What is the best AWD system?

Danny Tran

or <br /><div class="bigusername">Tranny Dan?</div
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I'm really liking the new Volkswagen Passat CC and I've been really thinking about getting a VR6-powered 4motion (in a couple of years).

This got me thinking of which is the best AWD system out of all the manufacturers?

Mitsubishi's S-AWC (Super All Wheel Control)?
Audi's quattro?
Nissan's ATTESA?
BMW X-drive?
Subarus's all-wheel drive?

Every manufacturer has its own version but how does Volkswagen's compare?

Are some of the more high-end systems only noticeable of the track?
 
Remember that the 4motion is out of the same parts bin as the quattro, so they're not going to be that different!
 
Remember that the 4motion is out of the same parts bin as the quattro, so they're not going to be that different!
Well, yes and no. Anything from VAG with a logitudinally mounted engine's got torsen, whereas anything with a transversely mounted engine's got haldex. The current gen Passat's got a tranversely mounted engine, whereas all A4s (and the bigger Audis as well) have got logitudinally mounted engines. The Golf based Audis have got haldex, like most Volkswagens.
 
Well....it depends, there are basically (and this is a rough generalisation) three different kinds of AWD systems:

1. constant, simple like Subaru and Audi Quattro: Subaru has traction split 50:50 between front and rear tires, always, no excpetions. Audi Quattro, if I remember correctly is the same, but 40:60.

2. Electronic, clever, self adjusting, like Mitsubishi or BMWs X-drive: the on-board computer constantly monitors traction on each wheel, your throttle position, speed etc. and distributes power, cuts off, adds baraking etc. however the situation demands.

3. "Fake" AWD systems: Systems that are normally FWD or heavily FWD biased and transfer traction to rear wheels only when the front ones start to slip. Volkswagen 4-motion to my understanding is one of these.

I myself prefer simple, mechanical systems, so my vote goes to Subaru and Audi. However the new smart and electronic systems are, according to many car magazines, pretty much better in every way and keep you out of trouble and you have to pretty much try to get yourself in the ditch with, say an x-drive BMW. I still prefer Subaru and Audi: you know exactly what it is and what it isn't, all the time.

On a track Mitsubishi and the likes are in the league of their own, because they give the power whereever and whenever it is needed, therefore making a much quicker lap time: in essence they are really, very fancy traction control and ESP systems, so you can (basically) just go through the corner full throttle and the computer will make sure you go as fast as possble. Nissan GT-R is perhaps the best example when talking about AWD machines going fast on a track. A conventional AWD car will understeer and the driver must counteract that behaviour.

I'm sure I have some inaccurasies here and there, so most likely pretty soon someone will come and give you more detailed info, because as I said this was only a rough way to divide different systems and each one is a bit different and it's not that simple when you really start picking apart the differences and characteristics of each system.
 
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Quattro is great when it uses torsens and crap when it's got a haldex. 4Motion uses haldex and this falls into the category of "crap". ATESSA is great I hear, although I don't know much about it. Subaru's system is pretty good, with the STi's being one of the very best systems out there. The Evo has some impressive tech tricks up its sleeve. X-drive is mostly electronic... gets you around in the snow but not great dynamically. It really depends on what you want from the car. Under normal driving conditions your average driver will never be able to tell the differences. I personally like Subaru.
Basic differential systems are pretty straight-forward and easy to understand. If you're really interested just do the research but be warned - it's a lot of reading. This should start you off: http://home.comcast.net/~eliot_www/awd.html
 
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Nah, the best AWD system is the Borg-Warner 1339 Quadratrac
 
:think:

I would say the most advanced would be Nissan's ATTESA, Audi's quattro and Mitsubishi's AYC, the AYC being the top of the game in the mid priced car range, Nissan being the pioneer of electronically aided AWD. ATTESA is really phenomenal, and Nissan used a similar design for the GT-R, making it light years ahead of everyone else.

The AWD system in the Subaru STI is about in the middle of the three above. The WRX with a manual transmission is stone simple. Open diff in front, limited slip in the middle and rear. But, and I mean BUT, you learn how to drive an AWD car, rather than it correcting your mistakes, as the Evolutions AYC does.

I myself gravitate towards a more organic AWD system, whereas others will take a computer laden one, and as such I cannot be totally objective. So I will say this: if you want to learn car control, drive a WRX. If you want to drive fast from the start, get an EVO.
 
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Quattro system is basically a 50:50 split with a torsen in the middle and EDL's (open diff basically) in the front and back. AFAIK only the B8 S4 and the B7 RS4 got the 40:60 split in torque. What that means is that torque will be transferred between front and rear wheels as needed (before slip occurs thanks to torsen) and the car will brake the wheel that is attempting to lose traction forcing torque to the opposite wheel. I remember reading that next gen S4 is getting a different AWD system that will not use EDL's anymore but will actually be able to transfer torque between driver and passenger side by some other means. Can't remember what the means were but it wasn't braking.

Subaru AFAIK uses a viscous diff in the middle. Not sure what is used between wheels though. The STi has a driver controlled center diff so you can change your torque split yourself. I think you can go as far as 30:70 but not sure.

Mitsu has a fully electronic system, which is quite good.

ATTESA is an intersting beast. The car is RWD for the most part until slip occurs at which point torque is electronically transfered to the front wheels.
 
Subaru AFAIK uses a viscous diff in the middle. Not sure what is used between wheels though.

Front is open, rear is limited slip on every model excluding STI. STI is limited slip front and rear.

The STi has a driver controlled center diff so you can change your torque split yourself. I think you can go as far as 30:70 but not sure.

You are right.
 
Quattro system is basically a 50:50 split with a torsen in the middle and EDL's (open diff basically) in the front and back. AFAIK only the B8 S4 and the B7 RS4 got the 40:60 split in torque. What that means is that torque will be transferred between front and rear wheels as needed (before slip occurs thanks to torsen) and the car will brake the wheel that is attempting to lose traction forcing torque to the opposite wheel. I remember reading that next gen S4 is getting a different AWD system that will not use EDL's anymore but will actually be able to transfer torque between driver and passenger side by some other means. Can't remember what the means were but it wasn't braking.

Subaru AFAIK uses a viscous diff in the middle. Not sure what is used between wheels though. The STi has a driver controlled center diff so you can change your torque split yourself. I think you can go as far as 30:70 but not sure.

Mitsu has a fully electronic system, which is quite good.

ATTESA is an intersting beast. The car is RWD for the most part until slip occurs at which point torque is electronically transfered to the front wheels.

Yeah, in terms of straight-line traction Quattro is pretty good, but the fact that EDL brakes slipping wheels is a downside dynamically. I'm really interested in the new S4 though - if what you say is true and they are ditching EDL then it might be one hell of a system, depending on what they use.
Subarus generally put power down pretty well and they do well in the snow (we all know that). Keep in mind though that viscous systems are incapable of locking. In my car, for example, if the right wheels are on ice and the left wheels on dry pavement, the car won't go anywhere, the right wheel will just spin; my buddy's CRX has a clutch-pack LSD which would simply lock in that situation and the car would go without a problem (although it would tug at the wheel). The STi is in a whole different league - it's got a great mechanical system that puts power down (dare I say it?) better than pretty much anything else. I'm a big fan of the STi and it's diffs.
When it comes to the Evo and Nissan's ATESSA, they work great on a track but are often criticized for feeling artificial - the fancy electronics sort everything out for you and some people don't like feeling sort of disconnected from the action - the cars drive themselves. This is all personal opinion, of course, but I personally prefer mechanical systems (did I mention that I love the STi? lol)
 
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Yeah, in terms of straight-line traction Quattro is pretty good, but the fact that EDL brakes slipping wheels is a downside dynamically.
Yep EDL sux, horribly.
 
Nah, the best AWD system is the Borg-Warner 1339 Quadratrac

Hehe. I was going to say the same thing :)

Never got stuck once in my Grand Cherokee. (actually once... but it was a stupid move on my part)
 
Nissan TX10A > Quadrajunk. :D (Former Jeep owner here.)
 
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Nissan TX10A > Quadrajunk. :D (Former Jeep owner here.)

Did you maintain your Quadratrac? When properly taken care of, they are actually quite strong units.

Also, the Quadratrac came out in 1973, when does that Nissan system date from again? :mrgreen:
 
I had an NP228 in my Jeep, that thing never fell apart. (Everything *else* on the Jeep fell apart or fell off, but the transfer case was solid.) However, I've seen Quadrajunks explode and pictures of them having exploded after being properly cared for. The best part is when you discover what the 1305 version of the Quadratrac is missing.... What kind of moron puts a transfer case in an offroad-intended 4WD truck and then leaves low range out of it????

The TX10A came out in the 80s and has been shown to completely not care how much power you put through it, whereas you can break a 1305 or 1339 with the application of more than 300hp.
 
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True, some exploded, usually when the chain wears out. However, this race prepped 401 powered 79 FSJ proves that the q-trac can survive when properly cared for.

Now, don't get me wrong, its not the greatest, strongest unit ever, but, considering when it came out, it was really the beginning of modern full time 4wd.
 
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Yeah, I know about that SJ. You also conveniently left this out:

The big problem, as most of you fullsize guys know, is the durability of the Quadratrac. Yes, this Jeep is still running the full-time transfer case behind that fire-breathing 401, but this team swaps the chain out every race or two, and it's sporting a MileMarker part-time conversion kit. Sure, they have a small mint in stock of transfer-case chains, but from watching this thing go, it's well worth it.

I've seen a properly rebuilt (by an expert) 1339 grenade on 121 behind a mildly warmed up 360, less than 1000 miles since rebuild. Yeah.... NO.
 
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Yeah, they swap the chain out, which is why I said
usually when the chain wears out

I'm not trying to say its a brilliantly designed masterpiece, but it is one of the first attempts at a workable full time 4wd system that did actually work (most of the time.)
 
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So, basically, what you're saying is that the chain is only good for 1000 miles of city and highway driving in Dallas? And you say that's acceptable? :lmao:
 
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