3.90 GR86 Diff in a 2013 BRZ - Good combo for boost?
 

I ran my first dry event with my new turbo setup today. I'm running a 4.30 diff in my 2013 and I ran out of gear very quickly and frequently. Everything I'm seeing/reading seems to indicate that the 3.90 from the 22+ GR86/BRZ automatics would work in my car. Is that the general consensus?

I guess I'm going to find out. I bought one.

I think that would be a good change for your setup.
Let us know how it goes!

I ran 3.91 in my '16 FRS when I was Harrop'd and it was a great combo. You'll be happy with the change

Hey....do you want to buy a 4.30 diff? :lol:

I ran at Mid-Ohio today and the 4.30 is a nightmare on my setup. I had to shift into 6th on the back straight. :lol:

Yeah, I believe it.

Even NA I was close to topping out 5th even on the 4.1

I think if I move to the 3.91 and consider a larger diameter rear tire then I believe I wouldn't have such a problem.

Honestly, that was a pain but there were so many other places on the track where I was losing time because I was at the top of the RPM range but I didn't want to shift up only to have to shift back down almost immediately. The front straight into turn one, the entrance into the chicane, and the exit in Thunder Valley were all like that.

Price and Shipping to WA state? :D

Let's figure it out. The shipping weight on my "new" one is showing as 82lbs. Shipping looks to be around $200 via UPS from Central Ohio to Seattle. It looks like the going rate for one of these is about $600.

Honestly, I think you could find a better deal than from me because the shipping is terrible.

Correct, this won't work and $600 is on the high side. I just bought one locally from a wrecking yard that had to transfer it from OR to WA and after tax and transfer it was ~$450 ($360 was the sale price). If anyone in Ohio is running SCCA, they will likely want this as an upgrade, especially if they race in T4 and are converting from a 13-16 to 17+.

Agreed. It seems like you guys can get better prices on this stuff on the west coast. These rarely even come up for sale in this neck of the woods.

I also have a 4.10 that I could probably go ahead and sell too. :lol:

I paid between 4-450 for the last two I bought since I have gone back and forth between 4.1 and 4.3 a couple times.

In this part of the country they definitely go for more. Of course, that's just looking at things sitting behind a screen. I actually bought my 4.30 from Kyle since he's in my neck of the woods.

I'm in the middle of some pretty active SCCA regions so I'll probably find a buyer pretty quick. As long as I can break even on what I just bought I'll be happy.

I did 3.73s on mine, no regrets.