Yes, the stocker with the 75-90 and no, the lock up is incredible on cornering and no more understeer. Seriously best mod/upgrade ever. The heavier fluid (75-140) just means less breakdown and more protection.

 

Ya the Grouppe-S reflash is pretty awesome for Turn-In, Mid-Corner... but exit sucks ***!

I think this is the next mod for me

Here is a video of a local auto-x dude that swears by the TRE rear diff, and he is pretty fast

http://www.youtube.com/watch?v=bQGM8gcuQaE

 

im not 100% sure about the heavier fluid meaning more protection.. especially if it's cold - unless im mistaken on that. and i believe a thicker weight oil, if you do drive enough to get it hot enough, will be much hotter than a lighter weight fluid.

not necessarily saying that's bad or isn't appropriate for the diff, just saying. im going to see if i can get a hold of "cusco" tomorrow.

http://www.cusco.co.jp/en/parts_prod...s/lsd_oil.html

seems cusco themselves use 80w-140 for "high load and heat"

though if you look at their description for their 80w90 which isnt even full synthetic, they say it's fine for all mechanical diffs from daily use to competition - which makes me more confused. if the 140 weight is for "high load and heat," what do they expect other people are doing? maybe i still fit into the 90 weight category, since i only autocross once in a while etc. and the fluid will get pretty cold in the winters here (IL). also, i definitely think amsoil svg is a higher quality than cusco's hydrocracked 80w90.. maybe im just justifying staying with the 75w90 though..

 

subscribed

 

hahaha wow this car power oversteers like a rwd car

 

Nice video...he was definitely showing off the power oversteer.

 

isn't diaqueen a 90w oil?

 

Kyooch

did u end up going with the ACD flash too?
i was talking to a friend, and he advised me to skip the flash and send the diff to shep or tre

 

i did - if i had to pick one or the other i would go with the diff, but i think they really complement each other. i dont have any independent testing but their functions indicate that they do. the flash locks the rear more aggressively, and the diff will shuffle that extra locked torque or whatever. in a way i think it makes the diff do it's job better. but yea if i had to choose i'd pick the diff for sure.

the diff is the real issue with our cars, and it's the "must do" in terms of upgrading

 

for now i think i'll switch to 75w110 - even the amsoil wbesite says it works in place of a 75w90 and just protects better.. in case anyone cares lol.

sorry i didnt mean to jack my own thread with rear differential oil options but i think its fairly important for anyone considering upgrading theirs anyway


description of amsoil's 75w90 -

AMSOIL SEVERE GEAR® (75W-90) provides superior performance and replaces competitors’ 75W-90 and 80W-90 gear oils. It delivers the best fuel efficiency and cold temperature performance of the SEVERE GEAR oils.

description of their 75w110 -

AMSOIL SEVERE GEAR® (75W-110) provides superior performance and replaces competitors’ 75W-110, 75W- 90 and 80W-90 gear oils. It delivers better viscosity protection than SEVERE GEAR 75W-90 and better fuel efficiency than SEVERE GEAR 75W-140.

seems the 75w110 is specifically for higher protection.. so anyone running 75w90 can switch to this anyway. a good compromise between the 140, which says

AMSOIL SEVERE GEAR® (75W-140) provides superior performance and replaces competitors’ 75W-140, 80W- 140 and 85W-140 gear oils. Use where these viscosities are required by OEMs and where maximum viscosity protection is needed for extreme severe-duty applications.

still.. "maximum viscosity protection" does sound good... but overall for my dd, cold weather, and twice a month autocross.. i think i will say the 75w110 is the way to go!

 

anyone else have any awesome vids of any of these diffs in action??

 

The rear diff improved my autox lap times on a .75 course by about 1.5 sec on average. I had the acd race flash before the diff and it improved my times by about half a second average. It improved my times by about as much as when I went from compleltely stock to the robispec springs.
Remember the acd still works on a 50/50 split, the rear diff actually makes just the rear itself more agressive. They all compliment each other but the acd flash also effects the front end of the car. In short I would recommend the TRE rear diff first and go from there.

 

Thanks for the input Tommi

 

I run the TRE 1.5 Maxx lock.

Absolutely transformed the performance of the car from understeer to "WOW, THAT WAS AWESOME"

Having an upgraded rear diff in the CT9A > A bigger turbo, cams, or a date with your BFF's mom.

Too tired to write anything comprehensive, but the throttle control and the overall fun factor of the car on track is amazing. Highly recommend this service.

TRE was slow to turn around (2.5 weeks).

 

nice reviews!