Does pushing in the clutch while going downhill saves fuel?

If they go inside you roadkill, they'll find your problem. Good luck.

You have to admit it is a challenging thread. You come out contradicting everyone, you will get some feedback. I found that out a long time ago. just normal forum stuff.

 

Have to disagree here.

I have hauled patients in and as soon as they hit the ER, they are then sent to the Cath lab. No tests to pass or fail.

As far as the heart specialist (cardiologist), I would get a different doctor.

My sister had many open heart surgeries and we met with the specialist the night before and by phone prior at the last one.

 

That's exactly right. I really don't understand someone giving unsafe advice just to prove a point. I don't care if anyone can prove any fuel savings it's agains't the law to do such a stupid thing. Someone with 4 years of so called experience should be promoting professional driving and I think the meaning of the word has slipped here on the professors part. You can save just as much fuel in the way you drive and your habits. To the OP, I don't know how or where you picked up such bad advice but it is.

 

In my post I made very clear freewheeling was dangerous as well as illegal and that I wouldn't advocate anyone to use such a practice.

Pretty much everyone in the early replies said so much as well.

I answered the question as he asked it which is yes it can and went on to say it is dangerous, illegal and a bad idea.

Most of the debate then was me against the world as no one would acknowledge a truck rolling 65 mph in gear taching 1900-2000rpms is going to use more fuel than a truck with an engine at idle speeds traveling 70mph.

I tried to find common ground with the sledding scenario. I conceded it wouldn't always be a big difference depending on topography and load. But no one would concede anything about rpm speed, momentum or resistance in how it relates to fuel economy. I get that its dangerous and horrible advise to give anyone much less a newbie but geez how many disclaimers do we need?

The personal attacks are regrettable. You should be prepared to defend your position as posted regarding a certain topic. But bringing in someone's personal health situation and making charges of lying and judgements about such things you have no basis for goes over the line in my opinion.

I welcome a debate even a heated one but can we keep from getting so personal?

 

Now you're crying about the responses you got. You came on here with an aggressive attitude and got called out. Be a man and admit your shortcomings. But you try to cover your tracks and double talk trying to make people believe you know what you're talking about. The simple fact is your advice is dangerous and way off in facts and creditability. You describe a heart condition that the doctors have done many test on. That alone should tell you that driving a CMV is questionable and therefore illegal. One call to you company and I'm sure you'd be pulled off the road. God forbid you have an accident because with this medical history you'll be held liable which you may even do some jail time. You're no professional driver and have no business giving advice. You try to cover your statements when called out which makes you look even worse. Do us all a favor and take you rude postings elsewhere. You've clearly establish that you are unsafe and a liar. So take your medicine like a man and quit crying like a baby.

 

As stated, the fuel injectors are closed with clutch engaged going down hill. You push the clutch in or go to neutral the injectors open up and squirt fuel at a rate of 1 gallon per hour. Even if it were 15 minutes I highly doubt you could save more than a gatorade bottle full of fuel your way.

 

I haven't read all the replies so I'll just say it incase nobody else has. Putting your truck in neutral while on a downgrad (of any degree) is not only dangerous but ILLEGAL.

 

Unless you're willing to debate the physics and thermodynamics involved, being illegal isn't a good enough reason. We're all waiting on Stephen Hawking to validate weather or not you can in fact save .00000000000001mpg by simply pushing in the clutch.

 

X2^3

As another and I have been trying to point out all along, when the driveline is spinning the engine above idle with the throttle at idle, it does not inject fuel. Go put your transmission in neutral and rev the engine up. As it's accelerating, it growls from the combustion noise, as it slows down, it just hums from the intake and exhaust and other noises (accessories, belt drive, gear train whine, valve train noises, ect), but you'll notice a lack of combustion noise until it nears idle again, then you'll hear that Diesel rattle come back as the fuel starts getting squirted in again. I can also get screen shots of a couple different electonic min-max (autmotive) governed Diesels that show the fuel rate tables and how they command 0mm^3 of fuel above a certain point with the throttle position at 0%.

 

If it doesn't inject fuel then how does it run? I've got manuals around here that can tell you how much a fuel certain diesel will burn per hour at idle. If it's not injected then where does it go.??????