[diss7]

Re final drive. Best way to calc what to get is to base in on your local race track.

Our gearing is pretty good in these cars, except for 5th to 6th, its a big jump, certainly not one you want to have to make on a race track. When calculating this way, also consider that you may have extra revs to play with.

For example, my 200rwhp NA ae86 hits 5th gear limiter about 100m before I need to brake. That's with a 4.3 FD, which seems tall, but I run 195/50/15. In 5th (which is 1:1 like most 6 speeds) @ 8000rpm, its doing 202km/h. Changing the FD to 4.1, gives me 211km/h at the same revs in 5th.

So, I know that for myself, I want to aim around that 210km/h mark for the new 86. Because, even if it gets to 200rwhp, it won't weight 900kg like the ae86 does.

I run 205/40/17 semis on the new 86. And I'll work to my rev limit being 7800rpm. Based on that, 4.1 is ideal for me. Say if I swapped out to a 4.5, I'd only reach 194km/h in 5th.

What I'm getting at, is don't just assume "ZOMG final drive is teh business!11!1!!one!"
It moves all your gearing.

You need to do your own calc before changing final drive. Your rev range, tyre circumference, and target speed at a particular point, are all critical variables.

And I for one, certainly want to avoid the 5th - 6th change on the back straight.