YACT --- how/why does cruise control decrease fuel milage?

[otispunkmeyer]

jus watching a top gear episode (where he drives up n down england in a Audi A8 V8 diesel twin turbo)

he said he was averaging 31-32mpg with cruise control on
but then nearly 40mpg when he turned it off an used his foot

 

[Eli]

I would've thought that it raised it.... More consistant and all....

😕

 

[Pepsi90919]

because when you go up a hill it tries to accelerate really fast to get up to the set speed un-necessarily

 

[Fingers]

Cruise control is harsh when you are on hills and if you use the steering wheel controls. Otherwise you should get better milage.

 

[CrackRabbit]

The opposite should be true, unless you have a VERY steady foot. The cruise controll should keep the car at a fairly constant throttle position. A normal driver tends to fluctuate slightly while driving, using a bit more gas.

 

[kami333]

what sort of roads?

 

[cjgallen]

Originally posted by: otispunkmeyer
jus watching a top gear episode (where he drives up n down england in a Audi A8 V8 diesel twin turbo)

he said he was averaging 31-32mpg with cruise control on
but then nearly 40mpg when he turned it off an used his foot

I just watched that episode, I was wondering the same thing.

With cruise control it will hold a certain speed, so if you're going up hills, it accelerates, but I think he was just holding his foot steady and riding up hills without giving it more gas, ie letting it slow down.

 

[otispunkmeyer]

Originally posted by: kami333
what sort of roads?

british A-roads and motorways

 

[otispunkmeyer]

Originally posted by: cjgallen

Originally posted by: otispunkmeyer
jus watching a top gear episode (where he drives up n down england in a Audi A8 V8 diesel twin turbo)

he said he was averaging 31-32mpg with cruise control on
but then nearly 40mpg when he turned it off an used his foot

I just watched that episode, I was wondering the same thing.

With cruise control it will hold a certain speed, so if you're going up hills, it accelerates, but I think he was just holding his foot steady and riding up hills without giving it more gas, ie letting it slow down.

no he said he acclerated before he got to the hill, with the hope that the momentum carried you up with out using much more fuel

 

[eelw]

It depends on how much attention you want to gently feather the accelerator. I can also get 5-10MPG better myself over using cruise.

 

[MustangSVT]

wastes gas by matching set speed all the time.

 

[otispunkmeyer]

Originally posted by: eelw
It depends on how much attention you want to gently feather the accelerator. I can also get 5-10MPG better myself over using cruise.

think it can be put down to simply inefficient control on the computers part?

 

[radioouman]

Originally posted by: otispunkmeyer

Originally posted by: cjgallen

Originally posted by: otispunkmeyer
jus watching a top gear episode (where he drives up n down england in a Audi A8 V8 diesel twin turbo)

he said he was averaging 31-32mpg with cruise control on
but then nearly 40mpg when he turned it off an used his foot

I just watched that episode, I was wondering the same thing.

With cruise control it will hold a certain speed, so if you're going up hills, it accelerates, but I think he was just holding his foot steady and riding up hills without giving it more gas, ie letting it slow down.

no he said he acclerated before he got to the hill, with the hope that the momentum carried you up with out using much more fuel

That is correct. A person can anticipate a hill whereas a computer can't.

 

[spidey07]

Hills will make the cruise control really push down on the accelerator and pump gas.

where as when your driving and going downhill you can build up some speed so you don't waste as much fuel getting up the hill.

 

[Baked]

Because it makes the engine work real hard by running really high RPM when you leave the cruise control on for inclines.

 

[cavemanmoron]

Originally posted by: radioouman
[

no he said he acclerated before he got to the hill, with the hope that the momentum carried you up with out using much more fuel

That is correct. A person can anticipate a hill whereas a computer can't.

[/quote]

I can get better mileage,if not overly tired,by not using Cruise.

If I am tired,I use the cruise,and avoid a speeding ticket.😉

 

[PHiuR]

hills.
/end

 

[DaiShan]

Originally posted by: eelw
It depends on how much attention you want to gently feather the accelerator. I can also get 5-10MPG better myself over using cruise.

Shens. You are saying that on a 15 gallon tank of gas, you can get 150miles more range than had you used cruise control? Prove it. As has been stated already, on hills, cruise control will use more gas than just keeping the gas pedal at a constant position. However I live in florida, which is extremely flat, and there is no discernible difference between cruise control and using my foot.

 

[eelw]

Originally posted by: DaiShan

Originally posted by: eelw
It depends on how much attention you want to gently feather the accelerator. I can also get 5-10MPG better myself over using cruise.

Shens. You are saying that on a 15 gallon tank of gas, you can get 150miles more range than had you used cruise control? Prove it. As has been stated already, on hills, cruise control will use more gas than just keeping the gas pedal at a constant position. However I live in florida, which is extremely flat, and there is no discernible difference between cruise control and using my foot.

Oops, forgot to note, I drive a Civic Hybrid. So I can get 55MPG 🙂 With cruise, it gets around 45MPG. Sorry about the confusion.