markcincinnati

I've had nearly 30 Audis since 1977. Almost all of them have been quattros. All but three of the quattro badged cars (TT's) had TorSen set ups, the TT's of course were Haldex.

My first quattro had the vacuum **** on the console that could LOCK the front and rear diffs -- making for some interesting "hopping" if locked on dry pavement then ask to turn 360 degrees. God I'm old.

All, but four, of my quattros, were said to have a 50 50 F/R torque split -- but since they were TorSen equipped, I did not consider that a negative, since TorSen, unlike other AWD systems is a real-time, (TorSen is said, because it is mechanical, to "bind in real time") rather than a "reaction-time" system.

That is my 50 50 torque split (TorSen) quattro's would send power to the front or rear when it was needed, as it was needed. So what, in the case of the 50 50 TorSen quattros is the advantage over 50 50 of a rear-biased torque split (say 40 60 F/R)?

I understand and appreciate the merits of torque vectoring or SH-AWD or whatever name the various brands want to associate with rear left-right torque shifting capabilities -- but, what, other than "perception" is the real value of 40 60 vs 50 50 in a car with real time torque shifting capabilties as provided by the mechanical TorSen system?

Audis, as far as I am concerned, have had a weight bias (not torque split bias) problem-- they are nose heavy, i.e. (and somewhat they still do and are, despite almost miraculous engineering that seems to come close to nullifying the effects of most of the weight being over the front wheels). I would think that doing more, ever more and ever more, to shift more weight to the rear would be a more noticable improvement than biasing the torque to the rear (not that I am opposed to the shift).

So, what is the real advantage -- specifically on my 2009 A4 2.0T quattro -- to its rear bias as compared, for example, to my 2005 A6 which was simply offered with a real time 50 50 TorSen set up?

Now, to be fair, saying that the A4 is superior and including that it is, in part, thus, due to its better balance, will be, from me, a given. I accept and appreciate the improvements due to Audis efforts at moving weight rearward. I simply don't know what benefit came from the engineering efforts and dollars associated with engineering a rear wheel biased TorSen system.

I am asking for someone who actually knows the quantitative improvements of the 40 60 TorSen vs the 50 50 TorSen setup to enlighten and edumacate me.

Oh, BTW, if the RWD bias is a prerequisite to rear axel torque vectoring, that counts -- but only a little at this point, since Audi's Sport Differential (a.k.a, torque vectoring) for all of its obvious and easily documented benefits and advantages is not standard -- even though, IMHO, the Sport Differential should be as much a standard equipment item as ESP and ABS w/Brake-Assist is.

Finally, I have the RWD bias kool aid; I actually have sipped it and am willing to drink the rest of it -- thus far, in the context of Audi, quattro and its long history with TorSen set ups, my view is that RWD biased quattro is more for marketing copy than for a real benefit.

I stands to be enlightened and corrected.

Kirk out.

a4Happy

Similar to you, I went from a 2006 B7 to a 2009 B8. The B7 was of course a 50/50 split and the B8 is 40/60. I can tell you that the B8 in winter driving drives a LOT more like a rear wheel drive car. When I accelerate around a corner, the rear swings out WAY more. I REALLY miss the 50/50 split of my B7 for winter driving. I used to power slide a 4-wheel drift around corners ALL the time. In my new B8, I don't do this as much because the rear end swings out sooooo much more (well, that and the fact that the ESP is much more sensitive than previous models to prevent you from power sliding, even after a quick turn off of the ASR.) I truly found the B7 to be much more predictable in the snow. Now don't get me wrong, the B8 is still wonderful in the snow, it just doesn't match the B7 with the 50/50 split in my opinion.

As far as summer driving goes... The B8 seems much more lively around corners than the B7 did. I for sure prefer the B8 for summer driving. My assumption is that the 40/60 split is the difference, but it's hard to say as the wheelbase is longer, suspension is better, tires are wider, weight distribution is better etc. So who knows how much of this is attributed to the 40/60 split.

Hope this helps provide some real-world experience to your question.

irenesbob

I would agree - the 60/40 improves dry road "handling" - making it easier to induce oversteer or hang the tail out.

Moviela

The main advantage of changing the front to rear torque ratio is to allow you to accelerate through turns, going faster than you could with a 50/50 torque split.

The B8 is better at balancing the weight between the front and rear tires because of the 60/40 split. Most cars are heavy in the front end and this makes the front want to swing to the outside of a corner. The B8 attacked this undesirable effect by moving the position of the front differential and the engine to get a better weight split. This also chased the battery to the boot.

The benefit is that you can take a corner faster than in a car with a 50/50 torque split. Or you can turn off the stability computer and enjoy your rear end passing your front end faster than ever before. (unless you have a Porsche, then you know how quickly you can do a pirouette.)

NJRoadFan

Hey now, I actually own one of those cars! Would be nice if the lockers worked consistently with the car's old age. As others have said, the 40/60 split is a compromise in a way. Yes it gives much better dry road dynamics and balance, but it causes the car to be tail happy (oversteer) in the snow. Having a quattro I (open lockable center and rear diff) and a quattro V (Torsen 40:60center, open rear) to compare, the oldskool Audi wins by a long shot in the snow. The older car is much more predictable in the snow and its just a matter of pointing the car in the direction you want to go (even mid slide) and punching the throttle.

mart242

I actually much prefer the 40/60 split for control in the snow. Disable that ESP crap when you want fun in the snow, it's a real mood killer otherwise. Disabling the ASR isn't enough.

equ

I agree with some of the above folks.. I was worried about losing some winter "fun" when I moved from a e90 330i to my b8 a4 q. Well, this car is just as tail-happy, seriously! The 330xi I had before was possibly more stable, as was the b5 a4 50/50 that I had. My tires have changed and the pilot alpins on my b8 s4 seem to be a little weak on sideways grip on the white stuff compared to the dunlop wintersports I ran on a bunch of bmw's... But, the 40/60 car, still with a 56/44 weight balance really sticks the tail out quite a bit. I haven't done a deep snow, long highway trek yet, so I'm not sure how much steering correction it's going to require. If it is as bad as the 330i, I will be a bit bummed. Of course, it's much faster/better out of a stop then the 330i, but the bmw's middle traction setting (DTC) was very good, allowing some slip but not too much. Haven't played with audi ESP too much just yet. It does seem to help less?

markcincinnati

My Audi driving instructor in Seefeld, Austria gave us, as part of the ice driving school, a lecture before we got behind the wheel of the A4 quattros we would be driving. He indicated that, as a practical matter, there is no difference to driving on dry pavement or on snow and ice in terms of understeer and oversteer.

Without telling us, in so many words, that Audi chose to offer their courses on snow and ice to "protect us amateurs," he continued by telling us that whatever we experience with respect to under and over steer behavior are identical on dry pavement and slick pavement.

The difference is not in the dynamic behavior the A4 exhibits on dry or slick surfaces -- for they are the same; the difference is the speed at which the dynamic behavior is observable and can be effectively and safely (and I would add at a lower cost, with respect to tire and brake wear, for instance) used in a classroom/teaching experience.

For example, we were taught how to run through the cones on a snow and ice covered field. And part of the training was to push the car to its handling limits. Were the course on dry pavement with summer tires, the limit might be 120kph, but on a snow and ice covered course with four studded winter tires, the limit is reached at perhaps 30 or 40kph.

The exact same reactions happen regardless of the surface co-efficient of friction (the instructor called it the "friction circle") it is simply that on dry pavement it takes a much higher speed to "do a donut" than it does on snow covered ice.

I can just imagine our group being given an exercise meant to induce either extreme oversteer or understeer on dry pavement in an A4 -- the speeds at which these events would occur would be an insurance company's nightmare. The same thing happens, on snow covered ice, it just seems to happen in slow motion since the speed at which the "event" happens is perhaps 25% of the speed of the same event on dry pavement.

I agree, however, it does seem to be easier to go to an abandoned snow covered parking lot (unplowed) and get the B8 A4 to "do donuts" than in any previous Audi I have owned or driven -- but, I had been, perhaps until now, reading the responses, thinking this was more the effect of balance, in that the front end of a B8 2.0T A4 carries less weight than previous generations of this car from a percentage standpoint.

Now, maybe, I am giving at least some credit to the 40 60 f/r torque split.

Yet, on the other hand -- maybe, I am still sticking to my guns that with respect to the B8 that the torque split is more for talking than walking, and that the weight shift from front to rear is the real hero here.

u2jrmw

Interesting, I am not a pro driver by any means, but my 2010 seems to handle better in the snow than my 06. Maybe it is engineered for drivers who don't know what they are doing...

Probably tires make a difference as well.

mart242

Probably? The biggest difference is right there!