Pulse and Glide driving technique - the forum says NO! ;)

darich

Surely the only people interested in annoying other drivers this way would be the ones driving the smallest engines since they're the most economical?
I mean what's the point in buying a 3.0 then trying get another 3-4mpg out of it? Why not just buy a cheaper car?

And to claim that "3mph isn't as notcieable as you think" - think about this - when a truck pulls out to overtake another and it's only doing 3mph more, it takes ages to pass - proobably close to a mile.
That 3mph difference doesn't bother you when there's a rolling road block caused by two trucks?

Conor_3

redux wrote: »

None of the people recommending it say anything about hills.

On the economical driving course I did, it said to maintain speed up hills. Strangely, they never mentioned pulse and glide...:p

redux

pault123 wrote: »

In 6th gear doing 65mph and taking your foot off the revs and dropping to 60mph isn't an instant thing. It really isn't as noticable as you think.

I'm not advocating using this when its busy, or on singlecarriage ways with cars close behind and infront, etc please use a bit of common sense. But when conditions allow its just another techinique that can be used and when practiced properly will increase fuel economy.

On descents it can be used in some cases for the entire length and no change in speed whatsoever due to momentum.

But that isn't the same as what you suggested to begin with

Varying the speed with other conditions constant can't make the difference; it takes effort to regain that lost speed

On a downhill stretch, if you were in a car equipped to freewheel with the engine off and in a position to safely let it actually accelerate, then you would be making an overall gain. But in an ordinary car, rumbling down a long and multiple-curved gradient with a speed limit of 50 mph doesn't use any fuel anyway.

Even an internet search for the phrase pulse and glide turns up results that tend to suggest this would only be worthwhile on hybrids. But another thing about hybrids is they are known to generally underachieve the fuel consumption claims made for them, like a newspaper's recent test of the Prius against a 5-series BMW diesel, both about 50 mpg.

iltisman

In years of saving fuel on a 281 mile comute I found a Volvo S80 D5 manual with cruise control really economical (60-65 mpg) I bled speed off using the cruise when climbing and recovered the speed when descending I also found GPS useful as you could start slowing for the congested junction 2 miles away and let the fuel wasters charge up to it.
I wonder how much fuel will have to be before the people who whinge about us fuel savers actually have to join us.£2.50 a litre ?

redux

darich wrote: »

Surely the only people interested in annoying other drivers this way would be the ones driving the smallest engines since they're the most economical?

Some of the adherents seem to spend the other half of their time writing webpages about getting 100 mpg from a Toyota Prius by driving at between 26 and 41 miles an hour, complete with detailed instrument panel photographs which might lead some to suspect they aren't duly concentrating on looking where they are going

http://www.cleanmpg.com/forums/articles/t-pulse-and-glide-plus-warp-stealth-in-the-prius-ii-for-maximum-fe--1224.html

I think most people would become neurotic if forcing themselves to drive like this for more than about 40 minutes at a time

I wonder if they bothered with any comparison tests to figure out if the car might manage 100 mpg anyway at a constant 31 miles an hour?

Tojo_Ralph

pault123 wrote: »

In 6th gear doing 65mph and taking your foot off the revs and dropping to 60mph isn't an instant thing. It really isn't as noticable as you think.

In the interests of research, I tried the 65 to 60 and back again today and I am now even more convinced that it is dangerous and I now realise just how bl00dy difficult it is!!

So driving along at 65 on the flat, I lift my foot off the accelerator and it takes just 7 seconds for the speedo to fall to 60 mph .... So it's back on the accelerator and easing the car back to 65 mph takes 8 seconds .... Then it's foot off the accelerator for 7 seconds .... On for 8 seconds .... off for 7 seconds, etc, etc, etc .... And all the time I am spending more time monitoring the speedo than I am spending watching where I am going.

And above all else, it's hard work monitoring your speed to the point of fluctuating up and down between 60 mph and 65 mph TWO HUNDRED AND FORTY times an hour!!!

Sorry..... Give me cruise control any day.

pault123

Tojo you may have a point there LOL :rotfl:

I've only used it when conditions allow, perhaps the mpgs from the constant speeds have positively skewed my averages

banger9365

so it's all you lot thats slowing us down when we are trying to do ower jobs is it and leaving in us the middle lane when we are overtaking you when you pull and away slowing us down for no reason .
have you ever through of how much fuel them lorry are using by the way you lott are driving trying to get a few more miles out of a litre of fuel.
it wastes more fuel that you save in money ,lorrys uses it and putts your shopping bill up
it's not strait away put evenally it do's

tinkerbell84

pault123 wrote: »

Tojo you may have a point there LOL :rotfl:

I've only used it when conditions allow, perhaps the mpgs from the constant speeds have positively skewed my averages

time to edit your OP and thread title

AdrianHi

I don't think this is really viable as a fuel saving technique in the main.
In order to avoid creating congestion, frustration and increasing fuel consumption for everyone around you, you need to be doing your P&G on an empty road.
How often does that happen?
OK some of us work shifts or whatever and are on the road when it's clear, most of us are not.

It creates congestion because by not travelling at a consistent speed with everyone else you are creating waves in the traffic flow behind you which get bigger as they go back down a line of traffic.