Driving in snow...ASC on or off?

Discussions on better road driving, advanced courses and the like

Moderator: Gazza

Post Reply
User avatar
BimBeema
Joined: Sun 16 Oct, 2005 23:55
Posts: 1753

  Z3 roadster 2.2i
Location: London

Driving in snow...ASC on or off?

Post by BimBeema » Mon 02 Feb, 2009 13:54

I was driving back last night about 1am, the snow admittedly wasn't as much as it is right now. The main roads were fine, however once I came off, the suburben roads were a bit of a nightmare. I ended up fishtailing all over the place with the ASC light flashing like a christmas tree. Luckily no one else was on the road and I avoided hitting any parked cars!

Anyway, naturally I wasn't canning it or anything, was in 1st/2nd gear and no more than 15mph but the car was still prone to sliding and fishtailing, but once I got in back under control I switched the ASC off and i think it made a difference, as in it was no loner so prone to sliding and made the rest of the journey abit easier.

What's everyone's take on this? Should it on or off when driving in such conditions?

User avatar
c_w
Joined: Thu 19 Aug, 2004 17:50
Posts: 4032

  M roadster S50

Post by c_w » Mon 02 Feb, 2009 13:59

Sounds like your switch is set the opposite way round!! :D

I think sometimes with ASC on it won't drive very well, sometimes cutting power so much it doesn't go and turning it off (so light is on) is actually better as the power isn't cut at the slightest but of wheelspin.

User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10003

  Z3 roadster 1.9
Location: Cheshire

Post by Robert T » Mon 02 Feb, 2009 14:02

Have driven on fresh snow in mine and I left the ASC very firmly ON. Yes, it was blinking away rather a lot, and all the more every time I turned the steering wheel, but it kept the car pointing in the right direction and I have nothing but praise for it. The only time I should have turned it off was when trying to do a hill start at a set of lights - it cut the power too much and the lights were turning back to red by the time I got away. Even with it on, you still have to treat snow with care, but it did at least make it possible to drive the 20 miles or so home.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image

User avatar
whiteminks
Joined: Tue 26 Sep, 2006 10:58
Posts: 2765

  M roadster S54
Location: Lincoln

Post by whiteminks » Mon 02 Feb, 2009 14:07

Hi BB,

Haven't you got DSC on your Zed? I have on my 02 2.2?

I was given a tip by someone that if you find the car doesn't seem to grip, switch the DSC off for a second, apply a little gentle throttle and then switch it straight back on again. It has worked for me getting up the hill outside out house in the snow.


Cheers P :wink:
big cheesy wrote:'I nearly cacked my trolleys till I quickly tuned in'. Yorkshire Cruise 2008.

User avatar
BimBeema
Joined: Sun 16 Oct, 2005 23:55
Posts: 1753

  Z3 roadster 2.2i
Location: London

Post by BimBeema » Mon 02 Feb, 2009 14:08

c_w wrote:
I think sometimes with ASC on it won't drive very well, sometimes cutting power so much it doesn't go and turning it off (so light is on) is actually better as the power isn't cut at the slightest but of wheelspin.
Yep that's exactly what I thought, as you're bound to get wheel spin and the ASC cutting power at the slightest bit exasperated the problem in getting the car under control.

Normally my is ALWAYS on and I've found it very helpful/useful in more than one occassion but last night in snow it seemed to be a bit of hinderance more than helping!

User avatar
PhoenixCoupe
Joined: Wed 02 May, 2007 01:46
Posts: 739

  Z4 coupe 3.0si
Location: Mars

Post by PhoenixCoupe » Mon 02 Feb, 2009 14:24

Off, and use you bottom (for feedback, not for worrying!), feet and hands to make fun progress...
Image
押忍!闘え!応援団

adam666999
Joined: Tue 08 Jul, 2008 15:15
Posts: 66

  Z3 roadster 1.9
Location: bradford/birmingham

Post by adam666999 » Mon 02 Feb, 2009 14:25

I have an ABS fault and T/C fault which needs seeing to so neither work! and i made the 120 mile weekly trip at 4am this morning from leeds to bham.!! but i must say u cuple of heart in mouth moments! Use as high gear as possible and keeps revs as low as possible, if it is patchy snow never use the throttle wen going over the snow as your asking for trouble!!

User avatar
c_w
Joined: Thu 19 Aug, 2004 17:50
Posts: 4032

  M roadster S50

Post by c_w » Mon 02 Feb, 2009 14:38

Try driving the handbrake slightly on to set off - this might limit wheelspin.

User avatar
Jonttt
Z Register member
Joined: Sun 28 Dec, 2008 16:32
Posts: 6536

  M roadster S54
Location: Liverpool

Post by Jonttt » Mon 02 Feb, 2009 15:25

Guys

Read the handbook. I don't have mine to hand right now but I'm sure it confirms that that in snow traction control should be switched off.

It is generally accepted that traction should be turned off in icey conditions to give more control using the throttle. Where possible a higher than normal gear should be used to limit revs and wheelspin. I often take away in 2nd gear when very icey (not something you normally try in a manual car so people not used to it - most automatics actually start in 2nd gear when in normal drive, sport mode changes this to first gear!)

Having said all of the above I have not tried in my Z3m as its warmly tucked up in the garage :D lots of torque for 2nd gear starts but not sure I would fancy it :wink:
Happiness is not around the corner........happiness is the corner
Image Video or Journal Garage: 2015 FFRR Black Edition, Porsche Boxster GTS, 1997 Porsche Carrara C4S, Ex 2001 BMW S54 Z3m Roadster

User avatar
stu
Site Admin
Joined: Fri 10 Oct, 2003 18:49
Posts: 3540

  Z3 roadster 2.8 supe
Location: On the edge!

Post by stu » Mon 02 Feb, 2009 15:44

I'd leave it on, unless playing in a suitably safe location.
someone in a minority once wrote:I know I'm in a minority
Image

greg_ch
Joined: Tue 30 Mar, 2004 14:38
Posts: 636

  Z4 M roadster
Location: Zug, Switzerland

Post by greg_ch » Mon 02 Feb, 2009 18:37

According to the BMW and TCS - our AA / RAC equivalent - winter driving courses I've done.

DSC should be left ON if the snow has been packed down and is thus constant and largely predictable. Typically this is common where you get a winter permafrost.

DSC should be OFF in the type of conditions the UK has been experiencing today, because the snow/slush/ice is creating a slippery unpredictable layer between the tire and road.

DSC is designed to intercede when the surface changes from predictable to occasionally unpredictable.

A few basic tips:

- very smooth on the throttle
- use higher gears to avoid putting down too much torque
- try to use the brakes as little as possible, anticipate more than normal and use engine braking through the gears (but NOT 2nd to 1st as this will put down too much torque)
- if you have to use your brakes gently feather them any more and you can induce a spin
- don't stop and start, keep your momentum
- leave plenty of space between you and other road users

Alternatively winter tires and a set of low profile snow chains can come in handy form time time ;) :)

<img src="http://api.photoshop.com/home_bf94b49cf ... 3aa5a497f4" alt="" width="" height="" border="0" />

<img src="http://api.photoshop.com/home_bf94b49cf ... 3172cabe1b" alt="" width="" height="" border="0" />
Last edited by greg_ch on Tue 03 Feb, 2009 07:44, edited 1 time in total.

User avatar
Torres09
Joined: Sun 21 Sep, 2008 15:16
Posts: 210

  Z3 roadster 2.0
Location: Southport

Post by Torres09 » Mon 02 Feb, 2009 19:11

Just to throw a spanner in the works as my Zed is an auto what is best for me :?:

Having just looked out of the window and a 50 mile slide to work on the cards in the morning good advice would be appreciated :lol: :lol:
Why does mineral water that takes a 1000 years to flow up through the earth, have a sell by date on the bottle?

Zed_Steve
Joined: Thu 19 Jan, 2006 20:19
Posts: 393

  Z4 roadster 3.0si
Location: Birmingham

Post by Zed_Steve » Mon 02 Feb, 2009 19:55

Kind of glad this question has been asked, as it made me re-read my owners manual.
Just realised I have both DSC and DTC (Dynamic Traction Control) I thought the latter was a replacement for DSC, but is actually an optimised version. Also read, for DTC to be activated the telltale light must be ON. :rtm: opposite to DSC where the telltale light must be off for it to be activated.
Image

User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10003

  Z3 roadster 1.9
Location: Cheshire

Post by Robert T » Mon 02 Feb, 2009 20:03

I do remember from my manual that is says you should turn it off if you fit snow chains. :P

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image

Zed_Steve
Joined: Thu 19 Jan, 2006 20:19
Posts: 393

  Z4 roadster 3.0si
Location: Birmingham

Post by Zed_Steve » Mon 02 Feb, 2009 20:08

That is one of the situations mentioned where its advisable to have this DTC system switched on.
Image

User avatar
TitanTim
Joined: Mon 23 Jun, 2008 19:56
Posts: 5488

  Z3 roadster 1.9i
Location: Stafford

Post by TitanTim » Mon 02 Feb, 2009 20:54

Sorry if this sounds silly, but surely wouldn't it be better to keep everything switched on? lol wouldn't the cars traction control be helping you in slippery conditions? unless your a Stig Blomqvist :)

Tim.
Image
2001 Z3 1.9 Roadster Sport - 2012 Z4 sDrive 2.0 M Sport

Zed_Steve
Joined: Thu 19 Jan, 2006 20:19
Posts: 393

  Z4 roadster 3.0si
Location: Birmingham

Post by Zed_Steve » Mon 02 Feb, 2009 21:14

The DTC on the Z4 is only to be activated in exceptional situations, such as the current weather conditions.
Image

User avatar
Jonttt
Z Register member
Joined: Sun 28 Dec, 2008 16:32
Posts: 6536

  M roadster S54
Location: Liverpool

Post by Jonttt » Mon 02 Feb, 2009 21:26

Happiness is not around the corner........happiness is the corner
Image Video or Journal Garage: 2015 FFRR Black Edition, Porsche Boxster GTS, 1997 Porsche Carrara C4S, Ex 2001 BMW S54 Z3m Roadster

gookah
Z Register member
Joined: Thu 07 Aug, 2008 10:51
Posts: 2725

  Z3 roadster 2.8

Post by gookah » Tue 03 Feb, 2009 00:25

TitanTim wrote:Sorry if this sounds silly, but surely wouldn't it be better to keep everything switched on? lol wouldn't the cars traction control be helping you in slippery conditions? unless your a Stig Blomqvist :)

Tim.


I am the Stig...... no not that one... the other one

Rob13
Joined: Mon 05 May, 2008 09:18
Posts: 263

  Z3 roadster 2.8
Location: Sutton, London

Post by Rob13 » Tue 03 Feb, 2009 12:34

A quick question, on a 97 2.8 with ASC, does it just cut the power or does it brake the wheels as well??
I used to have a '97 2.8 Z3 50k FOR SALE £4699 Shorter 'M' Cup Sport gear knob,M Steering wheel, Alpine / Infinity audio, 18" Alpina style wheels, Clear indicators all round, cold air feed and modified airbox. Miss April in the '09 Calendar.
ImageImage

Guest

  

Asc

Post by Guest » Sun 08 Feb, 2009 13:56

Both actions take place at different speeds - but it's the braking action which causes problems.

When one wheel loses grip and spins, the differential causes the other wheel to lose torque and stop. The ASC senses the difference in rotational speed, and applies the brake on the spinning wheel to force torque through the diff to the stationary wheel.

As the braking action is very rapid, the wheel may lock instead of just slowing down, which really confuses things.

This means that the stationary wheel - which had grip - is suddenly fed with more torque than it may not be able to handle, and can also lose its grip.

If this process is combines with even slight cornering, the resultant centrifugal force can cause the (now grip-less) rear end to slide - hence the problems with ASC turned on.

It depends on conditions, but ASC is not a save-all for use on snow and ice - it's main function is to provide traction, as distinct from stability - the two do not always go together.

A similar problem in that a car with a clutch pack LSD can suddenly have the diff action locked up, so promoting a loss of traction on both rear wheels in slippery conditions.

Likewise, the ABS is confused on snow, but it is inoperative at under about 10 mph, when the best braking medium is a locked wheel, which builds up a wedge of snow in front of it.

The best way to drive on snow and ice is to treat the throttle pedal as if it were red hot, use high gears, and apply ots of anticipation. better still, stay at home!

Rob13
Joined: Mon 05 May, 2008 09:18
Posts: 263

  Z3 roadster 2.8
Location: Sutton, London

Post by Rob13 » Sun 08 Feb, 2009 14:06

Thanks for the reply Mike

Makes sense, and I guess being one of the first versions it is pretty rudimentary compared to the latest types. The snow and ice really did confuse it - with the rear end bouncing up and down - most probably as it applied the brakes. I had thought that it just cut the throttle.

I usually drive with ASC off but it did help on my drive which was totally iced over. Compared to the other car and the Van I was also driving, it is definatly not intended for snow and ice, grip was shocking....I just had to get it home and into the garage though.

....us Africans are not used to Snow and ice!
I used to have a '97 2.8 Z3 50k FOR SALE £4699 Shorter 'M' Cup Sport gear knob,M Steering wheel, Alpine / Infinity audio, 18" Alpina style wheels, Clear indicators all round, cold air feed and modified airbox. Miss April in the '09 Calendar.
ImageImage

HomeStoned
Joined: Thu 06 Nov, 2008 19:58
Posts: 87

  Z3 roadster 2.0

Post by HomeStoned » Mon 09 Feb, 2009 18:44

I only drive with ASC off, when i want to pull off some power slides or 360's with the use of my magic wand (handbrake)
with all this Fairy dust around at the moment it's cool :twisted:

P.S i used to do the LLYN Rally N.Wales :D

Zed Carer
Joined: Thu 13 Dec, 2007 20:27
Posts: 1641

  Z3 roadster 2.8
Location: Wakefield

Post by Zed Carer » Mon 09 Feb, 2009 19:13

We live on a hill and as I was in Darlington today we couldn't car share and I took the Z4 to the station - bit of overnight snow / frost so the road was a mixture of snow with a frozen crust and ice.

Backed out, made sure I was straightened up and set off - no problems at first very steady - about 50 yds before the end of the road it steepens - lost traction and came to a halt. DSC was on at this point and the car basically just stood still - as soon as a wheel lost grip the system braked it. Turned the DCT on - see Zed_Steve post above - a little better did go forward a bit and no sign of it getting out of shape.

In the end turned everything off - except the engine - and just used the clutch / throttle to induce a bit of wheelspin to cut down through the crust on the snow, balanced clutch and power when I got some grip and stop/started my way to the top - no sign of it getting out of shape either. Not sure that the neighbours appreciated it at 6:20 this morning!
Hers: Z4 2.0i Sp --------------------- His: Z3 2.8
Image

Guest

  

DTC etc

Post by Guest » Tue 10 Feb, 2009 10:28

Makes you wonder why you have paid for all these gizmos, doesn't it?

I suspect that - apart from making money for BMW etc - they are an attempt to sanitise the car so the unskilled/unwary Americans can drive a powerful car.

If the ASC or ABS on my Z3 failed, I would simply have them disabled and do without - it would not worry me at all.

I never saw any divers who had problems withtheir E-type Jaguars etc, which only had an LSD . . .

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest