I don't know if you're actually saving much fuel that way. When you're idling, the car's mixture is at it's richest, so you're actually burning more fuel. That's one of the reasons why your gas mileage during city driving is so bad. You're wasting a ton of gas when you're sitting at a stop light.
If I'm at a light that I know I'm going to be waiting for a minute or so, I go ahead and shut off my engine. I save a little gas, and I'm doing my part for the environment.
If I'm at a light that I know I'm going to be waiting for a minute or so, I go ahead and shut off my engine. I save a little gas, and I'm doing my part for the environment.
I'm not sure at what speed the amount of fuel burned becomes less than at idle. It could be that coasting instead of going 70 will save fuel. Hopefully someone that knows more about this will chime in.
I always read in all the car magazines that all modern cars can recognize coasting and nearly completely shut down fuel flow, making it more efficient to stay in gear. They recommend doing this, and they don't mention why it might damage the engine or transmission.
As far as damage, I'm not sure, but for gas mileage, here is an easy way to tell. Day 1, coast at the speed limit for say 10 min or so. Reset your average gas mileage counter. Day 2, leave it in gear starting at the same spot for the same distance. Again, reset the mileage before you start. Let us know the results!
As far as damage, I'm not sure, but for gas mileage, here is an easy way to tell. Day 1, coast at the speed limit for say 10 min or so. Reset your average gas mileage counter. Day 2, leave it in gear starting at the same spot for the same distance. Again, reset the mileage before you start. Let us know the results!
Not to mention (if you're 5speed) that depending on the situation you may be placing yourself at risk if you release the clutch too suddenly or do so over dust/dirt the rear might lock and send you spinning.
I don't usually do that because I like to use engine braking to check the speed on those descents. Also I have read that with fuel injected engines, they shut off the fuel anyway where as in Neutral they have to keep the engine turning over. You make the trip every day, so try the test some one mentioned. Let us know cause I am guessing here as well.
i'd monitor your fuel mileage going both ways. I live in florida but coast often to stop lights and it actually helps with fuel mileage technically. If your coast a mile it's still registering the mileage on your vehicle in turn showing better MPG. I was in tenn. over x-mas and coasted 14.5 miles down a mountain in my f150 but them brakes were HOT and receiving major brake fade towards the end, so something else to keep in mind...then again the f150 gets more momentum than the mustang due to weight.
I just wanted to resurrect this thread and share my 2c. I have been making a conscious effort to try and drive under 2k rpm as I heard that was a sweet spot for good fuel economy.
I'm driving an 03 so I don't' have a gas mileage indicator. But lately I have been resetting the trip odometer each time I fill up and then logging my mileage/refill qty in a spread sheet to figure out my mpg. During the last 4 fill ups I have averaged 20.08 mpg with my best at 20.958 mpg (I still had half a gallon before filling up). I'll be filling up again in the morning and I expect to be close too 21 again.
My commute distance is only 12 miles (but sometimes a little extra city driving after work to get some fast food)
Basically the last few weeks my driving practices have been as follows. Stay under 2k rpm (even when getting on the freeway). Sometimes I can't help it cause one on ramp is a steep incline but usually I'm barely over for just a short time.
Coast down hill
Coast exiting freeway (typically until stop sign/light)
Coast to stop signs/lights.
I encounter several hills during my commute and of course on the return trip too. When school is out I can typically get to work in about 12 minutes so that's a 60 mph average. When school is in it takes about 25 minutes so that's about 28.8 mph if my math is right.
So with my main goal being low rpms I just figured low rpm = low fuel consumption. Prior to reading this topic I never considered fuel injection would shut off during coasting. All I knew was the RPM's would would stay around 1500 vs about 900 when coasting.
Now, I did know that keeping it in drive provides a slight breaking affect but breaking doesn't help fuel efficiency because you lose a lot of momentum and therefore cannot coast as long. My max coasting speed is about 75 and I don't break that much.
I am curious to know if there is any article that documents a transmission wearing out much faster because of this. I've never heard it from anyone with any mechanical experience and usually they heard it from someone else.
I'm driving an 03 so I don't' have a gas mileage indicator. But lately I have been resetting the trip odometer each time I fill up and then logging my mileage/refill qty in a spread sheet to figure out my mpg. During the last 4 fill ups I have averaged 20.08 mpg with my best at 20.958 mpg (I still had half a gallon before filling up). I'll be filling up again in the morning and I expect to be close too 21 again.
My commute distance is only 12 miles (but sometimes a little extra city driving after work to get some fast food)
Basically the last few weeks my driving practices have been as follows. Stay under 2k rpm (even when getting on the freeway). Sometimes I can't help it cause one on ramp is a steep incline but usually I'm barely over for just a short time.
Coast down hill
Coast exiting freeway (typically until stop sign/light)
Coast to stop signs/lights.
I encounter several hills during my commute and of course on the return trip too. When school is out I can typically get to work in about 12 minutes so that's a 60 mph average. When school is in it takes about 25 minutes so that's about 28.8 mph if my math is right.
So with my main goal being low rpms I just figured low rpm = low fuel consumption. Prior to reading this topic I never considered fuel injection would shut off during coasting. All I knew was the RPM's would would stay around 1500 vs about 900 when coasting.
Now, I did know that keeping it in drive provides a slight breaking affect but breaking doesn't help fuel efficiency because you lose a lot of momentum and therefore cannot coast as long. My max coasting speed is about 75 and I don't break that much.
I am curious to know if there is any article that documents a transmission wearing out much faster because of this. I've never heard it from anyone with any mechanical experience and usually they heard it from someone else.
I've heard this too, that on decel your fuel injectors are basically closed unlike at idle.
Hey everyone. Just wanted to report back here with my fuel log.
One important thing to realize is the MPG is based on the fuel from the last fill up because you can't know your rate of consumption until you, you know... consume it. hehe.
I have logged all pertinent info, date of fuel up, mileage since last fill up, volume fille, name of station, fill cost, cost per gallon etc.
What I find interesting is I have achieved the best MPG when filling up at chevron. And keep in mind I always fill with regular no matter where I go.
And as you can see, chevron always costs about 10 cents more per gallon. So in a full tank of 14 gallons, I am paying $1.40 more for chevron than other places...BUT I get half a mile more per gallon efficiency which is like getting like 1/3 of a gallon saved for if that makes sense. Or tell me if my logic is flawed.
One thing I hope to see more clearly is how much traffic really plays a role in fuel economy for me. As I mentioned I have a pretty short commute but I do no i'm on the road longer when school is in. So hopefully this summer I'll have a good few months to fill up at a variety of stations and get more consistent results.
Just in case the attachment messed up when I replied here's another link.
One important thing to realize is the MPG is based on the fuel from the last fill up because you can't know your rate of consumption until you, you know... consume it. hehe.
I have logged all pertinent info, date of fuel up, mileage since last fill up, volume fille, name of station, fill cost, cost per gallon etc.
What I find interesting is I have achieved the best MPG when filling up at chevron. And keep in mind I always fill with regular no matter where I go.
And as you can see, chevron always costs about 10 cents more per gallon. So in a full tank of 14 gallons, I am paying $1.40 more for chevron than other places...BUT I get half a mile more per gallon efficiency which is like getting like 1/3 of a gallon saved for if that makes sense. Or tell me if my logic is flawed.
One thing I hope to see more clearly is how much traffic really plays a role in fuel economy for me. As I mentioned I have a pretty short commute but I do no i'm on the road longer when school is in. So hopefully this summer I'll have a good few months to fill up at a variety of stations and get more consistent results.
Just in case the attachment messed up when I replied here's another link.
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