ACC: Is 'Sport' more economical?

[RisingRoc]

Bear with me here as this is all somewhat counter-intuitive, but I have a theory that 'Sport' may be the most fuel efficient ACC selection.

I had a habit of getting into my car on a Friday night after work, switching it from Comfort to Sport and having some fun on my end of week drive home instead of my general midweek cruise. I started to notice that I was usually getting better MPG than throughout the week for the exact same route. I at first put this down to slightly less traffic holding me up and therefore less stationary time and wasted fuel - but then I came up with another theory which might explain it.

It's generally understood that soft tyres waste fuel as it takes more energy to rotate the wheel. Extending that idea, does softer suspension also then lower MPG due to energy going into compression of the suspension?

I have tried using Sport midweek now and generally see better figures too. I know there are a whole lot of other factors that will affect MPG (traffic, gear selection, ambient and engine temperature, time since service etc) but assuming all is equal, am I completely mental in my suspension thinking here?!

[Cuprabob]

I can't see it myself

[abc121710]

i can see what you mean, its like with bikes, i have a road bike and a mountain bike that has rear suspension and its quite soft, its easier to ride the road bike because on the mountain bike the suspension takes some of the force out of the pedalling and makes it harder. but i think it would be difficult to apply that theory to cars, a bit more complicated

[ScottC25]

I can see some merit in that, however in sport mode, would it not be harder on the tyres as the suspension is stiffened up?

[abc121710]

doesnt the acc stiffen up the steering in sport, does it do it by reducing the electrical assistance or using the electrics to firm it up, if it reduces the electrical assistance this may have a small factor in fuel consumption perhaps???

[Macman]

It goes towards the way that TSI engines generally prefer higher revs and the old saying from driving school that a car is to be accelerating or breaking and not coasting as the engine would be asking for power to be on/off and not efficient. Also why chip tuning makes it faster yet more efficient. I want this button on the steering wheel!
Can they get GEET to get as much power as petrol yet?
All that air resistance at speed yet they still haven't turned it into any form of power. Hows about mini ramjets hehe!

[Cuprabob]

It goes towards the way that TSI engines generally prefer higher revs and the old saying from driving school that a car is to be accelerating or breaking and not coasting as the engine would be asking for power to be on/off and not efficient. Also why chip tuning makes it faster yet more efficient. I want this button on the steering wheel!
Can they get GEET to get as much power as petrol yet?
All that air resistance at speed yet they still haven't turned it into any form of power. Hows about mini ramjets hehe!

Whatever you've been taking, I would suggest you've had enough:-)

[whiteDevil_170]

Haha brilliant

[Macman]

I got bored of Sky TV

The sad truth of more efficiency...See this inventor's full summary of his Electric Solar Thermal Ramjet. More efficient the faster it goes yet the industry won't build it as its cheap and no patent will protect it.
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Here's a DC2000 HHO kit on a Tiguan 170 TSI. " onclick="window.open(this.href);return false; Info: http://www.hho2.org/" onclick="window.open(this.href);return false;

[dimexi]

I don't think the argument of softer tyres and softer/stiffer suspension go hand in hand. One is to do with rolling friction resistance and the other is just dynamics and damping of the car's movements. I don't see the relationship straight off, might be an anomaly perhaps?

[maisbitt]

I have long thought that my Roc is more efficient with Sport on than either comfort or normal. I used to tinker with it for a while in early ownership - I always seemed to get about 2mpg more for the same journey and same conditions on my commute to work.

Maybe the ACC is working hard in normal, putting a bit of strain on the alternator, and the steering is getting less assistance in Sport as well as the stiffened suspension is helping aid more efficient transfer of kinetic energy to the road? Perhaps the "wallowing" of the car on softer suspension affects the aerodynamics in a negative way. It is probably a combination of all of this.

It could be the fact that I tend not to use Sport in the worst of winter when there are potholes about, or that you switch to comfort when you are faced with a poor road surface, and that poor road surface is going to affect your efficiencies.

[whiteDevil_170]

I have long thought that my Roc is more efficient with Sport on than either comfort or normal. I used to tinker with it for a while in early ownership - I always seemed to get about 2mpg more for the same journey and same conditions on my commute to work.

Maybe the ACC is working hard in normal, putting a bit of strain on the alternator, and the steering is getting less assistance in Sport as well as the stiffened suspension is helping aid more efficient transfer of kinetic energy to the road? Perhaps the "wallowing" of the car on softer suspension affects the aerodynamics in a negative way. It is probably a combination of all of this.

It could be the fact that I tend not to use Sport in the worst of winter when there are potholes about, or that you switch to comfort when you are faced with a poor road surface, and that poor road surface is going to affect your efficiencies.

where I live all the roads are poor and coverd in potholes so I have it in comfort.... If only rw1 was here he could of put us straight!

[Macman]

(If only, RIP Chris) This is what I wondered too about the acceleration on corners if its faster due to the XDS acting only on one wheel so not using it for anti-torque steer breaking. It would pull 90degrees to the axis (to the left) and so add more breaking to the right wheel on a straight road. If you are turning left it will not need to. If I felt it as you guys notice the change then it surely is there!
The XDS anti-torque steer is for a "refined fury" as they advertise. This car would be faster without it yet (you got it) a crazy car like the others.