Terrain responce - Grass Gravel Snow, DSC-off, whistling sound

Hi!

I have an TD4 manual. It has 1500km.
Yesterday we got about 10 cm of snow.
It was -9 Celsius and of course I went for a little snow test with Evoque.
I chosen the Grass - Gravel - Snow terrain responce. First I left the DSC on. Here is a pic of the setup.
   
I went on the road and all was okay. Then I went on a big parking space where
there is a combination of asphalt and some gravel areas. I put DSC off and the fun began.
It is not so easy to slide it without manual handbrake.
But you can do it with the clutch and gas combination. Otherwise I have to say the car handles
very very good. I also have very good winter tyres and I have to say I was impressed with handling in snow.
It was very hard to bring the car to drift and the parking wasnt really that big...so I had to watch not to hit the fence

Here is the problem.
After a coulple of drift circles on the parking I noticed a very loud whistling sound somewhere on the outside of the car. I also noticed a smell similar to burning rubber. It was not a strong smell but I could sence a little smell like that. I am not exactly sure from where it came from but I think its more from the front.
A colleague of mine noticed the sound also from standing far away and he suggested that maybe it is differential.
I though it was turbine. Is this normal? Otherwise the car goes normal.

When my friend mentioned the diferential i got a little scared the next day.
Why? I noticed that in Grass - Gravel - Snow terrain responce if you turn the steering wheel left or right fully a graphich is dispayed on lcd showing front wheels turned. Then I remembered I heared that whistling sound the previous day when I turn my steering wheel fully to the left or right.
   

Is there a connection with "Snow" terrain responce and the whistling sound when steering fully?
I tried the same thing today on a cold engine and there was no whistling sound.
Is it something else? Should I be worried? Was it maybe overheating? The car was doing up to 5.000 rpm
at some moments to bring it to drift. It's pretty much for a diesel I know.
Day after the crazy drive the car goes normal.

And one more question? What does "Grass - Gravel - Snow" mode really do. I mean technicaly?
If you ask my wife she will tell you:"It's for driving in snow" But I mean does it lock differentials or something like that? When drifting I put DSC off but did I make a mistake not living the car in "normal" mode?

Anyone has any suggestion ?

Thanx!

RR, your wife is right, always - have you learned nothing since getting married?

Each of the settings on the terrain response remaps the car's ECU's to give the optimum settings for the selected conditions. RRE doesn't have it but on the air suspended cars there is also another Rock Crawl setting that retunes the suspension as well as the engine. You could if you wanted never select a TR setting and drive the car as a conventional 4WD vehicle but then you wouldn't get all the systems working properly together or the benefit of LR's expert programming of the ECUs.
I would suggest that if you were driving at 5000 rpm it could have been your turbo waste gap dumping over boost pressure - it would not have been the steering as the Evoque has electronic steering rather than hydraulic assistance. What it may have been was the cooling fan for the Viscous Coupling as you might have been getting things down there a bit warm using all those revs to go round in a circle. If it worries you then take the car to the dealership and get it checked out. You didn't make any mistake driving with the DSC off and not in normal mode - LR has made all the functions switchable so if you don't feel you need them you can switch them off

In simple terms the various Terrain Response settings alter the Engine Mapping to provide optimum performance for the condition selected. The wheel position symbol is a normal feature when Terrain Response programs are selected. In relation to Grass Gravel Snow:

The Engine Management System is altered to provide more gradual torque delivery for a given accelerator pedal travel to reduce the risk of wheel spin. In Automatic gearbox cars the change up will occur earlier to minimise loss of traction. There are also changes made to the Electronic Centre Coupling to transfer torque to the wheels with traction. Hill Descent Control is off unless manually selected and Traction Control is highly sensitive to slip.

I suspect the whistling sound was caused by overheating possibly of the differential or the Haldex unit (Electronic Centre Coupling) as the problem did not reappear when the car was cold.

Remember that DSC is designed to prevent drift as are a number of other systems built into the vehicle. Turning off DSC while fun is not recommended for normal use. Grass Gravel Snow is however recommended when the surface is slippery such as in snow.

(05-02-2012 10:42pm)XFullFatTim Wrote:  RR, your wife is right, always - have you learned nothing since getting married?

Each of the settings on the terrain response remaps the car's ECU's to give the optimum settings for the selected conditions. RRE doesn't have it but on the air suspended cars there is also another Rock Crawl setting that retunes the suspension as well as the engine. You could if you wanted never select a TR setting and drive the car as a conventional 4WD vehicle but then you wouldn't get all the systems working properly together or the benefit of LR's expert programming of the ECUs.
I would suggest that if you were driving at 5000 rpm it could have been your turbo waste gap dumping over boost pressure - it would not have been the steering as the Evoque has electronic steering rather than hydraulic assistance. What it may have been was the cooling fan for the Viscous Coupling as you might have been getting things down there a bit warm using all those revs to go round in a circle. If it worries you then take the car to the dealership and get it checked out. You didn't make any mistake driving with the DSC off and not in normal mode - LR has made all the functions switchable so if you don't feel you need them you can switch them off

thx for the wife suggestion. thx for all the suggestions but basicly would still like to know...when doing the thing i did in snow...i know that DSC has to be off but TR confuses me a bit...is it better to just leave it normal mode when drifting...i am worried that by drifting in "snow" mode i made some damage to the car because this mode is not intended for such things.

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(05-02-2012 10:45pm)rchrdleigh Wrote:  In simple terms the various Terrain Response settings alter the Engine Mapping to provide optimum performance for the condition selected. The wheel position symbol is a normal feature when Terrain Response programs are selected. In relation to Grass Gravel Snow:

The Engine Management System is altered to provide more gradual torque delivery for a given accelerator pedal travel to reduce the risk of wheel spin. In Automatic gearbox cars the change up will occur earlier to minimise loss of traction. There are also changes made to the Electronic Centre Coupling to transfer torque to the wheels with traction. Hill Descent Control is off unless manually selected and Traction Control is highly sensitive to slip.

I suspect the whistling sound was caused by overheating possibly of the differential or the Haldex unit (Electronic Centre Coupling) as the problem did not reappear when the car was cold.

Remember that DSC is designed to prevent drift as are a number of other systems built into the vehicle. Turning off DSC while fun is not recommended for normal use. Grass Gravel Snow is however recommended when the surface is slippery such as in snow.

Im completely aware what DSC does that is why i turned it off when drifting...but Terrain Responce worries me...can I make some unwanted damage to the car by drifting in GrassGravelSnow mode? Because like you said, this program is ment to prevent slipping aso...thx

I doubt you will have done any serious damage, you have made the system work very very hard to do what it was designed to do. Next time though, try it in Normal with the DSC off and see if you get the same result!

When LR Experience Centres are demonstrating drift they do it with the TR in normal mode and DSC off. This reduced the loading on the vehicles systems such as Electronic Traction Control, Hill Descent Control, DSC, Corner Brake Control all of which are designed in their own way to help you maintain control of the vehicle in all conditions.
You are unlikely to damage the car by drifting in GGS mode but as XFullFatTim says next time do it in Normal mode and leave GGS for when you want to progress safely in slippery conditions without drifting.

Ok...thx a lot!

what are these blue tiers that show when u select terrain responce means anyway ? whats the purpose of it ?