Is there any point to P&G in a diesel?

[MetroMPG]

Originally Posted by bluetwo

I just hope people will be safe when they're navigating a 2,000 lbs. plus vehicle

So do I. I don't think anyone will argue against that.

Nobody should attempt any newdriving technique without a full understanding of the way it will affect their vehicle (as Tasdrouille mentions), and certainly shouldn't use it around other road users until they're competent. Sometimes conditions dictate it's not appropriate at all.

[JacobAziza]

My source said for every 1% increase in speed there is a 4% increase in fatality rate, but yeah, either way the conclusion is the same.

Saving the environment, saving money, and saving your life are all compatible

[bluetwo]

I have nothing against pulse and glide or any other legal technique but I'm looking at it from a law enforcement perspective as well as from a safety conscience mind. I agree about people texting and driving too and I'm glad a lot more states have outlawed it. Hell most of the military bases I frequent have rules against operating a cell phone at all while on the installation so that's nothing new to me at all. I'm a military policeman if anyone cares and sometimes I actually want to pull someone over for stupid driving practices when I'm in my own car or truck but of course I have to just sit there and watch them put others in danger at those times.

I'm not saying coasting with the engine off is like drunk driving but if it kills one little kid or something that's one too many. I have a heightened awareness of the dangers on the road because I've seen too many vehicle related deaths and so it's for those reasons that I speak out against and oppose unsafe practices and definitely don't encourage people to talk about breaking the law on the internet. That's just not smart.

[tasdrouille]

Bluetwo, I do not condone breaking the law either. Around here, driving with the engine off is only potentially illegal, simply because there's a law stating that you can't do anything that could put others at risk on the road. AFAIK it's never been trialled though.

I honestly cannot see a single risk when done by someone knowing what he's doing.

It's kind of funny when people bring up the risks associated with hypermiling. Maybe they are not speaking up, but I've never heard of someone being responsible of an accident while hypermiling.

[MetroMPG]

I don't think anyone's advocating that safety not be the top priority.

From a strictly legal point of view... laws vary by region - I was unable to find anything on the books where I live that even mentions neutral coasting. I realize in some US states it's on the books.

From the intro to the 100+ ecodriving/hypermiling tips:

Note that the list on this page describes some techniques that may be illegal in some areas, and potentially unsafe (or inconsiderate) depending on the traffic situation where they're used.


So don't be stupid! Make safety your first priority. Use good judgment and be considerate toward drivers around you. Take care to learn new techniques in an isolated environment, and incorporate them gradually into regular use.

[bluetwo]

Originally Posted by tasdrouille

Bluetwo, I do not condone breaking the law either......

Originally Posted by MetroMPG

I don't think anyone's advocating that safety not be the top priority.

From a strictly legal point of view... laws vary by region - I was unable to find a law on the books where I live that even mentions neutral coasting. I realize in some US states it's on the books.

Thanks guys. I'm just massively disappointed because I honestly never thought I would have this conversation with any of you and I don't mean to be a sore thumb or discourage anyone at all.

Like I said, I'm in law enforcement myself but I'm not a hypocrite at all, nor do I claim to be a perfect driver all the time, yet I rarely ever speed excessively, I stop at every stop sign and don't put other people at risk certainly not for some selfish obsession of mine. So the thing to take away from it really: is I don't want hypermilers, ecomodders or even just the slightly concerned mileage watchers to get a bad name because I can guarantee that there are people out there who would love to smear us at the first opportunity. Please everybody continue to be safe and aware drivers so none of our cars ever end up in pictures anywhere.

[Frank Lee]

I can't think of a circumstance where trying to power out of it would have helped.

Well, OK, if you're on or almost on r.r. tracks and a train is coming you might want to goose it.

99.99% of the time evasive maneuvering is 1. steering 2. braking. I guess I never encounter what I'd consider a potentially dangerous situation while gliding.

[rmay635703]

Pulse and gliding a NATURALLY APIRATED diesel is almost pointless.

My 1982 diesel Suburban I drove for years with a 3speed auto and 4.10 gears got the best MPGs accellerating very very slowly and holding constant speed and coasting to stop. I could get around 22mpg in town and approx 21.2 on the highway if I was careful.

I do recommend letting the vehicle slow uphill and speed up going down however, thats all I did to get decent mileage from such a poorly configured rig. heck I was in 3rd at 15mph or so.

[Frank Lee]

Originally Posted by rmay635703

Pulse and gliding a NATURALLY APIRATED diesel is almost pointless.

I'm thinking no.

I'm thinking the biggest reason P&G works is simply due to the percentage of time the engine is off.

Maybe someone more ambitious than I could math it out. But I feel this is the case.

[rmay635703]

Originally Posted by Frank Lee

I'm thinking no.

I'm thinking the biggest reason P&G works is simply due to the percentage of time the engine is off.

Maybe someone more ambitious than I could math it out. But I feel this is the case.

I think it depends on the engine to weight ratio, my engine had little power and there was a STEEP penalty for accelerating more than lightly.

To pulse and glide effectively I would have had to enter a very inefficient area, though it might be worth a try if the thing was a manual, mine was not.