Tried and true! Frs torsen diff on 14-15 is250
08-02-15, 01:08 PM
#1
Driver
Thread Starter
Tried and true! Frs torsen diff on 14-15 is250
Lexus did something great for the 3rd gen IS by utilizing the Lexus GS rear suspension. It handles remarkably well and turn in is crisp with no body roll. the steering response is incredible too but it doesnt have a limited slip differential.
The Scion FRS uses a Torsen Differential. my goal was to use a FRS diff in a 3is 250F. I service toyota/scions every day and i gathered up information, pictures and measurements on the diff before the transplant. i have access to TIS and techstream and i use that to get gear ratio, final drive ratio, planetary gear tooth count, pinion gear count, ring gear size and axle specs. FRS uses a 4.1 final drive ratio and Lexus Is250F uses a 3.7 final drive ratio. the FRS uses the same transmission in the Lexus is250F with the exact same 1st-6th gear ratio. i had done my research and it was time to locate a FRS Diff. i found a wrecked FRS on ebay. i bought the diff only 13,000 miles for 700 shipped.
the install is straight forward requiring a skill level of 6-7. tools needed 12mm, 14mm, 17mm, 19mm, 21mm, 22mm, air hammer, large prybar, ratchet, swivel sockets and impact gun.
i team up with 2 master techs at a Lexus dealer, im a toyota tech that supplied the info, the education on the product and for pure labor. Lexus techs use their shortcuts and tricks of the trade to remove and replace this diff in a snap of a finger. i was amazed how two different manufacturer techs work different from each other. We removed the passenger side complete hub assembly with the brakes intact. a air hammer was needed to break the inner axle loose. I test fit the loose axle on the FRS diff and it was a fit. with the right passenger side axle removed we decided to drop the diff supported with a trans jack and move it towards the right. I pry the drivers side axle off and lowered the stock diff. approx time was 45 mins with the help of Lexus techs.
TRIED AND TRUE..
1st 3IS 250F with FRS Torsen diff.
FRS is a direct fit on 3is 250/F and 3is 250/F AWD.
2 performance bang for the buck?
A limited slip and a 4.1 final drive ratio. The limited slip is very useful for daily driving and hardcore spirited driving. i already did both. straight line stability did not change but acceleration increased by a little and cornering traction gives more confidence. the limited slip is quiet and gives off no noise or unwanted jerks, jitters and vibrations. This car is an automatic and the e-shift on it is great. The car comes alive in e-shift sport mode with TRAC off. with the Limited slip on i feel like it isnt fair to other cars because how great my car is now. Now cruising in 6th gear @80mph my rpm is at 2500, +400 rpm increase. it downshifts less and there is more power to move the car in 6th gear. MPG have dropped about 1mpg but the trade was worth it. dead stop acceleration have increased and exiting a corner is more lively. I have not drift the car yet, but i will.
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Japz (11-16-21)
08-02-15, 01:26 PM
#3
Driver
Thread Starter
08-02-15, 01:49 PM
#4
Awesome, professionally executed research! Could You share the part numbers required for this swap? Any spares/additional maintenance part to buy? And is any cutting/drilling of metal required or the parts are simple plug and play?
08-02-15, 02:13 PM
#5
Driver
Thread Starter
differential carrier assembly of 13-16 FRS Y38 auto or manual (same final drive ratio)
its a direct remove and replace. 541 motorsports have good deals on low milege diffs for 600-750 shipped.
08-02-15, 02:22 PM
#6
You mean that the whole unit pictured below is a direct replacement:
And I don't have to dig into internals and the take out the Torsen mechanism:
Did I understand right? )
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08-02-15, 02:36 PM
#9
08-02-15, 02:49 PM
#10
Driver
Thread Starter
the whole carrier assembly brand new is $3500 from toyota parts. For $700 it is worth the money. the car feels more planted to the ground. Im waiting for a thunder storm. it should perform great in both wet/snow road condition.
08-02-15, 05:18 PM
#12
Driver
Thread Starter
y38 diff is the factory unit on 13-16 scion frs (torsen)
3.9 gearing was on the 01 is300 automatic trans (LSD) opt.
you can simply gut out the frs diff and use the torsen in your lexus is250. adding more shims or more less i wouldnt know. i went with the 4.1 final gear to fill in the hiccups of the is250. it revs high but slow.
08-02-15, 05:58 PM
#14
Tried and true! Frs torsen diff on 14-15 is250
Originally Posted by LexoDAV
Y32 diff is the factory unit on 14-15 is250
y38 diff is the factory unit on 13-16 scion frs (torsen)
3.9 gearing was on the 01 is300 automatic trans (LSD) opt.
you can simply gut out the frs diff and use the torsen in your lexus is250. adding more shims or more less i wouldnt know. i went with the 4.1 final gear to fill in the hiccups of the is250. it revs high but slow.
y38 diff is the factory unit on 13-16 scion frs (torsen)
3.9 gearing was on the 01 is300 automatic trans (LSD) opt.
you can simply gut out the frs diff and use the torsen in your lexus is250. adding more shims or more less i wouldnt know. i went with the 4.1 final gear to fill in the hiccups of the is250. it revs high but slow.
