Longer Gears
 

My car is FI but I feel like the gears arent long enough. What option are there for me since I hit 148 pretty often and it starts slowing down drastically there. I will be doing e85 so power isnt gonna be a problem. And if right now I just have 330 hp how much will it affect the speed of the car for the time being not e85.

Grab yourself an M85 differential out of a 02-05 IS300.

3.73 FD as opposed to the stock FT86 being 4.10.

EDIT: Not terribly hard to find, but they aren't plentiful. I bought mine for $575 shipped. It is a *direct* swap. You need to pull the IS300 axle shafts out, and the rest is straight bolt in.

Agree with what slicktop is saying. Pulled my diff out of an IS300, but it was only $250 for mine. If you live in a big city (Houston for me), there are quite a few for sale if you call around.

M98 diff will work as well, but will have a 3.9 FD in it instead of the 3.73 tha the M85 has.

What is the stock gear ratio?

Read post #2

@Dipstik-sportech

You rang!!! I've done the 3.73 diff swap. For forced induction it's almost a must do. Makes highway pulls a much less frantic experience lol, less shifting and more speed per gear.

So to do this install is there a diy what exactly do i need to buy to get this fully swapped.

Its 4 bolts and two axles, you want an is300 diff tagged m85

Thats all i need? Is just the differential? Whats the normal price for one too

I paid $600 for mine. It's a whole differential unit so u just pop the axles, remove the driveshaft and take the 4 mount bolts out and replace it with the is300 one.

I dont get how any of this works but i have a guy that sells the diff for that car do i just say i need the m85 differntial and thats it?

Just checking read the post above

It's literally bolt in. The transfer case/pumpkin is the exact same unit with different gearing inside.

Google "frs differential" and google "m85 differential". They're the same *exact* transfer case. On the M85, you will see the axle stubs where the axles go in. Those litereally pull out and you install it.

I had questions and @Dipstik-sportech helped me out because I couldn't believe it was literally drop in. It was. I don't know how else to put it.

EDIT: Look at my build thread, I have some pics there.