quaiffe or cusco centre diff ?????

[number3]

Quoting number3:
I had both the front and center installed in number3 and loved the way the car handled. (Quaife)



I was using the OEM 4 bolt rear LSD.

You could turn the steering wheel on the car and let it go and it would stay turned in that arc. It wouldn't just snap back to center. It was awesome. I put down over 500hp and busted third gear but never the Quaife. Not saying that it coouldn't happen I just never did. Mike owns the car now he should be able to tell you how well the car handles. (the cage, coilovers, and wheels don't hurt either)

 

Quoting H05TYL:
I was under the impression the cusco tarmac centre diff was intended to be used with the stock vcu,
this way you'll never get zero forward motion even if the rear wheels are off the ground.
note it still has the extended output shafts and circlip groove...

also found this on evolutionm - explains my understanding of things quite well.

Quote:

Now, what you're suggesting is to leave the VCU out, but just as has been mentioned, that would make for just an open centre differential. I don't think that's a good thing.

The one person I have talked to who has a Tarmac gear left the VCU on and says that since the VCU takes a finite amount of time to lock up, the Tarmac gear has plenty of time to exercise its rear biased characteristics. Perhaps more importantly, the VCU does not redistribute torque per-se. All it does is link the two output shafts together so that in the event one end slips, the other is dragged along with it. Actually, I should mention that the w5m33's VCU resides in the rear output shaft and the differential body, but it does the same thing in that the short of it is that its action is slip dependent. It is worth remembering too that the Viscous Coupling doesn't really solidly lock up until a remarkable amount speed differential is detected. In fact, it still only transfers a limited amount of torque. I've heard that the w5m33 stock center viscous is rated at 16kgf per 100rpm? Not sure, but it's something along those lines.



The Cusco has assymetrical torque split due to the leverages of its internal gearing.
-the VCU does not redistribute torque until a speed differential is detected, leaving torque distribution alone until one end is spinning more than the other.
-and even when spin is detected, the VCU takes a while to react and only gives a limited amount of torque transfer. In short, it keeps you from getting too crossed up.



Since I was the one quoted on the above post, I feel I must share a new finding I came upon regarding the subject.

The Cusco Tarmac gear for the Impreza is indeed an Open differential. For Mitsubishi's W5M33 however, we have the option of either keeping the stock VCU or leaving it out and running a vcu eliminator. Note that this eliminator is different from how most Talon guys understand it as their eliminator effectively "welds" the center diff together; the tarmac gear's VCU eliminator is just meant to keep something from getting pulled out or something.

Personally, I would run the VCU even for tight autocross use. But I drive the car in the Winter herein Alberta, Canada. Japanese guys on the other hand who do Gymkhana, and love yanking the Ebrake leave the VCU out.

 

[H05TYL]

That VCE in your pic look like it is used to hold in place the ball bearing that stops the t-case output shaft from sliding out.

 

[Whoodoo]

I have been pondering lately about differentials because I was reading about audi's new crown gear differential. Here's a link to a video on you tube portraying it's function. Basically it does the same thing as the Cuzco tarmac differential but also limits slip mechanically like a clutch type lsd.

It looks like the entire unit is small and believe me when I tell you I would love to get my hand on one to see if I could make it work. Then, you could leave the front diff open and use the 4 bolt rear lsd and have a really well handling car. /ubbthreads/images/graemlins/devil.gif

 

I finally went with the quaife centre diff,the gaurantee on the quaife is valid i spoke to them regarding the old problems and it turns out there were problems but not theres,it was the 3rd gear exploding and taking the diff with it and people trying to claim.
To be honest i wish i had done this upgrade years ago,the car holds a tighter line in the corners and the understeer has gone,which means i can carry more speed through the corner making the car faster to drive,you can also brake harder and down change quicker,launch harder and not have to worry about the viscous catching up or exploding,i would 100% reccomend this upgrade it will transform your handling,as for which centre diff to go for i can only reccomend the quaife as i have no experience of the cusco,but i would imagine the end result is the same. cheers Guy

 

[turboaddict]

they are reinstating the warranty on the dsm center diff????

 

Yes, i asked them about the warranty and it was for life,so i bought one,please note im in london England please check with quaife Usa,to be fair i cant see it makes any difference where you are,but manufacturers like to have get outs,so worth checking before you buy.but all is ok in uk.cheers Guy

 

[randedge]

Bump for knowledge's sake.
Here is an interesting discussion on DSMtuners.

click

The same guy I had originally been quoting about leaving the Viscous Coupler ON with the Cusco Tarmac Gear now runs without it! Why? Because apparently, if you don't drive slick surfaces, and provided you have an excellent rear and front LSD (preferably one with lots of locking capability in the rear and one with less up front), then you could have power oversteer galore.

 

[jepherz]

Quoting number3:
Quoting number3:
I had both the front and center installed in number3 and loved the way the car handled. (Quaife)



I was using the OEM 4 bolt rear LSD.

You could turn the steering wheel on the car and let it go and it would stay turned in that arc. It wouldn't just snap back to center. It was awesome. I put down over 500hp and busted third gear but never the Quaife. Not saying that it coouldn't happen I just never did. Mike owns the car now he should be able to tell you how well the car handles. (the cage, coilovers, and wheels don't hurt either)



I'm not sure why this would be the case as the diffs are all intending on spinning every wheel the same speed, nor why you would want your car to behave like that? That sounds like bad alignment to me.