JDKane527

iTrader: (10)

Cusco has announced they will be selling final drive gears for the FRS/BRZ. These will fit IS250 MT and AT. Will not fit IS350 because it is a different sized differential.



Stock MT comes with 3.7:1, AT with 3.9:1. They are offering a 4.556:1. Can't comment on price. To give you an idea, I got my 4.1:1 set with rebuild kit from Weir Performance for around $450 + shipping.

http://www.cusco.co.jp/en/parts_prod...ion_gears.html

ohiois350

iTrader: (13)

sorry for a dump question? what is the final gear for? the lower number is better for top speed? the high number for the off line track speed?

JDKane527

iTrader: (10)

You can think of gearing as the first number being how many rotations on the input equate to 1 rotation on the output.

Between torque and rotations, if you want more torque, reduce rotations with higher number. If you want higher top speed, but with less torque, increase rotations with lower number. It's a compromise, in that you can't get both.

With more torque, you would have improved acceleration, with decreased MPG.

Gville350

iTrader: (10)

^So in other words, the higher the ratio # the quicker the acceleration and loss of overall top end speed. That 4.5 ratio would be best for on-track use, but would be hella fun as a DD too.

Howiefied

How much quicker we talking here? As in 0-60mph wise?

Vq4life

those are pretty high gears im thinking low 6's for 0-60 i know on a 350z when they jump up from 3.3 to 3.5 its .3 tenth of a sec faster on the 1/4 miles and the jump from 3.7 is .5 second in the quarter !!! but espect gas milage and rpms to higher by a couple hundred at cruising speeds . The Z guys said they lost up to 3-4mpg highway

Vq4life

but i think with this mod lil weight reduction headers /exhaust/intake and light wheels we should be somewhere in the mid 14's hopefully !!! I may get one lol i ran a 15 flat with just a joez intake and my winter setup which the rims are 20lbs my summer setup theyll be around 16.5lbs

JDKane527

iTrader: (10)

I averaged 28-29 mpg, and then dropped to a solid 25 mpg after changing my FD. I only tracked it with the LSD, so can't comment on how the open diff operates, but it was awesome with the LSD and gearing.

buister

iTrader: (1)

I had the ring & pinion swapped on my old IS300 from 3.7 to 4.11 about 6 years or 100k miles ago and since then I had to replace the pinion bearing twice. My advice to you guys who contemplate doing this is to use heavier diff oil and change it often because the higher ratio will generate more heat. If IS250 uses the 3.7 manual and 3.9 auto then it sounds exactly the same as IS300. In that case, you can find the real Toyota gears that came from a Tacoma or Landcruiser (like on mine) or other trucks since they tend to be high ratio gearing rather than buying aftermarket parts . I believe in genuine Toyota parts because even after 2 burned bearings my gears are still in excellent condition. Is all this worth the trouble? Hell yeah. The car is a lot more zippy and fun to drive, but be prepared to sacrifice your gas mileage by the same ratio.

webra

Is this gear swap experience with the IS or the Toyota/Scion?

webra

Sorry. Just read your signature. Thanks for the post. Any swapping issues to note?