Installed 3.91 rear diff from Lexus is300- amazing

[Dr. BRZ]

I have the 3.56 gears and at 70mph, it's between 3400-3500. It's not too bad, I just keep it at 60mph at 3000rpms

[Spawn_Of_Creation]

Originally Posted by Dr. BRZ

I have the 3.56 gears and at 70mph, it's between 3400-3500. It's not too bad, I just keep it at 60mph at 3000rpms

That rpm seems high for the speed you go. I have stock 4.1 diff on slightly larger than stock 235/40 tires on 18x8 (a 3.1% larger size) and 80mph is 3500rpm in 6th gear.

[Dr. BRZ]

Originally Posted by Spawn_Of_Creation

That rpm seems high for the speed you go. I have stock 4.1 diff on slightly larger than stock 235/40 on 18x8 tires (a 3% larger size) and 80mph is 3500rpm in 6th gear.

The rpms are definitely higher. I'm on 225/45 tires on 17x7 wheels. It doesn't bother me. I don't take the car on the highway much, mostly streets.

[86TOYO2k17]

Originally Posted by Dr. BRZ

I have the 3.56 gears and at 70mph, it's between 3400-3500. It's not too bad, I just keep it at 60mph at 3000rpms

You mean 4.5 final drive?

[Spawn_Of_Creation]

Originally Posted by Dr. BRZ

The rpms are definitely higher. I'm on 225/45 tires on 17x7 wheels. It doesn't bother me. I don't take the car on the highway much, mostly streets.

With your stats you should be at 80mph @ 3000rpm with your 3.56 fd. If that is really your speed, you might have clutch slippage.

[churchx]

Worth also to take into account by how much speedo lies even with stock FD, if one tries to draw some lines between something calculated and reading from dash.

[Dr. BRZ]

Originally Posted by Spawn_Of_Creation

With your stats you should be at 80mph @ 3000rpm with your 3.56 fd. If that is really your speed, you might have clutch slippage.

Oops my bad, I just realized I typed 3.56 and not 4.5. My bad, yes I have the 4.5 gears. Thanks for the heads up cause I had to think about it lol

[Dr. BRZ]

Originally Posted by 86TOYO2k17

You mean 4.5 final drive?

Yeah that's what I meant to say, when I read your comment lol

[86TOYO2k17]

Originally Posted by Dr. BRZ

Yeah that's what I meant to say, when I read your comment lol

Lol all good. How you liking it?
I thought it was best NA mod besides header/tune. Lets it pull hard through 5th.

[churchx]

86TOYO2k17: i like how those FD swaps can make upper gears more usable on track and add up that subjective feel of more performance due better gearing (up there).. but then again i dislike how 1st, and in more extreme ratio cases even 2nd, can be less usable, too quickly hitting redline and adding redundant shifts. Hence always thought that FD swaps should in most cases be used together with close ratio gearset, that makes 1st & 2nd gear longer. If only later wouldn't cost that much .

[NoHaveMSG]

Originally Posted by churchx

86TOYO2k17: i like how those FD swaps can make upper gears more usable on track and add up that subjective feel of more performance due better gearing (up there).. but then again i dislike how 1st, and in more extreme ratio cases even 2nd, can be less usable, too quickly hitting redline and adding redundant shifts. Hence always thought that FD swaps should in most cases be used together with close ratio gearset, that makes 1st & 2nd gear longer. If only later wouldn't cost that much .

It's not as bad as you think though obviously track dependent. I almost never have to go down to 2nd anymore.

[churchx]

On tracks i go to most used are 2nd and 3rd (as 2/3 of those tracks are for karts, and just two, "full size"), 4th a bit less, and just on one i'd almost need 5th for 5sec at end of longest straight, but decide lingering at redline, as extra upshift-downshift would probably hurt times more. +I daily drive car a lot, and also have to crawl in traffic jams with no gas in 1st often. Hence why i wouldn't want just make top gears more usable .. at cost of making lowest gears less usable, but something that would improve overall, or add gains much more then (hopefully) little loss, for "win-win" lol . And to that imho close gear ratio set together with FD swap should fit best. Watching charts for eg. TRD/Cusco gear set, 1st & 2nd seem distanced more apart from rest, thus wished combo should make keeping in power band easier, keep 1st & 2nd almost same as before, easing their dailying usage, but keep 3-4-5-6 down for better gearing/acceleration .. unfortunately at high cost, much higher then just FD

[Dr. BRZ]

Originally Posted by 86TOYO2k17

Lol all good. How you liking it?
I thought it was best NA mod besides header/tune. Lets it pull hard through 5th.

I LOVE it! With it, I lost to a 335i by a bumper because I missed up the shift from 4th to 5th. On a roll, I was tied with a challenger rt in 6th gear. Good freaking mod.

[Gam3rBlue]

Doing this swap, Is it only good for Turbos or should It also be done for SC pushing 350whp? Lemme know, If its worth it.


Thank you,