Not at all. It handles awesome. I was able to win my class last season with this setup, and I just got a basic suspension setup. I have robispec springs on stock kybs, acd race flash, tre 1.5 max lock, 265/35/18 star specs on enkeis.
After I had my springs and acd reflash I still had understeer coming out of turns. Part of it was that I was still overdriving the car a bit, but I asked around to the local evo guys up here. Nobody up here had a tre rear diff and acd race flash, but were against it saying that I would just drift uncontrollably and I would be nuts to want more oversteer. Well I like proving people wrong, I did my research and decided to go ahead and order a tre 1.5 way rear diff.
After I got it installed, I took it out autoxing. Well first session out I was all smiles. I literally had a grin on my face the first lap out. NO other mod was as noticeable and fun as the tre diff.. It just complimented the rest of my setup so well.
Like alot of people are saying on here, this IS one of the weak points of the evo and should be one of the first mods to do.

 

^^

Thanks

 

I made three little video's. Sorry for the poor video skills...i was using my left hand :P Enjoy the power oversteer

 

my car is actually kinda clunky at low speeds, but i think it's the clutch/my driving. it was bothering me just today though, so when i took the car out to do some low speed figure 8s there wasnt any noise at all. must be the clutch engagement at super low speed. even doing the low speed figure 8s i could tell the dif was working though.. car wants to rotate as soon as i put more foot down.. understeer has been replaced with power oversteer.. completely different from when people say "i added rsb or i increased tire pressure or coilovers this or that and now i dont understeer anymore" ..they still understeer, just less or at a higher limit

 

ooo i don't get any noise like that with the cusco. jon said it's normal though?

 

Go take a video of your cusco at full lock on dry pavement launching from 4k or so and accelerating away.

Like I'm saying... its rare that you would ever do that and it's the only way to get the diff to make noise. Yeah its normal. The diff is still super fresh and from what I've been told that it gets quieter with time (wear of friction plates reduces lockup over time)

Remember you put in a WHOLE bottle of friction modifier. You're slipping

 

IF you can, get some videos from the outside to show cornering if possible. thanks for all the info.

 

R/TErnie,

Do you have any videos of you at an autox or track so we can see it in action. Links if any? Good stuff.

 

I'll have some video of the car racing at PGP this coming weekend. My next race is on the 13th of August.

I plan to get some nice in car and external shots of the car rotating

 

Sounds good.

 

this is true. hopefully it's breaking in gently though. when the time comes to do the fluids i'll snag a vid of it

 

nice review. though i think there is more oversteer, it's nothing uncontrollable. like u said, it actually compliments the acd in that it makes better use of the increased lock up going to the rear. even with acd reflash the car still needs that push u get from the outside rear wheel to rotate the car

 

I've got the Shep upgrade, and everything that can be said about this upgrade has been.

Literally, if you are interested in turning your EVO at all, I would do this mod before anything on the suspension.

As for noise/harshness, I don't get any clicking, but if I am going slow and turning tight, I can hear the rear inside tire slip-grab-slip, just like a when you lock in the hubs on a 4WD truck. Otherwise, you'd never know it was there, until you toss it into a corner, then it is heaven.

 

did you put friction modifier in your diff? What fluid?

I run the 75/140 NON SLIP.

 

Diagueen LSD no modifier. Just what Shep recommended.

I'm not sure if the Shep is the same lock up as the TRE, but it's enough lock up that it works great.

Just thought I emphasis something that goes along with R/T Ernie post. You can try to tune an EVO like a FWD by taking away traction from the back and getting a ton upfront. All this does though is make the car want to snap oversteer anytime you get off the throttle or trail brake which makes the car hard to drive.

This diff is like the complete opposite. It let's you slide the back around under power, the FWD tuning will never do that. But it also provides better rotation on trail braking, but it is MUCH more predictable and less "snappy" then the FWD tuning method.

Just to complete the specs, I run 10k/12k coil overs on the stock swaybars. I also have an RS front diff. It is the perfect balance IMO. I'd say rear diff #1 mod and front diff a close second. The rear diff lets you get the back end pointing where you want it, and the front diff lets you hit the apex hard under full throttle, it just goes where ever you point it.

I got the front diff/T-case upgrade and rear diff done at the same time. It was just slightly over $1000 from Shep for both combined.