Safe Speed Forums

I 'dab' the throttle........I set the trip computer to give me instantaneous MPG and try to keep it as high as possible....as the mpg rises to a peak i give a dab then let momentum take its course until it needs another go..trying to keep around 80mph..I can get some really good figures out of my barge....i think clarkson was doing something like this when he did london/edinburgh rtn in an A8.

More often than not though I just drive normally.

I have seen it stated that this approach of "rowing" the car along the road tends to lead to lower fuel consumption than maintaining a steady speed.

Certainly, without taking it too far, taking the foot off the gas on long motorway downgrades will usually show a benefit on the trip computer.

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"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace." (Austin Williams - Director, Transport Research Group)

Any views expressed in this post are personal opinions and may not represent the views of Safe Speed

Is this why a human can beat cruise control for economy?

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

although i havent attended the Safe And Fuel Efficient Driving (SAFED) course myself (government pulled their funding) i have been told some of the things taught ie when approaching a junction/roundabout etc, knock it out of gear until you can see whether or not you can go then select the appropriate gear when you are about to go. block changing is another big one. a truck uses 1.4p per gear change so cut down on them. the long term saving will add up (admittedly to a lesser extent for a private user over an operator with 100 trucks).
having conducted an amateur experiment myself i have concluded that cruise control is more expensive than human control. i know that when i knock the cruise control off in my car and reactivate it the accelerator does move to around half way whereas i use the terrain to accelerate and slow down.

generally i would say my driving style is averaged by economical driving when i can and booting it when i need to. im guessing my fuel consumptiom would equate to the average driver rather than those here who know how to drive properly.

in addition:
put your car on a diet. anything carried in your car that is not needed is dead weight and is costing you
ditto roof racks etc spoiling the air flow over and around your car.
night driving is cheaper on longer journeys. yes you need lights but you will avoid traffic jams and cut down on previous points ie stop/starts at junctions/roundabouts etc.
look ahead. i look as far as i can see. if there is something coming up, get off the accelerator early and allow gravity and friction to slow you down gradually rather than use the brakes (saving wear and tear on the brakes too) until you need to press a pedal.

from experience a 500 mile motorway journey is far cheaper at 60MPH than 70 or 80. in my cars case it is around 1/4 of a tank ie southampton to stirling cost me 3/4 of a tank in a 2.0i petrol saloon
dont buy a G reg toyota supra 3.0i turbo. it costs a tank and a half for the same journey

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Richie

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From personal experience I can only say that it works.

its a little like a hula hoop with a stick just tapping every so often to maintain momentum......theres a marked difference between this approach and cruise control...the car is much quieter using the 'dabbing' method which implies to me that te engine isn't working as hard.

It certainly gives you something to occupy yourself on a long journey!!

This is not exactly the same as you describe, but I recalled reading about in auto express some time ago and did a bit of a search, and found it on the driving times online website:

http://driving.timesonline.co.uk/tol/li ... 649402.ece

Apparently, drive hard to 2000 rpm then coast can improve consumption.

Unlike others above, my cruise control generally gives me a slightly better fuel consumption than my right foot; well, I say that but thinking about it that's just an impression and not backed up by any statistics so should probably be ignored!

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COAST Not just somewhere to keep a beach.

A young loner on a crusade to champion the cause of the innocent, the helpless, the powerless, in a world of criminals who operate above the law.

I can see both sides here, but quite frankly, I have limited sympathy for anyone who's feeling the pinch at the pumps. There's nothing new in Peter E's suggestions in the original post - I can remember all those being trotted out in the 1973 oil crisis. One of the problems is the refusal of many people to take matters into their own hands and choose a suitable vehicle that delivers adequate performance and economy. Then, when fuel suddenly gets expensive, these people get caught with their pants down. On another (American) board, I'm reading posts by guys crying in their beer about having to dump the 16mpg SUV.



A few years ago, I asked on this board, in this thread - viewtopic.php?f=9&t=1347 - what type of fuel people used in their vehicles. 68% said petrol. I had seen the writing on the wall with regard to petrol prices, and in deference to the huge advances made in diesel engine technology, I bought a Golf 1.9 TDi-150, and nearly doubled my mpg from 27 to around 50.

But in that thread, some people steadfastly refused to consider diesel!

Some interesting quotes from that thread


Whoever wrote that has no idea of how to drive a diesel. You DON'T redline the thing as you might a petrol engine. Max torque will be somewhere around 1800rpm, not 3300rpm as it might be for petrol. I rarely exceed 3800rpm with mine.


My Audi A4 3.0TDi has a top speed of 150mph, and accelerates to 62mph in 7 secs. How much faster does it have to be to qualify as a "performance car"?


Mine hardly makes a sound. Gizmo, I'm offering you a ride in my A4 - you will definitely change your mind! PM me with your whereabouts.

I do a lot of long journeys. I've just come back from a round trip to southern Germany. Where permitted I let it rip - 135mph at times, but mostly 110-120. Er, yes the fuel economy takes a knock then. But even my 150mph car can and will achieve 43+mpg on a long run up the M6 - partly because it's usually busy in Staffs/Cheshire, and I have to do 70! On one tank of fuel (63 litre tank) I can even drive from home up to the Ormskirk area of Lancs - and back.

So, in addition to Peter E's recommendations made in his original post, I would like to add this: If money is tight, consider alternative fuels. Do not dismiss diesel out of hand just because of something you read or heard about it 20 years ago. I have 4-5 diesel convert friends. My ex girlfriend bought a 2nd hand Skoda Fabia (18 months old, 18K miles) for £7.1K. It has the 1.9 105PS TDi engine, and gets 68mpg. I've driven it myself, and it's no slouch.

But my wife's 325ti will do 39mpg if driven at 70, given the higher price of diesel it works out to near enough the same cost. If it was a manual I dare say it would do an even better mpg and the 0-62 dash is the same as yours.

We did consider the Seat TDI range with the dsg box but she did not like the cars.

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Driving fast is for a particular time and place, I can do it I just only do it occasionally because I am a gentleman.
- James May

I don't think any Diesel gives a "performance feel" when driving as the flat torque/power curves don't give you the petrol kick at high revs. That doesn't stop them being very fast though.

My Diesel 4x4 is a fantastic piece of work with dual turbos to give seamless (no lag) power up to 5,000rpm. It's not a sports car.

My sports car has a lot of torque but it's the top end power and noise that makes the experience of driving it. It's not a Diesel.

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

drive with you windows shut,
air con off,
tyre presures correct
remove all the spare junk you keep in the car
remove roof bars
fit narrower tyres
(do you really need those wing mirrors and second windscreen wiper? )

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Speed limit sign radio interview. TV Snap Unhappy
“It has never been the rule in this country – I hope it never will be - that suspected criminal offences must automatically be the subject of prosecution” He added that there should be a prosecution: “wherever it appears that the offence or the circumstances of its commission is or are of such a character that a prosecution in respect thereof is required in the public interest”
This approach has been endorsed by Attorney General ever since 1951. CPS Code

I get about 40 mpg out of my Jag 2.7 TDi which I think is pretty good going for a motorway/urban mix. I actually rarely drive as I described earlier but rarely floor it.

Mind you when I do it doesn't half shift.

For some reason I'm picturing a Class C Amplifier...

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Andrew.

According to this chart, cruising between 35MpH and 60 MpH /55KpH and 97KpH yields best Fuel Economy (in a gasoline vehicle, though I doubt diesels would get better Fuel Economy above 65MpH / 105KpH).

Assuming it were possible, I guess the best way to get incredible Fuel Economy would be to accelerate up to about 60MpH, then coast back down to 35MpH, then repeat for best MpG. This would also no doubt enrage everyone around you.

I'd love to put a diesel engine in my Caprice Classic Wagon (you might call it an estate). It gets about 15MpG when I can keep my foot out of it, which isn't often.

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The Rules for ALL ROAD USERS:
1) No one gets hurt
2) Nothing gets hit, except to protect others; see Rule#1
3) The Laws of Physics are invincible and immutable - so-called 'laws' of men are not
4) You are always immediately and ultimately responsible for your safety first, then proximately responsible for everyone's
Do not let other road users' mistakes become yours, nor yours become others
5) The rest, including laws of the land, is thoughtful observation, prescience, etiquette, decorum, and cooperation

Hey! Chill out!

I did understand that you were quoting Jeremy C and it was HIM I was disagreeing with - not you! That said, I understand a bit more now that you've explained some more background and, of course I agree with much of it. I still, however, don't believe that the most economical drive is necessarily the safest.

Yes they are all true but the extent to which they make a difference needs careful scrutiny. They're a bit like the blanket "every 1 MPH of speed reduction gives a corresponding "x%" reduction in KSIs. Clearly, when disected an analyzed, it can't always be true!

Aircon. On a hot day, there is no doubting that aircon DOES consume power. It will be removing several kilojoules of heat energy from the car per unit time - which means several kilowatts of power. That power can only come from the engine. In fact, on some cars if you drive very slowly with the throttle at a very small opening and switch on the aircon on a hot day, you can sometimes feel the car slow down very slughtly. On the other hand, on a cold day, it will hardly use ny power at all. Below a certain tmperature, the compressor won't cut in at all - regardless of whether or not the switch is pressed. Also, the aircon on a small, well-insulated car with a smal lglass area will use less power than the one on a big "people carrier" on a hot day. I'd guess at an average saloon car on a farily hot (say 25 degree ambient) day might use a couple of kilowatts (about 3 bhp).

Headlights consume a tiny amount of electricity by comparison. The old fashioned "halogen" bulbs are 55 Watts apiece. Sidelight at each corner are about 10 Watts. Call it 200 Watts total for a car with multiple tail light bulbs and number plate light bulbs. An order of magnitude smaller than the aircon. Nevertheless, the power for this does, ultimately, come from the engine.

Sound system - well, unless you subscribe to "Max Power" and have more power driving the bas tube and sub-woofers than you have driving the car, it's almost negligable!

Incidentally, nobody has yet mentioned bumps! Road irregularities cause the wheels to move up and down. This measn that energy needs to be put into the springs and dampers. The springs don't use much "power" because they store the energy and release it again, but the dampers definitely dissipate power - they get warm. The bumpier the road, the warmr they get. It's all "waste" heat that MUSt come from the engine initially! The government could do something useful for the Nation's CO2 emissions and smooth out all the roads!

HoHum-problem is that some of the big names are low on both quality and economy .
Me - my latest is a non UK/non GERMAN CAR .
Working out figures for my last trip south - full tank at Glasgow - trip miles said 610 miles . At around 45litres in the tank (approx 9.8 gal) =62 mpg.(andthat was slowing down around J37 to 70 ).Oh-it's a TDi ,only 70 BHP on the box-more like 120 outside .

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

One of my diesel converts bought a Seat Leon TDi when he came to sell his Ford Focus. I think he's getting 50mpg+ with the 2.0 TDi-140 engine.

And his girlfriend has just bought a Mini TDi. I don't know much about that model range, but it gets 69mpg. But the downside is that whereas her previous Mini seats were excellent, the seats in the new one are crap.