Has anyone ever worked out which is more economical on the motorway. Cruise control on or off?

id say it depends on the level of precise control and discipline of the driver some would find it exhausting to maintain a high MPG effectively for long distances I only do it when im bored or to keep awake or like at moment to see what I can get from car rest of time I just turn it on because im lazy and ive paid for it since I bought the car ! likewise with air con if I want it its ON!

Personally my foot is more economical i can average 40mpg at 70mph only thing is it gets terrible cramp then i'm onto the CC lmao

I have always found CC to be more economical, the only exception is when going up steep hills, as CC obviously can't read the road so will accelerate all the way up it, whereas a driver can lift off towards the top of the hill.

It does however need you to read the road much further ahead, driven this way you rarely need to turn the CC off unless you are in really heavy traffic.

One thing you do tend to notice when using CC a lot is other motorists speeds go up and down quite a lot!!

I drove from Calais to Bordeaux in one day and apart from a couple of autoroute junctions and Rouen, cruise control was used the whole way to maintain 130KMH. There is no way that over 500 miles I would be able to maintain an economical driving style, and I did not want to get the unwanted attention of the Gendarmes. Fuel economy was pretty good, in my DSG PD140 Superb2 I got the whole way on the same tank.

I only use it over long distances on really quiet roads. Using it on the M1 or M25, even with flowing traffic is going to be difficult and you'll spend more time engaging and dis-engaging it.

"on" for me.

but i only use it when doing long distances at speeds of more than 100km/h.

Absolutely invaluable for those 50mpg average speed checks on roadworks.

But sticking to the point of the post I can't see how CC can be less economical, even if you are going up hill it stops accelerating at the "set" speed. I've never known CC make me go faster than the set speed because it doesn't know you are nearing the top of a hill. They computer puts just enough petrol in to maintain the speed.

I suspect that when people say they can drive more economically without it they are not actually maintaining the same average speed as CC will.

Of course if you put the CC on and then just fly up to slower drivers and slam the anchors on at the last moment when they don't get out your way I guess that won't be very economical, but its also a bit anti-social!

Edited 18 July, 201114 yr by juan27

Personally my foot is more economical i can average 40mpg at 70mph only thing is it gets terrible cramp then i'm onto the CC lmao

TSI will do 40 mpg with the CC on.

Edited 18 July, 201114 yr by juan27

Depends on the route really. If it's quite hilly for the duration, then CC will have a harder time and will try to maintain your set speed no matter what, which ends up using more fuel.

But as said, over longer journeys I find it invaluable, mainly because I don't have to spend the whole time watching my speed, and I'm also less likely to try to keep up with other traffic - which results in me travelling quicker and using more fuel and also possibly attracting the attention of the law

If you are a good driver and anticipate the road conditions you will be more economical than CC, it will simply try to maintain the desired speed uphill and downdale. By looking ahead you can see the top of the hill and lift off the throttle just before. You can go slower up an hill and use the downhill sections to gently gain speed so that you can be gentle with the throttle and use less going uphill. Your speed will fluctuate but you will be using the topography in order to maintain your average speed and use less fuel to get there.

Ian

If you are a good driver and anticipate the road conditions you will be more economical than CC, it will simply try to maintain the desired speed uphill and downdale. By looking ahead you can see the top of the hill and lift off the throttle just before. You can go slower up an hill and use the downhill sections to gently gain speed so that you can be gentle with the throttle and use less going uphill. Your speed will fluctuate but you will be using the topography in order to maintain your average speed and use less fuel to get there.

Ian

Hmmm I'm still unconvinced as CC doesn't put the brakes on to maintain speed downhill, so if you slow down without it going up hill you will be doing a lower average speed overall

If you are a good driver and anticipate the road conditions you will be more economical than CC, it will simply try to maintain the desired speed uphill and downdale. By looking ahead you can see the top of the hill and lift off the throttle just before. You can go slower up an hill and use the downhill sections to gently gain speed so that you can be gentle with the throttle and use less going uphill. Your speed will fluctuate but you will be using the topography in order to maintain your average speed and use less fuel to get there.

Ian

+1

CC is designed for convenience and comfort, it isn't a fuel saving feature, it simply maintains the desired speed and isn't bothered about how much fuel it uses in doing so.

Assuming the driver doesn't mind if his speed fluctuates and is therefore able to drive in a style that maximises fuel economy then I believe CC over the same route would prove to use more fuel.

Where CC works best and may be able to increase fuel economy is when it is used to maintain a steady constant speed over long distances on a flat road with light traffic.