I added two links to the original first post to make things easier for people. Thanks Piro Fyre!

 

Very interesting and inexpensive way to Get A TRU JDM Diff dat should work the right way outta the Box! Now wished they would've given us the AYC too.Good Post OP!

 

Could you or someone else elaborate on this? I took my diff out and rerranged the plates yesterday, but it hasn't made much difference in the handling. It made the car more neutral, but it still won't kick the tail out like in the OP's videos. So I'm wondering if maybe I swapped those things around?


EDIT: After some more testing the diff is definitely working properly. Just not oversteering quite as much as I would like it to. This mod is still worthwhile if you're running STU or a similar class where you can't go to a 12-plate, but if you can go to a 12-plate from Weir/Shep/TRE...I'd do it. A friend of mine has a VIII with the Shep 12-plate and it's impressive.

 

are evo 8s set up wrong from the factory aslo? or is it just the 9s?

 

all

 

Does anyone know why these diffs were setup differently ?. If they were built "incorrectly" I would have thought a TSB would have been issued by now.

 

As mentionned in the thread, it's believed it was either to avoid having too much throttle oversteer that could catch inattentive drivers by surprise, and/or to not have owners complaining of noise coming from the diff when it's in fact working perfectly fine.

 

The concensus is noise. Some have cited some other manufacturer (I forget) having a performance car with a diff that was 'too noisy' and it generated a TSB callback / warranty fix.

So.. "incorrect" is in the eye of the beholder..
Different than the shop manual - yes.
More quiet than how it's done in the shop manual - yes.

As someone who competes with a pretty strict ruleset, a TSB is not something that I'd push for - since it's more likely that said TSB would correct the shop manual to match the existing build.

-'chono'

 

What fluids are people using.

Diaqueen, Redline Heavy , etc

I have used the redline and it does feel more agressive even without the plate swap.

 

Wow, great thread!
I can't wait to do this! Once I get the ***** to, that is.

 

Running Amsoil 75W-90 Severe Gear. Since the diff easily locks up, I'm guessing it doesn't have any additives like friction modifier, which is good.

When I was running my original diff without the plate swap, it was aggressive too with the same fluids. Then I switched to stock struts and lowering springs and the aggressiveness went away... Time to get coil overs again.

 

It does feel 100 % better. It kicks the tail out nicely. I put Diaqueen in the diff and it still locks well. Next time mabe I will try the Redline.

 

I just did this upgrade (OEM Incorrect to Weir 12-plate) last week and spent the weekend with NASA at Road Atlanta. I'll put a more detailed write up in the Motorsports section, but after all the other changes (coilovers, RSB, Whiteline RCK, Bump Steer, Bushings, agressive alignment) this was the final piece that brought the car into a mostly neutral state.

And it is really easy to do, hardest part is removing/re-installing the diff in the car.

 

Here's a write up and video of the Weir unit in action:

https://www.evolutionm.net/forums/mo...a-nasa-se.html

 

good job on the write up.

i pulled my diff and did this and went with redline fluid in there. seems like its working perfectly. i also got alil chatter in the rear only at like 5mph after that nothing