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Haldex front/rear bias


Y Cymro
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Hi

I’m using Carista diagnostics on my UK mark 7.5 2018 Golf R and see under ‘Chassis & Engine configurations’  there is a setting for ‘Haldex AWD System Setup’ which allows me to change the parameters from the current ‘Standard’ to ‘Rear bias’.


Has anyone tried this using a diagnostic tool and does it work/is it worth the change, or would it work only on the mark 8?

 

Many thanks
 

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So ’rear bias’ was turned on yesterday using the Carista app, and as @sibbers confirms above it definitely makes the rear more lively.  On a short drive it appears that any delay in triggering the Haldex coupling has been removed, and that torque is sent instantaneously to the rear diff once cornering forces are identified.  I’ve read many road test reviews of the mk7/7.5 R and the results are often that the car is ‘boring to drive’.  I think reviewers confuse the feeling of being boring with being massively capable, but from my very brief drive I would suggest that with this new setting the car is more exciting, and drives more like a rear-wheel drive car with very good rear grip and traction, though any rear waywardness is quickly controlled by ESC. It might be that ESC Sport will be even more lively so will try this over the weekend.

Of course, this may not be what you (or I) want on the public road - where capability is far more important than excitement! - though it might be fun to explore on a track day.

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19 hours ago, Y Cymro said:

So ’rear bias’ was turned on yesterday using the Carista app, and as @sibbers confirms above it definitely makes the rear more lively.  On a short drive it appears that any delay in triggering the Haldex coupling has been removed, and that torque is sent instantaneously to the rear diff once cornering forces are identified.  I’ve read many road test reviews of the mk7/7.5 R and the results are often that the car is ‘boring to drive’.  I think reviewers confuse the feeling of being boring with being massively capable, but from my very brief drive I would suggest that with this new setting the car is more exciting, and drives more like a rear-wheel drive car with very good rear grip and traction, though any rear waywardness is quickly controlled by ESC. It might be that ESC Sport will be even more lively so will try this over the weekend.

Of course, this may not be what you (or I) want on the public road - where capability is far more important than excitement! - though it might be fun to explore on a track day.

I have had the rear bias turned on on both my mk7 after trying the standard setup for a few months and mk7.5 almost immediately after collecting it. There is a definite difference that I think is most noticeable when pulling out into fast moving traffic from a side road. I find it instils far greater confidence on a wet road as well. I also found this on Carista but now use OBDII so I haven't bothered to look at it on the OBDII app or long coding.

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  • 2 weeks later...

I tried it again. Instantly noticeable. It does feel more grippy, but it doesn’t feel quicker and I think that it’s a false economy to want something that feel more like full time 4 wheel drive in this car - it’s a FWD car with the ability to engage the rear wheels when needed. I think the balance is about right for what is essentially a passenger car. 
 

I tried the XDS settings too. Strong interferes too much. I’m not sure if I prefer weak or deactivated but am leaning towards deactivated. 
 

I would love to find some definitive explanations of all the things going on, but regarding the increased traction option - I think that unless you’re spending time driving on dirt, it’s better left at default. 
 

Oh yeah, and definitely more juicy. Makes sense as said above. 

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I’m not so sure how clever it really is. Is it just as simple applying braking force to the inside wheel(s) according to steering input, or does it do clever stuff in addition to that under any other circumstances that make it behave more like an actual diff?

 

Do you know of it takes effect on front only, rear only or both inside brakes? I assumed rear but actually I have no idea. It just felt like that. 

 

I think my preference will be to deactivate seeing as an open diff is fine when the inside wheel doesn’t lift and there’s no traction benefit when it comes to laying down the power etc…

 

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