Quattro vs. Symmetrical

Well i have come to the conclusion that Audi's Quattro system is by far better than Subaru's Symmetrical sytem, in the rain. Before my Legacy GT i had a 00 Audi S4, and in the rain it was planted on the ground, no matter how bad it was raining. while the legacy just now in the rain seem to want to go everywhere (side to side), it just didn't seem to stay planted. I wonder if the sorry ass tires that the Subaru came with has alot to do with the poor handling. but anyways just my .02 cents.

I have come to the opposite conclusion and I had a 00 S4 as well.

RE92s = poop

 

Tire size and width have a lot to bad weather handling too. What size tire were you running on your S4? Were you running an all-season tire or not. I have 16" Pzero Nero M/S on my 2.5i and I'm pretty stable in the rain and snow.

stock 225/45/17 Yokahoma AVS ES100

+1 for suby

The legacy has one more real LSD than the B5 S4

RTFM - Rain tires recommended for rain. hehe

 

Yeah, it's the tires, StupidOnArrival are you listening.

Hmm, that side-to-side is why I think the Subaru system is better. Much more performance oriented...

 

Ted

 

Was that a white WAGON that just fish-tailed?

Electronics ???

 

Im pretty sure the S4 has some form of traction control to keep the car straight even if it has some crappy tires.

 

Where as Subaru's is strictly mechanical.

00 didn't come with traction control, 01 and on came with traction control

stock 225/45/17 Yokahoma AVS ES100

 

The ES100s are in a different class when compared to the REcrappy2s.

00 didn't come with traction control, 01 and on came with traction control

You mean ESP. The 00 had EDL/traction

I had a scary situation driving in near white-out conditions last winter. The road was jammed with traffic and the surface varied in traction from left to right. The diffs did their thing and the car was pulling hard left......had to let off the gas and steer a little to keep it going straight. As soon as the conditions evened out, the diffs stop and the car wanted to shoot right. I'll chalk it up to poor snow/ice traction of the RE92's, but I don't remember the WRX feeling this way at all. Maybe just a freak set of circumstances?

2000 S4 had traction control and EDL - Electronic Differencial Lock, pls see:

http://www.audiusa.com/search_result/0,3829,,00.html?searchbox=Electronic+Differential+Locks+(EDL)

 

Also, traction and stability control system, aka ESP, was designed to monitor driver inputs and vehicle dynamics and intervenes if something goes seriously wrong by using the anti-lock brake system and traction control to keep the car pointed straight. While such a system can't defeat the laws of physics, it comes pretty close. If you are driving your S4 and get carried away and overcooks it into a corner, ESP can help correct that...

 

My personal experience... I also had an S4, 2001 though, but what we are comparing here are apples and oranges... First, Audi does all the tricks and magics using an ECU just for that matter, not fully mechanic like Subaru... In some circumstances Audi QUATTRO is better, in others Subaru Symmetrical AWD is better...

 

One thing for sure is unquestionable are the tires, once you replace your tires to more "All Weather" Performance ones, not just REcrappy2 ones...

 

Hope it helped...

 

Flavio Zanetti

Boston, MA

the 2000's did not have traction control.

Except for reliablity and repair cost, electronically controlled active diffs are better provided they are programmed correctly.

 

If you look at the extreme, rally racing, a mechanical center diff cannot keep up with a full active diff. Part of Mitsubishi's rally program was developing a new car bit by bit. Last year they ran with a mechanical diff and the drivers were working a lot more to get the car to go in the right direction. They improved significantly when they switched to an active center diff.

Well i have come to the conclusion that Audi's Quattro system is by far better than Subaru's Symmetrical sytem, in the rain. Before my Legacy GT i had a 00 Audi S4, and in the rain it was planted on the ground, no matter how bad it was raining. while the legacy just now in the rain seem to want to go everywhere (side to side), it just didn't seem to stay planted. I wonder if the sorry ass tires that the Subaru came with has alot to do with the poor handling. but anyways just my .02 cents.

 

FWIW I felt the same way about my 01 Base OB 4EAT vs. the 05 OBXT 5MT. I believe the 4EAT in the 01 had an electronic system vs. the viscous system on the 5MT. Changing the tires from 92a's to Pilot Sport A/S has helped greatly.

 

However, the old OB was much more controlled in the rain and snow. And that was with those Firestone Wilderness tires! Later added Micheline XGT H4's.

 

Of course, I think, you had just a little more power in the s4......

audi used the ABS system in the AWD, which technially does take power away from a slipping wheel.

 

the problem is, it doesn't give that power to other wheels, so you end up with a net power loss in a slipping situation.

 

i prefer suby.

 

dR

FWIW I felt the same way about my 01 Base OB 4EAT vs. the 05 OBXT 5MT. I believe the 4EAT in the 01 had an electronic system vs. the viscous system on the 5MT. Changing the tires from 92a's to Pilot Sport A/S has helped greatly.

 

However, the old OB was much more controlled in the rain and snow. And that was with those Firestone Wilderness tires! Later added Micheline XGT H4's.

 

Of course, I think, you had just a little more power in the s4......

 

Maybe the considerable difference in torque between a base OB and an OBXT makes the turbo model feel a little tougher to control in bad weather? Just a thought..

Except for reliablity and repair cost, electronically controlled active diffs are better provided they are programmed correctly.

 

If you look at the extreme, rally racing, a mechanical center diff cannot keep up with a full active diff. Part of Mitsubishi's rally program was developing a new car bit by bit. Last year they ran with a mechanical diff and the drivers were working a lot more to get the car to go in the right direction. They improved significantly when they switched to an active center diff.

 

Except they used REAL active diffs in rally racing...

 

Audi's current quattro is no more than 2 regular diffs hobbed together using the brake system to control the wheel thats spinning wildly out of control. The system also shuts itself off after 50mph so you get no LSD action above that speed.

 

Ahh the joys of marketing and costsavings...

stock 225/45/17 Yokahoma AVS ES100

 

http://www.tirerack.com/tires/tires.jsp?tireMake=Yokohama&tireModel=AVS+ES100

 

So your comparing that to this....

 

http://www.tirerack.com/tires/tires.jsp?tireMake=Bridgestone&tireModel=Potenza+RE92&vehicleSearch=true&partnum=055VR6RE92&fromCompare1=yes

 

 

Your comparing a car equipped with fantastic performance tires to one equipped with craptastic rim to pavement spacers.

"The system also shuts itself off after 50mph"

 

Where did you get that info?????? Pretty interesting, where you most need it they shut it off?????

 

Flavio Zanetti

Boston, MA

There's a lot of misinformation here on quattro. Audi has two AWD systems. Cars like the A4, A6 and A8 (and VW Passat) with a longitudinal engine have a system with a Torsen (mechanical) differential in the middle. They use an open diff with EDL at either end. EDL simply grabs the brake of the wheel that is spinning to send the torque to the other side. It's not traction control per se since it never cuts engine power.

 

The cars with a transverse engine (like the TT, A3, Golf R32) use a Haldex clutch (similar to the system Subie uses in automatic cars) in the middle with EDL at either end.

 

I can't say which system is better yet but Torsen diffs don't break and their torque direction is very smooth. Quattro with torsen is a nice system.

 

I think what the original poster was feeling has a lot more to do with tires.

audi used the ABS system in the AWD, which technially does take power away from a slipping wheel.

 

the problem is, it doesn't give that power to other wheels, so you end up with a net power loss in a slipping situation.

 

i prefer suby.

 

dR

 

This is incorrect. If you have an open diff and you grab the brake on one side, it mechanically sends the power to the other side. Mercedes 4Matic does the same thing but it has an open diff in the middle and if one end is slipping it grabs both wheels on that end and sends power to the other end.

There is one thing I must add to this also:

 

Audi QUATTRO nowadays is in its 4th generation, and some of the systems are different as you pointed out...

 

Type 1. Full-time "proactive" all-wheel drive Torsen centre differential based

Type 2. Part-time "reactive" front-wheel drive Haldex LSC differential based

 

Type 1 are equipped on newer A4's, A6's, A8's and S4's...

 

Type 2 are equipped on A3's, old A4's, TT's, Passats and Golfs, aka as 4Motion

 

In the case of quattro type 2, this layout is predominantly front-wheel drive biased designed to suit the transversly (sideways in engine bay) mounted engine layout associated with every front wheel drive car out there (i.e. your typical hatchback).

Only when the front wheels start to experience wheel spin (or the onset thereof) will a Swedish made Haldex coupling apportion the torque away from the front toward the rear wheels. Once the slipping stops, so does the all wheel drive.

This concept also applies to cars like Volvo AWD's and VW R32.

 

Conversly quattro type 1 is amongst the purest, most balanced forms of AWD one can get. In this case a centre differential apportions 50% of torque to the front and 50% of torque to the rear axle. It is permanent four wheel drive. The benefit of such a system is quite simply that the amount of torque applied to each wheel is effectively halved thus dramatically reducing the chances of that wheel to exceed its co-efficient of grip. Spread across all four wheels such power distribution is what bestows Audi's fitted with this system with such amazing traction.

This form of quattro is associated only with engines mounted longitudinally (lengthways) in the engine bay and is found in the newer A4, A6 and A8 model ranges. The big innovation with this form of quattro is the inclusion of the Torsen (torque-sensing) helical gear centre differential that is able to direct torque to the axle with the most grip before the other axle loses grip. Very clever.

 

So now to your question about what the differences are... as a fine Subaru advert states "Man has created so many different types of all wheel drive..."

 

You need to be more specific as to the make and model against which you wish to compare quattro.

 

Flavio Zanetti

Boston, MA