Engine on or off at traffic lights

mockingjay

I drive a Diesel car and on my way to work I stop at traffic lights at a large intersection for about 5-7 minutes without having to move for this time. If I turn off the engine will I save much Diesel, or is that a myth? Will the restart use up the Diesel I save? As this is five mornings and evenings per week I'd love to know what is the best thing to do.

coylemj

Provided you start it gently (no revving) I'd say you're definitely in the money.

Supergurrier

I would leave it on, best to keep a diesel engine warm tbh

mockingjay

coylemj wrote: »

Provided you start it gently (no revving) I'd say you're definitely in the money.

It's a push button starter, are they gentle?

mockingjay

mockingjay wrote: »

.................... will I save much Diesel............ As this is five mornings and evenings per week .............

How much do you spend on diesel a week and how many miles/kms do you travel a week?

GreeBo

RoverJames wrote: »

How much do you spend on diesel a week and how many miles/kms do you travel a week?

How does that matter?

Jonty

Not trying to be smart, but is this for real?

In the event of having to perform an emergency manouver what do you do?

GreeBo

GreeBo wrote: »

How does that matter?

Well if the OP spends a tenner a week on diesel it's safe to assume they'd save close to sweet f**k all
How much you potentially save would be proportional to the existing spend you see.

Ristiano Conaldo

Stingy Thread

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>>>>>>>>>>>>>

mockingjay

RoverJames wrote: »

mockingjay wrote: »

.................... will I save much Diesel............ As this is five mornings and evenings per week .............

How much do you spend on diesel a week and how many miles/kms do you travel a week?

I travel about 66 km per day - spend abt 80 - 100 per week.

mockingjay

Jonty wrote: »

Not trying to be smart, but is this for real?

In the event of having to perform an emergency manouver what do you do?

simple, I would turn on the engine and move.....

Tallon

Leave the car on

For obvious safety reasons and because if you're not watching, you'll be let know when the lights go green

Yawns

if you know the light change sequences and are stopped for more than 5 mins everyday there then I would turn it off if anything like 5 cars or more in the queue. If you are in the first few cars I'd leave it on. If you knock it off and are in the first few cars, you might be inclined to pull away a bit harsher if you get caught out on the lights.

If the lights change quickly and your 7th in queue it shouldn't matter as by the time the cars ahead start moving you're already switched back on and rolling gently.

mockingjay

mockingjay wrote: »

I travel about 66 km per day - spend abt 80 - 100 per week.

.... that's potentially 20mpg

coylemj

Supergurrier wrote: »

I would leave it on, best to keep a diesel engine warm tbh

You think it's going to lose a serious amount of heat in 5 minutes? If the temperature drops below a certain level, the thermostat will close which will prevent water from the radiator circulating around the engine so it will stay at operating temperature for much longer than the delay at the lights.

The energy equation says that the engine is burning fuel but the car isn't moving so you are wasting energy. The reason for not stopping and starting the engine every time you stop is because there is a blast of fuel used to start the engine and you draw a certain amount of energy from the battery which takes time (and miles) to replace so there is a break-even point above which it does make sense to stop the engine, I'd say 5 minutes is well above the threshold.

mockingjay

Ristiano Conaldo wrote: »

Stingy Thread

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>>>>>>>>>>>>>

Over a quarter of my salary goes on Diesel and toll fees - it's well for the 'rich' on these threads!

Silvera

When I saw the thread title I thought the question would be environment-related...i.e cutting down on emissions.

I noticed when driving in Switzerland that they have small signs on many traffic lights encouraging drivers to turn off their engines to help the environment.

_Kaiser_

mockingjay wrote: »

Over a quarter of my salary goes on Diesel and toll fees - it's well for the 'rich' on these threads!

By the sound of it you need a better car. The same €100 you're spending per week would get me 1000-1100km per week (2L TDI)

I think though turning it on and off will not save you much/if anything and I'd think there'd be more wear and tear on the engine as a result,so any savings would be eaten up that way?

challengemaster

Silvera wrote: »

When I saw the thread title I thought the question would be environment-related...i.e cutting down on emissions.

I don't think anyone in Ireland really cares THAT much about emissions, unless it's in relation to how much motor tax they have to pay

blindside88

mockingjay wrote: »

RoverJames wrote: »

mockingjay wrote: »

.................... will I save much Diesel............ As this is five mornings and evenings per week .............

How much do you spend on diesel a week and how many miles/kms do you travel a week?

I travel about 66 km per day - spend abt 80 - 100 per week.

Nothing to do with your question but what kind of a car is it, sounds thirsty

Yawns

Jesus OP I drive a big petrol hatchback with an underpowered engine that does better mpg than that.

Jonty

do you coast down hills as well?

Jonty

mockingjay wrote: »

simple, I would turn on the engine and move.....

but i mentioned an emergency manouver, not a "ah sure I'll move in my own time" manouver.

I fail to see how you would be as quick with an engine turned off

Yawns

Jonty wrote: »

but i mentioned an emergency manouver, not a "ah sure I'll move in my own time" manouver.

I fail to see how you would be as quick with an engine turned off

If he's stuck in the middle of a queue for 5 - 7 mins every day on what i gather is a minor junction awaiting light sequence change onto a major road, what kind of emergency maneuver will he have to performs that he won't have any sort of warning about.

If an emergency vehicle was coming with sirens and lights on, then he can use his mirrors to look behind and other cars will also need to move out of the way. If he is in a queue of cars there is only so much maneuvering room to begin with. If he sees cars behind moving out of the way he presses his starter button and moves too. If's he's in the front of the queue as my eg he should really leave the engine on as I said.

mockingjay

How much do you spend on diesel a week and how many miles/kms do you travel a week?[/Quote]

I travel about 66 km per day - spend abt 80 - 100 per week.[/Quote]


Nothing to do with your question but what kind of a car is it, sounds thirsty[/Quote]

It's an old Volkswagen Golf VI, definitely can't afford a new car - might get 400 km per week out if it - thought that was normal
think now there's a problem with the car!

Jonty

Yawns wrote: »

If he's stuck in the middle of a queue for 5 - 7 mins every day on what i gather is a minor junction awaiting light sequence change onto a major road, what kind of emergency maneuver will he have to performs that he won't have any sort of warning about.

If an emergency vehicle was coming with sirens and lights on, then he can use his mirrors to look behind and other cars will also need to move out of the way. If he is in a queue of cars there is only so much maneuvering room to begin with. If he sees cars behind moving out of the way he presses his starter button and moves too. If's he's in the front of the queue as my eg he should really leave the engine on as I said.

Point taken, but if the OP turned off the engine at lights during a driving test, what would the outcome be? pass/fail

Hypothetical situation - not trolling!!

Yawns

Do you do a lot of start - stop driving? Is there many junctions on your commute?

Yawns

Jonty wrote: »

Point taken, but if the OP turned off the engine at lights during a driving test, what would the outcome be? pass/fail

Hypothetical situation - not trolling!!

I know what you mean and yes he would fail. However you would also fail the driving test for doing 40 in a 50 zone even tho it's a speed limit and not a target etc

mockingjay

Yawns wrote: »

Do you do a lot of start - stop driving? Is there many junctions on your commute?

No M50 whole way to this junction at Newlands Cross

Yawns

Very thirsty car so tbh.

Jonty

Going O/T on this, you don't fail for doing 40 in a 50, you fail for holding up traffic and not making progress.

fasttalkerchat

Possibly if the junction is a few miles into your journey you could save a few cent but its not worth it IMO. If just one time you have to start and move off quickly you lose all that was saved that week.

You would save much more by turning off air con.

Tallon

Yawns wrote: »

If he's stuck in the middle of a queue for 5 - 7 mins every day on what i gather is a minor junction awaiting light sequence change onto a major road, what kind of emergency maneuver will he have to performs that he won't have any sort of warning about.

If an emergency vehicle was coming with sirens and lights on, then he can use his mirrors to look behind and other cars will also need to move out of the way. If he is in a queue of cars there is only so much maneuvering room to begin with. If he sees cars behind moving out of the way he presses his starter button and moves too. If's he's in the front of the queue as my eg he should really leave the engine on as I said.

Words fail me on this post...

Can you honestly not think of one single instance that could be an emergency?

How about if he's sitting at the front of the queue and there's a truck, on it's side, sliding towards him?

What about if the car in front starts to roll back

What if.. What if...

Yawns

Tallon wrote: »

How about if he's sitting at the front of the queue and there's a truck, on it's side, sliding towards him?

I already said if he was in the first 5 or so cars that he should have his engine on...

if you are going to nit pick at least do it right.

If a car in front rolls back and he's in the middle of the queue where's he gonna go? Reverse into the person behind?

If a truck slides towards him and he's in the middle of a queue where's he gonna go? Oh wait the engine on will magically make everything ok cos he has the ability to move a foot in either direction. That junction he's on about is bumper to bumper in rush hour. He's going nowhere in a queue of cars. If he's in the first 5 cars he leaves engine on as per my eg. Simple really...

mockingjay

fasttalkerchat wrote: »

Possibly if the junction is a few miles into your journey you could save a few cent but its not worth it IMO. If just one time you have to start and move off quickly you lose all that was saved that week.

You would save much more by turning off air con.

Great, well that's settled, the reason I asked is that I've seen some taxi drivers and van drivers doing it and wondered if it was really worthwhile - thanks for all your help:)

Tallon

Yawns wrote: »

I already said if he was in the first 5 or so cars that he should have his engine on...

if you are going to nit pick at least do it right.

What if he's sitting in traffic, 6 cars from the front, and a truck, on it's side, sliding towards him?

maddragon

If you are stopped for more than 60 seconds then the savings on fuel will offset the increased maintenance etc.

https://www.greatersudbury.ca/cms/index.cfm?app=div_earthcare&lang=en&currID=904

Tallon

Tallon wrote: »

Words fail me on this post...

Can you honestly not think of one single instance that could be an emergency?

How about if he's sitting at the front of the queue and there's a truck, on it's side, sliding towards him?

What about if the car in front starts to roll back

What if.. What if...

Presumably he'd have the engine on if he was at the front of the queue, personally I don't understand how anyone can claim to be stationary for 5 to 7 mins every morning at the same junction but once he's at the actual junction I reckon he has the engine on, the OP can confirm.

Car in front rolling back isn't an emergency

They're both really really really sh1t examples

Words did literally fail you it seems.

Tallon

Yeah, I'm not arsed giving examples to someone who cannot understand what an emergency is... plus, I added two what if's.. obviously you don't have much of an imagination :rolleyes:

The lights at Blanch exit of the N3 are 5-6 mins

Yawns

Jonty wrote: »

Going O/T on this, you don't fail for doing 40 in a 50, you fail for holding up traffic and not making progress.

You would still get the mark for failing to make progress even if the road was empty of traffic except yourself. But it is O/T

areyawell

Kaiser2000 wrote: »

By the sound of it you need a better car. The same €100 you're spending per week would get me 1000-1100km per week (2L TDI)

I think though turning it on and off will not save you much/if anything and I'd think there'd be more wear and tear on the engine as a result,so any savings would be eaten up that way?

I bet its a fairly new car though.

mockingjay

Tallon wrote: »

Yawns wrote: »

I already said if he was in the first 5 or so cars that he should have his engine on...

if you are going to nit pick at least do it right.

What if he's sitting in traffic, 6 cars from the front, and a truck, on it's side, sliding towards him?

Thanks for the consideration lads but the junction at Newlands Cross has three lanes either side and a good size median, I pull into the median and wait with loads of cars and prob wouldn't see anything come on my left from behind and as its a crossroad in front it's highly unlikely a truck could veer across three lanes, through the crossroads, barriers etc, it is possible but too hypothetical to think about on every journey - and lads - enough if the 'he' - it's not only men on boards;)

Tallon

Tallon wrote: »

Yeah, I'm not arsed giving examples to someone who cannot understand what an emergency is... plus, I added two what if's.. obviously you don't have much of an imagination :rolleyes:.........

Coming from someone who reckons the car in front starting to roll back is an emergency :pac:

Savage imagination.

I can't wait until it's released on Dash Cam :pac:

Yawns

Tallon wrote: »

Yeah, I'm not arsed giving examples to someone who cannot understand what an emergency is...

Well if your idea of an emergency is a truck sliding towards a pile of cars and you think there's a way that every single car in the queue can avoid it if they all if the engines on and ready to peel away despite no room to do so, then yes you'd be right.

A far better emergency example would have been what if an emergency vehicle needed to get by. What if an ambulance was in traffic behind and suddenly gets a call and needs to go. Then yes in that situation you could be holding them up by a few seconds and you never know a few seconds could be life or death for someone somewhere.

But it still comes down to having room for an emergency maneuver in the middle of a queue of cars at a busy junction.

It's not like I'm telling the OP to turn off the engine at every set of lights or something like that. However if you are stopped at a busy light junction that you know extremely well driving it every day and are in the middle of a queue, then yes it makes sense to switch the engine off. Keep an eye on your surroundings and there's not much that will catch you by surprise but I'd expect you to be doing that with or without your engine on.

Tallon

RoverJames wrote: »

Coming from someone who reckons the car in front starting to roll back is an emergency :pac:

You don't think so? And you have a license? hmm

Tallon

Tallon wrote: »

You don't think so? And you have a license? hmm

Indeed I don't think so and indeed I do have a license.

hmm

Yawns

Tallon wrote: »

What if he's sitting in traffic, 6 cars from the front, and a truck, on it's side, sliding towards him?

I'd seriously doubt if the 3rd car onwards managed to get out of the queue anyway so he's screwed either way :P

The first 2 might make it and the blind panic of the 3rd driving harshly might make him cut out

Yawns

Everyone knows the only solution to the emergency of a car rolling back into you is to go red in the face with anger whilst pounding the car horn

mockingjay

Presumably he'd have the engine on if he was at the front of the queue, personally I don't understand how anyone can claim to be stationary for 5 to 7 mins every morning at the same junction but once he's at the actual junction I reckon he has the engine on, the OP can confirm.

Coming off M50 Southbound, turning right at Newlands Cross junction towards Clondalkin. Southbound traffic stopped, traffic from Tallaght get lights to turn left, Naas traffic still pushing toward town, they stop, naas traffic get right toward Tallaght signal, then Tallaght traffic get right signal towards town, then Clondalkin traffic get signals to move toward M50 and Southbound, finally Southbound traffic moves and I get right signal if I'm near top it's first time - it takes ages!

Tallon

Yawns wrote: »

I'd seriously doubt if the 3rd car onwards managed to get out of the queue anyway so he's screwed either way :P

The first 2 might make it and the blind panic of the 3rd driving harshly might make him cut out

You're assuming the truck is coming from the front...

Yawns

Tallon wrote: »

You're assuming the truck is coming from the front...

you're assuming the 5 cars ahead of him get out of the way in time for him to get out even if he had his engine on. Any one of those drivers might miss it or have an engine cut out due to panicking.

Either way with or without his engine on, in the middle of a queue of cars with no room to maneuver, the OP would be screwed if a truck was sliding towards him. Also if he's in the middle of a huge junction like the one he described and the traffic is that bad that he'll be there for 7 mins how would the truck be coming from behind at such speed so as to tip onto it's side and slide towards him?

The example you gave is just completely bizarre when you could have used something like an ambulance in traffic behind who suddenly gets an emergency call. It's far more likely to happen and the op be more of a hindrance to it with his engine off.