[s-cars] Off topic - New Volvo S60 ? - Drat and double DRAT!

[John Cody Forbes]

VW's Haldex self study manual, everything you want to know:
http://www.volkspage.net/technik/ssp/ssp/SSP_206.pdf


It's simple really. The Haldex is an electronically controlled clutch. There is no center diff at all. When the Haldex clutch is disengaged the rear wheels are not connected to the engine at all. When the clutch is engaged the rear wheels are completely locked to the engine. It can slip at any rate in between locked and unlocked. Power is therefore variable between 100/0 and 50/50 front to rear.

-Cody (mobile)

On Jan 5, 2011, at 9:04 AM, Taka Mizutani <t44tqtro at gmail.com> wrote:

> Scott-
> Does that mean that Haldex is either fully engaged at whatever the torque
> split is with it engaged or not at all?
> 
> I guess I don't really understand the Haldex system and how it works.
> 
> Now I have to find someone that makes a Haldex box for the Volvo, if I
> decide to keep the Volvo. Otherwise, I'll get a BMW 5 series xi with a stick
> or a diesel SUV.
> 
> Your opinion on the Porsche Cayenne AWD or the VW Touraeg (which I think is
> the same setup)?
> 
> Thanks,
> 
> Taka
> 
> 
> On Tue, Jan 4, 2011 at 12:18 PM, <qshipq at aol.com> wrote:
> 
>>  The Haldex system can be modified, and the torque can be handled with
>> that modification.  Haldex makes performance upgrade boxes for the R32 and
>> TT (
>> http://www.europeancarweb.com/features/epcp_0505_haldex_lsc_performance_upgrade/index.html).  I understand that we will have one of these modified units at Steamboat
>> this year in an R32 (former B5S4 owner), so more to come on that effort.
>> The 'problem' with Haldex in any car, including the Volvos, is that it's a
>> coupler, not a differential.  So, it's either partially or fully locked OR
>> completely unlocked (braking, cruising, etc).  So the 'modified' units will
>> still uncouple during braking and/or other sensored inputs.
>> 
>> The modification is to the CAN bus controller, which gives 3 levels of lock
>> on most synchro systems 6/9/12v.  6 being partial lockup and 12 being fully
>> locked up.  I understand the newer systems give a much larger range of
>> lockup vs voltage.  I spent many weeks with a friend's XC90 AWD 2.5T with a
>> faulty rear Haldex unit.  This made for a FWD ride for many weeks, then
>> after the repair, the awd system was restored to normal.  I'm not a fan of
>> synchro systems (specifically non-center differential 4x4's) of any type, as
>> the characteristics of the car change much more dramatically than in a full
>> time awd vehicle.  I have driven a few S60's and the V70 in 6speed trim, and
>> they are a lot of fun, 2.5L turbo 300hp gives a lot of torque, and they have
>> great brakes to boot.  I don't ever see them being a real competitor for a
>> full time quattro, but it will certainly keep up with any Haldex 'quattro'
>> or '4motion' VAG car.
>> 
>> To the question, "can the Haldex take the torque" of full time, the answer
>> is yes, in fact Haldex designed it that way.  It was the choice of the
>> manufacturers to use it as a synchro application.  Our former S2 rally
>> driver has a Volvo shop, and we had spoken extensively to Haldex regarding a
>> rally S60 with a modified Haldex, and they were very supportive to the idea,
>> and had no qualms about the unit being able to handle a full time race
>> environment.
>> 
>> My folks have a year old 530ix, and I find it to be much more quattro-like
>> than Haldex like in it's snow manners.  BMW certainly complicated the awd
>> concept, but the new RS5 seems to follow the same path in engineering and
>> supplier, so I guess the 'new' generation of awd can't be bested or ignored
>> by Audi either.
>> 
>> All good things for German car buyers.  I was surprised that Haldex chose
>> to not do the Haldex-over-center-diff awd that was to be Haldex IV, but that
>> might have been strictly a cost thing.  Having two vehicles with LSD
>> over-center-diff vehicles (1992 v8 with electronic plate- over center diff
>> awd, and 1994 Supercharged Landcruiser with VC over center diff awd with
>> locked center diff over-ride ability), I find them much more civilized in
>> all applications of power/slip than the Haldex systems.
>> 
>> My .02
>> Scott "Torsen Boy" J
>> Lockers
>> Torsens
>> VC...  Gots them all in the driveway.....
>> 
>> 
>> 
>> 
>> -----Original Message-----
>> From: pkrasusky at ups.com
>> To: s-car-list at audifans.com
>> Cc: mtgadbois at aol.com
>> Sent: Tue, Jan 4, 2011 9:49 am
>> Subject: [s-cars] Off topic - New Volvo S60 ? - Drat and double DRAT!
>> 
>> Mark fargin sneaky bastid'd:
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>> <<<Date: Mon, 03 Jan 2011 15:56:30 -0500
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>> From: mtgadbois at aol.com
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>> Subject: Re: [s-cars] Off topic - New Volvo S60 ?
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>> I participated in Volvo's "come on out and beat one."
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>> I drove it in a head-to-head comparison against an Audi A4 and it was
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>> impressive.
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>> The Audi was a bit more imprecise.  I also did a lap in Volvo's S60 autocross
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>> car.
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>> Came in 3rd or 4th out of 300 drivers. That car was impressive too but it had
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>> well-used race rubber on it.
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>> I'd consider one but I'm not in the market right now to drop $50K on a sedan.
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>> BTW last year was weird - got invites from BMW (now have a new wedge), Cadillac
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>> and Volvo.
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>> Mark near Chicago>>>
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>> Drats!  Foiled!  My invite musta gotten "lost in the mail".  D'oh 8-)
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>> Man, aren't those events just the best?  Good stuff.  Great to hear you
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>> represented and had a baul.
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>> Agree w/ sagedom of JC 'n Taka - I'd love a Volvo product but for 'the reasons'
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>> not to.  Shame.  Seen a MkII XC70 do quite well @ a local winterx yearses ago
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>> tho - guess it can, just mustn't feel good in doing so heh heh.  The ones I've
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>> rented have been damn good cars - but - I've also found their Kryptonite, which,
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>> is never good.  JNR.
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>> Schpeaking of winterx, fawk - I just learned the NERSCCA's hosting winterx
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>> turn-right-5-miles from me on 1/15.  Things that make you go hmmm.  Alumibitch?
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>> Keep up the good (JNR) werk out there men.
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>> -Paul
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