"The engine is using ZERO gas when coasting down a hill in gear. Therefore, you are putting miles on the car with no fuel use whatsoever. "---Hitman

Hitman, please, if a car was using no gas when coasting, the engine would stop---COMPLETELY! Today's modern engines with their electronic controls via computer management do, in fact, use very little gas while coasting in gear down a hill. That much is correct.

However, coasting out of gear may use even less gas. And it really depends on a series of factors, both unique to the car and its mechanicals as well as the external enviroment such as the road surface, temperature, wind, etc.

If readers know about the various "economy runs" that used to be conducted (and some still are under "green environmental" auspices or even the "solar racers"), many of the cars were made to coast in one form of neutral or another. That's one of the ways they achieved their record-setting mileage-per-gallon of gas.

As to the safety issue of coasting down a hill, it is strongly recommended by every expert on auto safety I've seen that you NOT coast, either with the gear shift in neutral and the clutch let out, or with the shifter in a gear, but the clutch depressed to the floor.

With that said, however, driving with the clutch pushed to the floor and gearshift lever in a gear permits a driver to have a very quick response to an emergency situation, assuming the driver is alert. That last part, " the driver is alert" goes for someone completely in gear AND who is also daydreaming, which could obviously lengthen the reaction time to a dangerous situation.

I've been driving for over 21 years that one responder mentioned using different methods of in-gear, out-of-gear coasting down a hill or up to a light. It depends on the traffic around me and just how awake and aware I am. But I am probably a little over cautious. And I still do "coast with the clutch pushed to the floor but the car in gear". It isn't the end of the world, nor will it take more gas, I can assure you of both as factual statements.

BONDg35c

 

No, I actually do the dangerous leave the car and neutral without depressing the clutch.

Anyway. Since I can't tell from this post if I save gas by doing that, or lose gas for that matter... Let's just say we can all get down the hill, (without an accident I hope).

Black / Black 2004 GcoupeMT. Premium. Splash Guardz.

 

Thanks for the warning RainMeister. I used to cruise with clutch down on my old Prelude, but I only did that once on my G. . . may that be the first and last time. . .

 

<blockquote><font class="small">In reply to:</font><hr>

Hitman, please, if a car was using no gas when coasting, the engine would stop---COMPLETELY

<hr></blockquote>

You're wrong. The engine would not stop, even with the fuel injectors shut down completely. I'm not asking you, I"m telling you. If you don't believe it, just do a little research on your own.

Hint: Look up fuel injector pulse rate and cross reference it with deceleration.

Shutting down fuel injector pulse to zero is common upon deceleration/coasting for years now... it's nothing new.

That said, coasting down a hill in gear uses ZERO gas (for the thousandth time!!), so it's impossible to get better mileage than that!

 

<blockquote><font class="small">In reply to:</font><hr>

As for the so called emergency application of full throttle to avoid some phantom something or other. That is jus not the case. If you are going 65 MPH the only emergency things you are going to do is change lanes or break really hard or both.

<hr></blockquote> You've never had a car/truck pull out of a driveway infront of you without looking? Why would I waste my brakes performing an emergency stop when I can punch it and pass the infraction before impact point. Changing lanes at the same speed may not "clear" you from the impact zone.

---------------------------------
http://www.anythingbox.net

 

Juss messing around Afro, but wht happens when the idiot backs out real fast and you end up slamming into him full speed? =P I'd brake my car just to avoid an accident heh. Since you know, we usually don't drive down our streets at 60mph. =)

Black / Black 2004 GcoupeMT. Premium. Splash Guardz.

 

>>You've never had a car/truck pull out of a driveway infront of you without looking? Why would I waste my brakes performing an emergency stop when I can punch it and pass the infraction before impact point. Changing lanes at the same speed may not "clear" you from the impact zone.<<

I experienced this situation on the freeway a few years ago where a Camry in the right lane over began to lose control after some idiot cut her off. I quickly moved to the left lane, but only after punching the gas as I had to clear the front of a car in that lane. Had I simply stayed in my lane and braked hard, I would have struck the spinning Camry and/or been rear-ended by the car behind me.

The point is, if you believe in active driving (using accelerator, brake, gears and steering to always maintain control over the car rather than slamming the brakes and freezing the steering in a straight-line skid like most drivers), you'll always be prepared for emergency maneuvers.

RainMeister
'04 G35C 6MT, diamond graphite, premium, nav, aero

 

I love that other thread (related to this one) The genius that is worried about the legality of putting a manual transmission car into neutral while waiting at a stop light. HAHAHA!

Coasting downhill in neutral probably won't really make a difference in overall mpg or wear and tear on your vehicle. I've done it a few times when I was worried about running out of fuel on a long haul.

 

>>I love that other thread (related to this one) The genius that is worried about the legality of putting a manual transmission car into neutral while waiting at a stop light. HAHAHA!<<

Ahhh, the mental futility of those unversed in all things mechanical trying to justify their prediliction for imbecilic driving tricks and other socially repulsive behavior. Did art school leave you ill-prepared to get thy delicate hands greasy in pursuit of learning about the technical wonders that lay beneath your car's sheetmetal? May you continue in blissful oblivion.

RainMeister
'04 G35C 6MT, diamond graphite, premium, nav, aero

 

Re: Clutch/neutral on down hill? [re: dopeymon]

Hitman (Member)
01/08/04 05:27 PM
<< When you coast in neutral, the engine is using fuel to run the engine at idle RPM. When you coast in gear, the fuel pulse is shut off completely, so you're actually using no gas at all. >>


http://www.firstfives.org/faq/throttle/throttle.html

Hitman is right.. I don't think that he was implying that the fuel cuts off for an extended period of time...



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<blockquote><font class="small">In reply to:</font><hr>

Hitman is right.. I don't think that he was implying that the fuel cuts off for an extended period of time...



<hr></blockquote>

Like I said, the fuel will not always cut off in all situations..... certain conditions must be met.

But the fuel is cut completely for the majority of the time you are coasting/decelerating. If you are coasting down a long hill in gear, a condition might occur where too much oxygen is being pushed through the catalytic converters (not a good thing), so the ECM will very briefly pulse the injectors. This is done soley for the protection of the catalytic converters. Other than this short injector pulse, no fuel is used at all.

And to add to Mr.Ellusive's post-- this is not only on manual trans cars. Automatics shut the fuel off too.

 

Go Rainmeister and keep on calling people names because you do not like what they say.
As for this whole coasting thing, Hitman is dead wrong. The best proof is the on board computer if you have NAV. Coast in neutral for a while right after you reset the fule ecomony counter. See what it says.
Then do the same with the car in gear and see what is says...The reason coasting in neutral is better is because the car goes much further before having to give it gas to keep up the speed.

 

Goboy,

If you believe that computer, then I can't even argue with you.... but believe me, I'm 100% right.

The trip computer doesn't take into account things such as fuel injector pulse being shut down while decelerating. Sorry, but it's just not that complicated.

But believe what you want, okay?

 

Actualy, this fuel cut-off occurs until the engine RPM fall to a set value at which point fuel is restored for idle condition

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