Jamz3k

I thought that due to keeping a constant speed etc with Cruise Control I would gain better MPG but last night and thismorning whilst going down the motorway i could only achieve 33MPG whereas generally on the same route i was get around 38/40MPG.

Surely that can't be right?

Never really bothered to use CC before this so never noticed until now.

farmer1

I guess its probably similar to the problem that large ships get when run on autopilot. They make corrections to often causing a higher fuel burn.

MJW

Your mpg is mainly dictated by your throttle opening & revs rather than constant speed. To maintain a constant speed for example by going up a slight incline, the throttle will need to be opened more, hence the reduced mpg. Similarly for going down hill the speed is maintained whereas if the CC was switched off you'd just back off the throttle.

LG John

In my experience cruise control always trounces my right foot for MPG. I mean, I could probably beat it if I was really trying but for 99% of driving having the cruise on saves petrol IMHO.

gpssti4

iTrader: (6)

I find my car uses more fuel with CC - the same as has been posted; it's trying to maintain speed up hills rather than slowing by 5-10mph which is what I usually do.

Leslie

It may depend on the design of the cruise control, I used to get better mpg on an old Beemer seven series I used to have, and I have a light foot on the throttle too.

Les

Jamz3k

LOL no clue what so ever mate, its an Alfa Romeo 147 1.6 Twinspark

richs2891

Odd I get worse mpg if I use the cruise on say a motorway in my S3 than if I dont and stick to the same speed.
Doesnt help that if slow down / tap brake or disengage cruise then resume it seems to use 3/4 full power to get back to its speed - first time I used it almost went into the back of someone !

Maybe some cruise controls are better set up towards a fuel saving ?

Richard

greenonedave

My Alfa is worse on fuel using cruise control.I think the unit is constantly pushing in fuel to maintain the set speed.

Jamz3k

well i believe the lesson to learn here is that Cruise Control sucks and Alfa's suck too!

4X4BOB

I too have found I can get metter mpg than my cruise control can.

There are times though when its nice to let the CC do the work - 'spesh when driving 1,000 miles across Europe!

Freak

definitely the case with the saab- dont use cc on it any more because of that.

Audi is a little better...

Turbo2

Slightly off-topic as I am not talking here about cruise control, but I remember doing a journey of about 200 miles (mainly M1) and finding that the same journey a few weeks later in proper wet weather used up about 15% more fuel according to the MPG computer (Passat TDi 140). Could that be right?

greenonedave

Going North is uphill so you will use more

Turbo2

Well obviously I know that (), so I was actually talking about comparing a return trip to include the downhill southbound leg.