A6/S6/RS6 2009 Audi RS6 Sedan

[SDNR]

Ha ha ha

 

[Tumbo]

I have to disagree with you there, I think it really suits it well, moreso than the other Audis!

That's what I meant man

 

[Mockenrue]

Maybe the RS6 needs so much more air that it cannot have LED lights in the bumper, just like the M3/M5/M6 do not have fog lights.

I believe this is correct.

 

[Giannis]

Its amazing how you can be so un moved.. or un interested by a car with 580 hp

I couldn't agree more with that! It's not that the RS6 is ugly, but it is that it should be MORE than that design-wise....

 

[Zafiro]

Apparently there are transmission errors for the new RS6. Several owners in Germany is taking the car back to the workshop. Some say the engine might be to powerful for the transmission.

 

[Amo]

That's what I meant man

Ooops, sorry misread your post!

 

[martinbo]

Apparently there are transmission errors for the new RS6. Several owners in Germany is taking the car back to the workshop. Some say the engine might be to powerful for the transmission.

I read in EVO's transmission special insert a few months back that a regular torque convertor has an RPM limit of between 6500 and 7000 rpm. I know the M156 engine revs to over 6800 RPM and haven't heard of any transmission failures in the Mercs but, with 426 kW @ 6750 RPM - who knows, maybe that tiptronic gearbox is the the RS6's mechanical achilles heel?

 

[Poverty]

The sedan RS6 is so sexy!

 

[VroomVroom]

The sedan RS6 is so sexy!

Sure is! Will be even better if it has the QVT quattro system same as the R8

 

[Beemer B773ER]

Its amazing how you can be so un moved.. or un interested by a car with 580 hp

Ditto.

It's groundbreakingly boring.

Audi really backed themselves into a corner with that 'shield' grille, because it seems a very difficult task to create a proportionate yet aggressive look for the RS variants.

 

[martinbo]

Sure is! Will be even better if it has the QVT quattro system same as the R8

QVT? Nope - you must be referring to QTV or Quattro Torque Vectoring, which the R8 doesn't have. In fact its AWD system is quite and obviously different as a result of the mid-engined application. The R8 makes use of a viscous clutch centre differential that can apportion only up to 35% of the torque to the front axle but the current bias if I recall correctly is 10/90 in favour of the rear axle. It also has an electronic rear differential lock or limited slip differential to limit the amount of slip at a given wheel. The reason that an R8 earns such accolades in the handling department has much more to do with its mid-engined supercar layout and not the level of technology thrown at the AWD system.

This is not torque vectoring. Torque vectoring involves the method of directing more torque to a rear-wheel with the best grip in the onset of understeer so traditionally associated with AWD vehicles. This is done via a electro-mechanical clutch and gear pack located in the rear axle differential.

Torque Vectoring is a holistic application - not just focussed on the mechanicals at a given axle. It relies on steering angle sensors, yaw and grip level measurement to determine the dynamic attitude of a vehicle vs. the driver's intended direction. When it senses understeer through all of these systems, QTV then applies more torque to the desired rear wheel in order to turn the nose of the car into the corner.

 

[SDNR]

Great post Martin .......I learn a great deal from your posts.

 

[Centurion]

QVT? Nope - you must be referring to QTV or Quattro Torque Vectoring, which the R8 doesn't have.

Thanks for the info, I didn't know that. The absense of QTV must be the reason you can play around with the R8 and tail it in corners unlike the RS4 and RS6 which ride like trains on rails. Hopefully Audi will offer an "optional performance kit" or something with a a different center diff, LSD and no QVT for people who would like their RS5 or RS4 more adventurous.

 

[Merc1]

I didn't know that either. So the R8 doesn't have the latest quattro or the best gearbox. I don't think it has mattered though!

M

 

[VroomVroom]

Thanks Learnt alot more now

 

[martinbo]

Thanks Rob.

I find Audi's array of AWD and traction management systems to be bordering on bewildering. It's very interesting that Audi - for all their quattro heritage and hype are actually the AWD whores of the world. From the FWD-based Haldex systems to the straightforward "relatively low-tech" viscous coupling system in the R8, Audi seems to have an AWD philosophy that is so broad that I'm surprised they haven't just gone and done a RWD offering while they're at it. Let's see, there's:

Front wheel biased Haldex Coupling AWD (A3 3.2, S3 and TT)
Symmetrical Torsen AWD (RS cars - Differential behind engine and clutch)
Asymmetrical Torsen AWD (new A4 and A5 - Differential behind engine but ahead of clutch; internally housed front propshaft)
Asymmetrical Torsen AWD (Q7 - Differential offset to right and underneath engine; external propshaft; more akin to BMW's xDrive)
Asymmetrical Mid-engine AWD (R8 - Rear mounted, rearward biased, viscous centre differential)

Can anyone think of anymore?

 

[Merc1]

NO. Martin your're on a roll. I bet the regular Audi fanatics couldn't have rattled off all of those!

M

 

[martinbo]

I didn't know that either. So the R8 doesn't have the latest quattro or the best gearbox. I don't think it has mattered though!

M

That's an interesting statement you make Marcus. It's amazing how marketing spin can create and impression of the "latest version of quattro" when actually quattro is less of a mechanical innovation these days and more of a "philosophy" if you will - irrespective of the technical layout. So, technically speaking there isn't a latest version of quattro from an innovation point of view.

The latest version of quattro is simply the one employed in the most recent model release I suppose. It's possibly better to understand what is the most advanced or sophisticated version of quattro and again, even that is a difficult one to pin down. In my opinion it would be the lastest asymmetrical version employed on front-engined A4 and A5s coupled with a QTV rear differential.

In principle as I've laboriously stated on a number of occasions, there's no such thing as the perfect AWD system - each and every one of them has some or other mechanical or dynamic penalty. Some, though are as close as possible to the best practical compromise.

 

[Centurion]

Audi are using the their array of AWD systems to calibrate the behavior of their cars. The A3, Q7 and R8 are three different cars with completely distinct purposes, therefore they can't all share the same Quattro configuration. Some degree of tailoring is necessary and right now the R8 has the best AWD system suitable for a sports car since it's closest to how a normal car should behave.

 

[martinbo]

Thanks for the info, I didn't know that. The absense of QTV must be the reason you can play around with the R8 and tail it in corners unlike the RS4 and RS6 which ride like trains on rails. Hopefully Audi will offer an "optional performance kit" or something with a a different center diff, LSD and no QVT for people who would like their RS5 or RS4 more adventurous.

Interestingly no, Luw, the absence of QTV is not the reason for the difference in handling between the R8 and say the RS4. The primary and practically sole reason is down to the mid-engined layout coupled to a drivetrain that's pumping 90% of the torque to the rear wheels. Add in a locking rear diff (the term locking is used loosely here) and voila! great supercar-like handling is there for the taking. This has much more to do with polar moment of inertia and weight distribution physics than the type of AWD system.

Consider now an RS6, its quattro system employs a torsen helical gear mechanical centre differential that sends 60% of the torque to the rear axle. The reason for this? To negate as much as possible the effect of hanging a huge V engine ahead of the front axle. This amount of weight ahead of the front wheels means that from an inertia and grip perspective the car leads with its (heavy) nose. It understeers in extreme cornering no matter how sophisticated the AWD system is. To get it to oversteer would first necessitate using lateral momentum to flick the tail out. Again it's all about where the weight and grip is.

It would've been nice to see Audi employ QTV on this RS6. It may have improved the inherent handling characteristics by a small margin.