[s-cars] Video RS5 and urQ running side by side

[qshipq at aol.com]

 I believe it's both.  The difference of the v5, as I understand it, the car is on, the Haldex is under (partial) locking.  60R/40F in the S5 if I recall.  Which means that technically this version of Haldex is more 'quattro' less 'coupler'.  I remember when Haldex was first introduced, a good friend of mine was at an SAE convention where Haldex Engineers were in the booth.  Those very engineers said that the unit itself could be full time (partial) locking, and it was designed and tested to be that way, audi 'chose' to make the 4motion/TT a synchro part time awd car.  Some techical issues I could see from that statement due to 'required' slip issues, but the new 'sumped' v4 started to address the issues of 'preload'.  It appears v5 took them the next step, and I see this as a very desire-able progression of 'Quattro' technology.  The unfortunate part for VAG IMO, is a lot of bread and butter manufacturers see the Haldex as their future as well.  

S 'T-B' J

 


 

 

-----Original Message-----
From: Taka Mizutani <t44tqtro at gmail.com>
To: qshipq at aol.com
Cc: airbil at gmail.com; s-car-list at audifans.com
Sent: Tue, Mar 9, 2010 6:57 am
Subject: Re: [s-cars] Video RS5 and urQ running side by side


Is that just for the rear diff or also the center diff?

I hate the Haldex systems that are FWD until the wheels slip- unpredictable handling characteristics, esp. in snow. I guess I could blame DSTC for that as well, as they are all interconnected.

Taka



On Mon, Mar 8, 2010 at 11:59 PM,  <qshipq at aol.com> wrote:


 I suspect the S5 "Crown gear differential" is actually Haldex XWD version 5.  Since VAG just completed a $4.5B deal with Haldex last October to develop XWD v5 for 2012 platforms, I suspect the S5 is as good an initial test bed as any. The video QW put up is incomplete to 'how' it's controlled, but the claims of it's dynamics certainly dictate all these performance enhancers are tied to the CAN Bus of the Haldex v4 with "improvements" for the yet to be introduced v5 (Haldex claims it can control EDL functions with the XWD platform).

The difference from XWD v4 appears to be that v5 can allocate engine torque without any slippage, and has that capability at any engine applied torque (unlike the limted preload torque of the v4 in the Saab 9-3 of 59lb/ft).  I also suspect it's pretty easy to add a locking switch to lock the center diff.


My .02

S "torsen boy" J