2021 S3 with 100% RWD ability?

[Lehn]

EDIT: It seems to be true!

Haldex 6 and a new generation of Quattro all-wheel drive
One of the main higlights of the 2020 Audi S3 family is its drivetrain. Part of the reason this model has become a significant seller, accounting for one in five A3 sales in the UK, is its all-weather ability and grippy Quattro all-wheel drive. New for the fourth generation is a brand new Haldex 6 multi-plate clutch slung under the boot floor, apportioning drive front and rear in a more sophisticated way than systems from the past two decades.

It’s the VW Group debut for this Borg Warner hardware, which does away with some of the complexity of earlier Haldex clutches and is designed to be lighter and faster to respond; drive at a cruise and the pump is switched off entirely, but the moment the ECU detects slip or a likely need for extra traction (when cornering or driving uphill, say) it primes the pump and applies an extraordinary 44 bars of pressure within 100 milliseconds to engage the mechanical clutch and send drive rearwards. The all-wheel drive systems adds around 70kg of extra weight and will be available on lesser A3s before too long.

For the first time, the S3’s Quattro system can now be entirely rear-wheel drive in extremis, and the electronic brain brakes individual wheels for a torque vectoring effect. Power around a slippery corner at speed, plant the throttle and you can feel the Audi tuck in to the corner, with an impressively neutral feeling and a high level of grip. Instead of having different control systems for the Quattro, dampers and brakes there is now a single unified digital brain making decisions for a smoother, quicker, more reliable response. On this evidence, it works well.
https://www.carmagazine.co.uk/car-reviews/audi/s3-sportback/


My original post:

So, this might get a bit nerdy for some but isn't that why we're here anyway?

People are talking a lot about the new 2021 model Audi S3 and its looks but as an engineer I'm more into the technical and geeky stuff.

After reading an Australian article it made me question if the new S3 will have Torsen quattro instead of Haldex quattro OR if they have found a new way to make the Haldex system work 100% RWD (and here I'm not talking about torque destribution but real RWD).

So why do I question this? Because of the statement below:

"Audi has also reworked the quattro four-wheel drive system that will be used by selected new A3 models, including the initial top of the line S3. Its electro-hydraulic pump now operates at up to 44bar of pressure, leading to faster operation of the multi-plate clutch integrated within the rear axle and with it a more rapid apportioning of drive to the axle with the most grip.

In a long-overdue development, the drive split between the front and rear axles is now fully variable, meaning up to 100 per cent of the engine's reserves can be delivered to the road through either the front or rear wheels depending on the driving conditions. This hints to increased traction and ore neutral handling characteristics compared to the old A3, whose quattro four wheel drive system was only able to send 50 per cent of drive to the rear wheels."
https://www.drive.com.au/review/2020-audi-a3-review-audi-s3-sportback-prototype-123195.html

What can we conclude from this?

1. The new quattro system must be Haldex due to several facts:
   - Because an electro-hydraulic pump is mentioned (this is to control the clutch plates which are a trademark of the Haldex system).
   - Audi's Torsen type quattro can only destritbue a maximum of 85% of the power to the rear wheels and not 100% as described.
   - A Haldex setup makes most sense due to the engine being placed transverse.
   
2. It must be a Gen 6 Haldex system since it will have to be way different than the current Gen 5 which only allows a 50/50 split in power to the wheels.
3. The front wheels will somehow have to be disengaged to make this 100% power distribution to the rear wheels = expensive.
   AND
4. I don't believe for a second that Audi would make the new S3 completely RWD as seen from a cost perspective since a system like that would be too expensive. I would believe this if we were talking about the new RS3 though.

What do you guys think - Is it a plausible scenario or just journalists not understanding the information they get?


(If you want to know more about Haldex Gen 5 @GSB have been so kind to make a great write up here: https://www.audi-sport.net/xf/threads/quattro-settings.341579/#post-3088627)

 

[w.h.i.p.p.e.t]

Haldex's at the front and rear perhaps?

How does the flashy electronic front diff in the Golf GTI Performance work? Perhaps it could disengage the front wheels completely?

 

[Lehn]

Haldex's at the front and rear perhaps?

How does the flashy electronic front diff in the Golf GTI Performance work? Perhaps it could disengage the front wheels completely?

I also thought about that but that would just be too expensive (if you ask me*). And the electronic front differential is just to lock the axle to be able to launch harder.

Of course I should say I might be wrong since I know the new A45 has two clutches to make the drift mode available but it's just not something I would expect to be fitted to the S3.

"Drift mode is only available with the gearbox in manual, the drive mode in Race and stability control disabled. The four-wheel drive system uses a similar setup to the E63, with two separate clutches able to send up to 100 per cent of power to each rear wheel."
https://www.autocar.co.uk/opinion/m...edes-amg-a45-sideways-ride-drift-mode-engaged

 

[w.h.i.p.p.e.t]

Just had a little read and the GTI's VAQ diff seems to be pretty much a haldex on the driver's side drive shaft only. If you slapped one on the other side then that could work.

Saying "up to 100%" just sounds better I guess. Doesn't mean that it would actually happen on a factory car.

 

[Lehn]

Just had a little read and the GTI's VAQ diff seems to be pretty much a haldex on the driver's side drive shaft only. If you slapped one on the other side then that could work.

Saying "up to 100%" just sounds better I guess. Doesn't mean that it would actually happen on a factory car.

Just made an edit to my post, it seems to be true with the 100% RWD ability

 

[w.h.i.p.p.e.t]

I could imagine them saving it for the RS3 and making it an option for the S3.

 

[AlS3BE]

“the S3’s Quattro system can now be entirely rear-wheel drive in extremis”

this pretty much says it all. All they need to do is put a fancy centre diff/Haldex coupling and use the traction control to brake the front wheels. By default 100% torque can be sent to the rear. This will purely only work in slippery conditions.
Current version activates the Haldex pump to turn the rear wheels. The prop shaft from gearbox is constantly connected that’s why it’s 50/50 split. they can put a diff on the gearbox side of prop shaft to allow 100% power to rear or do as mentioned put the gubbins backwards similar to the R8 where the Haldex engages front not rear.
Other thing is it could be a similar quattro ultra system on the newer quattro cars which sounds like to me a Haldex type system
https://www.autocar.co.uk/car-news/new-cars/new-audi-quattro-ultra-four-wheel-drive-system-detailed

 

[w.h.i.p.p.e.t]

So it's an efficiency move. Everything is happening at the front of the car, meaning less drive-train losses from the spinning prop shaft.

 

[AlS3BE]

So it's an efficiency move. Everything is happening at the front of the car, meaning less drive-train losses from the spinning prop shaft.

that’s what it sounds like to me.
Surprised they didn’t try and fit some hybrid/e drive type system in there.

 

[w.h.i.p.p.e.t]

that’s what it sounds like to me.
Surprised they didn’t try and fit some hybrid/e drive type system in there.

They'll save that for the face-lift in 2025

 

[JohnM100]

Is this a true up to 100% RWD or a Marketing Department’s 100% eg only when front wheels off the ground?

 

[Lehn]

Is this a true up to 100% RWD or a Marketing Department’s 100% eg only when front wheels off the ground?

Hard to say since no reporter seems to have tried to drift it yet But if it doesn't have a drift mode like the A45 it would be hard to keep drifting in it - the behaviour depends on how aggressive the software in Dynamic is programmed I guess but on the Gen 5 Haldex the engagement of the rear wheels are progressive at least and doesn't depend on slippage.

Post no. 1.000!

 

[mfl]

Drift mode in an S3, I'd buy another one just for that, but Audi engineers allowing fun in a S3, driver enjoyment , that just isn't allowed is it ?

 

[VWNCC]

I am glad it has the new Haldex system. As long as it isn't as unreliable as the Haldex V system, I could care less about whether it can send 100% torque to the rear wheels.

The Haldex V should definitely be discontinued. What a crappy unreliable system (failing twice within 4 years and 60000 km is just unacceptable).

 

[mfl]

I am glad it has the new Haldex system. As long as it isn't as unreliable as the Haldex V system, I could care less about whether it can send 100% torque to the rear wheels.

The Haldex V should definitely be discontinued. What a crappy unreliable system (failing twice within 4 years and 60000 km is just unacceptable).

Oh you mean the system , that burns the clutches in the rear diff, especially in the My14/15 models and you can't replace the clutches by themselves so the entire diff needs to be replaced , at my indie my s3 was the 5th one he did in 2019.

 

[VWNCC]

Oh you mean the system , that burns the clutches in the rear diff, especially in the My14/15 models and you can't replace the clutches by themselves so the entire diff needs to be replaced , at my indie my s3 was the 5th one he did in 2019.

Yea, an extremely crappy unreliable AWD system.

If the Haldex 6 turns out to be more reliable, it will be the best news for the new model. I can careless about the other trade-offs. If not, then S4 is the way I guess...

 

[GSB]

There’s an awful of journalistic waffle and unquestioning regurgitation of the VAG key messages PowerPoint slide in there.

Based up on the evidence presented. Gen 6 seems to be evolutionary, not revolutionary. More of the same concept, but with greater optimisation of weight, drag, control parameters etc enabling them to keep the AWD feel, recover some of the reaction abilities they lost from the gen 4 design, and most importantly, chase down those CO2 numbers.

I’m afraid the key news here is not an enhancement of driver feel and capability, but rather maintaining what feel they had whilst reducing weight and drag to lower the overall emissions, and reducing cost to maximise the profits.

The age old marketing BS of 100% rear bias ‘in extremis’ is utterly meaningless and devoid of any relevance at all when applied to actual driving, and since it seems that one of gen 6’s USP’s is its low parasitic loss combined with an ability to totally disconnect the rear driveline (i.e. the greatest gains appear to be in the amount of torque it doesn’t transmit to the rear driveline) this is a message that seems even more at odds with the way the car you eventually buy will behave. But what the hell, it sells cars...

 

[wab172uk]

Drift mode in an S3, I'd buy another one just for that, but Audi engineers allowing fun in a S3, driver enjoyment , that just isn't allowed is it ?

I'm curious. Why would you want a drift mode?

Realistically you'd never use it on the road. A few Focus RS drivers tried it, and failed when the hit something immovable. You can't really use it on a track day as you'd get black flagged. So what is the point in these systems?

I also think Launch control is a bit pointless too. Yeah, fun to see just how fast it'll accelerate, but how many times do people use them? How much extra strain does it put on drive-train etc.

 

[GSB]

Driftmode? Surely the result of GKN’s engineers having a bit of fun seeing what their diff-less rear axle could do if they turn one side off and the other side up to eleven. It should never really have made it onto a production car, but it seems Ford’s RS dept share a similar sense of humour as GKN’s guys.

Relevance and usefulness on street and track? Nil. Do it on the street and they’ll rightly throw the book at you for being an almighty ****. Do it on track and you’ll get black flagged for being an almighty ****. Do it at a drift event and everyone will just laugh at you and your amateur display of fake drifters and think you’re a ****, and an almighty one at that.

Launch Control? Perhaps slightly more utility on track. On the road though? Sitting there with your engine going “Ba-ba-ba-ba-ba-ba!” as it bounces off a rev limiter while you wait for a light to go green is only going to attract the wrong sort of attention, prompt anyone within 200 yards to get their phones out to record the inevitable crime, crash or near miss, and at best see you uploaded onto the ‘almighty Twats’ channel on YouTube.

The stresses and strains imposed on a transmission system are huge, but there is an argument that launch control still has a great deal more mechanical sympathy than a lead footed knuckle dragger using a manual ‘box. Still doesn’t get round the fact that using launch control in a public place is only marginally more socially acceptable than whipping your old chap out and urinating on a war memorial.

 

[wab172uk]

Driftmode? Surely the result of GKN’s engineers having a bit of fun seeing what their diff-less rear axle could do if they turn one side off and the other side up to eleven. It should never really have made it onto a production car, but it seems Ford’s RS dept share a similar sense of humour as GKN’s guys.

Relevance and usefulness on street and track? Nil. Do it on the street and they’ll rightly throw the book at you for being an almighty ****. Do it on track and you’ll get black flagged for being an almighty ****. Do it at a drift event and everyone will just laugh at you and your amateur display of fake drifters and think you’re a ****, and an almighty one at that.

Launch Control? Perhaps slightly more utility on track. On the road though? Sitting there with your engine going “Ba-ba-ba-ba-ba-ba!” as it bounces off a rev limiter while you wait for a light to go green is only going to attract the wrong sort of attention, prompt anyone within 200 yards to get their phones out to record the inevitable crime, crash or near miss, and at best see you uploaded onto the ‘almighty Twats’ channel on YouTube.

The stresses and strains imposed on a transmission system are huge, but there is an argument that launch control still has a great deal more mechanical sympathy than a lead footed knuckle dragger using a manual ‘box. Still doesn’t get round the fact that using launch control in a public place is only marginally more socially acceptable than whipping your old chap out and urinating on a war memorial.

Great post.

 

[mfl]

I'm curious. Why would you want a drift mode?

Realistically you'd never use it on the road. A few Focus RS drivers tried it, and failed when the hit something immovable. You can't really use it on a track day as you'd get black flagged. So what is the point in these systems?

I also think Launch control is a bit pointless too. Yeah, fun to see just how fast it'll accelerate, but how many times do people use them? How much extra strain does it put on drive-train etc.

Pardon me while I take my cardigan off, Every now and again, I take the S3 onto a track and have some fun with it.
The fun factor would increase if there was more drive to the rear wheels. As I haven't taken the S3 to a drag strip , I haven't actually used launch control , because there aren't public roads to use it on sensibly around here.

I've long realised that driver involvement and fun, aren't part of the S3 language.

 

[wab172uk]

Pardon me while I take my cardigan off, Every now and again, I take the S3 onto a track and have some fun with it.
The fun factor would increase if there was more drive to the rear wheels. As I haven't taken the S3 to a drag strip , I haven't actually used launch control , because there aren't public roads to use it on sensibly around here.

I've long realised that driver involvement and fun, aren't part of the S3 language.

It's not no. But I don't think anyone bought an S3 expecting it to be fun. But what it does, (looks, ride, build quality, interior design and all weather ability) it does better than most as an everyday all weather car. A Focus RS is just as practical, and far more fun to drive, but I bet most would still prefer their S3 over a Focus RS.

But I do agree, a 40/60 bias in the AWD system front to rear would be most welcome in the S3.

 

[Daz Auto]

*** bump ***

Our A3 is due a change. I'm considering the new S3 saloon. I was wondering if they had changed the 4 wheel drive system for this generation of cars. Haldex 6 looks interesting.

 

[Daz Auto]

Just had a little read and the GTI's VAQ diff seems to be pretty much a haldex on the driver's side drive shaft only. If you slapped one on the other side then that could work.

Where did you read that?

I'm curious as it's fitted to my Golf

https://www.borgwarner.com/newsroom...-(fxd)-technology-for-the-new-seat-leon-cupra

"FXD technology is capable of distributing a specific locking torque of up to 100 percent to either the right or left front wheel"