edhohoho

I've been contemplating on upgrading to LSD on my automatic IS250. I don't know a whole lot about this so I was wondering if forum members can help me.

1. For those who had performed the upgrade, was there a significant improvement in handling compared to stock? How would you say the improvement this upgrade provided compares to things like sway bars, RR Racing USRS, ISF steering ECU upgrade, F Sport struts/springs?

2. I read that the LSD from the FRS/BRZ can be used in the IS250. Is this an exact fit replacement? Do any modifications need to be done? What should I look for when buying one of these?

3. There are aftermarket LSDs available (GIken, Cusco, OBX, TOM'S), has anyone had any experience with them? Are there any brands that are known to perform well and be of good quality/durability?

4. Most aftermarket LSDs only provide the internals, do they simply drop into the OEM housing/pumpkin? Do any parts from the original need to be retained or modifications made?

5. About how much would it cost to have an LSD installed? On the TOM'S website, it says the approximate amount of time for installation is 10 hours. Based on hourly rates for mechanics, that would cost more than the LSD.

6. I live in Los Angeles, are there any shops in the area you would recommend to do this type of work?

Thanks.

Kmasyl

iTrader: (2)

What are you trying to accomplish? Is your 250 boosted or way over stock power levels? Even with the open diff I rarely have traction issues on my ovtuned 350. I suppose on a track I may benefit.

Sorry I can't answer any of the questions asked.

kolyan

If you track, yes there is an improvement, if you have lots of power you will also benefit, its a good weather aid as well. Stock 250 is too weak to have any traction issues

Jeff Lange

iTrader: (1)

There are a great many situations when a limited slip differential is beneficial, not just power related. There is a reason LSD was option in the AE86 with all of its 112hp, or the IS300 which has similar performance to the IS250 as well.

I loved the Torsen LSD in my IS250, it doesn't behave quite like a clutch-type, but it was a fantastic addition to the car, both on and off the track.

Jeff

redspencer

iTrader: (1)

1. For those who had performed the upgrade, was there a significant improvement in handling compared to stock? How would you say the improvement this upgrade provided compares to things like sway bars, RR Racing USRS, ISF steering ECU upgrade, F Sport struts/springs?

It really depends on the type of differential that you end up buying (torsen or clutch). Much like the other upgrades like sway bars, coilovers, etc, the goal of the LSD is to help maintain traction on the road though while the other upgrades help to keep the tires flat on the surface for maximum tire contact, the LSD will help transfer torque to the tire that has the most traction (typically the outside wheel when cornering). For the most part, there is a big performance difference between torsen and clutch differentials but there's also a noticeable price difference between the two types as well (plus maintenance requirements depending on the clutch diff brand).

2. I read that the LSD from the FRS/BRZ can be used in the IS250. Is this an exact fit replacement? Do any modifications need to be done? What should I look for when buying one of these?

For the IS250, you can use the LSD from the FRS/BRZ, the IS300, or the MKIII Supra (I forget which one as I believe both a torsen and clutch type were once available for the MKIII Supra). We had some install threads on this discussion previously so that should help if you can find them.

3. There are aftermarket LSDs available (GIken, Cusco, OBX, TOM'S), has anyone had any experience with them? Are there any brands that are known to perform well and be of good quality/durability?

OS Giken is the top tier of the LSD options but is also the most expensive to obtain.
Cusco offers a clutch diff as well but requires a rebuild after a certain amount of miles (OS Giken LSD does not require a rebuild).
I think the TOM's LSD is a torsen type but the price to obtain one would make it cost-prohibitive for the performance it provides.
Here's an excellent review thread of the OS Giken differential which includes feedback from IS-F owners and myself:
https://www.clublexus.com/forums/cl-...on-thread.html

4. Most aftermarket LSDs only provide the internals, do they simply drop into the OEM housing/pumpkin? Do any parts from the original need to be retained or modifications made?

Yes, the aftermarket LSD should be a simple drop-in for the OEM pumpkin. FIGS engineering did a great write-up on what to look out for during installation:
http://figsengineering.blogspot.com/...-lock-tcd.html

5. About how much would it cost to have an LSD installed? On the TOM'S website, it says the approximate amount of time for installation is 10 hours. Based on hourly rates for mechanics, that would cost more than the LSD.

You're looking at a 8-10 hour install time for the LSD (depends on the shop).

6. I live in Los Angeles, are there any shops in the area you would recommend to do this type of work?

You can try posting this question on the SoCal subforum to see if they can help:
https://www.clublexus.com/forums/cl-...alifornia-149/

Hope this info was useful to you!

kolyan

But the difference between AE86 and IS250 is that AE86 was lightweight sports compact car back then (fast too for the 80s) and IS250 is a heavy slow family sedan.

redspencer

iTrader: (1)

The IS250 has a relatively slow straight-line performance by today's standards but with the proper suspension upgrade, the IS250 can handle as well as the IS-F with comparable skidpad and slalom figures (as noted in the below test video). A limited slip differential would enhance the performance handling capabilities of the IS250 even further.

kolyan

Hence the 1st 2 replies. For track use and/or with track setup anyone will benefit from LSD. In 2006 250 was slow too.....my 1995 Maxima was a rocketship in comparison. (came with LSD too in Canadian models....as a weather aid I think)

PS. thats a whopping $12,500 F-sport package on that 2008 IS F-sport 6-speed manual, combined with $1,400 X-Package which I assume drops the suspension. $14k total in OEM performance mods (power and handling etc) I am surprised V8 was not an option for another $10k or so

Gville350

iTrader: (10)

Find a good, used FRS/BRZ rear carrier and run with it!

edhohoho

Thank you! Super helpful.

I am am a little concerned about maintenance issues for the LSD. Supposedly viscous type doesn't require rebuild but I don't see any of this type readily available.

What does 1.5 and 2 way mean?

redspencer

iTrader: (1)

You definitely don't need the entire F-Sport catalog to make the ISx50 handle as well as an IS-F. The shocks/springs (or coilovers), sway bars, and chassis brace are sufficient to transform the ISx50 into a formidable corner carver (at around $2k in parts). Also, instead of spending nearly $6k for the F-Sport BBK, an IS250 owner can upgrade to the IS350 brake set-up for a few hundred bucks (much like Jeff Lange did with his Lexus).

Yup, this is my recommendation as well as they are fairly easy to acquire. I see differentials for sale all the time in the classifieds section of the ft86club forums.

Yeah, I'm not sure if a viscous type differential is available for the IS250. A torsen differential would be the most economical option and would require the least amount of maintenance (simply change the differential fluid every 30k-60k miles).

1.5-way and 2-way refers to the lock-up rate of the differential when accelerating or decelerating. You'll want a 1.5 way for daily driving and for track use. A 2-way differential is recommended for future Drift Kings wanting to compete in Formula D.

Gville350

iTrader: (10)

There's a good explanation by Kaaz on this topic at the very bottom of this page : http://www.kaazusa.com/tech_intro.html

edhohoho

Is there anything special that needs to be done if you buy the differential innards and put it in the original housing or a replacement housing? Is it simply drop in or does there have to be some adjustments/setup/calibration? Do all differentials from 2006-2013 fit the same? Where can I get new seals and such to recondition an old housing?

Gville350

iTrader: (10)

If you were to just purchase the LSD and nothing else AND assuming your current carrier is in good shape (no leaky seals), you'll need to properly shim your new LSD into the used housing and apply new high temp RTV to re-seal the diff cover. Not to mention whatever diff fluid necessary to refill the carrier. Oh, new crush washers for the carrier would be recommended as well.

edhohoho

If I brought the LSD innards to the mechanic, will they automatically do the shimming, re-sealing and fluid? Are seals and washers fairly standard or do they have to be ordered from OEM? I wonder if the 8-10 hour installation includes all this or just removing the old diff and putting in the new one.

I've read that using genuine Giken fluid for a Giken diff is best. So many variables. Man, I wish I knew more about cars and were mechanically inclined.