Considering the price of diesel is now hitting £5.50 a gallon , does anyone do any of the "hypermiling" techniques?, are there any that make a difference?.
I have, for the last half a tank of fuel, tried to drive a bit more sensisibly, but I just wondered if anyone had other tips/tricks that they use and they know that work.
I generally get 56mpg out of my car, it will be interesting to see how many extra mpg's hypermiling techniques will give.
I spend a few days in Malta some years ago and the bus drivers have an interesting fuel saving technique:
Put it in neutral as soon as you reach the desired speed. Never brake except in emergency situations. Traffic lights are an indication vaguely similar to "use some caution when red".
Efficient but scary?
On a daily basis I try to anticipate as much as possible to avoid accelerating, keeping good distances with the cars ahead helps making a buffer for the nervous speed changes that take a high toll in your consumption.
Take it easy uphills,
do not carry useless stuff in your car,
close windows to reduce drag,
change gear up asap at steady speed,
check tyres pressure,
take the bus
Depends on the car and the conditions. With a tail wind it'll be more in favour of windows down, with a head wind more in favour of AC. But stop being a girl and just use the cooling fan without AC, and wear thinner t-shifts.
The economy competitions people do are usually carried out by full throttle runs up to cruising speed, and then coasting for a bit, then full throttle, then coasting. This is the most efficient way of driving. The worst way of driving is how 99% of people drive to 'save fuel', by trying to not press the accelerator, and taking hours to get up to speed. So, by trying to save the planet, they actually harm it more.
I just drive like I normally did, and go with a magazine less per month (or equivalent). Fuel won't run out in my lifetime, and there was some news recently that Global Warming is on hold for a bit too. Ignore the polititians, and drive like you always did.
Depends on the efficiency of you A/C system and the temp you set it at...
and also at what speed you are driving
no easy answer there, but for newer cars a self regulating A/C not too cold (max 4-5°C below outside air temp) is more efficient that open windows outside the cities (from my own experiments, instant fuel consumption on screen so not utterly reliable).
Edit: and Tristan is right about the elderly lady taking 5 minute to reach 50km/h after the green light...
It is the cost of fuel though, I can see it being £2 a litre before long, which is a kick in the teeth when you have a 70 litre tank and weren't born with a silver spoon.
I blame the gov't though, because they take such a huge cut from each litre, it'd almost be free if they weren't such greedy [explicitly deleted].
[edit: Also, contrary to popular belief slowing down in the lights in gear uses less fuel than changing to neutral. As the momentum of the engine is maintained by the wheels, rather than idling in neutral.]
Practical evidence with my diesel Bora suggests this is a bad idea tbh.
I've also got to take umbridge with the advice of "accelerate slowly" that many hypermilers have given out. For the cars I've owned it actually makes things worse than if I accelerate to speed, and then keep in the highest possible gear.
Ditto, I'll never brake on the motorway unless I absolutely have to. Doing so is a killer.
It's a relative thing. They did an experiment on Mythbusters and turns out that the drag caused by open windows only really exceeds AC at higher speeds, if I recall correctly. Something around 50mph.
If I'm teaching people to suck eggs, shoot me
* Getting into the highest possible gear (leaves you with no acceleration, obviously). For instance I can just about manage 6th slightly above 30 on a flat, so if I can I'll get into that. Gives me on average about 10mpg more if I'm doing a short run city trip. I've always been taught this, but a few people I've been in the car with don't do it?
* I've been starting to time my traffic light changes a lot more, i.e. if I'm coming up to the lights I'll do my best, without being annoying, to not stop. Even just crawling forward made a difference.
* Tend not to use as much significant engine braking
* Around Bath some of the hills are derestricted and are safe to do this - effectively coasting in-gear with the brakes applied lightly as needed. Whilst this can cause your brakes to wear our a little quicker, it seems to be more cost efficient.
* Filling your tank when it's cold - you actually get a slight bit more for you money. Maybe over time you might get significant savings, I'm not sure.
* Normal things like tyres being properly inflated, etc.
That's a good point. If you are after petrol mileage then double your tyre pressures (as long as they remain below the tyres maximum as on the sidewall). Ride comfort will go down, grip will increase (the lower pressure - more grip rule is actually inverted at road car speeds/pressures/loads/constructions), and roll resistance will decrease a bit. But only a bit.
It now costs me close to £70 for fill my tank from empty, and whilst it's not a huge amount of money, trying to ek out every last mile from a tank is probably prudent, regards of the pollution.
As for the neutral thing, yeah, I think diesels are more effiecent running on engine braking rather than rolling in neutral, I don't know why, but they are.
Another myth........
Sitting at traffic lights, engine on, or engine off, I have been told that any idle time of more than 5 secs is better to switch the engine off than leave it running.
Diesels don't have throttles, so they are more efficient at part throttle. But regardless of that, if you are coasting in gear with the clutch out the fuel supply will be almost nothing. With the clutch in, or the car in neutral, the fuel supply increases a bit.
Leave it on. Otherwise the engine won't get warm (diesels are very thermodynamically efficient, so take ages to get up to temperature) so the fuelling will constantly be richer to compensate for wetting, and constant starting will put huge load demands on batteries, starters etc.
That is quite interesting to know as I am planning on buying a diesel. This site is awesome for useful information.
But the whole leave it on turn it off, what I can't get my head round is the extra fuel required to start an engine, wouldn't that out do the menial fuel spent idle?
Interesting thread, a lot of the techniques described here I've started applying recently, resulting in a jump from ~25mpg to my run yesterday of 36.8mpg over 220 miles, with a 1.8 petrol Focus. Mixed A-road & town/city driving. And I still drive it fairly normal - firm acceleration up to a speed, overtake slower moving vehicles (normally tractors), revs kept just inside its powerband. Still enjoy the drive, it just costs me less now.
One thing I found that helps, is fuel economy goes up if I coast in-gear as opposed to in neutral. I guess it cuts the fuel supply off under these conditions.
It's interesting you should say that, because I've been told before that like diesels, modern petrol cars effectively only inject enough fuel into the engine to keep the thing going and that it's pretty much kept going through momentum.. Nice to see it's actually true in practise though!
This annoys the hell out of me. On the flat with no throttle it might just about work but as soon as you approach an incline or need to accelerate you just end up with a fully open throttle and no movement. It's also pretty bad for drive components to be running near the stall threshold all the time. Surely it's better to either be coasting out of gear or accelerating with reasonable engine speed (probably around 2000rpm depending on car) with little throttle than being in gear at low revs.
Edit: Actually I can understand why. I drive what is traditionally termed "aggresively", although I'm not anywhere near as bad as I used to be. People who sit under the speed limit, or aren't moving at my pace, do my head in also. I've been known to be on the way to a client's site following a co-worker and then have to take a longer, different route, because they were going too slowly.
Which is why you then change down a gear or two to one that's appropriate? If someone stays in the lowest gear possible all the time then they're being a dick. There's saving fuel and there's driving like a cock. The two shouldn't be mixed and confused.
I've seen no evidence as such to be honest
Nope, there's a marked increase in the cars I've owned over the last few years. Even my '97 petrol Clio would be better off coasting in gear than out of gear I'm afraid.
My old Pug 307 had a trip computer, remember in neutral the consumption would be around 100mpg @ 50mph, but coasting in gear would send it to 999mpg.....
You know, I dont see how deisel is better. My car can take £30 MAX petrol. It will do, On average 350 miles per tank. That said, Deisels reward you when it comes to tax and insurance. GAH!
Diesel personally is still best in vehicles designed to pull your house down the street, Land Rovers for example, in little town cars it just doesn't feel right.
Sorry you seem to have overlooked the fact that Dan literally just said the diesel clio will do 70mpg, whereas a petrol equivalent would do around 45-50 I guess. That seems like a reward to me.
I like diesel's, just as I like v-twins, simply because of the way they drive/ride, maybe because I am a lazy ass and just like the "stick it in any gear and go" type of driving style
The price differential isn't that great now, and it won't be long before the price of diesel negates any finincial benifits.
Like Tristan said, neutral is bad for saving fuel, since it takes a bit of fuel to keep the engine running. That and most cars nowadays cut off your fuel above a certain rpm (I think 2-2.5k).
For the A/C: The little trip computer told me an increase of up to 1l/100km (let's say 35 instead of 40 mpg) for using the A/C. A quite useful solution for that: Switch on the A/C until it's cool, then turn off the A/C, usually there is no need to turn it on again for quite a while.
This acceleration thingy - didn't know that full speed ahead is really beneficial, I usually accelerate moderatly (no granny speed, but no full throttle either).
, does anyone do any of the "hypermiling" techniques?, are there any that make a difference?.
