Cruise control increasing fuel consumption??

[_williams_]

just a quick one . . i've been told that the use of cruise control can increase the fuel consumption, now i was planning on getting cruise control fitted but am i gunna end up paying out more for long journeys for a luxury which i can easily live without?

cheers

 

[Nath.]

No it doesn't what wally told you that and do they know how CC actually works.

You can drive like a proper diesel geek and pre-empt hills and stuff and get 1-2 MPG better on a very long run. This takes a lot of concentration and totally defeats the idea of stress free driving with both eyes on what's going on up the road rather than one eye on the speedo needle.

That said, you can pre-empt hills whilst on the CC if you want but this means that you are not keeping a steady (exact speed) in average speed camera areas.

Anyone that reckons they get better MPG without CC is either a liar or superhuman.

With CC I can get over 100 miles more to a tank because it changes my driving psycology. I look in the mirrors so much more and think a lot further ahed as I want to stay on the CC as much as possible.

One thing to remember is that CC is designed to keep your speed exact, better MPG is just a result of keeping the speed steady. Some people drive like fools and are on the motorway doing 80, brakes, 65, floor it, 80, brakes, 65, floor it. CC will not interest these people and they will diss it, also people will diss it because they haven't got it and they don't want you to have a toy on your car that they haven't got.

 

[bluearosatdi]

I have heard that on some VAG cars that on flat roads / constant speed scenarios then cc is effective at keeping fuel consumption down. However on downhills the car "brakes" to stop speed rising thus you are in effect going downhill with the brakes applying. In a non cc car you would simply back off and watch your fuel consumption go off the scale. But as I dont have cc, I can only say what I have heard.

 

[m0rk]

I have heard that on some VAG cars that on flat roads / constant speed scenarios then cc is effective at keeping fuel consumption down. However on downhills the car "brakes" to stop speed rising thus you are in effect going downhill with the brakes applying. In a non cc car you would simply back off and watch your fuel consumption go off the scale. But as I dont have cc, I can only say what I have heard.

total rubbish

 

[Nath.]

total rubbish

So true.

This is where morks sig pic comes in.

To quote myself>>>>>what wally told you that and do they know how CC actually works?

 

[chispadete]

total rubbish

err no it isnt? thats 100% true? might be different on all none seat cars you own fella, but here in seat land, oh and vag land thats how cc works...

 

[truCido]

CC doesn't apply the brakes......does it!?!?

 

[chispadete]

CC doesn't apply the brakes......does it!?!?

it doesnt apply your brakes, but it does use engine braking to KEEP the car at the same speed, so as above it does exactly what the OP asks...

/me waits for a warning for stating facts against long term members, as per usual

 

[m0rk]

'tard

RTFQ

However on downhills the car "brakes" to stop speed rising thus you are in effect going downhill with the brakes applying

Where in there does it talk about the throttle closing?

Braking is done by brakes.

You're talking about overrun, which does very little 'braking'

Infact, you'd find that with zero throttle down a hill you can still accelerate, VAG or whatever.

I think the only exception I can think of is the Merc & Volvo with the clever cruise

 

[chispadete]

'tard

RTFQ



Where in there does it talk about the throttle closing?

Braking is done by brakes.

You're talking about overrun, which does very little 'braking'

Infact, you'd find that with zero throttle down a hill you can still accelerate, VAG or whatever.

I think the only exception I can think of is the Merc & Volvo with the clever cruise

'tard

Where did I say the throttle closed? I didnt. arosatdi said from what he knows the car brake going downhill to keep the speed set, inturn making the car less efficient on fuel...

you said thats crap

no it isnt.

pretty simple 'tard?

 

[jaz205gti]

I had cc on a Toledo tdi, after many journeys I concluded that cc used more fuel !
In theory its simple my journey was Birmingham to Yorkshire with lots of climbing ect.
Cc when going up hill applies a lot of power to maintain speed and like wise when its going down hill it didn’t do as much without cruise iv tested this!. When driving without cruises you don’t generally boot the car giving you better fuel economy. Computer cant anticipate road conditions. Cc is only better on FLAT roads .

 

[chris4500uk]

Ladies calm down

http://en.wikipedia.org/wiki/Cruise_control

Not all cars brake with cruise.

Chris

 

[chispadete]

Ladies calm down

http://en.wikipedia.org/wiki/Cruise_control

Not all cars brake with cruise.

Chris

from my understanding, that wasnt what was asked. if you read the above link, it clearly states downhill it lets off, but not fully and will always use more fuel than if not in use and you take your foot of the pedal.

 

[jaz205gti]

ha my theory was right
thanks chris

 

[chris4500uk]

from my understanding, that wasnt what was asked. if you read the above link, it clearly states downhill it lets off, but not fully and will always use more fuel than if not in use and you take your foot of the pedal.

The link I posted?

Erm, which bit does it say it doesn't let it off fully? It says the car might accelerate with the engine idling downhill?

As far as I know CC on the MK4 doesn't brake.
A skilled driver would be better than CC on MPG when going over a 'rolling' terrain.

What else have I missed?

Chris

 

[_williams_]

lol sorry i asked now . . ! i understand what's being said about the car not fully letting off when going down hill but im not the type that will try and roll along a decline to try and get the miles up so shouldn't make that much difference! i was thinkig more along the lines of in general on a mix of incline/decline and flat roads!

 

[Nath.]

To quote wiki>>>>>Its usefulness for long drives across sparsely populated roads. This usually results in better fuel efficiency.

I can categorically tell all of you that in the 6 cars that I have had with CC (4 of them have done 100k miles plus by me). All of them have returned considerably more MPG than I am able to without CC and I have been driving for 20 years or more.

Also these days, with modern ECU's the system cuts fuel to a dribble when the brakes are used anyway.

I think superhuman people who reckon they get better MPG without CC need to maybe use it correctly. For example on the mk5 Astra you can have the CC set to 70 and then brake down to 20 for a roundabout or whatever, if you then floor it from 20 in top gear and hit resume simultaneously the CC will take you to 70 at full throttle, it will also overshoot 70 and need to lift off and coast down to 70. this uses more fuel than hitting resume with no foot on the gas and gently wafting up to 70. Therefore in that situation CC uses more fuel but only if you're a tit.

 

[Nath.]

Cc when going up hill applies a lot of power to maintain speed

How does that work then?

Can you explain?

All the CC does is monitor the speed of the car and adjust throttle input to maintain that speed. It cant apply more power than is needed to maintain a speed weather it's up hill or down hill. This is because more power will build up the speed and therefore make the CC lift off as it has reached it's requirement.

CC does not make you go everywhere on full throttle and then adjust your speed by applying the handbrake

 

[Nath.]

err no it isnt? thats 100% true? might be different on all none seat cars you own fella, but here in seat land, oh and vag land thats how cc works...

Total rubbish,

AFAIK the only system that does that is on high end cars that have the new laser guided safety system, that isn't really CC though is it, it's a system in it's own right.

See this vid, and check out at 2mins 30secs "my car reduces speed gradually without the need for brakes" and on screen the caption says "gap distance is almost reached. the ACC starts to reduce speed gradually" "it has no need to brake as it has time enough to slow down gradually" no mention of brakes being used there, just lift off/over run or engine braking, whatever name you choose to give it.

The slamming on of brakes is the safety system that helps to stop you crashing into a slow or stopped car that is detected by the laser system whilst you are on the phone or asleep, this is not really CC any more than ABS is a brake servo.

You sir should fuel up before attempting to flame, all you did was make a tiny spark.



Vid link >>>>http://www.youtube.com/watch?v=CkEipB8lvOA

 

[jaz205gti]

as stated a SKILLED driver can get more mpg without usng cc so its down to the driver
i dont know why people are getting worked up about it
if your feeling lazy use it?
its going to make marginal difference around 10% from my experience