10% Mileage increase... free...

[Ken35i]

Ken,
At least where I live in the U.S.A., Illinois, there is no law that prohibits coasting. At least according to my 1998 copy of the Illinois Vehicle Code. I'm curious to know your referrence.
Here in the U.S.A. an individual is afforded the freedom to do stupid things, this is a mixed blessing.
Ross

I read in the bimmerforums.com that learner drivers were taught not to coast because it was illegal, may have been in Cali. Coisidently it was in a hypermiling thread. But most drive automatics anyway.
To be stupid or to be an ******* shouldn't be illegal because we're all stupid and were all *******s.

Hypermiling is dangerous, as we all know, when you turn your engine off you loose brakes and steering. If somthing/someone were suddenly jump/run/turn infront of you, all that money you saved will go flying out the window when/if you hit them.

All in all your saving $dick-all when you're trying to increase economy like driving really close behind a truck. Do all the maths you want.
Internal combustion engines aren't very efficient anyway.

[pingu]

Not that I've tried this method but I'm a big cynic - and also, even with petrol at £1.10 a litre, I only do about 10 miles a week so doing 95 mph is no drag (pun intended - sorry!) to me.

"Technically true" seems to me the only way of being true or not true when discussing something technical. We're not discussing an English essay - there's only one truth. (I presume you were joking about the fuel tank overflowing!) I can't see how you can avoid the extra drag (due to speed squared) that results from going alternately fast and slow, when compared to going at a steady speed. Also, I can't help but think that if this fast/slow method really worked then all manufacturers would build it into cruise control so as to massage/improve their mpg rating when being assessed.

You got me thinking when you pointed out how much quicker a car slows down when it's in gear compared to when it's in neutral. I think this shows just how much internal friction an engine has. If you slow down in neutral, the rate of loss of speed is less than it would be in gear. But when you slow down in neutral, you don't see the fuel that you're burning (at a low efficiency) in order to keep the engine idling. If you slow down by coasting in gear, the rate of loss of speed is higher (i.e. you slow down faster than you would do in neutral) but you don't use any fuel while slowing down as the DME turns the injectors off. So I don't think it's true to say that you use an idles-worth of fuel either way.

You're probably right about it being the same time, rather than distance, at each speed (in my example with the 50 mph and 70 mph).

Anyway, an interesting thread! Cheers!

[e34.535i.sport]

darn It! All Of You! Just Go Out...buff You Car, Clay It And Give It A Good Wax, And You Will Save On Gas! Lower Air Friction On Car Body Is Higher Fuel Mileage And Feeling Of More Power!

LoL!

[Tiger]

Hehehehe... you already done this! Didn't you get your extra 10% fuel mileage improvement?

[Bill R.]

kids nowdays... My 51 chevy truck had no power steering or power brakes, we hypermiled without knowing about it back then....Coming back from the mountains we would frequently shut the engine off and coast as far as possible which was at least half way back on a 50 mile one way trip. No a/c no power brakes, no power steering , no turn signals except your arm. My 63 VW was the same way with the exception of turn signals. But things that were common then aren't so simple now.

[Blitzkrieg Bob]

kids nowdays... My 51 chevy truck had no power steering or power brakes, we hypermiled without knowing about it back then....Coming back from the mountains we would frequently shut the engine off and coast as far as possible which was at least half way back on a 50 mile one way trip. No a/c no power brakes, no power steering , no turn signals except your arm. My 63 VW was the same way with the exception of turn signals. But things that were common then aren't so simple now.

The locking steering column kinda killed that when I was a kid.

Turn the key off and oooh sh!t can't steer

[Ken35i]

kids nowdays... My 51 chevy truck had no power steering or power brakes, we hypermiled without knowing about it back then....Coming back from the mountains we would frequently shut the engine off and coast as far as possible which was at least half way back on a 50 mile one way trip. No a/c no power brakes, no power steering , no turn signals except your arm. My 63 VW was the same way with the exception of turn signals. But things that were common then aren't so simple now.

My first car had no p/steering, it had power brakes and a column shift manual. It was awesome. I've coasted down a hill or decent with the engine off, then when I needed the engine, I'd just pop the clutch. Good times...was only a couple of years ago But a no-no in todays cars.

Miss that car

[Ross]

because constantly slowing and accelerating for no damn reason is a really *******d thing to do in traffic.
it's a damn good way to spend a few minutes taking a field sobriety test after you get reported as a possible dui. ( i know I call people in who drive erratically like that!)
Or be cited for failure to control speed or obstructing traffic ( i would hope).

Instead of accelerating and coasting between 45-60, just drive 50, or 55 on the freeway in the right lane, be less of an ******* to people who need to pass you, while using the exact same amount of fuel.
The reason you save gas doing so is because you are running a lower average speed. It isn;t the coasting that saves the gas, you waste that reaccelerating. Just drive on cruise at the lower average speed and viola, you saved the same amount of gas.

no one mentioned any danger aspects, though an ******* who accelerates on you when he is being passed because he's been slowing down as if he broke down, might catch people off guard as well.

Recently I came across a car holding up a long line of traffic. When I finally got past I noticed the offender had a hand lettered sign on the back window of his mini SUV that read HYPER-MILER.
In his defense he was in the far right lane on a six lane highway. This was morning rush hour on a road where the typical speeds, even in the right lane, are well above the posted limit. There were lots of on-ramps and his pace was impedeing not only the regular flow of traffic but causing people from the on-ramps to brake after accelerating for their anticipated merge into fast traffic.
This guy was a ****ing menace and should ride the bus, perhaps the short one.

[whiskychaser]

(Sir) Jackie Stewart said you should drive like there is a glass of water on the bonnet. He won 27 grand prix so he knew a little bit about driving.

[E34-520iSE]

I was told by an old guy once that WW2 air staff were told to polish the wings of the 'Spitfires' to keep their speed up. I don't know whether there was any truth in it, or if it was just a wartime morale boosting exercise, but with the E34 having the aerodynamics of a fridge then anything may help!

Cheers,

Shaun M