I own a WRX MY03 PPP with Spec C struts - Prodrive springs some more tweaks and recently have changed the rear diff with an R160 Suretrac from JDM WRX.
My plans are to change also my front open diff with an STI Helical LSD similar with what MY98-00 STI RA V-Limited uses keeping the center 4Kg viscous diff.
What concerns me is will I have more understeer due to more traction front or the Helical helps the rear to work better and sooner (while now part of the torque is loosed due to open front diff)?
Does anyone have experience with Suretrac rear and torsen type front diffs(Helical, Quaife etc)?
Thanks in advance.
JIM

 

Hi Jim,
Havent used a helical in a Subaru but had a Quaife in my old 205. Well worth having. It has the weird effect of putting more torque on the outside wheel when cornering on a good surface so helping to pull the front of the car round, reducing understeer. Don't see why it wouldn't work well in a Subaru.

Not sure if it will help traction all that much on a loose surface though. It really does a different job than a plated diff.


PS. some of your fronts and rears seem mixed-up.

 

Corrected!

 

Didn't run a plated rear at the time, but a front Quaife helped turn in and power out of corners.....as long as entry speed was not too high! Once the front lost grip, the Quaife just ensures you drift wider (whereas the open span an inside wheel). This was only ever a problem on track, on the road it was superb (you don't generally push quite as hard on the road!) and seemed to suck you into a corner at turn-in.

It also helped over-steer exits; push for a bit of lift off oversteer entering corner, nail throttle early which sucks front tighter, balance the drift on the exit. Great fun

Richard

 

I have a FRONT suretrac diff, as I converted my 1998 wagon to a JDM 6MT DCCD. When cornering, I can apply more throttle and tighten the line where it previously would start to understeer/run wide/spin inner wheel.