Ways of conserving fuel while driving

I've being trying the "hypermiling" approach for the last couple of weeks, I don't want to state my improved economy figures just yet, I want to do a few more miles yet before I make a judgement on it.

I've been driving under the legal limit (rarely ever over 90/ 95 anyway), accelerating gradually and slowly, using the gears to slow down, allowing the engine to "overdrive" ("coasting" whilst still in gear but not applying the accelerator) when descending hills etc. It's certainly a more "relaxed" style of driving and i'd imagine a lot safer, although I imagine it probably infuriates the one or two impatient drivers who are in a hurry and stuck behind me on the country roads I use each day! I notice that I'm braking far less often as I can safely anticipate the road and traffic conditions ahead. It's an easy enough challenge for because I'm driving mostly on country roads where high speed is not safe anyway, but Icouldn't imagine trying "hypermiling" on the motorway, I don't think it would be a terribly wise or safe thing to do. Another plus I would imagine for this driving style is that it has to significantly prolong the life of tyres, brakes, suspension etc so i think I'll be sticking with it for another while!
 
Not sure about diesels but for petrol cars, I've heard it said that fuel consumption increases quite dramatically if you either go over 60 mph or 3000 rpm.

Myth?
 
Caveat said:
Not sure about diesels but for petrol cars, I've heard it said that fuel consumption increases quite dramatically if you either go over 60 mph or 3000 rpm.

Myth?
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Definitely not a myth! Air pressure goes up exponentially as your speed increases. As for engine revs, well, less is always better since more revs equals more pulses of the injectors in a given time. Think of it like you were riding a bike. It would take a lot of energy to go like the clappers wouldn't it? And spinning the pedals like mad in a low gear would equally wear you out!
But back to cars; i find the most efficient speed in a petrol car is about 80kph. My diesel cee'd seems to (when the engine is hot) get better all the way down to 60kph when i have to drop to 4th. I got 188mpg in it between the N2 slip road on the M50 to Coolock. About 7 or 8 minutes driving. Diesels are strange beasts indeed!

ollie
 
Old thread i know but i found this article interesting.

[broken link removed]

I drive the same 60 mile route to work so i know the road well and as i normally have the road to myself and it's mainly two lane i free wheel down most hills, if i can get half a mile out of it i do it, reckon im getting 6-10 "free miles" out of it each way. But im just wondering how much petrol does a free wheeling car take?

Also for the record im very careful when i do it, i leave the motor on obviously and keep my distancee, normally doing 80-100 on a motorway or if someone's behind me i just keep the limit.
 
If your car has a fuel consumption display, set it to show the instant consumption. Then, while you are coasting you will see how much fuel you are using. Diesels seem to use approx 0.3 to 0.5L/100k which is virtually nothing. Petrols will probably use more but i'm open to correction.
The fact that they use nothing while engine braking is true, but you slow down much quicker and have to re-accelerate again. Although i did a test drive in the 308hdi recently and found it hardly slowed while engine braking. Very nice!
 
Speaking for myself I started to use Dipetane and it has certainly increased the mileage.
 
I got a bottle of that to see if it was snake oil. It did cut down the smoke and soot i get from hard acceleration after long distance nana driving, but i didn't see much mpg gains. The weather turning bad may have contributed though. I'll use it again next spring/summer and see how it goes.
 
ollie323 said:
I got a bottle of that to see if it was snake oil. It did cut down the smoke and soot i get from hard acceleration after long distance nana driving, but i didn't see much mpg gains. The weather turning bad may have contributed though. I'll use it again next spring/summer and see how it goes.
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Last time I went down to Cork (boating trip) I filled the tank up and put some Dipetane into it the tank lasted the complete drive down there and 3 days driving down there then when I was returing to Dublin I filled it up again and it barely lasted me getting home so for me it's an easy one I'll always use it.

Also if you use this regularly it will cut down on your emissions for the NCT (DOE in my case).
 
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