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Discussion Starter #1
A few weeks ago I was having a play with the functions in my 2017 225, and switched the traction control off, while in Max eDrive mode. I felt that doing so made the throttle response a little sharper, especially from a standing start - I think because the TCS 'nannies' the electric motor's instant torque output to avoid any risk of wheelspin.

So I started switching off TCS every time I got in the car, because it was more fun to drive. Then after a couple of days I noticed that I was arriving at work with 4 or 5% more battery charge remaining than normal (I always drive the same route to work, so it's predictable in terms of traffic conditions etc, and always in Max eDrive). I normally use 25% battery getting to work, but now I was only using 20 or 21%.

I wondered if it could be temperature related, so on consecutive days with similar ambient temps, I tried driving with TCS on, and the next day without. I still used 4% less charge with TCS off.

It's not a big difference, but it's still a difference. I'd be interested to see if other 225 drivers get similar results.
 

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Are you a little on the 'fierce' side around the racing lines in the corners?

I am wondering if the stability control is [no longer] dragging one of the rear brakes to keep you under control?
 

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Well I know the car launches much better with traction control off! I’ll never go back to a front wheel drive.

I might test this theory but holding down the button for so long every journey seems annoying.
 

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Hello guys.
An update of my experiment.
yesterday and today I've tried to run with the TCS turned off.
The parameters are:
Departure from home is 100% charge
Heating always turned off
Cruise control at 65 mph around 50% of the time
50% motorway driving with few overtaking
50% A road driving with some overtaking (short periods top speed 70 mph)
Cruise control turned off where road inclination would mean increased energy spending
Acceleration within 4 and 5 dots.
Eco mode always off
B mode used to slow down and using little breaking (exception to junctions where I had to go to a complete stop).
Journey duration is 49.8 miles (rounded to 50 for easier calculation)
Air temperature between 10 and 14C
On Monday (before the TCS trial) I arrived at work with 52% battery left
Tuesday same journey and similar parameters I arrived with 56% with TCS off all the journey
Wednesday (today) arrived with 53% (same as above).

It is still too early for a significant conclusion but I would say that the improvement in performance could be linked to the use of this process.
To be considered that there is a physiologic factor in the fact that you will be driving with a warning amber light on and that you will have to be more moderate on the acceleration.

Nevertheless, as said above 1% improvement could be significant.
I'll continue the experiment till Thursday and will report back on Friday morning.
NOTE: I will not consider turning the TCS off in adverse weather as safety is paramount and I have no intentions to takes risks for the sake of a little saving.

DISCLAIMER: this is far from a scientific accurate experiment so errors or deviations from actual accurate figures is to be expected :)
 

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I think you might be onto something, but it is so subtle as to not really be very obvious.

One thing I've noticed is that setting a speed limiter, which I would consider as delivering fuel saving, turns the TC back on.

I usually set it at 30 and sit there so I don't drop to 28 then need re-acceleration, then go to 32, then need to drop back etc.

I haven't had the chance to do a 'normal' commute yet. I will tonight though.

And I'll be very interested to hear the final outcome of your tests.
 

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I know the speed limiter is not an energy saving mode similar to cruise control.
When using either the system goes into "conflict" mode and on one hand try to control the speed while doesn't cut the power output.
I wasn't aware that TCS would work the same way even if not as much
 

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I think that on a 14 mile commute, I'm getting home with maybe an additional mile left on my range with TC turned off.

Not at all scientific, and there are a range of factors which could impact it, but I think it helps.
 

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Discussion Starter #13
Are you a little on the 'fierce' side around the racing lines in the corners?
I am wondering if the stability control is [no longer] dragging one of the rear brakes to keep you under control?
There are several roundabouts on my commute, so that is possible ... although traffic levels usually mean I can't be too enthusiastic in taking a racing line :)
 

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I've had a little experiment & while it's impossible to exactly replicate each journey (outside temp, volume of cars, start/ stopping etc) there seems to be a very slight gain. It's not a large enough gain to warrant turning the traction control off all the time though.
 

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UPDATE on previous post.

Similar parameters as previously (please read post above)
Today air temperature was between 12 and 15C
decided reduce by 1 mph the cruise control setting to 64 mph
traffic circumstances similar to previous days with approximately 3 miles of slow driving at 40 mph. (soooo annoying how this people drive :cool::rolleyes:)
There was no strong acceleration for overtaking, ok once for a big slow lorry :p
arrival charge at 53%

Interim conclusion is that, as previously and other users have stated, the saving is not really significant for this type of journey.

A point I will make is that, although the return journey can't be used for this experiment as I need to do a partial charge halfway and then a longer charge before heading home, i noticed that turning off the TCS between last charging section and home I now arrive at home with 3% more charge than previously.
This could mean that turning off the TCS in short journeys may have a bigger impact than long journeys.
 

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Discussion Starter #16
I always presumed that the TCS modulated power output as well as gently braking when needed, but the (small) savings in battery range imply that TCS just does its thing by applying the brakes (i.e. wasting battery power by not allowing it to be transferred into motion).
 

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I always presumed that the TCS modulated power output as well as gently braking when needed, but the (small) savings in battery range imply that TCS just does its thing by applying the brakes (i.e. wasting battery power by not allowing it to be transferred into motion).
I don't really know the mechanics how TCS (and other restricting methods) work.
If you play attention, you will notice that when you have the speed limiter on and you try to accelerate above the set speed the efficiency gauge will come down.
This gives me the idea that regardless of the limiter being on you can still use the battery power to try to accelerate.
I won't say that the system will apply the brakes but probably will let you apply the power to the motor but won't let it rev up.
 

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One thing I have to say is that being aware of economy likely helps by a couple of percent. I think when I've been experimenting with TC, I might be a bit lighter with the left foot.

Husoi, very interesting about limiter being able to drain more at the limited speed. I use it all the time to try and eke out a couple more %. I'll give that a look as well.
 
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