Final Drive Discussion
 

Hello all,

I know there are one or two threads discussion the Cusco final drive set, but I wanted to open one up for all final drives. Maybe we can offer some tips and tricks to the install as well has what shim kits were used. I'd like to know what the part numbers and brands of the shim kits are. I know a lot have asked and it fell on deaf ears. So maybe we can get it resourced here for everyone.

I hope to soon get one. Just not sure which.

So far we have:

Cusco
4.556

MFactory
4.44
4.67

There are a few other brands, but I have not been able to source them out yet. I've seen maybe a 3.9 and 4.3 in Japanese magazines, I'm just looking for the websites right now. If you know of any, please link them here. Thanks.

Pics would be cool too. Everyone loves pics! :D

Added: Gear ratios for each gear

1st : 3.626
2nd : 2.188
3rd : 1.541
4th : 1.213
5th : 1.000
6th : 0.767

Gear speed chart calculator: http://pw1.netcom.com/~sgalaba/mph.htm

I too have been trying to find out part numbers on shims and stuff like that. I just ordered a final drive kit that I believe I'll be the first one to test. Before I post too much information I'll guinea pig my car first before posting my review of the kit. But to give a little bit of information, it is another 4.56 final drive gear set.

Awesome! I heard a Nissan shim kit will work, but I forgot the part number for it.

Also, I notice a group buy for the MFactory set for cheap. But not many willing to jump in. I'd jump in on it now if I could get it at that price. The Cusco is costly, but I found it for under $900 in USA. I think a lot of USA dealers are over charging for it. I wish JapanParts had it for sale. Mark up on USA dealers seems to be several hundred dollars.

If the money isn't burning a hole in your pocket, wait a bit. The kit I'm getting is priced very well and doesn't require a group buy. I just don't want to jump the gun and tell people to buy it without testing it first. And I wouldn't suggest for you to wait if it was only saving pocket change. The savings will be worth the wait if the product is good.

I'm going to get 4.67 after my coilover, and now doing some research about the shim kit too, it's good to have a thread that talk about this.

If you have the Scion FR-S Repair Manual.pdf downloaded from this site (5009 pages), starting on page 241 is where they take apart the rear diff. Link is here:


There is also a BRZ factory service manual floating around too on this site.

We run the MFactory 4.67 in our race car. We can also add a shim kit to it which is OEM from Subaru.

Be wary of dealers selling this part who:

1. Don't even own an FR-S or know how this part works.
2. Can't supply a shim kit with it.

That goes for any final drive no matter the brand.

A 4.67 is pretty hefty for a daily driven car.

Do you have a part number for this kit? Also, what exactly do you mean... hefty? I know it might not be "ideal" for interstate highway use. But around town I see no issues.

how high is the rpm when its going 80 mph in 6 gear? the car is my daily drive, but I do track alot with this car as well!

I'm looking that up now (rpm at 80 with 4.67), but I found this on Cusco site. Scroll down and you will see shim numbers. It would be nice to have @FT-86 SpeedFactory give shim kit numbers as well... hint hint.

http://www.cusco.co.jp/en/parts_prod...z_rear_di.html

Where's the 3.8/3.9 final drives for us FI folks?

You can buy one from Toyota today for your car. Or from the Lexus parts bin.

O rly, any idea whic cars they come out of by chance? (As I which cars have our xmission and the 3.8/3.9 final drive?)

Using this site to calculate speeds, http://pw1.netcom.com/~sgalaba/mph.htm

A stock 4.1 final at 80mph will be close to 3500 rpms in 6th gear with stock tire size.
With 4.67 final at 80mph it will be close to 4000 rpms in 6th gear with stock tire size.

So a jump in 500 rpms.

Added: Gear ratios for each gear

1st : 3.626
2nd : 2.188
3rd : 1.541
4th : 1.213
5th : 1.000
6th : 0.767