't afford it on my salary.

so ive now started sticking to 50 instead of 80, which seems to be bringing the MPG up.

But something that is bugging me is, what is the best way of accelerating up to speed.

is it light acceleration, but accelerating for longer, so will be at low MPG for longer especially on hills.

or a couple of sharp bursts of acceleration, so will use more fuel inicially, but will be up to speed quicker?

or is somewhere in the middle best.

also the car (alfa 159 1.9 diesal) is rather heavy at 1500 KG

So what is best?


cheers

[944fan]

Keeping revs low is the best way of upping MPG. Change up early, but not to early you have to boot it to get it going.

Slowing down is the worst thing. Run those red lights!*

• This is a joke before anyone starts

[roachcoach]

That kind of bill for a diesel suggests serious miles, therefore motorways.

On that thesis, I suggest that acceleration will only have limited impact and the best results will happen from extending observation to minimise braking.

Unless you already do all that or my theory was wrong, in which case....carry on.

[WeirdNeville]

It is generally held that it is more efficient to hold a low gear and accelerate briskly but not violently (i.e. 3/4 throttle) is more efficient than using a high gear and prolonged gentle acceleration to reach the same speed.

However ,this depends on your particular car ,and the way it is mapped.

I'm not sure if, for example, in your turbo diesel it's better to stay off boost, or use the boost for the most efficient acceleration....

[hornetrider]

Light/medium throttle, don't let the engine labour too much down low. On a diesel I would keep the revs about 750rpm or so either side of the peak torque figure (fag packet). Try to spot things in advance and avoid heavy acceleration/deceleration.

FWIW I pretty much always hit or exceed manufacturers mpg figures.

[BarnatosGhost]

I believe a diesel will deliver its cheapest power under relatively heavy load at relatively low revs.

So: brisk acceleration from low revs with plenty of throttle, but a short-shift up, and into top gear and cruising as early as possible.

But the way you slow down is MUCH more important than the way you speed up when it comes to saving fuel.

Every time you use the brakes you're converting the expensive chemical energy in the tank into useless heat in the brake discs (via the kinetic energy in the car), and then drawing upon more expensive chemical energy to get you back up to speed.

[R1 Indy]

My daily commute is 70 miles in total, of mainly B roads, tiny bit of dual carriageway, and a couple of miles through hereford town centre

so lots of start stop, im getting on average 42MPG, but would be good to improve that to around 45+.

[BoRED S2upid]

You need to hit the red line in every gear all the time. This is Pistonheads afterall speed matters not MPG did you not read the joining instructions.

[jas xjr]

Have a look in your boot to see if you are carrying around any excess weight around

[roachcoach]

Those dead hookers REALLY do hurt your fuel economy.




More seriously, I don't know that there's much more you're going to see on that kind of drive/roads.

[R1 Indy]

oh and will removing the space saver and replacing with a can of tyre weld make much difference?

[BarnatosGhost]

R1 Indy said:

My daily commute is 70 miles in total, of mainly B roads, tiny bit of dual carriageway, and a couple of miles through hereford town centre

so lots of start stop, im getting on average 42MPG, but would be good to improve that to around 45+.

Are you turning the engine off at lights? Switched off the air con? Had the car serviced? checked tyre pressures?

If you're driving towards a light that you can see is red, have you taken your foot off the throttle? If not you're probably going to have to waste that momentum by braking.

[roachcoach]

Might be sacrificing too much for little gain.

70*5*4=1400 (miles*days*weeks)

at £1.40 a litre the difference between 42mpg and 45mpg is only £15 (ish) over the month.

Just a thought.


ETA: Those values were 197 & 211 per month....where's the rest of the fuel going? I suggest commuting might not hold the root of the issue?

[Bacon Is Proof]

You've admitted to being poor on PH?
You may as well fall on your automotive sword and buy a Micra (My OH gets 48mpg+ on her commute).

[BarnatosGhost]

R1 Indy said:

oh and will removing the space saver and replacing with a can of tyre weld make much difference?

No, but it will make *some* difference. Probably unmeasurable in practical terms, but it HAS to be having a small effect.

[Simbu]

R1 Indy said:

oh and will removing the space saver and replacing with a can of tyre weld make much difference?

If you have a puncture, certainly

Concentrate on driving style (sounds like you're starting to do this already), particularly anticipating the need to brake and lift off instead.

Also check things like tyre pressure, clean air filter etc which will have an effect on MPG.

[R1 Indy]

well ive just had a look at the spare wheel, and fk me its heavy, so have removed it (will prob get a blow out on way to work in the morning now)

and checked the tyres and all 4 were at 30 psi, so have increased them to 40 psi.

will see if this makes a difference.

[Bacon Is Proof]

R1 Indy said:

and checked the tyres and all 4 were at 30 psi, so have increased them to 40 psi.

Is that a joke?

[hornetrider]

R1 Indy said:

well ive just had a look at the spare wheel, and fk me its heavy, so have removed it (will prob get a blow out on way to work in the morning now)

and checked the tyres and all 4 were at 30 psi, so have increased them to 40 psi.

will see if this makes a difference.

[Simbu]

R1 Indy said:

and checked the tyres and all 4 were at 30 psi, so have increased them to 40 psi.

Please tell me you're joking?

You must be.