Does going down through the gears use fuel?

Do you use your gears to slow or coast up to a juncton?

  • Total voters
    237
eliroche

eliroche

Well-known member
Well lads,
I was doing a driving day the other day for work van and the instructor (lad from Mondello) noticed i was dropping through the gears as i came to a junction to help slow the van without using brakes until the last section.
He reckoned if i approached the junction and stayed in say 4th until it was just about to shudder and then depressed clutch and use brakes until at a full stop i would save a good bit on fuel consumption (in scooby!)
Does anyone know if this is the case? I was of the impression that downshifting was'nt using much fuel? (dunno why!)
Eli.
:thumbsup:
 
i heard once the engine in decrease of revs it uses less fuel and would use more on idle to stay alive
thats what i heard anyways
 
I seem to recall Clarkson saying in an episode that some modern cars dont use any fuel when the throttle is depressed!!! now i hardly think he had a subaru in mind as he spouted it out but said i'd mention anyway :thumbsup:
 
[quote author=Celtic03 link=topic=32327.msg370665#msg370665 date=1321996284]
i heard once the engine in decrease of revs it uses less fuel and would use more on idle to stay alive
thats what i heard anyways
[/quote]

Newer diesel engines do this :thumbsup: .. They have to inject fuel to keep the engine idling, but don't have to when you are slowing in gear as the gears keep the engine turning over..

Not so for subaru though, higher the revs, higher the consumption. I always downshift in the subaru, trying to get good at heel and toe for the trackdays :icon_grin:
 
i think you are wrong there rob we were always taught in college that a fuel injected car uses the air flow ,engine load and throttle position to determine amount of fuel so if an engine is on over run off the throttle with no load there will be no need for fuel as the throttle plate would be closed ,engine in vacuum so how would the fuel burn with no oxygen .i dont know specifically about the subaru system but all others do this
 
I'll have to bow to your better knowledge here dec as I was only going on something i was told, no factual data to back it up :thumbsup:
 
The instructor's reasoning sounds good, lower revs, less consumption. But if you're going to burn fuel on the downchanges, might as well do it properly - heel and toe and give her a nice dose of throttle between the downshifts, yup ya boya

@wagon dec/sweetcakes, I don't know much about the finer points of engines but I have heard of an idle air control valve before, does this allow a bypass of air into the throttle body during idle when the main throttle butterfly is closed? Then the ECU will pick up a tiny flow of air and inject a small squirt of fuel to combust therefore keeping it idling at a low speed? I defer to other's better knowledge though...
 
Crap instructor there. Always downshift,that clutch in and brake is an accident waiting to happen if something unexpected happens
 
To be fair to the instructor, he is employed to teach people who drive vans how to save money on fuel consumption, for companies with large fleets of vehicles on the road.
So downshifting uses no fuel is the answer to this one.
 
[quote author=eliroche link=topic=32327.msg370794#msg370794 date=1322074575]
To be fair to the instructor, he is employed to teach people who drive vans how to save money on fuel consumption, for companies with large fleets of vehicles on the road.
So downshifting uses no fuel is the answer to this one.
[/quote]

Why wouldn't you just put it into neutral?
 
[quote author=eliroche link=topic=32327.msg370794#msg370794 date=1322074575]
To be fair to the instructor, he is employed to teach people who drive vans how to save money on fuel consumption, for companies with large fleets of vehicles on the road.
So downshifting uses no fuel is the answer to this one.
[/quote]

Understood Eli,but take this as a scenario. Icy road and the van lets go,that second with no grip is the difference between getting it back and going off,plus if wheels were driving to start with it might not let go at all. Not arguing with you at all,just i dont count clutch and brake as terribly safe,and the fuel used by gearing down is cheaper than an insurance claim and new van or truck.
 
He did say to use engine braking during ice/snow! My fault never mentioned it!

I dunno why not put it into nuetral, he just said clutch it until stopped.
I was of the opinon that dropping down gears didnt use fuel, thats what i do, thats how it came up to begin with.
I agree that downshifting is a better way to drive, maintaining control of car and not coasting anywhere.
Just when he said that its pissin out fuel got me wondering, he was more qualified than me in driving (instructor/advanced license/instructor in the mazda'a in mondello and he races bikes!) so i took his opinion on board and put it to people who know better than me on here!
 
[quote author=B4 soon link=topic=32327.msg370768#msg370768 date=1322060420]
Crap instructor there. Always downshift,that clutch in and brake is an accident waiting to happen if something unexpected happens
[/quote]

id agree 100% , especially with any weight in the van , also when doing the driving test way back in 2001 , i took a few lessons and the instructors opinion was to always down shift coming to a junction , stopping always in second gear , then first gear and proceed , then again i just burnt €85 in my transporter in 3 days so what would i know about economy
 
That guy hasnt a clue what he is talking about.. Fuel consumption my arse.

Using gears to slow you down is the exact way to drive any vehicle, and esppecially any vehicle that carrys weight.
In a car the most economic way to drive is by down shifting,
Thats in a car, in any heavy goods vehicle its a must not an option.... i cant understand how he can tell you to do what he has. That would be a fail in your driving test, has he weighed up the fuel saving against the cost of replacing the brakes on van/lorry more frequent?
Use your gears to slow you down and forget what that donkey said..

Ask him when he is riding his bike would he coast up to a junction and hammer on the brakes or would he knock her down through the gears...
Fookn hell im some mad :angry1:

This reminds me of a supposed driving instructer that brought my woman out when she learning, got to a junction and she konked the car out, it was pitch dark at night, she went to go restart the car and the fookn gobshite told her to make sure and always turn the lights off when restarting as it can blow fuses if not :shock2: :shock2: :angry1:
 
my dear lord!!

i totally agree with the previous comments. down shift through the gears is the most stable way to control any vehicle in any condition. in snow/ice you have to be alot more gentle and keep your brain switched on 110% at all times.

the scary thing is this instructor races bikes???

ask him this, on the race track and road on his chosen bike.................

does he just dip the clutch and coast, when he needs to brake for a corner/ other vehicle?????????????????

fcuk me pink sideways without any lube!!!!!!!!!!!!!!!

i reckon i could and most level headed pepole on here, conduct brain surgery better than he could teach driving skills :angry1:
 
If we forget the serious issue about safety and just think on the fuel consumption, When you down shift through the gears, think what position is your Throttle in??? answer is closed as in the same as tickover.. I would take a guess at having a car/ van lorry etc etc struggling in a gear would be a lot more fuel heavy than down shifting and having the Throttle shut off and engine braking the car
 
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