hi

 

I'm sure that this question must have been asked a dozen times already, but having searched the forums I didnt find a definite answer.

 

I have just bought a 2008 Octavia Scout 2.0 PD (BMM).

 

Can anyone advise, how I can reliably find which Haldex version the car has?

 

I have already noted on this site that there seems to be a bit of ambiguity as to whether is its reactive Haldex 2 or preemptive Haldex 4.

 

cheers

 

 

Pre facelift = gen 2

Post facelift = gen 4

Thanks for the reply drmike.

 

Short n sweet :-)

 

For some reason I had hoped that my car had Haldex 4 - simply from the point of view that prevention must be better than cure (wheel spin)?

Is the main difference between Haldex 2 and 4 the fact that haldex 4 is anticpating loss of grip rather than reacting to it?

If it is anticipating loss of grip how does it do that?  What parameters are being measuring?

My (limited) understanding is that Gen 2 isn't a pre-tensioned device but relies on a pump that activates once slippage occurs. Gen 4 is pre-tensioned meaning it reacts AS the wheel slips, not ONCE is occurs.

My understanding is the same.

For Haldex IV,

• the throttle position,
• engine torque and
• road speed

are used in the decision making process as to when the clutch is pretensioned.

The pretensioning is electronically controlled, activating all wheel drive before the wheel slips.

Unless you provoke a significant amount of under steer I have found the gen2 hakdex to be pretty good and progressive. I have a couple of tightish bends I regularly travel round and you can feel the haldex working but smoothly.

Chuck it into a tight bend too quickly and you can feel the power kick in at the rear with a snap which can be a bit disconcerting.

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There is quite a good explanation if you google Haldex 4 @ http://www.awdwiki.com/en/proactive/

 

The system is still somewhat crippled by the back open diff IMO.

There is quite a good explanation if you google Haldex 4 @ http://www.awdwiki.com/en/proactive/

The system is still somewhat crippled by the back open diff IMO.

It's great in the winter though. Turn off the traction control and you can displace a significant amount of snow

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If it is anticipating loss of grip how does it do that?  What parameters are being measuring?

The answer may be in the Tiguan Haldex (Gen 4) All-Wheel Drive Self Study Program downloadable via the link below. It certainly makes interesting reading.

http://www.freel2.com/gallery/albums/userpics/11383/tiguan_haldex_gen4.pdf