Best Economy - Cruise Control use or not ?

[bertone]

Appologies if this has been debated before ( I've done a search but not found the specific topic) but to achieve the best economy, should cruise control be used?

I've always assumed that the best economy is with the use of cruise when the opportunity arises, eg decent traffic conditions on motorways, but somewhere I've read that this is not the case.

Can anybody advise please.

Many thanks.

[bertone]

Appologies if this has been debated before ( I've done a search but not found the specific topic) but to achieve the best economy, should cruise control be used?

I've always assumed that the best economy is with the use of cruise when the opportunity arises, eg decent traffic conditions on motorways, but somewhere I've read that this is not the case.

Can anybody advise please.

Many thanks.

Sorry should have mentioned that my Octavia is a DSG which may be relevant.

[VRSPhil]

It depends how hard you concentrate IMHO.

If you are using cruise control, the car will maintain a speed, regardless of hills. So it will open the throttle more to maintain a speed up a hill. If you are using your foot, you might accept a slight drop in speed up a hill in return for not using so much fuel.

I find I CAN get lower consumption if I control the speed myself, but at the same time it's easy to let the speed creep up, which ruins it!

[rwbaldwin]

CC is very good at maintaining a constant speed and that's all. It can't see the road ahead, so it doesn't know that there is standing/slower traffic, a roundabout, etc. When you want to drive economically, you rarely drive at a constant speed

[alkip]

Selective use works for me :yes:

[Aspman]

I always get better mpg using my right foot but I use cc on long steady runs because it's a convenience. It's not a big penalty to use it.

[littleade]

Like everyone says previous it depends on a number of factors including how smooth a driver you are. On roads that arn't too hilly when traffic is light I use cc, other times I don't. I'd say it doesn't make much difference over a long journey.

Plus point - good for avoiding speed creep and 3 points

(slight) minus point. I feel I'm more prone to loosing concentration on long boring runs as its 1 less thing to keep you occupied and alert, though others might dissagree

[biotechpete]

I tend to find CC is less economical than controlling seed myself. That said I rarely find a bit of motorway which is uncongested enough to use it these days.

[Phil-E]

As above.

CC can get you better economy if you're not the most economical driver to begin with.

A good example is my other half. They are much more economical with CC on than driving with their foot.

I can get better economy without CC if I can be bothered but sometimes, on an open stretch of road CC can be much nicer to use rather than concentrating on your speed all the time.

If you're on a very hilly road then not the CC off and drive manually where you might want to ease off going down hill, build up a bit more momentum going up or be prepared to loose a bit of speed in the name of saving fuel.

Flat motorways you may as well let the CC do it's thing.

Phil

[nickguzzi]

For me, CC everytime. I regularly do 600km stints from the Channel to Frankfurt, plus the 180 miles from Dover to home.

The A14+M11 had sufficient cameras (welcome back by the way) to make it so much easier to just plonk the CC on and just concentrate on not being involved in other peoples contretemps. Easier on the arthritis too and another topic aired on here, the too firm side bolsters digging in your leg.

Several times, I have done the Dunkerque - Lille - Liege - Koeln - Frankfurt only having to drop out of CC on a handful of occasions. Quite often, the A3 - A4 interchange can be done without interference, but the A4 - A44 cannot - under any circumstances, the road works there currently may change that. The interchange at Lille is also do-able, but the flyover and subsequent speed limit demand a slowing.

As I have only once done the journey in a Skoda with out CC, its hard to tell but my usual consumption is low 50's, CC clicked on at about 80/85. Under conditions of heavy traffic with the CC off, I find my speed creeps up to that of the native, ie 90+, so there is no saving there, with my undisciplined habits.

Of course, the other major saving is not having to pay speeding fines. I am getting much better at using the CC to control my speed rather than just following the herd. Obviously I would never dream of doing so without being led astray by the naughty boys.

[countryboy]

If you are on a long steady road then CC is probably better, however when the going is a bit hilly then I find I can get better mpg using my foot, the CC cannot see the hills and lift off as you approach the summit neither can it see the long decent to a junction and lift off early.

Ian

[booke23]

If you are on a long steady road then CC is probably better, however when the going is a bit hilly then I find I can get better mpg using my foot, the CC cannot see the hills and lift off as you approach the summit neither can it see the long decent to a junction and lift off early.

Ian

+1

CC is great on the motorway for economy, but for maximum economy on twisty/hilly roads then it's better to make use of your foot.

[andyvee]

Sorry, I disagree. Unless the road is completely level, cruise control is less economical.

When driving on motorways the natural thing to do is to keep a constant throttle position. This means that you will speed up down hills then scrub some of that speed off going up hill. Cruise control does the opposite as it maintains a constant speed. It will open the throttle up hills, and lift off going down. This uses more fuel. Just watch the instantaneous mpg when on cruise and going up hill - it gets into single figures sometimes in order to maintain a constant speed.

The only thing I use cruise for is average speed camera zones.

[booke23]

Sorry, I disagree. Unless the road is completely level, cruise control is less economical.

When driving on motorways the natural thing to do is to keep a constant throttle position. This means that you will speed up down hills then scrub some of that speed off going up hill. Cruise control does the opposite as it maintains a constant speed. It will open the throttle up hills, and lift off going down. This uses more fuel. Just watch the instantaneous mpg when on cruise and going up hill - it gets into single figures sometimes in order to maintain a constant speed.

The only thing I use cruise for is average speed camera zones.

I see what you are saying. But you still have to get up the hill somehow. Watch the instantaneous mpg when you're using your foot.....it still drops.....albeit very slightly less if you let the speed bleed off. But realistically how much speed will you let bleed off?.......probably no more than 5-10 mph.

You can turn the argument around and say that with CC set at a constant speed.....yes the throttle will open going up the hill, but going down the other side the CC will lift off to maintain speed, rather than let the speed built at the constant throttle setting you mention....so the CC actually saves you fuel on the way down.

[andyvee]

Try it, I get about 5mpg less on a 250 mile run I do regularly to London when I use cruise. I know what you say about cruise lifting off when you go downhill, but I find when not using cruise I am about 10% more economical.

[RainbowFire]

You can turn the argument around and say that with CC set at a constant speed.....yes the throttle will open going up the hill, but going down the other side the CC will lift off to maintain speed, rather than let the speed built at the constant throttle setting you mention....so the CC actually saves you fuel on the way down.

I take mine out of gear going downhill, the instant readout just goes "----" ;)

[andyvee]

Not something I would do at motorway speeds.

[Chappers.]

CC will never be as economical as a well driven car without it use - it's sole purpose is to maintain whatever speed has been set regardless of how much throttle is required to achieve that speed. That said, I notice that OP has stated that his is a DSG - surely for ultimate economy the manual version would have been better? Personally, whatever the difference in fuel consumption from using CC is worth it for the extra comfort of being able to set the speed and concentrate on pointing the car along the motorway (and also not worrying about my speed creeping up and any subsequent speeding ticket).

[Anddenton]

I take mine out of gear going downhill, the instant readout just goes "----" ;)

Even better cut the engine and take key out of ignition, the tank actually refills.

[4wheel]

Better still.Cut the engine and go in reverse.Not only does the tank refill but you actually end up with more fuel than when you started.I thought everyone new that. :evil:

[Zlin]

I usually get better mpg without the cruise control on, if I just hold the accelerator fairly constant and let the car speed drop a little up hill and then gain a little on downhills. Don't like doing that where I'd hold up folk behind me though.

[rwbaldwin]

I take mine out of gear going downhill, the instant readout just goes "----" ;)

No it doesn't. With the car out of gear, the engine needs fuel to idle.

You only see '----' when the car is in gear, with no throttle. The momentum of the car keeps the engine turning, so fuel is shutoff (indicated by '----').

It's also illegal to coast in Neutral as you are not considered to be in proper control of the vehicle.

[eccleshill]

No it doesn't. With the car out of gear, the engine needs fuel to idle.

You only see '----' when the car is in gear, with no throttle. The momentum of the car keeps the engine turning, so fuel is shutoff (indicated by '----').

The mpg readout on the computer is very coarse for instantaneous readout where very little fuel is being used - the l/100km gives more precision that proves your first point.

If you have maxidot then change the units for consumption/distance to km and l/100km

Foot off throtle, in neutral downhill and the instantaneous readout will show (on my 1.8TSi) 0.7 to 0.8 litres per hour - ie the fuel needed to maintain tickover

Foot off throttle in gear downhill and the instantaneous readout will shoe 0.0 litres per hour - ie the wheels are driving the engine and the management system has cut off the fuel.

Coasting in neutral saves fuel on an old carburettor engine but not on a modern vehicle with fuel injection and engine management system. There are legions of folk who refuse to accept this and I await the flack from the "hypermilers". But if it keeps them happy...

Edited 17 November, 2012 by eccleshill

[SJFISHER67]

I only really ever use mine when in a strange area so I can keep my eyes on the road or where there might be speed cameras, never use it on the motorway, it's handy to have though.

[mr_awol]

Not something I would do at motorway speeds.

Not something I would do at all. Not necessary on modern anyone's and dangerous if you conk out......