How to get more MPG out of a Ford Fiesta Ecoboost

forgotmyname

Extra load to recharge the battery maybe?

AdrianC

How on earth does starting a hot engine use more fuel than keeping it running?

We're not talking about those old saws about starting engines from stone cold. We're talking about an engine that's fully up to temp (stop-start doesn't stop cold engines), with a modern injection system. It needs the barest of nudges from the starter to return to a stable idle in a fraction of a second.

There is no way that there is sufficient accuracy in anecdotal self-reporting to determine empirically any such increase in fuel use.

Fuel use = emissions. If stop-start systems increased emissions and fuel consumption in the official test cycles (which are the only ones that matter, and which only have short stops), they simply would not exist.

Scrapit

AdrianC wrote: »

How on earth does starting a hot engine use more fuel than keeping it running?

We're not talking about those old saws about starting engines from stone cold. We're talking about an engine that's fully up to temp (stop-start doesn't stop cold engines), with a modern injection system. It needs the barest of nudges from the starter to return to a stable idle in a fraction of a second.

There is no way that there is sufficient accuracy in anecdotal self-reporting to determine empirically any such increase in fuel use.

Fuel use = emissions. If stop-start systems increased emissions and fuel consumption in the official test cycles (which are the only ones that matter, and which only have short stops), they simply would not exist.

My current stop start does stop a cold engine. Over the life of several vehicles I've found this to be the case. What's your experience? It is what it is and I will continue to save fuel by switching my stop start off in my current vehicle. I'll change my practices when I change vehicle to see what happens but I'm not expecting much change.

peter_the_piper

I used to use the equivelent on my Picanto. I found that since it was turned off the fuel economy is no different. I do use the setting on the odometer which shows how much fuel you use as a guide. Average mpg seems to be between 48 and 55 mpg, dependent on circumstances and who's driving.

Cupumber1

Wow thank you for the responses. Somewhat contradictory about stop start! It made sense to keep it on to me but I’ve read the opposite in a few places.
Where is the eco mode button?
Re changing gears, yes I appreciate its “driving test territory” - I was taught when to change and have a listen to the engine etc. I don’t think I was taught how it affects fuel economy - I know that keeping constant low-ish RPM saves fuel, if I remember correctly! However is there anything different to consider with an Ecoboost engine?
Definitely not an option to buy a diesel with my type of driving.
A hybrid will probably be my next car in a couple of years!
I’m a district nurse so while a bike or bus may have worked a few decades ago, with the amount of visits a day we have to do it’s simply not an option and I wouldn’t have been given the job without a car

AdrianC

Cupumber1 wrote: »

I know that keeping constant low-ish RPM saves fuel, if I remember correctly!

No, not that simple. Small throttle openings use less fuel than large throttle openings, so lugging the engine at low revs in to high a gear can use more fuel than changing down.

Does this Fiesta not have gear-change indication on the dash, as so many modern cars do?

agrinnall

AdrianC wrote: »

Does this Fiesta not have gear-change indication on the dash, as so many modern cars do?

It does, but in reality it's just a 2000rpm indicator in every gear except top. I ignore it and go by the road situation.

forgotmyname

Mines the same, stupid thing tells you to change up, but it cannot see the steep hill in front of me.

I drive to the sound of the engine, if it sounds laboured i change down.
Its a diesel so it doesnt need lots of revs anyway, but i dont drive around at 1000rpm. I would prefer my DMF to stay in one piece.

System

Cupumber1 wrote: »

Hi all,
I have just bought a Ford Fiesta Ecoboost 1.0l. I've discovered since that the real MPG on these is actually much lower than claimed (no surprise I guess!), however I like the car and would like to know how to maximise the MPG on it. )

Don't rev it as high before changing gear, use less throttle. Ecoboost engines can be either economical or powerful but not both.

AdrianC wrote:

When best to change gears?

That's basic driving lesson territory...

Is it? So when is best to change gear?

forgotmyname wrote: »

Mines the same, stupid thing tells you to change up, but it cannot see the steep hill in front of me.
I drive to the sound of the engine, if it sounds laboured i change down.

In which case you won't be getting the best economy and in fact even though it is labouring, from an economy point of view you're better in the higher gear going up the hill. In my lorry I have a realtime MPG indicator. The 2018 version of my truck wants to climb hills a gear higher than the 2014 version. The 2014 version climbs hills faster than the 2018 version, even though it is 30BHP down, unless I take it out of eco mode but then it uses almost double the fuel climbing up say M62 over Windy Hill. Over 350 miles of hilly journey on a night run I do regularly in both the difference is only a couple of minutes in journey time but the 2018 truck uses over 10% less fuel.

When you are wanting economy you change gear at an entirely different time than when you're wanting perfomance. To get the best economy you need to have a high engine load so you change gear quite early, being in top gear before you get close to 50MPH. If you want performance you need to be changing gear up near the redline. Nobody teaches you this.

Cupumber1

No not as far as I’m aware. I don’t even know what this would look like - this is the newest car I’ve ever had :rotfl: