Anyone tried hypermiling?
Before anyone says driving is supposed to be fun - I have the bike for fun. Cars are transport.
My first car (I use that term loosely as it was a Heinkel Trojan 197cc) did
100mpg without any special driving techniques - apart from picking up the back to park it as the reverse was cacked.
Did it have a reverse?
Yes but had to be blocked/locked out as I did not have a car licence and drove it as a 16 year old on a motorcycle & sidecar licence.
And no doubt it had to weigh no more than 8cwt as well. :-)
Martin
Now there's a coincidence, my first car was Trojan as well. It did about 50 miles to the pint of oil up until the point where the piston melted and a bit of piston ring got jammed in a valve. I still have the remains of the piston - it lives in on a shelf in the cloakroom!
I have a 101 Valve in the Kitchen window to remind me Dad actually knows what he's talking about and denial won't sort a V8.
:-)
Lee D
My first car was a BMW - well it actually was an Isetta bubble car with a 12BHP BMW engine so it had the badge. I only ever overtook one car, an old lady in a fiat 500 and the highest speed I ever attained was 50 mph downhill with a following wind - it was terryfying! My engine blew up one day - the piston seized and sheared the cylinder from the block which hit the shelf behind me with amazing force. I found the gudgeon pin rolling back down the hill - I picked it up an burnt my hand.
I only rolled it once, I remember being spreadeagled over the sunroof apperture watching the road fly by beneath me.
Being 6'2" I could look out of the sunroof as I drove it. I've no idea what mpg it did, I was just grateful to arrive!
The registration was VUJ 506 how sad is that?
Happy days
Tony
I have tried a tame version of this in my 135,000 mile 1996 300Tdi Disco. Taking it easy with the brakes and the loud pedal (no more than 2500rpm ever, and changing gear as soon as the higher gear will keep the turbo spinning), running the tyres at the correct pressures, changing air filter every 6000 miles, and keeping max speed to 60mph. I have not tried the "drafting" technique as it scares me a little too much. I have coasted down long straight hills when traffic has allowed, but not switched off the engine to maintain brakes and steering. Fortunately the summer has been so bad, I have not had to engage the air con!
Last tank (80% Diesel, 20% SVO) I got 32.2mpg over mixed conditions driving (some 7 mile each way commuting, some longer trips involving dual carriageways but mainly country A roads, and normal shorter trips in town and on country A and B roads, but most of it with the whole family, picnics, pushchairs and other kid accoutrements in the car). It shows that with a little thought, economies can be made.
I was generally getting about 28mpg before, and the previous record was
31mpg coming back from Scotland to Somerset (single trip, all motorway at around 70mph, stiff tail wind all the way).The difficult bit is when drivers in front brake too much or inappropriately, forcing you to lose momentum. This can be alleviated by leaving a bigger gap, but then someone always jumps into it! Traffic lights are the biggest pain. Over the last few years they seem to have multiplied (not always sensibly). I wonder how much fuel is wasted stopping and pulling away again as a result?
Tim
I got from 42 mpg to 50 mpg by some careful adjustments to the driving style, such as:
- gentle acceleration
- using the highest gear possible without labouring
- anticipating stops by slowing down early e.g. for traffic lights
- allowing the vehicle to slow gradually on uphills
- coasting in neutral where safe on downhills (engine running)
The last one seemed to have the greatest effect on the mpg figure. This was all on a fairly straight A-road journey. One day I was forced by the County Show to use a stop-start up-down B-road route, and the figure went down to
45 mpg. As to how much is wasted in starting & stopping, the answer seems to be 'lots'. Keeping the car moving, even slowly, is very beneficial, apparently.I've stopped doing it. I got bored :-)
Look further down the road - a green light only ever turns red, slow up on greens that are a 1/2 mile away. Increase speed on reds to catch them when they turn green, the increased acceleration and fuel used is negligible compared to that used when stopping and re starting.
Another technique to improve fuel economy can be done by progressively increasing engine rpm on each up shift eg; 1st go to 1000rpm, 2nd goto
1200rpm.....5th 2000rpm.Use your brakes to slow down - not the gearbox, but if you are looking further down the road all you need to do is take your foot off the throttle.
I've made a conscious effort not to drive above 80kph, on about a 110km commute, I used to fill up twice a week, now down to 3 times a fortnight. My trip time is about the same as the last 20kms is in heavy traffic which invariably is stop/start. I feel better for a couple of reasons - 1. I am not feeding the oil companies as much. 2. Driving at 80kph is relaxed.
I would have expected any recent engine management system to stop feeding fuel once the car was driving the engine rather than the other way round.
Pete
I quite agree. And yet a week of commuting with one or two big hills and a dash readout that responds pretty quickly to changes suggests otherwise. The difference between coasting down a hill in 6th with an idle throttle, and doing the same in neutral is quite significant. Don't ask me why.
You need to see any use of the brakes as a failure - energy you have stored in the car's motion is wasted as heat and is not recoverable. Anticipate any delays, and judge your coast to a slower speed carefully.
One technique which the serious guys use is called Pulse and Glide. Basically, you use gentle throttle to get your speed up to (say) 60 mph, and then coast (with the engine off, if you dare) until your speed drops to (say) 40. Repeat as necessary. Logic tells me this won't make any difference, but RW experience says it does. The theory is that you have divided your journey into two parts - 50% gently accelerating and 50% coasting. If you get (say) 40 mpg gently accelerating and (say) 100 mpg coasting, then your journey average is 70 mpg - compared to the (say) 60 mpg you might have got on a run with a steady throttle. There are obviously lots of variables, and this seems to me counterintuitive, but apparently it works. If you follow the links from the Wikipedia entry it explains it much better.
The serious guys also recommend coasting with the engine off at higher speeds. The reasoning is that at higher speeds you don't need power steering, and you have a decent reserve in the brake reservoir for 4-5 applications. I haven't tried this. It seems to be taking the desire for an extra 0.5 mpg a little far.
Some of these ideas (e.g. turning the engine off when it isn't needed) are getting to be mainstream hybrid technology now.
Modern diesels do that - not sure about petrol. So it is always best to coast in gear, rather than neutral.
I got 78.9MPG from my C4 the other day on a 100km 'country road' trip by driving efficiently (and not driving particularly slowly either - never less than 80kph and up to about 100 depending on hills etc) I reckon I could get a bit more too, but the odd car was too slow and I had to overtake.
Matt
On or around Sat, 23 Aug 2008 21:11:37 GMT, "Cruizin" enlightened us thusly:
depends on the motor.
modern engine management has fuel cut-off on over-run, so use a lower gear for decelerating to keep the revs above the cut-off level. Hell, my 91 rangie even does it, the low end of the cutoff is about 1300 revs - if you decelerate on petrol you can see the rev counter kick when the fuel comes back in (auto box).
On or around Sun, 24 Aug 2008 09:18:23 +0100, "Rich B" enlightened us thusly:
you're doing it wrong. Get the revs up to 1500 or more and it should cut out. Only applies where the hill/speed equation means you need retardation to keep the speed you want. But in 6th, at moderate speeds, the revs may be below the threshold. You need more information to really test that.
I only ever do that in a motor with no servo and no PAS. Used to do it in the SII, I could get about 5 miles of coasting down the black mountain towards Llangadog.
Basically, on modern stuff, it's really not safe. Suppose there's a minor vacuum leak, which normally you'd never even notice, but it bleeds the vacuum over a couple of minutes? Or suppose a sudden need to swerve due to something appearing in your lane?
Also, I reckon you'd lay yourself open to careless or reckless driving if it came to it. I'd go up in court and defend coasting with the engine live, but it'd be a sticky wicket to defend coasting dead-engine.
On or around Sun, 24 Aug 2008 10:24:19 +0200, Matt M enlightened us thusly:
Petrols do as well - and far from modern ones: the hotwire V8s do, the flapper V8s do, and my '86 sierra with bosch k-jet does. I don't see why newer stuff wouldn't.
Need to see about making the rangie do it on gas.
I didn't know there was a threshold. But the quiet of coasting down a long moderate hill in neutral is very pleasant.
Indeed. I wouldn't risk it for the tiny advantage gained.
I think you'd be on a sticky wicket either way - but coasting in neutral would be very hard to prove, whereas an accident to a car where the engine wasn't actually running should be pretty obvious to any investigator.
On or around Sun, 24 Aug 2008 09:45:12 +0100, "Rich B" enlightened us thusly:
used to do it in an ancient burper van, it made it go faster, hence the coining of the phrase "downhill overdrive".
you may or may not be able to detect the cut in/out points for ORFCO by ear, or by the way the car reacts. If it's manual, when the fuel comes back in you can normally hear/feel it.
similarly, if you start off slowly downhill and let the revs increase, you may be able to hear it cut off as well.
could on the V6 in the sierra.
Funny enough there was a Fifth gear programme on a couple of weeks ago testing the practice. It involved reducing weight, taking out the spare wheel using horrendously expensive fuel saver tyres setting the correct (my arse) manufacturers recommended tyre pressure etc etc and driving at the same constant speed around a test track. I won't spoil the ending and the conclusion which you might guess.( this means I already knew what was coming and dont require some smartarse to point out the obvious that we dont all drive on a test track or at a constant speed) which as I review the clip is missing oh bugger)
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