4 motion

[matsu]

stupid question of the day.... what does the 4 motion mean?

 
matsu

[MAT ED30]

all 4 wheels have drive to them

[Richn83]

isn't it basically just the haldex 4 wheel drive system like in the S3, R's etc.

[94Luke]

why is it that people say it isn't 'true' 4WD? what is true 4WD in comparison?

[parks]

I believe (could be wrong) that the golf etc are fwd most of the time until the front wheels loose tractiion and then the haldex kicks in and powers the rears.

'True' would be if all 4 were powered all the time.

[Richn83]

As parks says the Haldex application in transverse engines doesn't permanently power all for wheels, power is transfered via a clutch pack to the rear wheels in a reactive fashion so an amount of slip has to occur before torque is transferred.  It also de-couples the rear wheels under braking and ESP activation to stop the individual wheel braking from upsetting the power transfer. 

What people refer to as proper or full 4 wheel drive each wheel is permanently powered and power is transferred by a torsional centre diff.

[rich83]

As parks says the Haldex application in transverse engines doesn't permanently power all for wheels, power is transfered via a clutch pack to the rear wheels in a reactive fashion so an amount of slip has to occur before torque is transferred.  It also de-couples the rear wheels under braking and ESP activation to stop the individual wheel braking from upsetting the power transfer. 

What people refer to as proper or full 4 wheel drive each wheel is permanently powered and power is transferred by a torsional centre diff.

Which is where 4motion or Haldex differs to Quattro!

[Hedge]

As parks says the Haldex application in transverse engines doesn't permanently power all for wheels, power is transfered via a clutch pack to the rear wheels in a reactive fashion so an amount of slip has to occur before torque is transferred.  It also de-couples the rear wheels under braking and ESP activation to stop the individual wheel braking from upsetting the power transfer. 

What people refer to as proper or full 4 wheel drive each wheel is permanently powered and power is transferred by a torsional centre diff.

Which is where 4motion or Haldex differs to Quattro!

Shush there Rich you'll be upsetting all those S3 owners and their Quattro (not quattro) badges.

[94Luke]

So under 'normal' conditions there can be no drive to the rear wheels? Though it was always a 90:10 front to rear split that changes under conditions

[Richn83]

Under normal conditions, there is a 90:10 torque split, and the haldex is capable of transfering upto 100% of torque to the rear wheels.  Its only under certain conditions when the rear wheels are un-powered to stop things like the ESP and ABS causing sudden and sporadic transfers of power across the rear wheels.

[simonp]

You're  wrong. The front wheels are driven all the time. The most the Haldex can transmit to the rear wheels is 50% or, to put it another way, equal power/torque to the front wheels.

[Richn83]

You're  wrong. The front wheels are driven all the time. The most the Haldex can transmit to the rear wheels is 50% or, to put it another way, equal power/torque to the front wheels.

I never said the front wheels were undriven, its only the rears I have ever stated would be undriven.  And the information I have read suggested thats its capable of transferring up to 100% " A Haldex Traction LSC unit may divert up to a maximum 100% of the torque to the rear axle as conditions warrant. " this is off of wiki so there is a potential for it to be wrong but the potential for it too and what VAG code software to do can be very different things.

[Janner_Sy]

Which is where 4motion or Haldex differs to Quattro!

so is 4motion the same as haldex then?

[simonp]

100% to my mind implies that the R32 can be at times rear wheel drive and that cannot happen. The drive can be no more than a 50/50 split. The LSC can put all available power to the rear wheels, but the fronts will have an identical amount still going to them as well, hence 50/50.  

Only the XWD system that Saab uses can transfer 100% of the torque to the rear wheels. I believe it can even do it to just one wheel in the unlikely scenario that the other 3 were on ice.

[Richn83]

Ok well we are talking about a wording issue here then.  Looks like the XWD system is also a Haldex but Gen 4.  Does anyone know which system they have fitted in the MK6 R?