# How smart is Quattro?



## Pommerening (Jan 17, 2014)

Does the haldex system sense slipping and only kick on for a second and then back off? Or can it realize that after a couple of front wheel slips + freezing temps reading from the car that its probly snowy out and should stay engaged? 

Also, I rode in a Ford Edge with "Intelligent AWD" and the driver display would show the power distribution to each wheel. It would change a lot each second or so. Is there any way to get this info displayed on the MMI or on an app like torque?

Thanks


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## m_bolc (Oct 19, 2008)

You don't notice it working. On the A3/S3 quattro is FWD until slippage is detected, then torque is sent to the rear axle. It takes milliseconds, so you don't know what's happening.

I don't think MMI can be setup to display power distribution.


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## steve111b (Jun 2, 2011)

Starting with the gen. 4 Haldex, the system can engage from the inputs of the driver. This means that the throttle position can engage the Haldex. As far as I can tell, any significant push on the throttle will engage the Haldex. So I believe that the majority of engagements (of the Haldex) come from the throttle and not wheel slip.

The Crysler 200 AWD engages the AWD system when the windshield wipers are turned on or when the temperatures go below freezing.

For Audi, you can rely on the system to engage when necessary, or you can override it. By turning the ESP off or using Sport mode, the Haldex is always on (but not while braking). If you are wondering if the system is on, you can crack a window while doing your donuts in a parking lot and you can smell the fluid in the Haldex (which will get hot). Or you can stop the car and get your nose close to a rear wheel.


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## onerazorsharp (Mar 17, 2006)

Steve is right, the new MQB Haldex system is quite an improvement on the non-quattro "quattro" cars. However, this is Gen 5, not gen 4.

See Gen 5 Haldex: How it works.

Or see VW Golf 7 4Motion -Animation Technology. This vid has the vw 4Motion branding, which is the MQB platform using the Borg Warner/Haldex generation 5 - The same chassis as the S3. 

Although the motor is turned the wrong way (transversely) for cabin space and safety, this is closest thing haldex has come to quattro. 

I do get a little tired of seeing "quattro" written on cars that do not have it, but I suppose it's a form of branding at this point.


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## rabbitgtibbar (Apr 29, 2002)

onerazorsharp said:


> I do get a little tired of seeing "quattro" written on cars that do not have it, but I suppose it's a form of branding at this point.


"quattro" has always, only and ever been branding. You want an Audi with all four wheels driven at some point? It's got "quattro". You want a mechanically identical VW? It's "4MOTION" (née, "Snychro").


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## onerazorsharp (Mar 17, 2006)

To some extent, you are correct sir. If in that you mean the term is a branding tool. 

However, the significance of the term Quattro, and its implied meaning, refers to the engineering specifics of their AWD.

I’ll link portions my SAE article if I can find it, otherwise look up:
“Stages in the Development of Four-Wheel Drive Systems in Audi Passenger Cars”



rabbitgtibbar said:


> "quattro" has always, only and ever been branding. You want an Audi with all four wheels driven at some point? It's got "quattro". You want a mechanically identical VW? It's "4MOTION" (née, "Snychro").


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## rabbitgtibbar (Apr 29, 2002)

onerazorsharp said:


> To some extent, you are correct sir. If in that you mean the term is a branding tool.
> 
> However, the significance of the term Quattro, and its implied meaning, refers to the engineering specifics of their AWD.
> 
> ...


Its implied meaning is that the Audi bearing said moniker is AWD/4WD. That's it. Whether achieved through viscous couplings, Torsen diffs, a Haldex unit, a trasfer case, open diffs, or otherwise is wholly immaterial.


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## DasCC (Feb 24, 2009)

rabbitgtibbar said:


> Its implied meaning is that the Audi bearing said moniker is AWD/4WD. That's it. Whether achieved through viscous couplings, Torsen diffs, a Haldex unit, a trasfer case, open diffs, or otherwise is wholly immaterial.


:thumbup: exactly. The B5 Passat used Torsen, but you didnt see them running around with Quattro badges.


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## iceorbital (Jul 2, 2011)

steve111b said:


> By turning the ESP off or using Sport mode, the Haldex is always on (but not while braking).



You sure of that?


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## Chimera (Jul 6, 2002)

iceorbital said:


> You sure of that?


First time I'd heard of that also. Can anyone else confirm?


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## VR6Now (Dec 31, 2000)

onerazorsharp said:


> To some extent, you are correct sir. If in that you mean the term is a branding tool.
> 
> However, the significance of the term Quattro, and its implied meaning, refers to the engineering specifics of their AWD.
> 
> ...


He's 100% correct. Quattro means what Audi wants it to mean and not what you perceive it to stand for. It is nothing more than branding. There have been various systems that Audi has called Quattro.


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## onerazorsharp (Mar 17, 2006)

As an S3 owner, I take no issue with the awd system. But, just as the previous generation Audi TT's utilized, this is not an Audi designed system - its a vw design. 

Fact is, Audi has developed a multitude of awd generations. Each generation incorporated a new differential technology. Later they became platform dependent. If we were to be sticklers, a quattro would be the actual Audi quattro itself


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## VR6Now (Dec 31, 2000)

onerazorsharp said:


> As an S3 owner, I take no issue with the awd system. But, just as the previous generation Audi TT's utilized, this is not an Audi designed system - its a vw design.
> 
> Fact is, Audi has developed a multitude of awd generations. Each generation incorporated a new differential technology. Later they became platform dependent. If we were to be sticklers, a quattro would be the actual Audi quattro itself


The system the TT uses is not a VW nor an Audi designed system. It was designed by a company called Haldex. Haldex sold the AWD coupling division to Borg Warner so it is now a Borg Warner system. The TT, like the S3 uses a Haldex unit. The Haldex is used on other brands/manufacturers so it is not VW or Audi exclusive. Ford, Volvo, and others use Haldex too. The Torsen units Audi used to use were available to use by other manufacturers. The Haldex coupling design is fixed; the manufacturer is only responsible for specific system settings and options.


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## gtitx1 (Oct 6, 2014)

anecdotal evidence, but I do not believe this car ever puts 100% of power to the front wheels (at least on the S3). I was pulling out of a parking lot that had some gravel spilled. I had my front wheels sitting on completely clear blacktop, I had my rear wheels sitting on some gravel. As soon as I lightly hit the throttle to pull out, I had a quick bit of wheel spin from the rear wheels. If this car was 100% front until slipping is detected, my rear wheels would not have immediately slipped when I hit the throttle.

I know people cite the haldex video as evidence for this setup, but it is truly irrelevant with regard to power distribution. The power split is all controlled by software and can be set up however the manufacturer wants. For instance, the upcoming TTS will have the same system but be far more rear biased.


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## VR6Now (Dec 31, 2000)

gtitx1 said:


> anecdotal evidence, but I do not believe this car ever puts 100% of power to the front wheels (at least on the S3). I was pulling out of a parking lot that had some gravel spilled. I had my front wheels sitting on completely clear blacktop, I had my rear wheels sitting on some gravel. As soon as I lightly hit the throttle to pull out, I had a quick bit of wheel spin from the rear wheels. If this car was 100% front until slipping is detected, my rear wheels would not have immediately slipped when I hit the throttle.
> 
> I know people cite the haldex video as evidence for this setup, but it is truly irrelevant with regard to power distribution. The power split is all controlled by software and can be set up however the manufacturer wants. For instance, the upcoming TTS will have the same system but be far more rear biased.


Haldex 5 *can* completely decouple the rear wheels if there is no traction at the back so while technically incorrect, I think the default split is 5 or 10 percent to the rear in the S3. In a practical sense, the rear is usually coupled at some level. People have run Haldex equipped cars on 2wd dynos which is impossible if the rear wheels can not be decoupled.


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## steve111b (Jun 2, 2011)

Thanks for passing on your experience gtitx1. I agree with your explanation of the event. The Audi power split is 85/15. This information has been up on the Audi web site for years. So I assume the S3 would also be 85/15. It sounds like the 15% going to the rear was enough to spin the rear wheels.


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## gtitx1 (Oct 6, 2014)

VR6Now said:


> Haldex 5 *can* completely decouple the rear wheels if there is no traction at the back so while technically incorrect, I think the default split is 5 or 10 percent to the rear in the S3. In a practical sense, the rear is usually coupled at some level. People have run Haldex equipped cars on 2wd dynos which is impossible if the rear wheels can not be decoupled.


I realized I didn't clearly type what I meant. I was referring to people saying that the S3 drives around 100% fwd unless they experience slip. What I was saying is to me my experience with the gravel shows this car is always sending some amount of power to the rear.


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## rabbitgtibbar (Apr 29, 2002)

gtitx1 said:


> I realized I didn't clearly type what I meant. I was referring to people saying that the S3 drives around 100% fwd unless they experience slip. What I was saying is to me my experience with the gravel shows this car is always sending some amount of power to the rear.


Here's an uR32 (2004) launching on gravel.

[video]http://thud.us/videos/car-av/r32-launch-gravel2.avi[/video]

Even back then, the engagement was so quick (something like 15 degrees of front wheel slip was all it took to fully engage the rear), that it was all but instantaneous.


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## rabbitgtibbar (Apr 29, 2002)

In fact, here's a slo-mo gif of just the important part:


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## onerazorsharp (Mar 17, 2006)

Well, I wish I would have recorded my friends R32 stuck in my driveway while my other buddy in his B5 S4 went right around him. Both on Michelin x ice, although the B5's weight might of helped.


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## rabbitgtibbar (Apr 29, 2002)

onerazorsharp said:


> Well, I wish I would have recorded my friends R32 stuck in my driveway while my other buddy in his B5 S4 went right around him. Both on Michelin x ice, although the B5's weight might of helped.


Any number of things might *have *helped. There are far too many variables in your scenario to have come to the conclusion that you are trying to imply.


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## Revolver1966 (Mar 30, 2014)

Probably my favorite demo of the Haldex 5 system in a Golf Mk7 TDI 4Motion. Too bad they don't sell that here. Watch the lodge owner's face. 
http://youtu.be/jeR4DcRjtDI
Somewhere it was written the S3/R send up to 100% of their power (with some differences) to the rear while the CLA45 only sends 50%. Are these both Haldex 5?
Hearing the new system is always engaged makes me a lot happier knowing so even if the older systems worked well. 
That was a cool gravel launch but that's the last place I'll launch a new car lol.


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## rabbitgtibbar (Apr 29, 2002)

The only way the A/S3 can send 100% of the power rearward is if the Haldex clutch is fully engaged, both front wheels are on a frictionless surface and both rears have traction. That's true for every Haldex equipped AWD vehicle that doesn't have a center diff, including the MKI TT, every R32 and that CLA.

I'm dubious of the claim the new system is always engaged, as that would lead to premature wear/failure and remove one of the big advantages of Haldex, namely fuel economy.


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## Ricky11 (Jun 7, 2012)

Guys, check this link out: http://landofquattro.audi.ca/en/quattro 



*Self-locking centre differential*

Self-locking centre differential is the most common form of the quattro® all-wheel drive system. The mechanical differential is directly tied to the front and rear axles, allowing torque to be distributed instantly as the vehicle encounters difficult road conditions. It also gives you real-time feedback to deliver a more hands-on driving experience.

In normal driving conditions, the torque is split: 60% to the rear axle and 40% to the front (this permits high levels of traction and responsive handling characteristics). If one axle loses grip, up to 85% of the tractive power can be diverted to the rear axle and up to 70% to the front.

On certain models, we offer a sport differential option, which provides even more sporty dynamics by actively distributing power between the rear wheels. This differential is activated as you enter a corner, giving you greater traction and improved handling in the turn.



*Multi-plate clutch*

Audi uses a specially configured all-wheel drive system called multi-plate clutch for the Audi A3, Audi Q3 and Audi TT to ensure the optimal distribution of engine power between the front and rear wheels, when required.

The multi-plate clutch is an electronically controlled hydraulic system that works proactively, using advanced vehicle sensors to dynamically distribute the drive force between front and rear wheels. If the front wheels begin to lose traction, the multi-plate clutch channels power to the rear axle. This action occurs instantly, requiring no driver input, meaning no driver distraction.



*Raising the benchmark*

To transmit their full potential onto the road, sporty vehicles need a driveline to match.

The most dynamic version of the quattro® all-wheel drive system, found in the Audi R8, is called viscous coupling. This allows the Audi R8 to act like a rear wheel drive biased vehicle, but with the superior handling of quattro® all-wheel drive. With more agility on tight bends, it delivers an exhilarating performance.

The Audi RS 5 uses Audi’s latest generation of quattro® technology, called quattro® with crown gear centre differential and torque vectoring. The centre differential features two crown gears, which are used to distribute the drive force of the engine between the front and rear axles. Sporty handling is further enhanced by quattro® with sport differential. The active rear differential calculates the most suitable distribution of torque to the wheels, creating additional steering effect in corners and adding confidence to every driving situation.


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## steve111b (Jun 2, 2011)

Good find.


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## ThorMjolnir (Apr 9, 2014)

*This is not true.*

AWD is always engaged with Quattro. Not only with slippage.


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## Revolver1966 (Mar 30, 2014)

Here is what I think:
The S3 & R are two of the most powerful stock FWD cars in history. That means what? Wheel spin. Very very very easy wheel spin. Especially tuned with 350+ TQ. Wheel spin means loss of traction. Every time these cars have what would be wheel spin (AKA nearly always when it matter with a 300 TQ FWD car) the Haldex kicks in. Combine more power (AKA more wheel spin/axle hop) with a faster reacting system = nearly in use all the time. Cruising around like a Granny not invoking what would normally be wheel spin in a GTI? Haldex probably isn't working. So any time you get on it in the lower gears the Haldex probably kicks, then shuts off once up to a quicker speed. Turning ESP & TC off in race mode probably invokes more wheel spin and therefore more RWD-bias.


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## araemo (Dec 9, 2012)

ThorMjolnir said:


> AWD is always engaged with Quattro. Not only with slippage.


What you imply isn't true either. The haldex quattro isn't only engaged with slippage. It IS engaged when slippage happens, but it also engages before any slip happens when the control units tell it to (IE, you floor it.. it engages the haldex clutch BEFORE slip happens, possibly preventing it entirely).


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## rabbitgtibbar (Apr 29, 2002)

ThorMjolnir said:


> AWD is always engaged with Quattro. Not only with slippage.


Incorrect.


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## VR6Now (Dec 31, 2000)

onerazorsharp said:


> Well, I wish I would have recorded my friends R32 stuck in my driveway while my other buddy in his B5 S4 went right around him. Both on Michelin x ice, although the B5's weight might of helped.


A good way to get bogged down in some low traction situations is to leave the traction control on. The traction control clamps down on the throttle to prevent wheel spin. Wheel spin (power) is sometimes needed to break free. Your friend's Haldex controller may have malfunctioned or he has a malfuctioning sensor. What was the tread depth on both tires? What surface variations are we dealing with? Did the S4 have momentum already when it got to the position the R32 was stuck? The R32 Haldex clutch pack worn down? Either vehicle has modifications? As stated, there are are numerous variables that can affect the results you observered. Neither of these cars have AWD systems that torque vector at the axle, so they both have limitations. 

The advantage of Torsen is there no clutch pack to wear down or allow slippage, has no other other vehicle system dependencies (ABS and ECU modules) and it has a response time advantage. I prefer mechanical systems but a Haldex (Electro-mechanical) functioning properly should be 95% of what a Torsen is in reality.

One should be careful to extrapolate characteristics of these systems without having all the facts.


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## VR6Now (Dec 31, 2000)

ThorMjolnir said:


> AWD is always engaged with Quattro. Not only with slippage.


Some Quattro systems always have torque distributed to both axles, Quattro models with Haldex can completely decouple the rear. It might be helpful to read this thread again. If VW/Audi choose scenarios where they completely decouple the Haldex, it is not 100% engaged. Under braking, Haldex disengages completely. With no traction at the rear, Haldex can 100% disengage. Some Haldex controllers have a econ mode where it will bias towards no rear torque unless wheel slip occurs. There are situations even with Haldex 5 Quattro where the rear wheels get no torque.


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