Audi 2010 S4 Sport Differential Interview W Dr. Johan Fuchs

Interview with Dr. Johan Fuchs, discussing the driving advantages of the Sport Differential in the new 2010 Audi S4 in Mallorca Spain in October of 2008, by Paul Rivera

Category:

Autos & Vehicles

Tags:

• Audi
• S4
• Supercharged
• V6
• 2010
• B8
• quattro
• 3.0
• TFSI
• Sport
• Differential
• BMW
• M3
• 335i
• Mercedes
• C63

[Amidat]

@ZKev1 - thanks for the insight... that proves my point... each system was designed with some target in mind and had to compromise other things to get there... then over time systems are re-designed to bring more balance to them. Audi for instance started their quattro success in rallying... so that obviously shows what there starting point was. They have had to refine it more for on-road performance... quattro being banned for road racing for so long probably made that shift take longer.

[ZKev1]

@Amidat early gtr's are known to oversteer in the wet far too much, torque split controllers came out and sorted this problem out by fooling the centre accelerometer, in wet weather with a torque split controller the early gtr's are now awesome, the controller is a amazing mod for anyone with a attessa ets pro set up

[Amidat]

@bachiist - yeah and Audi just switched it up again... they are no longer using Torsen going forward... they are using their own in house crown gear center diff...

[bachiist]

Passive, mechanical system has natural response over broader driving environment that active system doesn't always have.

If two systems achieve the same performance, the simpler mechanical system is more desired (=One of the reasons Audi has kept the mechanical system).

I think B8S4 system (=Type C Torsen Ctr Diff w/ZF Active Torque Vectoring Rear diff) is a good architecture that is a good mix of both worlds.

- Another ACNA member

[bachiist]

Thanks for uploading this.

AWD system cannot be judged by advertised merits alone.

Active System: Pro=Engineer can program system behavior Con=Programming will determine the system  effectiveness, for better or worse There is inherent delay in system response

Passive System: Pro=Natural response, No delay (if Torsen) Con=Less tailoring of system behavior

[Amidat]

@gazboselectamo - check the november 2010 issue of Automobile magazine. They compare the AWD systems in the Acura ZDX - Subaru Outback - and Audi Q5. They praised the Acura system for switching torque side to side better than the other two....but other than that they didn't think it was so "special". It struggled in two tests (though one is partly because of ground clearance) and was noted as being slower to react than the Quattro.

[Amidat]

@gazboselectamo - of course it's not in the budget....but even exotics...how many of them use "active" steering or "active" suspension. Some....but only a few. It's just like craftsmanship....things may be automated and faster - but that doesn't mean you can build a structure better than the builders of old.

[Amidat]

@gazboselectamo - manufacturers don't like to give magss their AWD sedans to test against Quattro's or Subaru's....the same with steering of a Porsche or BMW - no matter how "advanced" the steering and suspension system. You didn't know they were the best in bad weather?? The old quattro was essentially what a Hummer now uses...so yes it did understeer. They still want to stay mechanical because they don't want to betray their roots of "all weather" performance. EVERYTHING is a trade-off!

[gazboselectamo]

@Amidat I've never heard of anyone saying the ATESSA system does not work well in wet weather or snowy conditions - equally I've never read that the Quattro system is particularly outstanding in these conditions. Where is your source for this information? The reason Audi have had to step up there game is because all older generations of quattro with the simple torsen centre diff and open diffs front/rear have inherent understeer uncorrectable by any means other than replacing the rear diff.

[gazboselectamo]

@Amidat They wouldn't because it's not within the budget of every car to have active suspension and transmission components.