DIY Start-Stop
Discussion
So I was travelling in a car with someone yesterday who turns their engine off at traffic lights. I didn't think this was a great idea for safety reasons. However, it got me wondering.
Does turning your engine off at traffic lights actually save you any fuel? I was under the impression that when a car started up, it fed a lot of fuel into the engine and therefore negated any benefit from turning the engine off. I know that Start-Stop systems leave most of the car's systems running.
Can anyone provide me with any evidence to back up my theory that turning your engine off for small periods of time doesn't save you any fuel?
Does turning your engine off at traffic lights actually save you any fuel? I was under the impression that when a car started up, it fed a lot of fuel into the engine and therefore negated any benefit from turning the engine off. I know that Start-Stop systems leave most of the car's systems running.
Can anyone provide me with any evidence to back up my theory that turning your engine off for small periods of time doesn't save you any fuel?
I'm sure I read or heard somewhere recently that the engine would need to be off for something like 3 minutes to save any fuel, due to the increased use of fuel at, prior to and immediatly after ignition.
This was in relation to maually turning the engine off. I would imagine a manufacturer would be able to adjust the ECU etc to allow them to make a saving.
Or else their figures are fudged to make it look like there is a saving.
This was in relation to maually turning the engine off. I would imagine a manufacturer would be able to adjust the ECU etc to allow them to make a saving.
Or else their figures are fudged to make it look like there is a saving.
This idea that you need 3 minutes of fuel to start a car is barking.
Where does all the additional fuel go then? I remember my driving instructor trying to kid me, 15 years ago and the idea is still daft.
Start stop cars have slightly different starter motors that are beefed up. Batteries stay the same.
So if you are really looking for a good reason then the starter motor may be a week point, but i guess 90% of them would be perfectly up to it.
There are two good reasons not to do it though, it would be tedious and i'd get in the way of the car behind.
On a completely seperate note you probably do more expensive damage by keeping your car in gear with your foot on the clutch waiting for green.
Where does all the additional fuel go then? I remember my driving instructor trying to kid me, 15 years ago and the idea is still daft.
Start stop cars have slightly different starter motors that are beefed up. Batteries stay the same.
So if you are really looking for a good reason then the starter motor may be a week point, but i guess 90% of them would be perfectly up to it.
There are two good reasons not to do it though, it would be tedious and i'd get in the way of the car behind.
On a completely seperate note you probably do more expensive damage by keeping your car in gear with your foot on the clutch waiting for green.
last summer i was bored and tested the theory over three days worth of commuting. - mpg increased by 4mpg, compared to the mpg i usually got on the same commute. (i do a lot of city driving) . I was also very aware of my driving during the experiement, so some mpg increase could have been due to driving smoother, reading road ahead far more than normal, and concentrating very hard.
apparently the start up thing is a bit of a myth. If your stopped for more than 10 secs, switching off the engine does save fuel. but, as mentioned, you.d ruin your started motor / battery pretty quickly
apparently the start up thing is a bit of a myth. If your stopped for more than 10 secs, switching off the engine does save fuel. but, as mentioned, you.d ruin your started motor / battery pretty quickly
I think start stop is pretty good technology really. It doesn't stop you having a powerful, petrol engined car yet it lowers fuel economy around town. It should be fairly PH friendly in principle.
Turning off normal starter motor cars all the time is probably a bad idea though. Start stop tech uses completely different ECU setup and reversible alternators etc.
Turning off normal starter motor cars all the time is probably a bad idea though. Start stop tech uses completely different ECU setup and reversible alternators etc.
snoopstah said:
Out of interest, do *all* cars with this functionality have the option to disable it? (I know some do).
If not, in 10-15 years the roads are going to be cluttered with cars that stopped the engine but can't restart it...
We've got an Audi A5 with the start stop. It can be turned off, but once you're used to it, it's fine. My wife mostly uses the A5, and she is used to it. It still surprises me when it cuts out at traffic lights.If not, in 10-15 years the roads are going to be cluttered with cars that stopped the engine but can't restart it...
I'm pretty sure you'd save a lot more fuel by judging the traffic lights so you lose as little momentum as possible.
I turn mine off when I know I won't be going anywhere for quite a long time, e.g. level crossings and queuing for fuel, but it seems an unecessary strain on the car and I would rather have full control should anything unexpected happen.
I turn mine off when I know I won't be going anywhere for quite a long time, e.g. level crossings and queuing for fuel, but it seems an unecessary strain on the car and I would rather have full control should anything unexpected happen.
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