CUSCO 4.55 FINAL DRIVE installed.

[ka-t_240]

Originally Posted by Icecreamtruk

If I did that I'be deaf, thats what I'd be.

I changed bearings on mine, maybe that explains a bit the difference. Or maybe you just have exhaust drone and not diff noice.

I haven't gotten ambitios enough to bolt a stock CB on to see if that changes anything. I do also have a bunch of bushings done, so its possible that amplifies anything thing.

[civicdrivr]

Originally Posted by Icecreamtruk

Its a very faint whine. I have to be actively looking for it to notice it, usually not audible over exhaust noice. Noice varies with speed and its not always present (more audible at around 40mph and then again at around 70mph, I cant hear anything if my engine revs are over 5000 because of my exhaust).

I have the 4.88 from weir.

By the way, I dont think this is a defect on the piece itself but rather how it normally works. 4 months and 6 track days (2-3 hours of track time on each) after the install, everything is fine and noice has actually gone down a bit (or I have gotten used to ignore it).

Originally Posted by ka-t_240

I have a pretty loud steady state while/drone from the rear end after the rear end swap. It is from about 70-82.

I have talked to Weir about it, discussed all my "settings" as far as bearing preload and backlash. His suggestion was to possibly pull it apart and put new bearings in(I reused the bearings as the doner diff I assembled had 3k on it. I am not worried about it at the moment, there is no accell/decel whine which is the primary concern. His other thoughts was that it was likely a resonance noise caused by the change in gearing that I would have heard previously, but at much higher speeds.



Diff has between 8-10 track days, and 9 auto-x events on it. Plus street miles.

***If I set the cruise in the 90-95MPH range, car is dead silent, wondering if it could be exhaust drone?

Originally Posted by jcw99

It's easy to hear and much louder than stock, but I've gotten used to it.

Thanks gents. I've installed all new bearings (from Weir) but still have a whine from the rear end at speeds above 20mph. It's hard to tell if there's anything at deceleration; sometimes I hear it, sometimes I don't. It's hard to hear over my obnoxious exhaust lol.

[B T]

Will switching the final drive still retain cruise control and VSC functionality?

[civicdrivr]

Originally Posted by B T

Will switching the final drive still retain cruise control and VSC functionality?

Yes. The speedometer maintains its OEM accuracy as well.

[B T]

Good to know, I asked because the way speed control was maintained in my G35 was due to a combination of wheel speed sensors and transmission speed sensing differentiation. A final gear change rendered it inoperable. Glad the engineers here had foresight to allow for this.

[mrbbs]

Can anyone tell me if the Cusco 4.875 is even easy to build in as the 4.556 one?
I used to have a 4.556 one on my GT86 but would prefer the 4.875 cusco on my new BRZ.

[makesdrivingfunagain]

I have the same issue the diff whines on deceleration sometimes. Not really loud but noticable.

[makesdrivingfunagain]

Thanks everyone for your help on this! I installed the 4:56 set in the automatic (2013). The car really likes it, it surprisingly much more enjoyable to drive when driving normal (around town etc.) It certainly is faster with respect to acceleration. I would have probably gone with a 4:67 if I was to do it again for my Automatic Trans. This is a daily driver so that is what influenced me to choose the 4:56. If it was my second car I might consider the 4:88. We changed the fluid with a little bit of metal in there. This was after the first 1000 miles. Hopefully this gets better... Besides the whine, this mod is great. I should have gone a bit higher with a 4:67 for the Automatic Trans it would have probably been more ideal. I've changed gears in other cars before and this mod works and you can feel it. Also the gear indicator is correct with the gear change. In other words when I am in 2, 3rd, 4th etc. it actually says 2, 3. 4 next to the speedometer/tach. The speedometer is also correct! I was initially worried about this, but it is correct. : )

[Teseo]

I dont find weir fd...

[Icecreamtruk]

Originally Posted by Teseo

I dont find weir fd...

Its the same as the supra. You need to contact them to place the order anyways, tell him its for a Ft86 (frs vs brz vs 86gt doesnt matter) and he will get you the right one.

[makesdrivingfunagain]

Well, I changed the diff fluid again. The first change was after 1000 miles and it had some metal. I was concerned but aware that this was part of the break in procedure and was to be expected. The second change after about 3k miles was clean : ) The diff does make a slight whine here and there and there but nothing I'm really to concerned about. The car performs noticeably better now.

[wro77]

Could anyone share their track experience going to a short FD (ex. 4.56 4.88) with a supercharger (ex: JRSC)? I know the experience will differ depending on track type...slow and technical vs. fast sweeper type.


Trying to decide on FD and don't want to swap gearing depending on track. Would like to know what works and what FD would not be recommended based on your experience.

[Bobster]

If your car is tuned will the FD throw out the tune?

[Teseo]

Originally Posted by Bobster

If your car is tuned will the FD throw out the tune?

No. Will adding wider tires screw the tune, well no.