I think a lot depends on your intended usage and the sort of power you are going to produce. I have no wish to give Quaife bad press but it is well known that the centre differential they produce for the DSM/VR4 is prone to breakage especially in high horsepower and applications involving hard launching of the car.
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Hello everyone -
This is Jon Ripple of T.R.E.
I rarely make posts here but I'd like to clarify some things.
Last winter we noticed that people were breaking their Quaife center diffs.
We found that the backlash between the center diff and intermediate shaft is
a little excessive. This will cause gear tooth breakage if and when the
gears are heavily loaded. I've contacted Quaife USA and UK and explained to
them why their diff is breaking. The backlash issue is the major problem
followed by the heat treating. I discussed this problem with Mike W @ RRE
and he talked Quaife USA into sending some DSM parts back to Quaife UK so
they could see if anything wasn't to spec. After a while Quaife stated that
yes there is some backlash but they have to leave it because they do not
final grind the tooth profile after heat treating, leaving any distortion
from the heat treating process. To allow for this distortion Quaife has
elected to ride close to the acceptable limits for backlash. This will cause
variances and the end result is some gear noise. Some of you may notice
that after you've installed a Quaife you will here some gear whine,
especially in 3rd gear - no load. This is the backlash issue.
What is my conclusion? If you launch your Mitsubishi AWD hard enough the
Quaife center diff will eventually loose some teeth. Sorry guys but the
teeth on your stock center diff are stronger. I've been in a lot of DSM
gearboxes and rarely do I see busted teeth on the factory center diff gear.
Pruven Performance has cut several mean 1.32sec 60' times with the
transmission that I built for them without any breakage. That is a full
season without any breakage. That trans has the factory center diff with
the spool that we sell.
The size of the planetary gearset inside the Quaife center diff is a little
small for the power that a built 4G6x can belt out. The thrust/friction
surface of the sun takes a fierce beating. Quaife could remedy this by
reducing the combined thrust/friction surface area of the planets, allowing
them to wear evenly with the sun's thrust/friction area. This will also
provide the Quaife with improved Auto-Torque-Biasing.
I do not feel that I'm dogging Quaife. Overall they built the best limited
slip differentials. I like the ATB (Auto-Torque-Biasing) action of the
Quaife because it will send equal power to the front and rear diff when you
launch hard. However I prefer the 4 spider center diff from Speed Design
that we sell. It is well built and holds up the best for the money. If
the car only spends time at the strip then the Spool will work the best in
this application. More info on transmission upgrades can be found here,
click
Secondly- We have not used the EVO forks with the plastic wear pads ever
since Scott Hidley wore his out. Last spring we started replacing the
plastic wear pads with a Bronze alloy. To deal with the high load of fast
shifting, the pads have twice the surface area of the plastic pads. I have
put about 5k miles of beat-ass on a set of forks and they looked perfect
with hardly any wear. I would like to point out that most of the wear pad
issue revolves around improper clutch adjustment and trying to stuff it into
gear.
As a result, I'd be inclined to go with either a clutch pack or the 4 spider Speed Design differential mentioned. The Quaife unit is nice however and if you aren't launching the car or running a high horsepower engine you might be okay. I personally wouldn't take the risk but that's just me.
Paul.