Drive Select

[Audi Bairn]

What set up are folks using in icy / snowy driving conditions to provide the best grip / traction.
Only asking as I've not had it on a car but will do soon.

 

[GSB]

Drive select options will be of very little influence when trying to pick your way through snow and ice, but obviously, avoid dynamic. Your best bet is very very very (very) smooth inputs on steering, brakes, throttle and clutch (if you swap your own cogs)

Remember Quattro will get you going, but the brakes work the same as any car. Ironically Quattro is more likely to get you into trouble since you're able to accelerate that much faster, whilst stopping and turning will still take eons.

Pulling away in 2nd gear, and all the other winter driving tricks are great, but nothing beats a set of winter tyres.

 

[Flying Scotsman]

To repeat GSB...."Nothing Beats a Set of Winter Tyres"

 

[Jassyo06]

S-tronic great for the winter, drive select pointless, winter tyres not necessary, especially with you having brand new tyres

 

[Audi Bairn]

Thanks.
Yeah I was assuming that, other than the usual winter driving techniques, that I'd avoid Dynamic for example but realise it'll have minimal effect in the scheme of things.

 

[steve111b]

What set up are folks using in icy / snowy driving conditions to provide the best grip / traction.

On your car select quattro and choose dynamic. This should engage the quattro all the time. You do not need drive select to engage the quattro, but it is easier.

On a snow covered road I can turn ninety degrees at city speeds one car width sooner with the quattro engaged. On the highway (on snow) I can drive 20 kms. faster, with the quattro engaged. Remember any application of the brakes (ESP,ESC) will disengage the quattro.

Braking is different in the snow. Brake early and brake hard. You want to be releasing the brakes as you come to a complete stop. Wheels are more prone to lock at lower speeds, so you want to do your braking at higher speeds. Leave an extra car length when you stop for a margin of safety.

Enjoy the snow. Turn off the ESP and the back end will step out with ease.

 

[Jassyo06]

To repeat GSB...."Nothing Beats a Set of Winter Tyres"

That's because Canada turns into a mini Alaska come winter lol

 

[GSB]

That's because Canada turns into a mini Alaska come winter lol

At anything under about 7 DegC, winter tyres will outperform a typical set of sporting summer tyres, even brand new ones, and often by a margin that is scarcely believable. The difference is like night and day. Even general duty 'all season' tyres such as those fitted to non "S / RS" versions of the A3 will show the likes of an Eagle F1 or PZero a clean set of heels in cold weather.

 

[AudiNutta]

So, am I right in saying the Hapdex 4WD is a part time system? I assumed it was full time Quattro?

Only other thing to note, what's pretty rubbish with the S Tronic is not being able to change into 2nd until you are above 10mph, very daft.
I have low ratings of the S Tronic Tiptronic setup, with how much it changes gear on its own.. it should let you hit the rev limiter, perhaps unless you are launching.

Countless times I've accelerated hard, changed from 2nd to midrange third and as soon as I backoff it's changed into 4th.. really irritating.

 

[GSB]

So, am I right in saying the Hapdex 4WD is a part time system? I assumed it was full time Quattro?

It is full time... ...almost.

Quoting myself here from another thread. It seems I was in a helpful mood...


There's a huge amount of mis-information and misunderstanding around this board on all wheel drive on the A3/S3 and how it works. I think it might be a good idea to get a few myths out in the open and dispel them once and for all;

Things like a maximum 90:10 torque split, the 'fact' that haldex only reacts to front wheelspin, and the "not as good as as 'proper' quattro" line are all very suspect, and for the most part, wrong.

Let's explore why...


Reading these pages it strikes me as odd that there's not an idiots guide to Quattro here somewhere. There's clearly a lot of knowledge here, but there's not a lot of explanation of what's actually happening in the oily bits of these cars, and what's so 'good' about it.

So, Perhaps an explanation of exactly what's going on will help.

In traditional all wheel drive, the engines effort emerges at the output from the gearbox and is sent to a centre differential. This works exactly the same way as the differential in a two wheel drive car, except instead of splitting power left and right to a wheel, it splits it forwards and backwards to the front and rear axles.

The front and rear axles also contain a differential, to allow the Left and Right wheels to turn at different speeds for cornering. So, you have three differentials fitted, two prop shafts, and four driveshafts. This is a lot of extra iron to lug around if you don't really need four wheel drive all the time. However, both the marketing men and we consumers love all this all wheel drive stuff, so we're all converts to the 'benefits' of all wheel drive, and have decided we definitely need it without really understanding the reasons why beyond a vague recollection that 30 odd years ago Audi wiped the floor with the competition on the world rally stage, and has been dining out on the back of the mythical Ur-Quattro ever since. There are many reasons it's good, but there is an equally compelling list of reasons we'd be better off without it. We'll touch in this later, but for now, let's look at what's actually going on under these cars...

Now, it is my experience that most people don't know how a differential works, and to understand four wheel drive, you need to understand differentials. It's not hard to understand and it's nothing to be embarrassed about it you don't know, but if this includes you then before we go any further, watch this film. Its retro, it's comical, and it's the best explanation of how a differential works you'll ever see;



So, now you're an expert in differentials, specifically so called 'open' differentials. With an open diff such as the one on that video, there's a distinct disadvantage. If one wheel has no grip, then that wheel spins away all the power and the car doesn't move. In a traditional four wheel drive system, one wheel with no grip will also spin away all the power through that axle, and because the affected axle is hooked up to the centre diff, that also spins away to all the power to the free side, and the four wheel drive is useless. All four wheels must have contact with something grippy for the system to work. There's many ways to get around this problem, but to save us getting bogged down in Torsen and other limited slip technologies that'll just confuse everyone, we'll stick with the traditional version, which is the locking centre diff.

Any off-roader worthy of the name had a locking centre diff in the good old days (the years BWEABD - Before Widespread Electronics And ****** Diesels), and this was a simple, light, and very effective way to dramatically improve your off-roaders chances on the trail by preventing the centre differential from being a differential. It locked the front and rear output shafts together to stop it from 'differentiating'. If you sat in an old Charles Spencer King Range Rover though, you couldn't help but notice this very stern warning about its use;

View attachment 107840

The problem with locking the front axle to the rear axle is a phenomenon called 'wind-up'.

This happens when the car turns, or even if the tyres are even slightly different diameters due to uneven wear. The difference in the speeds of the wheels relative to each other when turning corners creates enourmous stress on the transmission components, that can only be relieved when one or more wheels 'skips' by breaking traction and skidding slightly.
View attachment 107841
Fine when you're off road on slippy surfaces or ploughing a muddy field when the tyres can slip and slide with wild abandon, but on grippy Tarmac? Something has to give, and more often than not it's an expensive part of your oily bits. So, a centre diff is absolutely, no questions, do-not-pass-go-and-collect-£200, essential.

Or is it?

Take a look at a haldex equipped car. You can search for hours but you won't find a centre diff. It's extremely obvious in its absence. In fact, mechanically speaking, (and ignoring the haldex coupling for a moment) the front diff is locked to the rear diff just like an old Land Rover with centre diff lock engaged.

To avoid the perilous wind up, a clutch is fitted to the rear prop shaft to allow a bit of slip, and so relieve the wind up issue. This is the haldex coupling, and it's actually pretty simple. It's a clutch, same as the one the more adventurous, suave, sophisticated, attractive and sexually appealing members here operate with their left feet. Those of you with S&Tonic boxes will just have to use your imagination here, and try to remember what swapping your own cogs involved... ;-)

This haldex clutch can vary its amount of slip just like the one under your left foot, from no drive whatsoever, through slipping and transmitting a bit of torque, right up to fully locked up and transmitting everything you can throw at it.

This being the case, it can theoretically send 100% of the engines torque to the rear. It's only theoretical of course since you'd need to pulling a wheelie for this to actually happen. In practise, just like a traditional four wheel drive system it transmits torque all round.

When driving, the haldex clutch is partially engaged most of the time, with a bit of slip allowed to avoid transmission wind-up and save you from big repair bills. The computer driving the system looks at many variables and sensors like steering angle, throttle position, yaw, lateral and longitudinal accelleration, and compares these values on a map to see how much clutch should be engaged at any given time. It reduces clutch engagement to lower fuel consumption and stresses when the rear axle isn't needed, and when you give it the beans, it engages the clutch to full locking, allowing the rear axle to do its job of driving the car without wasting power.

In most situations though, the system is in full time four wheel drive mode. It can't transmit full torque to the rear axle all the time like 'proper' Quattro, but it does transmit full torque when it needs too.

So where do all these myths and misconceptions come from?

Well, the very first of these haldex type 'on demand' systems on which most bias and preconceptions are based, used a viscous coupling or some other reactive driveline system. It was a passive system that reacted to things that had already happened and diverted some power to the rear axle in very defined circumstances. The front wheels had to be going faster then than the rear wheels, i.e. The front wheels would be losing grip and maybe even spinning. This was advanced in later versions by using this difference in speed to trigger and power a mechanical pump to force the clutch plates together and drive the rear axle. As soon as the front and rear wheels were going the same speed again, the pump stopped and the clutch disengaged. This system was unable to drive the rear wheels under any other circumstances. The manufacturers jumped on this system though, offering 4wd 'soft roaders' to gullible fashion victims the world over. Technically they were indeed 4wd, but they were rubbish, and a traditional 4wd drive would run rings round them. The Honda CRV is a laughable and lamentable example of this trend. When tested the rear axle couldn't actually muster enough torque to move the car, since it was built by marketing men with a four wheel drive system consisting of lightweight (and therefore fuel efficient) driveshafts crafted from spaghetti, and a rear diff made of cheese. This is marketing cynicism at its worst, but hopefully Audi are above that, right?

Later, haldex made the pump electrically powered and lost the viscous element, meaning they could have active control of the clutch and engage it 'before' the front axle lost grip. It was no longer reactive, and could be controlled and engaged before something happened to require rear drive. Now we're on the 5th generation of this system and it's totally integrated into the cars dynamic control systems. It talks to traction control, esp, suspension systems and all manner of other stuff, making it more effective, less intrusive, and more importantly, vastly tunable to different applications, whether they be mud plugging or in our case, a more sporting intent. The software that drives the system is now key to how the system feels in the car. The Quattro selections in the MMI will define just how fast the clutch is ordered to engage in 'spirited' driving, or reduce the clutch engagement for more comfort and economy. When manoeuvring or at extreme steering lock you may find the rear drive line is isolated entirely, to avoid the wind up and odd hopping sensations as the tyres slip.

But I can't get the back end out. Why not?

No, you can't. This is because whilst the haldex equipped car can vary the torque transfer to its rear wheels, just like a 'proper' Quattro can, it can't reduce the torque transfer to the front. It's fixed, mechanically linked, and always fully engaged. It is this single fact that gives us the predominantly front drive feel to these cars. Well, that, and the fact that they're basically front drive cars to start with. If you really wanted to play at being an oversteer hero though, you should have rubbed a few brain cells together and realised that four wheel drive, of any type, is not really suited to such showboating. Try an ultimate driving machine, or better yet, an MX5.

The Focus RS can do it!

Yes yes, but it's faking it. The focus RS uses the system first employed in the tarts 4x4 of choice, the Range Rover Evoque. Instead of a clutch coupling feeding into a rear differential and then to the wheels, the focus doesn't have a rear differential at all. Instead the axle is effectively solid, but has a haldex style clutch for each wheel. This way it can allow the clutches to slip a bit so the car can still go round corners, or, for its party piece (and proof that even very sensible engineers can have a laugh if they get bored), it can completely disengage one wheel and send all the torque to one side of the axle. This, understandably, creates some very wierd chassis dynamics that would under any other circumstances be a hazard to health and well being, but is in fact a hooligans wet dream. It's still predominantly front wheel drive though, just like your A3/S3.

Why can't we have a 'proper' quattro system?

I'm sure Audi's marketing men would prefer it too, but the fact is that the full fat system is three things that the haldex system is not;

1/ heavy. A third differential, an extra prop shaft, a lot of extra hard points to bolt it all too. The extra weight is detrimental to handling, fuel economy and performance. It wouldn't be worth fitting it.
2/ bulky. Just where are you going to put this stuff? You need to get a transfer box in somewhere, plus an independent front diff and an extra prop shaft in the space normally occupied by the engine. Packaging is a bit tricky.
3/ expensive. Ok, maybe this isn't an issue, we all bought Audi's after all, but the fact is developing such a system for small cars isn't cheap, and the prices Audi would need to charge might be a bit prohibitive.

Besides, this misses the final, ultimate quandary. The fact no-one here will ever acknowledge...

We don't need four wheel drive. It's just a marketing ploy to make tarted up golfs more appealing. Front drive chassis tech can easily cope with 300hp these days and the benefits of a lighter car without all this ironmongery whirling around underneath it would far outweigh the benefits of driving the rear wheels a bit. However, without Quattro, Audi's history would look very different, and it would by now be about as desirable as Opel. Mercedes and BMW have shown that worldwide perception is this;

Rear drive = fun, premium, sporting, expensive and desirable.
Front drive = boring, cheap, nasty, and distinctly blue collar.
All wheel drive, see rear drive.

So, If Audi wants to play with the other germans, it needs to get some torque to the back axle. We should be grateful that what is really a bit of a token effort to do this is actually very effective on the road...

Now, what was the question again?

 

[Flying Scotsman]

I find it difficult to understand why UK drivers do not get the use and benefit of winter tyres. They are not just for snow they will out perform any other type of tyre in cold weather, that is below 7 degrees Celsius in stopping, grip and traction. UK cars are generally shod in summer tyres which are great in wet and dry performance but not in cold temperatures. They are cr*p on ice and snow. Yes, you do get frosty, black ice days and nights in the UK and once you try true winter tyres you will not believe how preform they believe in inclement weather. Trust me on this advice.

All season tyres come on most North American vehicles apart from performance cars. All season tyres are recognized here as a compromise tyre and are not very good in any weather condition; wet , dry, ice or snow. There is one all season that I have used that is pretty good, the Continental DWS-06 ultra high performance all season, but even then, that it is only good for light snow.
Just remember on the icy/snowy mornings, when you are white knuckling the steering wheel with your standard tyres, you might be muttering to yourself...winter tyres

 

[Audi Bairn]

I'm not so sure that it's because people in the U.K. dont get the benefit of winter tyres.
The number of days of icy / snowy weather these days probably mean that most consider it an unnecessary expense. Now hindsight is a great thing and following a collision due to loss of grip most would then wish they'd spent the money but that's not how most folk think. In countries where these wintry conditions run continuously for weeks and months on end then the decision is much easier to make.

 

[Flying Scotsman]

I'm not so sure that it's because people in the U.K. dont get the benefit of winter tyres.
The number of days of icy / snowy weather these days probably mean that most consider it an unnecessary expense. Now hindsight is a great thing and following a collision due to loss of grip most would then wish they'd spent the money but that's not how most folk think. In countries where these wintry conditions run continuously for weeks and months on end then the decision is much easier to make.

True, but up in Bonny Scotland and a lot of other parts in the UK, is it worth the risk? The A9 and most highland roads are not fun in the winter, even with spotty gritters.
Also where I live ...Vancouver BC ....all emergency vehicles are equipped with winter tyres and the climate is similar to Edinburgh/Glasgow in the winter. I would also state that 65% of other vehicles have winters and the balance all season tyres.

 

[Terminator x]

So, am I right in saying the Hapdex 4WD is a part time system? I assumed it was full time Quattro?

Only other thing to note, what's pretty rubbish with the S Tronic is not being able to change into 2nd until you are above 10mph, very daft.
I have low ratings of the S Tronic Tiptronic setup, with how much it changes gear on its own.. it should let you hit the rev limiter, perhaps unless you are launching.

Countless times I've accelerated hard, changed from 2nd to midrange third and as soon as I backoff it's changed into 4th.. really irritating.

Try manual

TX.

Sent from my STV100-4 using Tapatalk

 

[AudiNutta]

Try manual

TX.

Sent from my STV100-4 using Tapatalk

I have, that's what I meant I cannot manually change to 2nd gear neither at a standstill or below 11mph. If I try to change into second at 10mph and below, no matter how many times you pull it doesn't nothing. Once you reach 11, it changes right away.

 

[AudiNutta]

@GSB That is a very satisfying read, thank you very much.

I've gone from 0 understanding of what the Haldex means to having a total understanding Of sorts

Makes me realise just how clever these cars are today.. I am an electrical engineer, so I work with a lot of fascinating automated processes but reading that did not fail to impress me, how they can take simple concepts to perform so impressively.

 

[Terminator x]

I have, that's what I meant I cannot manually change to 2nd gear neither at a standstill or below 11mph. If I try to change into second at 10mph and below, no matter how many times you pull it doesn't nothing. Once you reach 11, it changes right away.

I'd noticed that it sometimes won't change up to 2nd at low speeds however I'd never twigged that it was speed limited in some way so appreciate you noticing! My original comment was more aimed at the car changing gear when you don't want it to generally eg stick it in manual and change when you want

TX.

 

[AudiNutta]

I'd noticed that it sometimes won't change up to 2nd at low speeds however I'd never twigged that it was speed limited in some way so appreciate you noticing! My original comment was more aimed at the car changing gear when you don't want it to generally eg stick it in manual and change when you want

TX.

I just noticed I always struggled to get it into 2nd, when driving sedately on the paddles. I've tested it a few times and you can sit at 10mph, pulling the paddle and it won't change.. quite irritating, it's like Audi don't trust us to know what gear to be in.. being auto drivers It would be better for winter for that not to be there, but there we go. I have the dilemma of not wanting to take the car out in snow for the sake of getting it dirty, but I find myself very curious as to how well it performs in snow Maybe if I had winter tyres it wouldn't be such a ballsy move..

I also meant when in manual with regards to that, haha. It seems to change on its own, if I've been under hard acceleration and back off in 3rd then it automatically changes to 4th occasionally.. annoying. I find myself wondering how this RS3 got it to bounce off the rev limiter when it changes up on its own

 

[Terminator x]

It won't change up in manual and will hit the rev limit. Are you saying yours auto changes UP when in manual? Mine will change down in manual if I'm going too slow for the gear I'm in but it has never changed up for me.

TX.

Sent from my STV100-4 using Tapatalk

 

[Audi Bairn]

True, but up in Bonny Scotland and a lot of other parts in the UK, is it worth the risk? The A9 and most highland roads are not fun in the winter, even with spotty gritters.
Also where I live ...Vancouver BC ....all emergency vehicles are equipped with winter tyres and the climate is similar to Edinburgh/Glasgow in the winter. I would also state that 65% of other vehicles have winters and the balance all season tyres.

Dont' disagree with any of what you say and there a selected areas of the UK where winters would certainly make sense, I just think it's easier not to spend the cash or go to the bother for some people here. Certainly in places like Vancouver and especially North of there I wouldn't hesitate to comit though. And to further back up what your saying, the UK grinds to a halt after half an inch of snow and chaos ensues in conditions that other countries would laugh at.

 

[AudiNutta]

It won't change up in manual and will hit the rev limit. Are you saying yours auto changes UP when in manual? Mine will change down in manual if I'm going too slow for the gear I'm in but it has never changed up for me.

TX.

Sent from my STV100-4 using Tapatalk

Yep it does, I can be in manual even with the gear selector in the manual position and if I don't change before it hits the limiter it changes gear. The car doesn't hit the limiter then change though, it changes at the normal threshold of the automatic changes. It's annoying because if I'm driving with the windows down, to be a hooligan and make noise ( ) if I get high in the revs and back off to hear the pops on the overrun, it changes gear.
It also changes down as yours does, which isn't a bad feature.

 

[Terminator x]

Perhaps the gearbox isn't in sport? If you put the car in dynamic it will be sport gearbox (or pull back on the stick), try that? I've launched in manual by mistake and the car stopped like it had hit a brick wall at the limiter, it did not change gear on me ...

TX.

 

[GSB]

Interesting issues. Guys, are you aware that Audi now provide a no-cost option that removes these unwanted shifts and allows you more control over gearbox functionality?

 

[Terminator x]

What the hell is that

TX.

 

[GSB]

What the hell is that

TX.

First shown at the Great Exhibition of the Works of Industry of All Nations in 1851, this is a fine example of Messrs Borg & Warner's improved Brunellian cog swapping apparatus for horseless carriages.

 

[AudiNutta]

Perhaps the gearbox isn't in sport? If you put the car in dynamic it will be sport gearbox (or pull back on the stick), try that? I've launched in manual by mistake and the car stopped like it had hit a brick wall at the limiter, it did not change gear on me ...

TX.

I've tried both. The car is always driven in individual, with the engine/gearbox set to dynamic. I've tried then both D and S settings on the box, same result.

Maybe this is just a new feature on the facelift? Or perhaps it's RS3 specific that it doesn't change up?

 

[Terminator x]

Give it a try in full on dynamic as imho it's changing up on you as you're not in sports gearbox. I'll try and hit the limiter in mine whilst not in dynamic as a comparison

TX.

Edit - tbh I'm rarely near the limit and often don't even give the car full beans! It's wasted on me

 

[AudiNutta]

Give it a try in full on dynamic as imho it's changing up on you as you're not in sports gearbox. I'll try and hit the limiter in mine whilst not in dynamic as a comparison

TX.

Edit - tbh I'm rarely near the limit and often don't even give the car full beans! It's wasted on me

I will give it a try later on

Something tells me, that isn't totally true.. I don't believe you can physically resist the loud pedal

 

[Terminator x]

Well it must be a FL or S3 thing as in auto mode normal gearbox (manual paddles) mine hit the limiter in 2nd. No auto change up.

TX.

Sent from my STV100-4 using Tapatalk

 

[AudiNutta]

Well it must be a FL or S3 thing as in auto mode normal gearbox (manual paddles) mine hit the limiter in 2nd. No auto change up.

TX.

Sent from my STV100-4 using Tapatalk

I tried it this afternoon. Full Dynamic, gearbox in Sport and it changed up automatically while in tiptronic... :/ Oh well, will have to learn to use it so it doesn't change up.

 

[pburv]

Give it a try in full on dynamic as imho it's changing up on you as you're not in sports gearbox. I'll try and hit the limiter in mine whilst not in dynamic as a comparison

TX.

Edit - tbh I'm rarely near the limit and often don't even give the car full beans! It's wasted on me

You can always swap with me mate....

 

[pburv]

Interesting issues. Guys, are you aware that Audi now provide a no-cost option that removes these unwanted shifts and allows you more control over gearbox functionality?

View attachment 109669

Up your's Grant.....lol