4.556 final drive with TRD gear ratio change - good or bad idea?
 

I'm thinking of doing the Toyota OEM final drive of 4.556:1 (same as Cusco but cheaper here).

I was wondering what it would be like with this AND the TRD cross gear set here http://www.trdparts.jp/release/2015_...ssmission.html

I know the effect the final drive will have and am keen but figured if they were playing around with the transmission I could get them to do the cross gear set at the same time but will the combo be better or stuff up the ratios?

And, yes, I did search but couldn't find out info about the combined effect.

final drive changes the ratio about 10% shorter.
higher final drive makes 3,4,5 gears more usable on a track.
trd gear set would make 1,2 usable on the track and closer gearing between 2nd and 3rd.

4.56 is a very nice upgrade for a NA car.

I Plan on it @nzer. I already have a 4.8!

I already envisioned the shorter change from 2nd to 3rd. Excited

Thanks for the feedback all. I've decided to do final drive first and consider gearing later. cost of gearing option is pretty steep with parts then quite a lot of labour as can't do it myself.

The 4.56 Final drive swap is a great upgrade to the car, It helps overall feeling throughout the car, but still maintains very derivable mpgs
[ame="https://www.youtube.com/watch?v=occuNSTlkIo"]UEL E85, 4.56 FD swap 0-80MPH - YouTube[/ame]

Do it! TRD stuff is obviously very good..... + this is actually one of the upgrade option for 86 in Japan when you purchase the car from dealer.

You might be interested in my thread:
http://www.ft86club.com/forums/showthread.php?t=94450

Today my car is in a shop switching 4.67 to 4.88. Then I will decide if I buy Cusco cross mission set or nothing.

Edit: I dont think you need longer gears on 4.56 FD, I run autocross here in Europe with 4.67 and it is manageable, but for 4.88 it will be probably too short. I will know for sure next week.

With the 5.125 ratio the second might become a long first and fifth could finally be used in a fast slalom. (But I think according to EU-law any change exceeding 8% needs to go through an individual approval procedure by a dedicated inspection agency = extremely expensive).

And who will ever know you have a shorter gear somewhere inside?

That's a good point.
We have to get the car inspected every 2 years and usually they take it on a very short test drive and this is where they could notice it. But this really depends on the person who's driving it.

Use this tire/wheel size calculator before you select a rear gear ratio

http://tire-size-conversion.com/gear-ratio-calculator/

it will be unless its a very VERY small course. majority of all of my autocross courses require 3rd gear with only 1 course that I can bang off the limiter in 2nd.

You know - Europe is different, we have everything smaller :confused0068:
Well, not everything.