The Lexus IS300 (welded) Differential swap.
 

This isn’t going to be a how to thread. But more or less my experience with doing this swap on my own Frs. The pros and cons with doing this swap. Tips and advice for the swap and information that will hopefully determine whether or not this modification is right for you.

Obviously this is geared towards drifters.


$$ Let’s talk money $$


The obvious better choice (than a welded differential)

A true 2-way differential $900-1000
Change the gearing (final drive)(ring and pinion)to better suit your needs. $700-900
Labor to have everything properly installed $500-1000

So for A true proper rear end you’re looking at $2100-2900!


The Lexus IS300 open differential (m96)

2001-2005 Lexus is300 open differential A/T or M/T. Part number designation (m96)
Final drive: 3.909 (Frs is 4.10). So you’ll have slightly longer gearing
(I have approximately 3-4 more mph to work with while in 2nd gear on my home track)

$$price$$ you can find a m96 on eBay or in a junkyard from $150-300
If you can weld you can save some cash. If not, expect to pay a professional welder 50-150 to have it welded up.

Total cost $ : $200-$450

https://www.ft86club.com/forums/pict...ictureid=11459

The Lexus m96 and the frs/brz differential have very slight differences. But with that being said the m96 is a direct swap with no modifications needed.

However!!

If you plan on replacing the pressed in forward (driveshaft side) bushings. There is a difference in the inner diameter (ID).

Frs id is approximately 60mm
M96 is approximately 57mm

3mm may not seem like a lot. But diff bushing that work for the frs diff will be to big for the Lexus IS300 differential

While doing the swap I also changed my diff mounts to PBM solid mounts. If you have access to a lathe, turning down the pbm aluminum solid mounts from 60mm to 57mm is easy as pie. You could even use a bolt as and arbor to hold the bushing. Mount the bolt to a drill press. And use a file to to remove the necessary material.

Here is a picture for reference.
https://www.ft86club.com/forums/pict...ictureid=11463

Pro’s/con’s

Pro’s
-inexpensive
-easy to do
-wheels will lock no matter what
-will make drifting easier/better
-great for a budget drift car

Con’s
-it’s a welded differential
-it’s noisy
-it’s clunky
-it will put additional stress on other driveline components (DS,axles,clutch)
-tight turning is annoying
-not a great idea for a daily driven car
-did I mention it’s noisy?

So you’ll have to prioritize what you want from your car before making this change. However you can literally swap our differentials out in about an hour.

Hope this hase been helpful. Dan @_southwell_86

IS300 diff pre welded.
https://www.ft86club.com/forums/pict...ictureid=11464

After the IS300 diff was welded.
https://www.ft86club.com/forums/pict...ictureid=11461

Lexus is300 diff with modified PBM solid bushing installed. Not that the side shafts are removed and our oem axles take thier place.
https://www.ft86club.com/forums/pict...ictureid=11462

Is300 diff mounted to Frs subframe. Note that the side shafts have been removed from the is300 diff
https://www.ft86club.com/forums/pict...ictureid=11453


Pre IS300 diff and subframe refresh.
https://www.ft86club.com/forums/pict...ictureid=11452

Finished product.

https://www.ft86club.com/forums/pict...ictureid=11450

https://www.ft86club.com/forums/pict...ictureid=11454

https://www.ft86club.com/forums/pict...ictureid=11449


Hope this helps some of you guys out!

Party on!

https://www.ft86club.com/forums/pict...ictureid=11460

Sweet!!! But... I'm only concerned about the final drive ratio difference.
Especially on 2017+ manual 86/BRZ cause stock diff has 4.3 final drive and IS300 has a 3.9 one...
Any issues with the TC/ABS/VSC?
The ECU speed sensor gets the signal from the transmission output shaft right?
At the same time (as I understand) the ABS is monitoring each wheel separately by the signals from the wheel speed sensors..
Will that speed difference make the ECU to freak out?
The difference between 4.3 and 3.9 is 9.3% seems a bit to high...

Swap out the final drive for the one you want.

No, speed signal only comes from the individual wheel speed sensors. I have a 5.29 final drive and ABS/TC/VSC works.

I have had zero issues relative to what you’re asking about. But with that said I do run the beattronix box thingy.

Who makes a 5.29 fd??

Weir Performance

Nitro Gear does as well IIRC. About to install one of their 4.88 kits.

I love my 4.88!

Question if I may

Would that be the 1992-95 Toyota 4runner ring and pinion?

I have an IS300 5MT that originally had an open diff which I swapped for an LSD. I'd be willing to sell the open diff for $150 if someone is in Jacksonville and wants to pick it up. Not sure what it would cost to ship an ~85lbs diff.

I really don't know if it's the same.. You would have to ask Weir Performance or check part numbers..

I was trying to find this out by looking at part numbers myself back then and couldn't find any conclusive evidence that they were the same..

Pictures are gone dude :eyebulge:

Could you upload them again? :-)