# Saving gas by shutting car off???



## clovis (May 13, 2002)

I have been a hyper-miler before hyper-miling even had a name. 

I have been doing this even when gas was $1.25 a gallon.

One way I have been conserving gas is to shut the car off at stop lights, train crossings, etc.

How long do I have to shut the car off to save more gas than what it takes to start it back up?

Years ago, sometime in the late 80's, when I was in college, the saying was anytime your average car was going to idle for more than 30 seconds, it was better to shut it off and restart later.

What time length applies to cars today?

I have:
95 Chevy S-10 with the bigger 4.something
98 Chevy Monte Carlo, 3.1
06 Chevy HHR 

Thank you so much!!!
Clove


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## FL.Boy (Dec 17, 2007)

Your really not saving much and your putting a lot of wear and tear on your engine. Starting your engine is one of the toughest things you do to your engine plus it takes a lot of fuel to start a car.


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## OntarioMan (Feb 11, 2007)

I really doubt that shutting the engine off at a 1 minute stop light is saving any fuel, and it may actually be costing you fuel. The battery of the vehicle is charged by the alternator, which is run by the engine. If your battery charge is depleted due to frequent starts, your engine will work harder to recharge the battery, which takes more fuel.

A long train : shutting off the engine probably makes sense here.

Some other considerations to save fuel :

- don't carry 300 lbs worth of tools in your trunk if you don't need the tools
- grill blocks : some cars may benefit from blocking off part of the open grill, which makes the car more aero dynamic
- when you have the vehicle jacked up, check to be sure that the brakes are not binding - I've seen "sticky" calipers which don't fully release, seen emergency brakes which don't fully release, etc.


What you don't want to do is save fuel at the expense of safety or at the expense of extreme wear'n'tear on your vehicle.


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## Gary in ohio (May 11, 2002)

YOU might save a couple of dollars in fuel, but you will eat it up in replacing the starter and battery.


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## Ross (May 9, 2002)

There's a swing bridge in a small city near me that if you're caught it's just as well to shut it off. Takes a good ten minutes for the boat to get through. I'm not sure what you'd save shutting down the engine for such short stops! I'd ask somebody (like Clovis) for their opinion. I wonder if there isn't some info online though. I's think about Gary's point too wear and tear has a cost but surely a hot engine starts faster and easier.


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## PhilJohnson (Dec 24, 2006)

I used to drive a 1995 Suzuki Swift 2dr hatchback, it is basically the same as a Geo Metro. It had a four cylinder and a 5 speed. Normally I got around 48 mpg, shutting it off at intersections and down hills I gained 7 mpg. Another time I had to follow my tractor while my friend was driving it to the shop. I was driving my old 89 Chevy truck with a 5 speed and V-8. I kept shutting it off, pretty much it was running only half the time. I went a total of 18 miles and used about half a gallon of gas. I figured that was pretty good considering I was averaging a whole 15 mph. I only do this with manual cars. While coasting down hills I just let out the clutch when I need to start the vehicle again.


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## Jim-mi (May 15, 2002)

I 'shut off' my old VW Beatles now and again . . of course they were stick trans.

But today if you 'shut off' aren't you going to lock the steering . . .???

Could be a tad bit messy...........................


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## Superman (Jul 16, 2008)

I read a writeup about this in Popular Mechanics about 2 years ago and you're probably fine. 
The consensus was that if your car will be idle for more than 45 seconds then you're better off shutting it off. However, by shutting your car off and turning it back on over and over you're causing more wear and tear on the engine, thereby limiting it's overall life. 
EDIT: This was on cars from 1990 to present, which was 2006 or so. 
Older cars use more fuel so I'd personally increase that to 1 minute or more.

Off topic - hello everyone! Newbie here. I can't BELIEVE all the info I've read in my first week! :dance::dance:


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## Blu3duk (Jun 2, 2002)

hi howdy superman, welcome to the forum

Here in Idaho the ISP have warned folks they will be giving tickets to folks hypermiling if they catch them.... 

On the river here, we dont have the hills that a person could use in the ways that other places might be able to utilize anyway, but I spose there are a few folks who would try shutting off and coasting anyway...... it is one of those things where i think folks maybe jumping over dollars to pick up a dime.

William


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## Gary in ohio (May 11, 2002)

PhilJohnson said:


> I used to drive a 1995 Suzuki Swift 2dr hatchback, it is basically the same as a Geo Metro. It had a four cylinder and a 5 speed. Normally I got around 48 mpg, shutting it off at intersections and down hills I gained 7 mpg.


Shutting off at intersections is one thing shutting off when your in motion is irresponsible and dangerous. Depending on the car that means you lost power steering and in many cases power breaks, abs. Its not safe to shut a vehicle off and coast, I dont care how "green" you think it is. I am still waiting for the lawsuit on a irresponsible hyper-miler that plows into a crowd of people because he can react quick enough because all the power devises are off.


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## OntarioMan (Feb 11, 2007)

There are different methods of "Pulse and glide" - you can leave the engine running and just basically coast during the glide cycle. Here is a decent description Pulse and Glide.

I bet many of us already take advantage of "glide" - like when we coast to a stop sign, or a stop light...


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## solidwoods (Dec 23, 2005)

Also
Keeping the air pressure correct in the tires will save more $ than anything you can bolt on to an engine.
jim


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## PhilJohnson (Dec 24, 2006)

Gary in ohio said:


> Shutting off at intersections is one thing shutting off when your in motion is irresponsible and dangerous. Depending on the car that means you lost power steering and in many cases power breaks, abs. Its not safe to shut a vehicle off and coast, I dont care how "green" you think it is. I am still waiting for the lawsuit on a irresponsible hyper-miler that plows into a crowd of people because he can react quick enough because all the power devises are off.


I don't see how it could be dangerous on a little Swift, since it has no power steering or brakes from the factory. I always kept the key on the on position so all the lights would work as they should. As far as ABS goes, I have found it is more trouble than it is worth especially on older GM vehicles. In my opinion ABS is put on there for the majority of people whose first reaction to any situation is to jam on the brakes instead of using anything resembling driver skill to avoid trouble. 

Also I don't normally shut the engine off on my full-sized truck because I like having power brakes, but as I previously stated I was going a whole 15 miles an hour while coasting so I think the risk is pretty much non-existent. 

The majority of my cars/trucks I have owned never had power steering or power brakes, and since all of the vehicles that I have logged hyper-miles on have no power assist it is no more dangerous for myself shutting off the engine versus someone taking advantage of the glide effect of putting a car in neutral.


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## OntarioMan (Feb 11, 2007)

My opinion : anytime you give folks more things to do or think about while they're driving, you increase the risk of bad things happening. Whether it be cell phones, engine-off coasting, eating a burger, etc. I remember when I first got a cell phone, and would talk while driving - that lasted all of about 2 minutes before I realized it was not a good idea. Even standard transmissions for new drivers are not the best choice.

Anytime you get in a vehicle, there is great risk - and the probability of you being hurt in a vehicle collision is probably higher than being hurt in any other way.



PhilJohnson said:


> I don't see how it could be dangerous on a little Swift, since it has no power steering or brakes from the factory. I always kept the key on the on position so all the lights would work as they should. As far as ABS goes, I have found it is more trouble than it is worth especially on older GM vehicles. In my opinion ABS is put on there for the majority of people whose first reaction to any situation is to jam on the brakes instead of using anything resembling driver skill to avoid trouble.
> 
> Also I don't normally shut the engine off on my full-sized truck because I like having power brakes, but as I previously stated I was going a whole 15 miles an hour while coasting so I think the risk is pretty much non-existent.
> 
> The majority of my cars/trucks I have owned never had power steering or power brakes, and since all of the vehicles that I have logged hyper-miles on have no power assist it is no more dangerous for myself shutting off the engine versus someone taking advantage of the glide effect of putting a car in neutral.


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## clovis (May 13, 2002)

Thanks everyone for your 2 cents!!!!!

Just to be clear, I am not a 'shut the engine off and coast in neutral hyper-miler'. 

It is just not for me. For 99.99% of my driving, I am in high traffic areas, or in stop and go traffic, or town, which I try to avoid. I don't find shutting a vehicle off and coasting (SOAC)a safe thing to do, especially when you consider the roads I travel. And even if I wanted to SOAC, there is really no place to do such a thing on the roads I drive.

Clove


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## adamtheha (Mar 14, 2007)

I hate to sound like I'm a dangerous driver or anything, but I completely disagree with some of people's thoughts on coasting with the engine off. On my car, you can get three full brake stops with no engine on (key in start position), all my lights are on, and I'm going straight. If I have to swerve, the car moves fine enough, and I can always put the car in gear to instantly get back all functionality. I would rather have someone doing that in front or behind me, than talking on a cellphone, or eating a burger, both of which are legal here in AB!
That being said, my hypermiling days are over soon, as my commute will become a 124 km straight road with no hills or anything. 
I do save a LOT of money on gas though, I get about 200km more per tank of gas than I ever used to, which probably saves me $10-15 per tank. Add that up over a year, and you get about $1000, which will buy a lot of starters and batteries!


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## coup (Feb 28, 2007)

while you are saving,,, it looks like you would be better off trading for more gas saving car.


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