Haldec 4wd tuning?

[Willy]

Hello,  -- sorry for type error in title: should read "Haldex" --
Since the nex Haldex 4WD coupling is commanded by electronics, it should be possible to force it in a certain "mode" in the same way an automatic gearbox is forced in sport or winter mode.
By doing so, it would for example be possible to have 50% front and 50% rear traction by choice.
If conditions indicate you will certainly need traction on all wheels, you could prevent a slip in the first place.
Would be nice, or not?
Willy

[1Lieutenant]

If the system detects slippage and directs traction to the wheel(s) with the greatest traction then why would one need to force traction to one wheel or the other?  As long as it is smart enough to direct force even if ALL four wheels are slipping (a failure in many traction control systems) it should be OK. (maybe this is what you were thinking about)

Steve

[Willy]

Yes and no. I think that staying ahead of slippage should be better than acting when it actually occurs.
This is an opinion, I can't prove it, it just seems logical to me but it may be wrong.
Willy

[tooberand]

Don't forget that the reaction time is handled by a computer.  It reacts so fast (I believe in the range of milliseconds) that you can't detect it.

Try driving a similar system (like the Passat 4Motion) and you'll see how well they work.  They are truly incredible.  I like the gravel test the best.  Stop the car on a gravel road or parking lot, roll down the windows, and punch it.  You won't hear a single pebble kick up and the car just takes off.

[AkXCman]

Yes, the Haldex system is a great system. We have a 01 Audi TT with Haldex. I think that the biggest improvement that Haldex offers is in regards to higher speed driving. On the TT, they have a button on the dash to turn off the "ESP", which is Audi's computerized electronic stabilization program- if for some reason the driver wants control.

I have done some testing with both our Audi and our XC on ice covered lots. Both systems are great. Its hard for me to compare the two as the XC and the TT are very different animals. It would be fun to do similar testing with an 01 and a 03 XC, but it could be dangerous to the pocket book!

I must admit that I have no complaints with the AWD system on our 01 XC.

http://www.tmurrell.com/ttgail.jpg

[Willy]

Volvo says it will take the wheel to slip 1/7th of a revolution before the system comes in.
Anyway, what you try to tell me is that Mr. Haldex is clever and fast enough to keep me out of trouble in any condition and that I should't worry so much about the issue.:-)
But the gravel test with the Passat 4motion tends to prove my point since to the best of my knowledge this car (and perhaps the Audi TT as well) has a constant 4WD, not on demand as a Volvo.
With a system on demand, I think some pebbles will be relocated http://xc70.com/iB_html/non-cgi/emoticons/wink.gif
Willy