With an average 100cc motorcycle, how long does a red light have to be before I can save gas by turning off my engine?
Michael
As a practical matter, it doesn’t really matter, does it? It’ll still be a bad idea.
Make a habit of it and you’ll burn out your starter.
More importantly, you’ll be immobilizing yourself. Given local driving norms, it’s always a good idea to be ready to get out of the way.
I reckon about 15 minutes. Lets face it 100CC bikes don’t burn much gas. What is it, about 3 quid for a weeks worth and you think yo are going to save big time by turning off for 30 seconds? Hmm I assume you are just trying to be more local?
Hey Vork, LTNS.
For your bike, yeah, anything under 15 minutes or so ain’t worth it.
Cars, however, esp. apparently those with fuel injection, seem to be another matter entirely…
http://www.cleverdude.com/content/save-money-save-gas-save-your-cars-engine-when-idling/
http://www.edmunds.com/advice/fueleconomy/articles/106842/article.html#test6
[quote=“Jaboney”]As a practical matter, it doesn’t really matter, does it? It’ll still be a bad idea.
Make a habit of it and you’ll burn out your starter.
More importantly, you’ll be immobilizing yourself. Given local driving norms, it’s always a good idea to be ready to get out of the way.[/quote]
Well my Kymco Movie hadn’t burned out its starter in the five years I practiced always turning off at any red light. A carburettor model will save fuel turning off at any light over any time, injection needs to be only off for seconds befre fuel saving begins.
I recommend always turning off as it saves the person behind you killing what’s left of their brain or at least from feeling sick.
I remember years ago at a fireworks display evening yelling at people to turn of their engines as nobody could properly breath and everyone was trapped in a narrow alley holding their noses and at the same time all the jammed up scooters were still running and hadn’t moved for 30 minutes. Absolutely nobody would open their mouth to complain. Strange folks around here!
As Jaboney says, it’s not a good idea, for safety reasons. I’ve heard of a number of cases of cars or vans not stopping at a red light and just plowing into the vehicle in front. I think one of those gore videos that was posted was that kind of situation.
my 1600cc car burn 1.2lt gasoline per hour when idle, AC on. AC off +/-0.8lt…so 100cc bike with a minute idle per traffic light, not much saving…
This is not really true. Idling an engine never saves fuel, when turning it off always saves fuel. Excessive idling can cause up to 75% of the deterioration of the oil within the engine and can decrease the service life of the engine. Idling at low revs decreases cyclinder pressure and increases carbon production as well as partially burned fuel deposits in the engine leading further to decreased economy and performance.
You know all that talk about banning the standby modes being installed into modern appliances because they account for up to 85% of power loss? This can be the same for motor vehicles too. This is one reason why motor vehicle manufacturers are now fitting idle stop systems to cars and such.
Regarding the safety element of keeping an engine running at intersections, this is a valid point, but as long as one stops in an appropriate place and starts up their engine before the light turns to green, then there should be little to no further risk envolved. Much of the time it is impossible to change direction whilst stopped anyway as traffic often blocks the route ahead anyway unless one is at the front of the traffic line.
Edit. Weird double post
To avoid being hit from behind by a speeding gravel truck, you have to look in your rear mirror a lot, and even then, when there is actually someone approaching from behind, you are probably paying attention to what is going on in front of you or your eyes are glued to the butt cleavage of a xiaojie. If you are the only or first scooter stopping at a red light, make sure you stop close to the pavement and NEVER stop abruptly when you see a yellow light, there is always someone behind who is trying to cross the junction who won’t have time to react.
To avoid being hit from behind by a speeding gravel truck, you have to look in your rear mirror a lot, and even then, when there is actually someone approaching from behind, you are probably paying attention to what is going on in front of you or your eyes are glued to the butt cleavage of a xiaojie. If you are the only or first scooter stopping at a red light, make sure you stop close to the pavement and NEVER stop abruptly when you see a yellow light, there is always someone behind who is trying to cross the junction who won’t have time to react.[/quote]Well, that’s what you practice all-round awareness for. Waiting at a stoplight is just as much “driving” as is buzzing along at 80kmh. Both situations require attention to what’s going on all around.
The OP’s in Taichung (Taichung County I believe) where there isn’t quite so much traffic and one very often ends up at the front of the traffic line.
This is not really true. Idling an engine never saves fuel, when turning it off always saves fuel. Excessive idling can cause up to 75% of the deterioration of the oil within the engine and can decrease the service life of the engine. Idling at low revs decreases cyclinder pressure and increases carbon production as well as partially burned fuel deposits in the engine leading further to decreased economy and performance.
You know all that talk about banning the standby modes being installed into modern appliances because they account for up to 85% of power loss? This can be the same for motor vehicles too. This is one reason why motor vehicle manufacturers are now fitting idle stop systems to cars and such.
Regarding the safety element of keeping an engine running at intersections, this is a valid point, but as long as one stops in an appropriate place and starts up their engine before the light turns to green, then there should be little to no further risk envolved. Much of the time it is impossible to change direction whilst stopped anyway as traffic often blocks the route ahead anyway unless one is at the front of the traffic line.[/quote]
Think you missed the point. Idling is what would have burned through if not turned off. I.E. divide the 1600CC car rate by 16 to get 100CC rate and that is the cost of running the bike engine at idle for an hour. I reckon you save 0.7ml per minute that you are turned off if I did my math right in my head.
I’ve been thinking about it as well. At the big intersections in Taipei there are tons of scooters that no one would run into from behind and there are signs showing how long it will stay red so you can switch it back on just in time. I hear all the arguments here but does anyone have some sources?
I have Ketchup, Daddies, Sweet Chilli and FOAM!
OP’s question:
[quote=“Vorkosigan”]With an average 100cc motorcycle, how long does a red light have to be before I can save gas by turning off my engine?
Michael[/quote]
Immediately turning the bike off saves fuel. Short answer.
The long answer is very long and not precise as to how much fuel can be saved, but that wasn’t the question. How fast does the engine idle? What is the cylinder capacity? What grade of sump oil? How long spent at all red lights accumulated? What is the outside temperature and humidity? What is the condition of the engine? I could go on, but the sure fact is that if all motorcycles could turn off at all red lights all year round, then Taiwan would save a shit load of fuel and reduce emissions by far. Even each person can save a LOT of fuel each year by turning their engine off, and repair bills to the starter circuit on most bikes would not exceed the savings in fuel.
Furthermore, comparing motorcycle engine fuel usage to car engine usage is not accurate. Cars can be much more fuel efficient per weight than motorcycles. The word “can” is used loosely.
OP’s question:
[quote=“Vorkosigan”]With an average 100cc motorcycle, how long does a red light have to be before I can save gas by turning off my engine?
Michael[/quote]
Immediately turning the bike off saves fuel. Short answer.
The long answer is very long and not precise as to how much fuel can be saved, but that wasn’t the question. How fast does the engine idle? What is the cylinder capacity? What grade of sump oil? How long spent at all red lights accumulated? What is the outside temperature and humidity? What is the condition of the engine? I could go on, but the sure fact is that if all motorcycles could turn off at all red lights all year round, then Taiwan would save a shit load of fuel and reduce emissions by far. Even each person can save a LOT of fuel each year by turning their engine off, and repair bills to the starter circuit on most bikes would not exceed the savings in fuel.
Furthermore, comparing motorcycle engine fuel usage to car engine usage is not accurate. Cars can be much more fuel efficient per weight than motorcycles. The word “can” is used loosely.[/quote]
Good post.
Thank you.
A question for the foremost forumosan combustion engine pro:
Assume you’re driving a well-maintained, one year old 1600cc car. When would you turn off your engine at a red light? What if the wait is 30 seconds? 60 seconds? When is it actually worth the effort and the wear and tear on the car?
I usually only turn it off when I’m in a queue that isn’t moving(or barely moving) or stuck behind a landslide/accident/other road obstacle.
I’ve been finding myself going through 8000NT in fuel a month so I’m certainly open to suggestions here.
Well assuming your vehicle has no problems starting, and you stopped knowing you weren’t required to move again for at least 30 seconds, I would recommend turning off. Having said that, I wouldn’t follow my own advice in Taiwan as I personally can’t bare the heat with no air conditioning. Still overall you will only save more fuel by adjusting all driving habits and not just turning off at the lights.
turn off at the lights.
turn the air-con down
At low speeds open windows.
Above 40kph, close the windows and use fan
remove any rear wing or spoilers, roof racks, bike carriers etc.
Ensure plugs are firing well and injectors are clean. Perhaps have an older vehicle compression tested.
Inflate tyres to appropriate pressures.
drive in a higher gear. About 2,000rpm is quite efficient.
allow more space between you and vehicles in front.
Don’t accelerate too slowly, and not to quickly either. pace the car as much as possible.
Look well ahead and rest off the accelerator as soon as you see lights changing to red ahead.
Drop excessive baggage out of the car, including spare tyre and jack if you dare and take tyre weld instead.
Always run to a minimum weight.
If you do all of those you will save more than simply turning off at the lights.
reducing your outgoings though will be limited by the fact that you cannot eliminate the need for fuel. You can eliminate needless expenses better than fuel however and small things like a hot coffee purchased outside, or a beer every other day, cigarettes, a nice restaurant dish once or twice a month, having the car waxed and instead do it yourself. You get the picture. You know your own lifestyle best and so if it comes down to money savings, there are bigger savings to be made on lifestyle choices than exactly when you should turn off your ignition. Sorry I can’t be more specific about when to turn an engine off. It isn’t an exact science and there are many factors involved as I stated earlier.
My best advice: Have a locally built Japanese car. It will be more fuel efficient than most generally, be more reliable, cheaper to repair, and more convenient. Toyotas have better residual value then Hondas, then Mazda, Nissan and Mitsubishi. Some Ford models are Japanese in essence too, although I’d stay away from European models.
Can you make do with an even smaller car? Toyota Yaris, Suzuki Swift, Mazda 2, Mitsubishi Colt are all good cars and fuel economy is great. Would a smaller car perhaps pay off in the long run for you?
8,000 per month is a lot in fuel. Do you mind me asking what car you have?
You will spend a lot of money on parking so plan trips in advance and figure out whether its cheaper to park or take a taxi. Buy used cars instead of new, although don’t scrimp on good insurance coverage to cover vehicles and passengers.
Also: Redwagon is also very good on combustion engines
Well, I drive a Mazda 3. In all fairness, I’m sure the consumption per km isn’t that bad as far as cars go.
I’m guilty of indulging in ac and speedy driving when driving conditions are safe for it. My daily driving is from Shijir to Songshan and back. I also head down to Hualien at least once a month to my girlfriend’s family’s vacation house. It beats the hell out of my own place so it’s quite tempting to get away.
I used to use a scooter for local trips but I’ve decided I enjoy driving the car more and you can’t really put a price on the safety and comfort of four wheels, so the scooter has been sold.
I considered a Yaris or a Swift when I was shopping around, but there just isn’t enough head room. I’m 192cm. I needed stitches once from bouncing my head off of the roof of a Vios while trying to get in. 