My Best Mpg Yet!

[Daveyonthemove]

No problem, i think that years ago when most of learned to drive and passed our tests, that was a common way to save fuel. We don't realise how much more advanced our cars are these days.

The only reason i know about it is because i saw the episode of Top Gear where JC drove an Audi from London to Glasgow and back on a single tank of fuel, and he explained breifly how it worked. I just did a bit more research to find out more.

[Adam C]

Ah right. Wasn't sure if that just applied to Audis or other cars, silly me.

Must admit I've noticed when I've coasted, the car's RPM was a little higher than normal warm idle. Have to drive a Corsa CTDI EcoFlex (not my first choice!) and I had a look when I coasted in it - that was also running higher than idle speed so I do see your point now. Plus with the deceleration in that and also the Yaris when you lift off the gas . . . where's my head at?

[wastedagen]

It was Mr T who after replacing my rear brakes, while doing there usual checks noticed my tyre wear was uneven. Because the tyre pressure was a little low. They pumped it up to 40psi. I've just kept it going like that ever since. They explained that on the Auris running at 40psi helped prolong the life of the tyre and give a better wear.

[Daveyonthemove]

Are you on 40psi all round?

I'm having new tyres fitted to the fronts tomorrow so i will see what they are inflated to and maybe put the pressure up to 40.

[wastedagen]

Yeah Mr T put 40psi all round.

[deej78]

ok no probs. Next time I'm in the car ill see what it says......

Edit: just had a quick look at it says 57.7mpg

Not particularly close. Reason why I never use it.

Agreed, The average mpg indicator displayed by the car is not calculated on the amount of gallons in the tank, it's calculated on infinity, e.g. You could do 57mpg over 46l of petrol/diesel and then hammer your car into the ground on the last couple of litres.... it would dramatically reduce the reading. The reason, the computer cannot calculate fuel vs miles accurately enough to give a perfect reading, or the exact fuel in your car based on the milage you are producing. What should happen, as it does in BMW's, is it re-assesses the amount of milage completed based on the last full tank vs the odo and updates the reading displayed, just like using a calculator. I believe it can only do this on full tanks.

A fuel flow meter, air flow, ambient temperature, coolant temperature, would all have to be measured, and all over a period of time. Personally, It's all accurate enough for me. If you took a year of computer readings and a year of calculated they would be almost identical after working out an average. The question we should really be asking is how accurate is the milage indicator? Its what everything is calculated on. At the end of the day it's calculated just as well.......GPS will tell you, then there are questions over that... Your milage could be myth, at the end of the day all we can do is averages over long periods of time. Five full tanks is not enough.

I'm sure foot off down a hill uses no fuel, i'll have to check, coasting uses fuel though, the engine needs fuel to stay awake.

[deej78]

Just did a little research. Auris has a fuel cut off under engine braking 9999mpg, the wheels keep the engine alive, similar to the effect of bump staring, free energy. Coasting in neutral uses fuel. Zero MPG.

[wastedagen]

Thanks for the info.

[andrewfq]

Well after doing my first 'granny drive' tank, I've managed to get 527.6miles from 45litres of fuel. As with most people, I fill up to the same point where I can see the fuel. Mostly 55mph driving with the odd bit of town driving.

Works out at 53.3mpg....I'm happy with that, although I'm hoping I'll be able to squeeze out more when on my run to London in the summer.

[minaswat1]

i do 58 MPG, thats without a chip ! yeeey