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I need some wisdom here. I am able to source LSD that would fit to my IS350. TOM hyper LSD. Problem is the LSD was install and fitted to a GS350 carrier and ringgear. Therefore, the final drive ratio is 3.77 if I am not mistaken
I know that the best solution would be to remove the LSD and install them to my is350 differential and get 4.06 final drive ratio.
But i dont have the skill for it. I can do the unit swap but not swaping internal parts.
I am afraid that the 350 will lost it neck snapping launch and acceleration across the rev range if I go with 3.77 ratio.
What do you think? Should I find the right machanic to do the ring gear swap? Is it hard to do? Or should I install it as is and try the 350 with 3.77 ratio
I need some wisdom here. I am able to source LSD that would fit to my IS350. TOM hyper LSD. Problem is the LSD was install and fitted to a GS350 carrier and ringgear. Therefore, the final drive ratio is 3.77 if I am not mistaken
I know that the best solution would be to remove the LSD and install them to my is350 differential and get 4.06 final drive ratio.
But i dont have the skill for it. I can do the unit swap but not swaping internal parts.
I am afraid that the 350 will lost it neck snapping launch and acceleration across the rev range if I go with 3.77 ratio.
What do you think? Should I find the right machanic to do the ring gear swap? Is it hard to do? Or should I install it as is and try the 350 with 3.77 ratio
All comment is welcome.
Before I talk about Option Option A), it would be nice to know if this LSD is smaller than the OS Giken and fits in the housing without modifying the housing.
If it does fit, you could do it or pay someone to swap the LSD became a lot easier. If it doesn't, it's a lot more work.
Option A, throw it in and try it. I've gone from 3.08 to 3.25, no real change, you notice the jump to 3.50, so this might be doable and ok for DD as >3.75 is pretty usable.
That said, if your OEM case doesn't need grinding to fit the Tom's LSD, plenty of shops can swap the LSD carrier into your 4.08 geared case. You could even pull the LSD so there is less labor.
Ask the owner if the case needed modification to fit this LSD. PS - what's it going for $$$?
Before I talk about Option Option A), it would be nice to know if this LSD is smaller than the OS Giken and fits in the housing without modifying the housing.
If it does fit, you could do it or pay someone to swap the LSD became a lot easier. If it doesn't, it's a lot more work.
Option A, throw it in and try it. I've gone from 3.08 to 3.25, no real change, you notice the jump to 3.50, so this might be doable and ok for DD as >3.75 is pretty usable.
That said, if your OEM case doesn't need grinding to fit the Tom's LSD, plenty of shops can swap the LSD carrier into your 4.08 geared case. You could even pull the LSD so there is less labor.
Ask the owner if the case needed modification to fit this LSD. PS - what's it going for $$$?
Thanks for your reply
I did more research and found out that the unit is in fact made from CUSCO and was sold by TOM's
There is no way I can talk to the seller cause he only speak Japanese. But I manage to get some picture. Maybe you could tell if he grind the carrier or no?
Price wise It is not bad around 300$ for the whole unit but I got to wait about a month for shipping time tho
There is no way I can talk to the seller cause he only speak Japanese. But I manage to get some picture. Maybe you could tell if he grind the carrier or no?
Price wise It is not bad around 300$ for the whole unit but I got to wait about a month for shipping time tho
Look here, you'll see what I mean about grinding the housing. Knowing it's a CUSCO, write them and ask about the install. What's the shipping cost? IIRC a new unit is only $1000 or there abouts....
My build thread has some stuff too... I have OS Giken but COVID messed up the install plans.
Post # 98 here... https://www.clublexus.com/forums/bui...nce-diy-5.html
#115, #120, #130 has the OS Giken boxed, #137 opened up... thread has stuff throughout. #216 the donor diff is cleaned and painted if that matters...
EDIT: Looking at that picture up there, it appear to be much smaller than the OS Giken, and should slip in without issues.
Some internal photos... I'm deleting some text but not nearly enough as there was some misunderstanding about what they shipped me.
Originally Posted by 2013FSport
Yep, TCD came earlier than expected and I am far from ready for the install. I have a holding fixture to make, tools to buy, and tools to make. For now, it will have to wait until I get my act together. A couple of teaser photos.
ORIGINAL LSD: TY391-HA Ramps - 25/38 | Lock Timing - 336 | Total Plates - 16 | Preload - 12S
Originally Posted by 2013FSport
OK, I opened it and inspected the innards. All is as documented with 16 plates for maximum surface area as none are deactivated by mating like plates. Here, it is about surface area and oil control so, other than the way the discs are locked (external = drive & internal = driven), they are all the same. Oil channels on one side and flat on the other.
One observation is that they ran an oil channeled driven plate directly to the surface of the pressure ring (inner locking mechanism with the 4 pinions) and the springs. See below.
As seen from pulling the cover off.
Steel on steel oil control disks, no fiber to degrade. Exterior tabs are drive plates. Interior splines are driven plates.
Flip the ^^ above stack and place it here vv. This is a wearing surface that I would not have used personally. Shown is 4 pinion spider gears inside the pressure ring. 12 of the 16 holes have springs and the cam timing is marked 25/35 on pinion gear shaft assembly.
I didn't open the pressure ring assembly. It has 12 springs in this application. Supposedly there are 3 different spring rates; 18kg, 28kg, and 38kg. Think in terms of less hold-off pressure applied would make the lock action apply quicker while stiffer springs will provide smoothest lock action and the softest spring would provide the most aggressive lock. Same is true of the higher quantity 16 vs 12. That said, the little V6 is not delivering 500hp so a line must be drawn that enables the cam assembly to lock on lighter power loads.
Pressure Ring Assembly with side gear in place:
Is the "12S" indicating the pressure ring has 12 springs?
At the bottom of the picture is a Belleville conical spring atop the disk pack. Reading finds there are 3 different cone springs available; 1.4mm, 1.6mm and 1.8mm. I wish I'd measured this when it was apart just so we know. The thicker the spring, the more preload is applied to the clutch packs. The stiffer the cone spring, the higher initial breakaway torque will be and the more the car will want to understeer off throttle or part-throttle.
Re-assembly is pretty simple. There are 4 bolts at low tension securing the unit together. Basically drop everything into the cover in the reverse order; cone spring, side gears, 8 plates, the pressure ring mechanism, 8 more plates, the side gear and the Belleville cone spring. Now drop on the other half and start a couple of bolts to draw the assembly together. It took many criss cross steps with the four bolts to compress the cone springs.
That's about it. Now to get it in the car....
Last edited by 2013FSport; 01-26-21 at 08:43 PM.
Reason: Added my own pic's past EDIT ...
Look here, you'll see what I mean about grinding the housing. Knowing it's a CUSCO, write them and ask about the install. What's the shipping cost? IIRC a new unit is only $1000 or there abouts....
My build thread has some stuff too... I have OS Giken but COVID messed up the install plans.
Post # 98 here... https://www.clublexus.com/forums/bui...nce-diy-5.html
#115, #120, #130 has the OS Giken boxed, #137 opened up... thread has stuff throughout. #216 the donor diff is cleaned and painted if that matters...
EDIT: Looking at that picture up there, it appear to be much smaller than the OS Giken, and should slip in without issues.
Some internal photos... I'm deleting some text but not nearly enough as there was some misunderstanding about what they shipped me.
thanks for the info
I am based in Thailand. Shipping won't cost much in total would not be more than 400$
A true locking diff was originally on my list, but I just don't have the time and I don't think I want to spend that kind of money right now. This is my daily so it cannot be down very long. I could buy a used transfer case and work on it over time, but it would end up sitting for a long time before I am able to get to it. Also I am seriously considering selling her and getting an LS460 in the next 3 years or so. This is not in stone, but I'm strongly leaning this way
01-26-21, 09:46 AM
Would you swap 4.06 opendiff to 3.77 1.5way LSD?
