What do you do to save fuel?

Margaret Clarke

I live in Asia where we have an unbelievable public transport system so I don’t drive here. When I lived at home and when I visit home I always drive at reduced speed.

The kinetic energy of the vehicle is proportional to the square of the velocity. Higher speeds will massively increase fuel consumption.

Where the following speed limits apply, I usually drive these speeds.

50 km/h - 30 km/h

60 km/h - 50 km/h

80 km/h - 60 km/h

100 km/h - 70 km/h

120 km/h - 80 km/h.

Just slow down, arrive on time and keep left.

PsychoPete

Drive on sure there's plenty of fuel at the pumps

MakersMark

Your licence should be yanked off you.

30 in a 50 zone is just being an utter pain in the arse to fellow motorists.

MakersMark

sam t smith

Freewheeling. Turn off the ignition on any sort of decline.

sam t smith

I also urinate in the diesel tank. Reckon I get an extra 20 km per gallon.

The housing crisis forced lots of us outside Dublin and we don't have good public transport. Driving is necessary but driving 40 below the speed limit will add serious time to my commute.

Allinall

https://www.boards.ie/discussion/comment/118912706#Comment_118912706

Don’t do this. I tried it and the car rolled back into a bus.

Noxegon

In most cars there's a sweet spot – generally it's the lowest RPM in the highest numbered gear you've got.

In my elderly Saab I get the best fuel economy by far when I drive in sixth gear at just over 60mph – the computer says that gives me around 51mpg.

I should say that I only ever do this when I can sit in the left hand lane on a motorway. To expand on what @MakersMark says, blocking slower roads by driving way under the limit is an absolute no-no. Don't do that.

Donald Trump

I have a few holes cut out of the floor so that I can propel the vehicle Flintstone-style

Atlantic Dawn

Driving 30 in a 50 is likely to burn more fuel. I've a magnet I put on the fuel gauge and since I started using it the needle hasn't dropped once.

French Toast

I drive from where I am to my destination along the shortest route possible at the highest (relatively safe) speed possible.

Looked at getting a motorbike instead of my 2.0 Avensis daysul but have been told that the savings on cost are minimal and therefore would barely be worth the hassle.

Margaret Clarke

https://www.boards.ie/discussion/comment/118912720#Comment_118912720

Just overtake. It’s a motorway. How am I holding you up?

bigroad

I drive behind other cars .

https://www.boards.ie/discussion/comment/118912824#Comment_118912824

I meant people with long commutes can't afford to drive so slow if they value their time.

But 80 on a motorway is insanely slow. I once had to drive 80 due to a mechanical fault and I kept my hazzards on so other drivers knew why I was so slow.

Margaret Clarke

https://www.boards.ie/discussion/comment/118912979#Comment_118912979

Artic lorries are restricted to 90 km/h, other vehicles 80 km/h and buses with standing passengers/ no seatbelts 65 km/h.

Should they drive with hazards on?

colml cule

People doing 60 in an 80 zone drives me bananas, you're likely to build up traffic behind you and make the road more dangerous imo

barneygumble99

Blank off two injectors, cuts fuel consumption in half. On a serious note, when I’m motorway driving I always use cruise control, coupled with ACC and an automatic transmission I think it’s as economical as you can get for the type of car I drive.

Margaret Clarke

https://www.boards.ie/discussion/comment/118913032#Comment_118913032

What about buses limited to 65 km/h? Are they creating a danger? What about a cyclist?

ednwireland

drive it like you stole it

Margaret Clarke

https://www.boards.ie/discussion/comment/118913034#Comment_118913034

What does “blank off the injectors mean”? I drive a Nissan Micra when in Ireland, cruise control, auto box.

colml cule

https://www.boards.ie/discussion/comment/118913041#Comment_118913041

If they're driving 20 slower than everyone else then potentially they are, yes.

Some cyclists can be quite hazardous on the roads too, and I say that as a cyclist myself. However they are generally not moving as fast and I need less space to overtake.

Margaret Clarke

https://www.boards.ie/discussion/comment/118913102#Comment_118913102

So buses driving (legally) at 65 km/h in a 100 zone are creating a danger? Just to confirm, is that what you are saying?

Margaret Clarke

https://www.boards.ie/discussion/comment/118913102#Comment_118913102

…

barneygumble99

https://www.boards.ie/discussion/comment/118913048#Comment_118913048

Micra is probably petrol, possibly 4 cyclinder. You could disconnect the electrical connector on two of the coil packs and you’d halve your fuel consumption.

guyfo

Change up earlier in the rev range and use less throttle input to get you up to speed especially away from a standstill. If you're coming up to a hill build speed before it and gradually lose a few kph going up it and vise versa let the car gain momentum on downhill sections and big one is don't brake when possible, let the engine braking slow the car down.

All of these things can help you not hold up other road users (air restistance in minimal up to 50kph in a car and that speed is generally easily maintained) and not put you in danger driving at 80kph on a motorway.

P.s. you can fail your driving test for consistently driving unnecessarily slowly or "Lack of progression"

Margaret Clarke

https://www.boards.ie/discussion/comment/118913256#Comment_118913256

So what’s happening to all that wasted fuel before they’re disconnected as opposed to after? 🤔

Would you have lower acceleration after they’re disconnected?

guyfo

https://www.boards.ie/discussion/comment/118913274#Comment_118913274

All the excess fuel would be farted out the exhaust with pops and bangs, and the car would barely get up to any sort of speed if it could run at all. And it would absolutely destroy the fuel economy because the 2 non firing cylinders wasting fuel would be working against the other 2.

I think the OP has an answer now anyways. Most people don't drive super slow to save on fuel and be an annoyance to other motorists in the process.

Whocare

Dual tanks 🤫

Ubbquittious

I drive a lot less than I used to but for the bit I do I drive like a demon in order to extract the same enjoyment from it

Margaret Clarke

https://www.boards.ie/discussion/comment/118913335#Comment_118913335

So disconnecting cylinders is a rubbish idea?

Margaret Clarke

https://www.boards.ie/discussion/comment/118913348#Comment_118913348

How is driving slow an annoyance? Can you not overtake?

mikeecho

100kph, on cruise control puts the car into 8th gear, any slower and it drops a gear.

However.. 160+ in sport mode is a lot more fun.

bosco12345

Cruise control and have cut down my speed by about 10% Also never pass out any cars ahead of me. Have noticed my tank lasts me about 20% longer as a result.

Margaret Clarke

https://www.boards.ie/discussion/comment/118913381#Comment_118913381

8th gear?

I did C and D before leaving Ireland. The D had 7 gears and rigid had 8 the gears were overlapping if that makes sense.

Never heard of a standard car with 8 gears.

dmc17

I've attached an industrial magnet to my front bumper and once I get close enough to the car in front it starts to pull me along with them. Takes a while to get the hang of it but it makes it easier if they drive a lot slower than the speed limits.

corner of hells

I find if you drive in reverse at speed, my fuel tank starts to fill up.

Also it cancels points and confuses speed vans.

https://www.boards.ie/discussion/comment/118913371#Comment_118913371

Lots of the back roads are 80km. If you're driving at 60km you'll very quickly have a bunch of cars behind you.

Overtaking can be very tricky on such roads. Same applies to lots of single lane roads.

colml cule

https://www.boards.ie/discussion/comment/118913179#Comment_118913179

Well I couldn't generalize as each situation is different, every road is different, but it's certainly a possibility.

Driving at those speeds you're likely to build up traffic behind, the traffic will be keen to overtake which itself is a danger (I'm at the risk of going full Stephen Donnelly).

Buses have a tendency to pull in every so often to let people on and off, which also allows the traffic behind a chance to pass.

Of course in an ideal world, buses wouldn't exist and everyone would be taking the train instead, but unfortunately that's not going to happen.

Gumbo

Asia Called. They want your licence back.

So dangerous and if you came up on a Garda driving those slow speeds, they would have you at the side of the road in an instant.

No point talking about buses as our bus system don’t use the motorway and they are certainly not restricted to 65km/h.

Gumbo

https://www.boards.ie/discussion/comment/118913363#Comment_118913363

Not rubbish. You can disconnect them in the car settings menu.

FintanMcluskey

https://www.boards.ie/discussion/comment/118913363#Comment_118913363

No it's a very good idea.

Lots of people in Mayo would be aware of that trick to save money.

1/2 the number of cylinders = 1/2 the fuel consumption.

It leaves changing gear slightly more difficult, as you must wait until either of the 2 remaining cylinders are on the power stroke before releasing the clutch to utilise the remaining torque.

Margaret Clarke

https://www.boards.ie/discussion/comment/118913551#Comment_118913551

Some of the Dublin Bus X routes use the motorway.

DB buses are restricted to 65 km/h.

I’ll wait for your reply to this point.

Borzoi

https://www.boards.ie/discussion/comment/118914258#Comment_118914258

Was behind a DB on Sunday, on a dual carriageway travelling at 77kph.

I had a load on roof rack, and 80 was my self imposed limit on cruise on a mix of dual carriageway and motorway - it was the only vehicle travelling slower than me.

https://www.boards.ie/discussion/comment/118914258#Comment_118914258

Is that supposed to be some sort of justification for your own irresponsible driving?

eggy81

Haven’t owned an auto yet but with a manual I find coasting in 6 at around 110-120 without acc on is more economical than having cruise on at the same speed.

https://www.boards.ie/discussion/comment/118913034#Comment_118913034

notAMember

Just use a bicycle or an EV for gods sake and stop that nonsense at low speed.

All the fumes behind you, ugh… thanks for the air pollution.

Margaret Clarke

https://www.boards.ie/discussion/comment/118914292#Comment_118914292

How am I being irresponsible?

What percentage below the limit does it become dangerous?

mikeecho

https://www.boards.ie/discussion/comment/118913406#Comment_118913406

It's an automatic, BMW 5er

Some mercedes have 9 gears.

The wife's car is also an auto, and it has 7gears

mikeecho

https://www.boards.ie/discussion/comment/118914621#Comment_118914621

There's no set lower limit, but if a vehicle is going considerably slower than the speed limit, ie a tractor pottering along at 30 in a 100, it can be considered an obstruction, and you can legally overtake it, even if that means crossing a white line.

Yes I didn't believe it when I was told it either.

But I've been assured that's it legal, as that what I was trained to do, while on an advanced driving course.