Coasting VS Driving Down Hills

ISTR that free-wheeling used to be illegal in IL. Is it still? In other states?

I tried to look it up in the online MA Driver's License Manual, but that has been so dumbed-down that I can't tell; I can't tell the difference between the illegal acts and the ill-advised. Arrrgh.

In California, it's illegal to do that. Having said that, I used to work with a guy that would shut his engine off while going down hills, in order to save gas. He was a real character.

Bob

Back in the day.... My grandfather did that, he would just pop his old car into neutral and leave it running so the brakes and steering still worked. He claimed it saved him a lot of gas.

I have noticed since I got my Libby that the little mpg indicator has a big change when I let off the accelerator or decelerate, from 17mpg under throttle to as high as 49 Soooooooooooo since we ALL know how bugus THAT is I would guess that you may save a little, BUT The only way to know for sure it so test the theory on the same course with and without your foot on the pedal.

I think it is risky. Suppose the engine stalls ? bye bye powerbrakes.

I don't think it's worth the small amount you save.

Then you let off the clutch again. Duhhh.

I've noticed that the fuel consumption (l/100km) indicator on my Durango will often go to zero on long down hill grades. My guess is that the computer is regulating fuel flow to maintain speed. Therefore with there being no fuel flow necessary to maintain speed the flow is closed to a trickle and possibly shut off.

I think it depends on your system. I recall when cruising in a 56 Pontiac 'vert, with a spark plug wired to the exhaust pipe, that you shut off the engine and coasted and then fired it up again and hit a toggle for the plug. You got a huge flame from the raw exhaust gases which were still being pumped through the system while coasting.

Newer systems which are computer controlled may prevent that.

That said, and aside from being illegal in a lot of places, as I recall you waste the most fuel when starting up. The second biggest waste of fuel is idling at traffic lights, in traffic (hello, LA), etc. Would not coasting be akin to idling, and restarting as bad as restarting if you were to have the engine shut off or die? So, could it be that, unless a computer is doing something to prevent waste, you'd be wasting more fuel trying to trick the system than just driving normally?

And what of any added wear and tear on parts?

I d>With the high prices of gas lately (you have to get a loan to fill up)

Spike

Gad what fools these morons be.... Children are obscene but should not be heard Give me a peperoni pizza... or give me a calzone!

Why? :-D

I have driven much of IL, south of I-74, right down to the Ohio River close to where it meets the mighty Mississip and have not see anything I would classify as a much of a hill..., but then I have the Cascades and Rockies in my back yard.

As for free wheeling, it is illegal here in BC as well (and for good reason.)

Hmmmmmm, maybe something for the Mythbusters?

It doesn't surprise me that it's illegal. What makes me wonder is how do they enforce it? When one gets pulled over, most people put it in park (or neutral) anyway. I can just imagine someone getting pulled over. The cop notices the neutral gearshift and screams into his radio whilst going for his weapon "Holy crap, HE'S IN NEUTRAL! GET THE SWAT TEAM DOWN HERE PRONTO!!!!" Which also makes me think that the only way they WOULD be able to tell is after an accident and they examine the wreckage. And if one is stupid enough to go careening down a hill out of control, they probably deserve to hit a tree....

Slightly Gray> > trotzo wrote:

Risky? Why would your engine be anymore likely to stall while coasting than it would be while driving???

If they only hit trees probably no one would give a damn. Unfortunately they would most likely take out some other driver.

Nobody said it would... but if it did - run out of fuel, spark, compression, it might stall & you would lose your accessories if coasting in neutral. If left in drive, you don't lose 'em, or put back in gear(stick shift), you get them back.

Rob

Rob, You should reread my post and the post I was responding to before you correct me.

I was responding to RT's statement against coasting: "I think it is risky. Suppose the engine stalls ? bye bye powerbrakes" Which was some how mysteriously snipped from your reply to me.

My point was simple, if you lose engine power weather you are coasting or under power the risk is no different...

wasnt this on an automatic ? Trust me, this could be an issue. I almost lost some good friends who accidentally put their rv's transmission in neutral when going downhill. He didn't notice the engine had stalled until he needed the brakes and they barely worked. then he looked at the tach and it said zero... he quickly started the engine and got brakes back. plus I dont' know what an automatic transmission would do with a stalled engine and then thrown in Drive... would it start ?

Nobody said it would... but if it did - run out of fuel, spark, compression, it might stall & you would lose your accessories if coasting in neutral. If left in drive, you don't lose 'em, or put back in gear(stick shift), you get them back.

Rob

No mystery, I was only responding to your statement. Nobody but you suggested your engine would be anymore likely to stall while coasting than it would be while driving.

EXCEPT, my point is that IF it stalls(runs out of fuel, spark, compression) in gear, auto or stick, the risk is lower, as you actually do not lose your accessories. Coasting, you do lose your accessories IF stalling occurs. Not "risk is no different" as you say. Losing engine power when you are coasting is much more dangerous.

Rob