I have recently bought a 3 year old 280 Sportline Estate with 4 wheel drive. Firstly, it is a brilliant car in every respect and an absolute bargain. I have had several 4 x 4 cars in the passed from  very quick Sierra Cosworths through various SUVs to BMW X5 and 3 series models. I have a strong preference for more power to the rear wheels so I have been interested to explore the power delivery of this Superb.

 

Living next to the Peak District I have had the opportunity to play in the snow recently and I am baffled by the way this 280+ car handles. According to articles I have read the Haldex 4 wheel drive system is biased to the front wheels but that is not my experience. With plenty of poke to play with my car is certainly delivering most power to the rear wheels. Never at any time has it felt like front wheel drive. This suits me fine as a bit of tail out fun is great even in such a big car but could it be my system is not working properly. Today I was able to drive around without any problems when many others were getting stuck but can someone tell me how the Haldex on this car apportions the grunt?

Since the Haldex engages to send drive to the rear wheels, the maximum it can send to the rear wheels is 50% of the available torque.  In a steady state cruise, it's more like 90% front, 10% rear. 

If you are playing with plenty of poke then the Haldex will be fully engaged & delivering 50% torque to the rear wheels as stated, if it feels tail happy then that will be a consequence of the powertrain weight over the front wheels providing more grip to them, the rear diff is not limited slip, when you are giving more power than the grip available one rear wheel will be spinning faster and one slower than the front wheels that are not slipping hence the drift.

 

I am actually very pleased to hear what you are experiencing, I dont have any poke to play with and would have to really abuse the vehicle on wet roads to find its transient behaviour, no snow here as yet to discover what you have.

It's not technically possible for Haldex to send more power to the rear wheels as you say, at least continuously. Allowing the rear end to momentarily step out and play with some opposite lock is possible even in the dry with ESP set to Sport but it's a short-lived event as the car tends to become straight rather quickly.
What you are experiencing is the natural behaviour of the Haldex when it senses that the front wheels are about to / have already started to slip (for example in a tight turn where you apply throttle or much earlier in slippery conditions): Rear axle is engaged and, with adequate throttle, since the front/rear axle ratio of turning is 1:1, the fronts are braking the car while the rears are accelerating it due to the different turning radii, in other words: the car oversteers.

But don't get too excited because the way the Haldex ECU is tuned is so as to only bring in the rear axle as little as possible, just enough to correct wheelspin and understeer, but not to maintain oversteer and drift. So as soon as the car starts to oversteer and you think "wow, am i in a BMW??" the ECU will lower the rear axle engagement to bring it back to a neutral behaviour and the party is over. The above is easier to provoke on slippery conditions (snow) and of-course with more torque (remapped cars).

This is where an aftermarket Haldex controller comes into play by locking the rear axle's engagement to a desired percentage up to 100% which in equal front/rear traction conditions would mean a 50-50 torque split. However even that 50-50 assumption is not always true and there can be moments where more torque is arriving to either axle due to traction differences, for example during acceleration where the front lifts and the rear dives, during drifting etc. In other words the percentage of engagement does not always guarantee a fixed torque split as that depends on the available traction from the tires. To go in even more detail, the axle weights and tire pressures come into play but it really gets too complicated beyond a certain point.

I run such a controller and it is very easy to provoke the rear end to step out (in the dry) and maintain the drift for longer, it is quite fun indeed, but again, the car eventually settles. It is more useful for providing an extra level of agility during turning as you can make the rear to rotate much more easily than stock and thus help you noticeably in cornering, but it can't turn it into an oversteer, tire eating monster due to the inherent design of Haldex.

 

Edited 14 January, 20215 yr by newbie69

Hi all, not a Skoda owner (so far) but looking at a Superb with this 4x4 system you`re discussing. Do they give any problems on say a 100k mile car? Whats long-term reliability like? Thanks!

Thank you for all the brilliant responses. Does the front wheel drive have a LSD?

It doesn't have a mechanical LSD but it does have a couple of electronic aids that achieve something appproaching the effect of an LSD, i.e. EDL and XDS.  

1 hour ago, newbie69 said:

But don't get too excited because the way the Haldex ECU is tuned is so as to only bring in the rear axle as little as possible, just enough to correct wheelspin and understeer,
 

So, is this a confirmation that the set up is still reactive rather predictive ?

Thanks. I am now in my 74th year so I have not planned to join any "drifting clubs" so my experience to date leaves me very happy with the set up. I might try the "Launch" option when the roads dry out!!

35 minutes ago, StewartM said:

So, is this a confirmation that the set up is still reactive rather predictive ?

I'd say it's as predictive as it can be. For example during launch control, the Haldex is fully engaged even before setting off and in general the system prepares itself based on various parameters like throttle position, steering angle, acceleration etc. to be ready for most scenarios.  On the other hand there are situations that simply can't be predicted, ie. if suddenly the fronts go over ice and lose traction, there's no way to foresee that.

What's important is that even in the unpredictable scenarios this latest gen is so fast in its responses that you don't ever get to feel the moment it has started to intervene, it is very seamless. Meaning nothing like the first Haldex generations that wheel slippage was required to trigger the system's response.

42 minutes ago, RSB said:

Thanks. I am now in my 74th year so I have not planned to join any "drifting clubs" so my experience to date leaves me very happy with the set up. I might try the "Launch" option when the roads dry out!!

It is a very efficient system indeed which has received undserved bashing by Torsen die-hards (and probably due to the fact the first generations weren't that good so the bad reputation continued on to the newer ones), but in reality it just works so well for 99% of the situations especially in its latest iteration that makes more complex systems un-necessary unless for very specific applications. That's why Audi is slowly switching to Haldex based Quattros even on its bigger cars above the A3 platform.

The fact that VAG chooses to tune it towards a safer feel (minimum rear axle engagement) and not to provide some driving fun doesn't help either but as can be seen from a Haldex controller, it can also provide some fun if tuned differently.

2 hours ago, loughside said:

Hi all, not a Skoda owner (so far) but looking at a Superb with this 4x4 system you`re discussing. Do they give any problems on say a 100k mile car? Whats long-term reliability like? Thanks!

The wearing friction material in the Haldex clutch does tend to clog things up. Regular Haldex oil changes are needed. There is no proper filter just a gauze at the pump inlet. Skoda’s servicing scheme doesn’t seem to include removing the pump to clean the gunge off the gauze, even though this isn’t hard to do. Eventually the gauze can clog and the system can stop working, possibly due to pump failure. I’m not sure if the clutch linings can wear out within 100k miles, depends on usage I’d guess.

 

One thing to be aware of when buying 2nd hand is that there is nothing to indicate that the system isn’t working - in terms of warning lights etc. You just notice that the front wheels become spin-happy.

6 hours ago, nicknorman said:

Skoda’s servicing scheme doesn’t seem to include removing the pump to clean the gunge off the gauze

It's more than "it doesn't seem to include...". It doesn't at all, indeed!

 

Simple reminder :

 

On 14/01/2021 at 15:39, newbie69 said:

It's not technically possible for Haldex to send more power to the rear wheels as you say, at least continuously. Allowing the rear end to momentarily step out and play with some opposite lock is possible even in the dry with ESP set to Sport but it's a short-lived event as the car tends to become straight rather quickly.
What you are experiencing is the natural behaviour of the Haldex when it senses that the front wheels are about to / have already started to slip (for example in a tight turn where you apply throttle or much earlier in slippery conditions): Rear axle is engaged and, with adequate throttle, since the front/rear axle ratio of turning is 1:1, the fronts are braking the car while the rears are accelerating it due to the different turning radii, in other words: the car oversteers.

But don't get too excited because the way the Haldex ECU is tuned is so as to only bring in the rear axle as little as possible, just enough to correct wheelspin and understeer, but not to maintain oversteer and drift. So as soon as the car starts to oversteer and you think "wow, am i in a BMW??" the ECU will lower the rear axle engagement to bring it back to a neutral behaviour and the party is over. The above is easier to provoke on slippery conditions (snow) and of-course with more torque (remapped cars).

This is where an aftermarket Haldex controller comes into play by locking the rear axle's engagement to a desired percentage up to 100% which in equal front/rear traction conditions would mean a 50-50 torque split. However even that 50-50 assumption is not always true and there can be moments where more torque is arriving to either axle due to traction differences, for example during acceleration where the front lifts and the rear dives, during drifting etc. In other words the percentage of engagement does not always guarantee a fixed torque split as that depends on the available traction from the tires. To go in even more detail, the axle weights and tire pressures come into play but it really gets too complicated beyond a certain point.

I run such a controller and it is very easy to provoke the rear end to step out (in the dry) and maintain the drift for longer, it is quite fun indeed, but again, the car eventually settles. It is more useful for providing an extra level of agility during turning as you can make the rear to rotate much more easily than stock and thus help you noticeably in cornering, but it can't turn it into an oversteer, tire eating monster due to the inherent design of Haldex.

 

What aftermarket Haldex controller is available, very interested in one for my 272, I’ve looked at altering the controller via vag com but this isn’t possible and didn’t realise that a aftermarket option was available I do  like the thought of going back to my youth and having some step out times. Cheers Phil.

On 14/01/2021 at 18:14, newbie69 said:

I'd say it's as predictive as it can be. For example during launch control, the Haldex is fully engaged even before setting off and in general the system prepares itself based on various parameters like throttle position, steering angle, acceleration etc. to be ready for most scenarios.  On the other hand there are situations that simply can't be predicted, ie. if suddenly the fronts go over ice and lose traction, there's no way to foresee that.

What's important is that even in the unpredictable scenarios this latest gen is so fast in its responses that you don't ever get to feel the moment it has started to intervene, it is very seamless. Meaning nothing like the first Haldex generations that wheel slippage was required to trigger the system's response.

Thanks Newbie. Interesting. Watching this video, which I think most of you have seen, around the 7 minutes mark, made me think it was being reactive.                  https://www.youtube.com/watch?v=1B_V5cZVIiE

3 hours ago, sherlocks VRS said:

What aftermarket Haldex controller is available, very interested in one for my 272, I’ve looked at altering the controller via vag com but this isn’t possible and didn’t realise that a aftermarket option was available I do  like the thought of going back to my youth and having some step out times. Cheers Phil.

Only a couple really, but I went with this one, below a small review:
 

Feel free to drop me a pm if you want to know more about it.
 

3 hours ago, StewartM said:

Thanks Newbie. Interesting. Watching this video, which I think most of you have seen, around the 7 minutes mark, made me think it was being reactive.                  https://www.youtube.com/watch?v=1B_V5cZVIiE

Yeah, I see. That's probably an exception due to a combination of factors like setting off on minimum traction conditions, amount of steering lock etc. The Haldex algorithm takes a lot of factors into account in deciding how much it should engage the rear axle and varies it continuously. In reality, in 2 years of owning the car I have not once managed to get the ESP to flash due to loss of traction including driving in the rain, and I do have quite some extra torque than stock going through those axles too...

Since the Haldex Gen 4 the 4x4 kicks in automatically from stand still and in any acceleration and critical driving situation, not just when front wheel slip is detected. The SIII has got a Gen5 system fitted. As mentioned above it is programmed to split 50:50 front and rear if need be or as little as 95:5. With software tweaks it can be rejigged to a rear wheel bias.

 

Audi used to use the Torsen in the in-line engine setups, but is also using transverse 4s now where a Haldex is more beneficial.

22 hours ago, StewartM said:

Thanks Newbie. Interesting. Watching this video, which I think most of you have seen, around the 7 minutes mark, made me think it was being reactive.                  https://www.youtube.com/watch?v=1B_V5cZVIiE

Wow  ! I've never thought that my 4x4 could have such "off road" ability, even from 6minute mark... 

A 'Scout' version or a Kodiaq might be recommended for such use.

 

I feel even amazed that one can think of activating launch control on such a 'poor road'... 

Probably because car testers don't use their own cars...