Coasting in gear vs putting in neutral

[joao44289]

When you're going downhill which of these 2 methods in a Renault 4 saves more fuel?

 

[Jnr-Renospeed]

Putting the car into neutral will save more fuel, but you shouldn't really have to do this to get good fuel economy and doing so takes you out of control somewhat...

Changing gear at lower rpms will be a better fuel saving method to start with.

 

[joao44289]

Putting the car into neutral will save more fuel, but you shouldn't really have to do this to get good fuel economy and doing so takes you out of control somewhat...

Changing gear at lower rpms will be a better fuel saving method to start with.

I always try to keep my rpm low. And I learned today the hard way that you really shouldn't be on neutral when going downhill. I built up too much speed which overheated my brakes. When I wanted to come to a full stop at a stop sign I found my brake pedal to be quite soft and she wasn't breaking like she usually does. I only came to a full stop after the stop sign and I was very lucky that there was no car near me.

 

[petak]

Very rarely i put car in neutral. Only at stop light when i know that will wait longer time.

On downhills i even put it in lower gear ,if speed and rpms are letting that, to use engine to brake when it is needed. If speed is higher i left it in that gear but remove foot from throttle.
That way brakes are used less and are more effective if you need to brake harder.
Of course if you need to brake instantly (almost to stop wheels to spin) then you must press clutch to keep engine running.

I have find out that, if everything is alright with ignition and carburetor, there is small difference between driving it at low revs or driving it normally. Bigger consumption starts in the cities with lot of stop lights or at highway if drive it 110-120km/h.

Noticed that if i have longer trips (outside of highway) i can make more km's with one tank of petrol.

During summertime i am at 5,3l/100km (53mpg) average, and wintertime 6l/100km (47mpg) and i am little bit harder on the throttle pedal.
When i am driving local roads on long trip i can go down under 5l/100km (56mpg) but that is lower i have ever been.

 

[Scoobyznack]

Hello all,

In the US there’s an interesting subculture of “hypermilers”, who go to astonishing lengths to coax more gas mileage out of their cars. There is a whole set of driving techniques you can apply, have a poke around this website & forum -

https://ecomodder.com/

If we get a Kamm-tail GTL surface in the Projects section it was nothing to do with me

Best wishes, Simon.

 

[André4Renaults]

May I interject a note of caution here? Allowing a car to "coast" in neutral of anything other than a short length of time in between gear changes is unsafe and may be dangerous. Under British Road Traffic laws this may lead to a charge of careless driving or possibly driving without due car and and attention (other countries' laws may differ). In any case, the amount of fuel saved would be microscopic. Good driving technique is to have the car "under load", particularly when cornering; in other words, a car should be "driven" round a corner, not coasted and certainly braked on one! Renault 4s have VERY soft, long travel suspension and allowing a 4 to "glide" round a corner at speed might make its handling differ from what the driver is used to-it would probably understeer less-and therefore may catch him (or her) unawares!

Many years ago I drove an east German manufactured "Wartburg", which had a 2-stroke engine, and a free-wheel. This meant that you WERE coasting whenever you took your foot off the throttle.....it took a great deal of getting used to.....

 

[petak]

Wartburg.... So familiar in Croatia.... Drive it once. Owner used to change gears without clutch while gliding.

Sedan or Estate verion?

 

[André4Renaults]

It was a saloon, called a "knight" here, although I did briefly own an estate, which was called a "tourist" in England.

 

[mojobaby]

When I was 18 and stupid, I decided to freewheel down a 2 mile hill to save petrol.

The problem is that I turned the engine off as well and of course the steering locked and I nearly ended up driving off the cliff.

 

[Piet]

Best method
Look for a nice tall truck going your direction at the speed you want. Pull in behind and get sucked along. You don't have to be dangerously close- in a R4 even quite far away - well within safe/normal distances you will notice you can let the throttle pedal up significantly. I just happened to score this on a 100 km trip a few months back and even well behind I could feel it. I managed to get 60 mpg for the return trip so that leg must have been really low!

 

[John Edmonds]

May I interject a note of caution here? Allowing a car to "coast" in neutral of anything other than a short length of time in between gear changes is unsafe and may be dangerous. Under British Road Traffic laws this may lead to a charge of careless driving or possibly driving without due car and and attention (other countries' laws may differ). In any case, the amount of fuel saved would be microscopic. Good driving technique is to have the car "under load", particularly when cornering; in other words, a car should be "driven" round a corner, not coasted and certainly braked on one! Renault 4s have VERY soft, long travel suspension and allowing a 4 to "glide" round a corner at speed might make its handling differ from what the driver is used to-it would probably understeer less-and therefore may catch him (or her) unawares!

: Many years ago I drove an east German manufactured "Wartburg", which had a 2-stroke engine, and a free-wheel. This meant that you WERE coasting whenever you took your foot off the throttle.....it took a great deal of getting used to.....

My '66 SAAB 96 two-stroke also has a freewheel which can be selected, also enabling clutchless gear changing. Most two-stroke cars had this device due to the engine lubrication for the pistons (roller bearing crankshaft) being entirely from the oil/petrol fuel mix. As such, with very long downhill situations using engine braking, there was a risk of the pistons seizing, but with the freewheel engaged the engine would just be idling. It worked well for Erik Carlssohn with his RAC and Monte Carlo rally successes, but his nickname was 'on the roof' as he would frequently roll the car! Not for the faint-hearted..... :

 

[Sage103]

The freewheel in the SAAB 96 persisted into the 4 stroke version powered by a Taunus V4. An added facility made possible by this was clutchless gearchanges. However my first SAAB was the first model of 99 and this also had a freewheel despite there never having been a 2 stroke version. Presumably coasting was a Scandinavian forté.........

 

[Rustyoldjcb]

My dad used to call coasting 'the silent fifth' in his Morris Traveller. But as others have said, you are deemed to be not in full control of your vehicle should something happen.

 

[Rustyoldjcb]

My '66 SAAB 96 two-stroke also has a freewheel which can be selected, also enabling clutchless gear changing. Most two-stroke cars had this device due to the engine lubrication for the pistons (roller bearing crankshaft) being entirely from the oil/petrol fuel mix. As such, with very long downhill situations using engine braking, there was a risk of the pistons seizing, but with the freewheel engaged the engine would just be idling. It worked well for Erik Carlssohn with his RAC and Monte Carlo rally successes, but his nickname was 'on the roof' as he would frequently roll the car! Not for the faint-hearted.....View attachment 26825 :

That's a fantastic looking car!

 

[laxeian]

Those were the days!, remember my dads rotten PA Cresta, brilliant things even if tarnished as a toddler, that had a silent fifth too!, (or spacecraft mode), the in car entertainment if sitting in the front ( don’t tell your mother) was watching the road surface through the gaping hole in the passenger footwell, Sooo much better than watching Blue Peter on the box, colour too. Mot’s and seatbelts, things of the future.
Nowadays cars turn themselves off at the lights if you stop long enough, wonder when their brains are going to advance enough to slow you down to a safe stop if you tried such a grave mistake as a bit of ‘freewheeling’, although it worked for Robert Zimmerman...

 

[Rustyoldjcb]

Those were the days!, remember my dads rotten PA Cresta, brilliant things even if tarnished as a toddler, that had a silent fifth too!, (or spacecraft mode), the in car entertainment if sitting in the front ( don’t tell your mother) was watching the road surface through the gaping hole in the passenger footwell, Sooo much better than watching Blue Peter on the box, colour too. Mot’s and seatbelts, things of the future.
Nowadays cars turn themselves off at the lights if you stop long enough, wonder when their brains are going to advance enough to slow you down to a safe stop if you tried such a grave mistake as a bit of ‘freewheeling’ ( seem to remember a song or album of that name)

My brother and I had 'out car' entertainment. We would open the rear windows in the Travellier and climb out so our backsides were sitting on the bottom rail, our legs inside the car, and the rest out in the breeze as the car bowled along country lanes. Happy days!

 

[Eccles60]

In the 'Fifties my father and friends used to challenge themselves to freewheel all the way from Fleet down into Farnham via the town's castle.

It's a couple of miles of twisty back road which is mostly downhill but has streches which flatten out and even go uphill slightly. The challenge was going fast enough to keep going but not too fast to get round the bends, not to mention avoiding other traffic...

This might be feasible in an MX-5 or something else that handles but my dad had an upright Ford Popular with cable and rod brakes, and 3.5 inch rims with crossplies. Thankfully in th 1950s traffic was minimal.

Fun indeed.