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How to get more MPG out of a Ford Fiesta Ecoboost
Comments
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When you haven't got much fuel left...Can someone tell me at which point I should refuel?
So long as you don't run out, it really doesn't matter one jot.I’m not used to “50 miles to 0” gauge and the other day the light came on at 35, then next time it was 50. I find myself frantically looking for petrol stations as I don’t want it to run out of petrol but perhaps could happily drive for a further x amount of miles without worrying.
Don't get hung up on the weight saving affecting economy. Your car weighs over a ton. 50 miles of fuel weighs a little over 3kg.0 -
Twaddle yourself. I got 2-3mpg less across 2 caddy's, never had stop start in my golf. Did have a Leon for a short while that seemed the same with it on and with it off. Get nearer 4mpg more in my ford with it off. It is a fact that starting an engine uses more fuel than idling for a short while. There is a point where this reaches equilibrium then tips the other way but depends how long you are stopped for. Best thing to do is try it and see, each drivers experience and driving patterns will differ but I know I'm better off with stop start off. Not really sure how people get better MPG the whole time they ain't doing M's.What a load of twaddle, I get an extra 2mpg using stop/start in my Golf.
I don't think the car manufacturers would have spent millions developing it if it made their cars thirstier when they are chasing economy figures.0 -
Stop starts systems are not all equal.
There are various systems that different manufacturers use and they all have different results.
The basic (cheap) system just uses an uprated battery and starter motor with a battery sensor to prevent the engine stopping if the battery isn't up to restart.
Along with this sensor, it'll use the temp and speed sensors that are already present to determine if it's viable to perform a stop and a certain restart.
It isn't the most efficient way as the ever decreasing battery charge of repeated stops needs effort (fuel to work the alternator) to return it to a reasonable state of charge.
As pointed out already, the engine can use more fuel to start this way than it does to idle for a short time and as there's really no way of detecting how long the stop will be, it's hit and miss if it's efficient to stop, so you end up with a certain amount of inefficient stops/restarts and all stops/restarts leave the engine to work the alternator harder to replace the energy.
Other systems, that tend to be more expensive use recovered, stored or wasted energy to restart, these overcome the battery drain recharge effect (cost of constantly working the alternator) and most restart the engine more efficiently than a normal restart.
Mazda's Skyactiv system stops the engine with a cylinder on compression (primed with fuel, ready to fire), once it detects a restart is needed it fires that cylinder to effectively bump the engine back to life.
Some other systems capture energy in capacitors while braking or on the over run with hybrid alternators and then use that to spin up the alternator rather than the starter motor to restart the engine, which uses less energy (that is "free" anyway).
We have a car that run the basic system and one the capacitor system.
Over the same city centre trips, the basic system uses the same fuel if switch on or off.
With it on it tends to work once the engine is warm a few times, then stops stopping to protects the battery while is works the alternator harder to replace it's energy and basically what it saves it then uses. We tend to leave is switched off these days and there is no real benefit, just a lot of wear and tear on parts caused by the repeated restarts. .
The capacitor system works every time once the engine is within normal operating temp, it never fails to stop and restart.
I've repeatedly calculated it is between 3% and 5% more efficient with it on than off.
As a bonus, the capacitor car's normal battery has so far lasted 30% longer than the basic system cars one, that required a new (and expensive) one after three years.0 -
OP re 50 miles to go. On mine, I get a warning bleep when the car thinks it's got 50 miles left before I run out of fuel, and the bit on the gauges that shows the mileage changes to the 'miles to go' display - arrow pointing at a fuel pump. Tends to be reasonably accurate, but can jump about if I go from motorway driving to city driving as the mpg changes. Think of it this way - if you are averaging 50 mpg, and you get a warning that you have 50 miles to go, then you have roughly 1 gallon of petrol left (or 4.5 litres). If you are in a city with decent priced petrol stations around, then I'd be looking to refuel when you get the warning at the latest. Otherwise, refuel when it's convenient, before you get the low fuel warning.0
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Twaddle yourself. I got 2-3mpg less across 2 caddy's, never had stop start in my golf. Did have a Leon for a short while that seemed the same with it on and with it off. Get nearer 4mpg more in my ford with it off. It is a fact that starting an engine uses more fuel than idling for a short while. There is a point where this reaches equilibrium then tips the other way but depends how long you are stopped for. Best thing to do is try it and see, each drivers experience and driving patterns will differ but I know I'm better off with stop start off. Not really sure how people get better MPG the whole time they ain't doing M's.
Search YouTube for a channel called Engineering explained. Really smart guy, and he did an experiment not so long ago on this. Like you say, there is an equilibrium. And he came to the conclusion that if you're stopping for 6 seconds or less, then its more efficient to keep the engine running. Any longer than 6 seconds then it's more efficient to switch off.
Fifth Gear also did a test in a Megane, which is also on YouTube. And guess what? The car travelled a few miles further with stop/start switched on.0 -
Not watching anything on YouTube. I have first hand experience of my current system over 65k miles. But also not saying that will be the case in all cars and it's easy to find out, try it!Search YouTube for a channel called Engineering explained. Really smart guy, and he did an experiment not so long ago on this. Like you say, there is an equilibrium. And he came to the conclusion that if you're stopping for 6 seconds or less, then its more efficient to keep the engine running. Any longer than 6 seconds then it's more efficient to switch off.
Fifth Gear also did a test in a Megane, which is also on YouTube. And guess what? The car travelled a few miles further with stop/start switched on.0 -
Search YouTube for a channel called Engineering explained. Really smart guy, and he did an experiment not so long ago on this. Like you say, there is an equilibrium. And he came to the conclusion that if you're stopping for 6 seconds or less, then its more efficient to keep the engine running. Any longer than 6 seconds then it's more efficient to switch off.
Fifth Gear also did a test in a Megane, which is also on YouTube. And guess what? The car travelled a few miles further with stop/start switched on.
Yeah sounds about right. Years ago in the days of carburettors you used to waste fuel on start up but not with fuel injection. My car stops at top dead centre and fires up in milliseconds probably a lot more efficient than the system on some cars (like Scrapits)0 -
It does fire up pretty quick, dipping the clutch is enough to get it started, engine running before a gear is selected.0
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Not watching anything on YouTube. I have first hand experience of my current system over 65k miles. But also not saying that will be the case in all cars and it's easy to find out, try it!
If you say so. At the end of the day the manufacturers wouldn't fit the system to their cars if it made them less efficient. :rotfl:0
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