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View Full Version : Quaife ATB Differential, a possibly good modification?


Weebitob
04-22-2005, 11:57 PM
Whilst looking up information on the Ford Focus RS. I discovered some things behind its technical specs and how it makes such a great handling car with plenty of punch. From a video review I saw about it on Top Gear they talked about a special differential that gave it improved acceleration, handling and throttle response. However the trade off seemed to be some major torque steer during a daily drive up a windy road in Scotland. So when looking up information on a proof of a probable Cosworth Focus being put into production I found some technical tidbits on the Focus RS. One which caught my eye was the special differential it used is the Quaife Differential (http://www.quaifeamerica.com/differentials/diffs.htm), which is actually found factory equipped in some in some cars while you for others you can order it from their in-house aftermarket supplier such as Mopar for the SRT-4. This page explains some of the technical details behind how it works and what it does.

When I looked up the list (http://www.quaifeamerica.com/differentials/diff_apps.htm) of which cars Quaife supplies diffs for, it sell both front and rear diffs for the Subaru WRX (since WRX have AWD), but interestingly enough it says it is not compatible with STis. Since the SVX is capable of using tranny parts from almost any other Subaru in their production from 1990+ (Has there been any successful transplant of the 5 speed auto?) so I figured this should work as well. One of the things that peaked my interest towards the application of thing in the SVX is the fact that this diff actively applies traction to the wheel that has stronger grip without retarding the other. In other words it would not only give the SVX more whp but also the affect of our transfer clutch AWD SVX having VTD without that traction retarded stuff.

So what this means is that this might be great for your average SVX, but also even better for any SVX that has Stage II and whom somebody who has it has been typing about getting even better drag times if it is not for wheel slippage (I am not good with remember names, not even usernames:rolleyes: ). And to longassname, perhaps this may reduce your tire spinning time for the Stage III SVX to perhaps half a second at least. Or even SVXRide's Auto-X SVX might see improvement, if this doesn't mess with SCCA rules of course :D. As for it having the torque steer issued that seem plague the Focus RS, I don't think there would be too much torque steer since I am talking about the AWD SVX. But you can always try it with a FWD SVX and it might not be as affected as much either since it is larger than a Focus with a larger N/A engine as well that probably has a more balanced torque curve.

So what da ya think?:p

mbtoloczko
04-23-2005, 12:33 AM
Unfortunately, there are no aftermarket front LSDs for the 4eat tranny. The Quaife unit only works in the 5MT (which is why it doesn't work in the STi).

Weebitob
04-23-2005, 12:54 AM
Than I guess this would be an option for any SVXer that opted for the 5 speed tranny swap.:rolleyes:

Not for our 4eat transmission but obviously there is one for the Pontiac Grand Prix. So there is hope just yet. The good news is at least we can put a Quaife rear diff on and this might be to give somewhat of a traction advantage, and since it is in the rear there would be still not as much direct torque steer. Is it a good idea to have a different diff in the rear than in the front for an AWD vehicle or do you think that would screw things up?

Perhaps a petition or letter of a kind demand for a one compatible with a Subaru 4EAT tranny is in order. Some of us on the forum have become quite accustomed and good at persuading aftermarket parts for the SVX, and in this case it may be easier since it would be for most Subaru autos in general.:D

ThetaReactor
04-23-2005, 08:50 AM
Different diff in the rear? The car already has a LSD in back and an open diff in the front. How would the Quaife be any different?

dieingSVX
04-23-2005, 12:38 PM
i'm pretty sure tq steer is more from fwd cars not rwd

Weebitob
04-23-2005, 01:29 PM
Different diff in the rear? The car already has a LSD in back and an open diff in the front. How would the Quaife be any different?

With an ordinary open differential, standard on most cars, a lot of precious power is wasted during wheelspin under acceleration.This happens because the open differential shifts power to the wheel with less grip (along the path of least resistance). The Quaife, however, does just the opposite. It senses which wheel has the better grip, and biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel.

Different mechanics, sort of works in the same fashion at least from what I can understand as a VTD for two wheels, without retarding the traction of the other. I am not saying it is totally better, just different. However for the SVX, it may achieve great results in handling without losing the traction or you might even gain a bit more whp and torque.

Earthworm
04-25-2005, 10:52 AM
I believe someone said that the SVX LSD is rather weak and if this is true then it's possible the Quaife LSD would be beneficial.

I believe the LSD is weak (I've been able to spin 2 opposite tires on many occasions). If I had the time and could afford it I would change both diffs on my SVX with Quaife diffs.

drivemusicnow
04-25-2005, 03:22 PM
quaife = not recommended... go to www.magnusmotorsports.com look under tech, Kaaz vs torsen a quaife is a torsen type of differential, which has some specific downfalls. however, depending on your application, you may prefer those over the clutch type. Kaaz are slightly louder, and they do "wear" however if you read the article, you can see how Marco, a very experienced car builder feels about torsen type differentials.

Earthworm
04-26-2005, 12:54 PM
quaife = not recommended... go to www.magnusmotorsports.com look under tech, Kaaz vs torsen a quaife is a torsen type of differential, which has some specific downfalls.Do you have the exact link? I can't find that information on their website.

drivemusicnow
04-26-2005, 01:05 PM
Do you have the exact link? I can't find that information on their website.

http://www.magnusmotorsports.com/article_kaazvstorsen.htm

There are some cross advantages of each... however in a "road racing' or autocrossing application, non-torsen types just seem to be a better overall option. I'll warn you that Marco is a bit candid in this article ;)

Earthworm
04-26-2005, 01:56 PM
Thanks for the link.

Weebitob
05-02-2005, 11:18 PM
Interesting find, sorry if I did not reply sooner, I assumed this thread was dead by the third reply.

As for the article about the KAAZ vs Torsen, it is obvious that they are sponsored by these people which you can tell by the slight side slander at times, but it still doesn't take away from the validity. What peaks me is the question in my head that after reading about these kind of diffs, from what I understand that even though they are mechanically more complicated, what they do for the wheels are much more simpler. While the Quaife or Torsen try to constantly manage the wheels using their own system of transferring the wheels that grip more whilst one other wheel is slipping, KAAZ ones seem to just manage putting down as much traction as possible to both wheels, constantly making them spin while leaving everything else up to how the suspension among other things and as for AWD cars leaving it up to the TCU.

Now don't get me wrong these sound like great diffs, but I was also pondering what changes in handling characteristics would be gained through the Quaife ones and whether if it is beneficial, which I said they would be since it would be like having a VTD without actually deliberately retarding the weaker wheel's traction. But I guess when it comes to rallying, road racing and autox with diffs being pushed a whole lot more and a more likely chance of the occasional wheel hop the KAAZ would be a better choice. Also perhaps most of you SVXers have a whole lot of faith in knowing the TCU will make the right choices, and perhaps I should as well. I would also like to know more about the affects and benefits of the KAAZ differential since the article seems to showboat more about it’s benefits through mechanics and less about actual results, which isn’t bad either.

Thanks

Earthworm
05-03-2005, 04:13 PM
Anyone know how much torque the stock LSD can transfer to the opposite side? There have been times where I had my car teetering on opposite corner wheels and being almost unable to move.

Is there a way of checking if the LSD is truely working?