[slpdLoad]

A recent how-to article in WIRED was talking about how to coax more mpg out of your car. One of the tips was "drive with the engine off":

"Shift into neutral, turn your key back a notch so the engine shuts down, then forward a click, so you can still have lights."

Now besides just sounding dangerous to me, how does this really save gas? I can only imagine a few hills where I drive where I could actually coast in neutral for more than a few seconds. And wouldn't turning the engine on and off frequently use more gas than just being moderate with how hard you accelerate and brake? Maybe this is more for people with manual transmissions?

Anyone more car-savvy than me care to shed some light on this tip?

[Doofy]

Yeah. Don't do that. Not even in a manual.

Whoever wrote that tip is an idiot who knows nothing about driving.

Think of the fun you'll have if you turn the key back one notch too far and the steering lock clicks on.

[Tomchu]

Also, don't you need the engine running for things like power steering and brakes to work correctly? Someone correct me if I'm wrong.

[rickey939]

You might as well say drive without using your feet...makes as much sense.

[Doofy]

Originally Posted by Tomchu 

Also, don't you need the engine running for things like power steering and brakes to work correctly? Someone correct me if I'm wrong.

You're not wrong.

Some motors will be OK without power steering if their steering design is somewhat old school (for example, my Cherokee is fine with no power steering, if a little heavy). Others, like a modern FWD car may not fare so well.

[Dork.]

Originally Posted by rickey939 

You might as well say drive without using your feet...makes as much sense.

[zro]

Here's a tip: Don't accelerate uphill (turn off your cruise control on hills).

[The Godfather]

Adding to the counter points already mentioned here, I don't believe it would save an ounce of gas, ever.

It would demand more energy to re-gain your cruise speed every time you feel you are going to slow, than the energy it would take to maintain your speed constant. ICE engines are most efficient at a steady RPM.

Also, the oxygen sensor in your car starts kicking in after a while driving. Your engine would be burning rich mix all the time.

If you want to improve your MPG, you should start driving at 60MPH, pretending you have an egg between the gas and your foot.

WIRED is on crack, and should not be driving.

[Railroader]

An engine at idle uses VERY little fuel. coasting, just as much. To turn off the engine reduces your ability to accelerate if conditions warrant it and turn off power to assist steering and braking. This is a VERy dangerous situation. Imagine if a deer ran out in front of your car and you could turn or stop as easily.

Some modern engines turn off cylinders when they aren't needed to save gas and improve efficiency.

[Railroader]

Originally Posted by The Godfather 

If you want to improve your MPG, you should start driving at 60MPH, pretending you have an egg between the gas and your foot.

Best advice in this thread.

But you'll spend a little bit on ear plugs to block out the sounds of the blaring horns of all of the drivers behind you.

[andi*pandi]

Originally Posted by Railroader 

An engine at idle uses VERY little fuel. coasting, just as much.

so then, if you're in a pinch, is there any advantage to just switching to neutral and coasting down big hills (not turning the key to off)? In a manual with hardly any power anything.

I did this once, just wondering if I was actually saving anything. I managed to coast into the next gas station (151 miles later!) on fumes. 15 gal tank, filled to 14.8. Talk about nerve-wracking...

[Railroader]

Originally Posted by andi*pandi 

so then, if you're in a pinch, is there any advantage to just switching to neutral and coasting down big hills (not turning the key to off)? In a manual with hardly any power anything.

Not really. As long as you aren't pressing on the accelerator, you aren't telling the engine to burn more fuel. It would be negligible.

The only real advantage would be less wear on transmission gearing. And even that would be negligible.

[Kerrigan]

Wired is a lame magazine anyways.

[CollinG3G4]

Gawd.. I'm so sick of people bitching about how "expensive" gas is. Every time I hear someone mention it, I have the desire to flog them with my keychain. Sorry, just had to get that out.

[TETENAL]

The break servo doesn't work with the engine off, so I wouldn't suggest "driving" with the engine off. At a traffic light it might be worth turning it off. I remember seeing some with an extra "turn off your engine"-light some years ago.

[Sage]

Um, where is this article? I can’t find it, even when searching for those exact words in your post.

[Eriamjh]

Just slow down a little and accelerate more gently. Top out at about 60mph on the freeway instead of 70 and you'll see a big difference. Hell, drive less if you can. Check your tire pressure and make it as high as you can without going into the overinflation range.

[slpdLoad]

Originally Posted by Sage 

Um, where is this article? I can’t find it, even when searching for those exact words in your post.

I don't know if it's online or not. It's in issue 15.08 (August 2007), at the bottom of page 114.

[G4ME]

when i drove a 72 super beetle for a while, i would shut her off while driving when i knew i was going to coast to a parking space or similar, still do it in an 80 rabbit and my motorcycle. I am sure it doesn't save that much gas but hell if i do it twice a day for a year or two its bound to add up.

As for coasting down hills in a manual, if i don't need the engine to hold me back i usually pop her in neutral and use gravity to gain speed. If you leave it in gear with your foot off the gas, depending on the compression of the engine you will slow down quite considerably.

[phantomdragonz]

I read the article in my issue...

what a retarded thing to suggest...

the egg thing is good advice, and remember people it's not about steady RPM... its about how much you push the gas...

the gas pedal is basically a valve, dont press it much and you wont use as much fuel.

Zach

[IceEnclosure]

just stay to the right if you're gonna drive like a pusssy

[PB2K]

My previous car was fuel injected, It would do 1:10km at normal speeds and 1:12 if I drove a steady 90 km/h. Now I drive a twin carburetted classic and it does 1:9 at whatever speed i drive. it consumes a lot more oil too (about 1:500)

[torsoboy]

I have read about doing this a while back (turning off the engine while driving), but what I read was talking about what to do with hybrid cars to stretch your milage out even further, and specifically said *not* to do it with a gas only engine (for the safety reasons previously mentioned). Maybe WIRED forgot to mention the part about doing this with hybrid cars only. They could possibly get sued into oblivion when someone follows their advice and gets severly injured or killed.

[Chuckit]

Originally Posted by Eriamjh 

Just slow down a little and accelerate more gently. Top out at about 60mph on the freeway instead of 70 and you'll see a big difference

Yeah, there will be a big line of cars behind me honking and driving around me and cutting me off with their middle fingers held proudly in the air.

[The Godfather]

Originally Posted by Chuckit 

Yeah, there will be a big line of cars behind me honking and driving around me and cutting me off with their middle fingers held proudly in the air.

Worth the 10-20% gas money that you'd have burned every month? You be the judge.

[angelmb]

Originally Posted by TETENAL 

The break servo doesn't work with the engine off, so I wouldn't suggest "driving" with the engine off.

Same goes for the power steering thought.

At a traffic light it might be worth turning it off. I remember seeing some with an extra "turn off your engine"-light some years ago.

Exactly, that is what I do… Actually some small cars comes with such system… I hope they can spread such system to every damn Diesel car… quiet on the inside, noisy on the outside

[fhoubi]

I once went downhill slowly but steep (actually in a funeral march) with my engine shut off. After a couple of time braking I found myself with no (power) brakes anymore, luckly enough I found the handbrake on time. It scared the sh!t out of me

The answer is no.