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

steve6375

Say you are in a lane that is doing 60mph. Make sure there is a large gap in front - this can be done by slowing down slightly. Now accelerate to 65mph - the cars behind you will be left behind as they were travelling at a constant 60mph. When you catch up to the cars in front, take your foot off the accelerator again.

It really is not dangerous at all. The important thing to remember is that you must take your foot right off the accelerator or you will not save much more fuel than granny driving.

If the road is very busy then don't do this - simply use your judgement. If you can do it you will save 10% more fuel at least!

shown73

Purely as a matter of interest, how would cruise control relate to this method? Anybody hazard a guess? On a lighter note, I would have thought that anyone fluctuating between say 55 and 65, on the inside lane, with lots of rather large lorries doing 56 or 57, is going to have a very short driving career!

tinkerbell84

You look like a complete t1t though.

Wonder what would happen if the car behind you were an unmarked police car who wondered why you were driving erratically, slowing without brake lights showing, speeding up for no reason whatsoever........................

"No officer, i'm not drunk. I'm saving petrol"

:rotfl:

tinkerbell84

shown73 wrote: »

Purely as a matter of interest, how would cruise control relate to this method? Anybody hazard a guess? On a lighter note, I would have thought that anyone fluctuating between say 55 and 65, on the inside lane, with lots of rather large lorries doing 56 or 57, is going to have a very short driving career!

Cruise control keeps your speed constant. You don't have your foot on the accelerator when using cruise control. and it uses engine braking when going downhill.

Conor_3

vaio wrote: »

Sounds like it would increase the amount of fuel used rather than decreasing it. (at least if my understanding of the laws of physics is right)

It doesn't. Some Scania lorries suffer what we call the "Scania Surge Syndrome" where the speed limiter cuts out the engine at 55 MPH until the speed drops down to 52-53MPH then allows acceleration again instead of maintaining a constant 55MPH. This basically results in the kind of driving the OP is on about albeit not with the same speed difference. They appear to use no more fuel than those working properly.

Tojo_Ralph

steve6375 wrote: »

Say you are in a lane that is doing 60mph. Make sure there is a large gap in front - this can be done by slowing down slightly. Now accelerate to 65mph - the cars behind you will be left behind as they were travelling at a constant 60mph. When you catch up to the cars in front, take your foot off the accelerator again.

Conor wrote: »

Some Scania lorries suffer what we call the "Scania Surge Syndrome" where the speed limiter cuts out the engine at 55 MPH until the speed drops down to 52-53MPH then allows acceleration again instead of maintaining a constant 55MPH. This basically results in the kind of driving the OP is on about albeit not with the same speed difference. They appear to use no more fuel than those working properly.

So......

In the inside lane we have lorries, who through no fault of their own are surging back and forth between 52mph and 55 mph..... We have car drivers scrimping and saving on fuel by surging back and forth between 60 mph and 65 mph and overtaking when necessary..... We have car drivers trying to save fuel by maintaining a constant 60 mph..... And last but not least, we have everyone else trying to avoid a fatal RTA.

tinkerbell84

Tojo_Ralph wrote: »

So we have lorries in the inside lane surging back and forth between 52mph and 55 mph and we have car drivers saving fuel by surging back and forth between 60 mph and 65 mph in the inside lane and overtaking when necessary.

First thing tomorrow I'm buying a helicopter.

Conor_3

pault123 wrote: »

The speed bracket you choose to use can be as little as 5mph so its not as detectable to the driver behind as you may think.

Following a Scania with aforementioned Scania Surge Syndrome where that only drops 3MPH is noticable and bloody annoying.

redux

None of the people recommending it say anything about hills. If they had, I wouldn't be so sceptical that there's anything significant to be gained from doing this, compared to driving at the same average speed without messing around, unless in a car that has some kind of freewheel arrangement.

pault123

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.