Clutch pack diffs for FDs
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From: Japanabama
Clutch pack diffs for FDs
Can anyone point me in the right direction for what brand, type, and initial torque setting will make my FD as fast as possible on the track without too much understeer?
I haven't played around with it much to make it the fastest setup as possible, but I have had good success on track with my Cusco RS 1.5way set to 100% torque setting.
You'll have some reading to do, but this should be a good guide to get you going
https://www.cusco.co.jp/en/pdf/LSD%20Guide%20Final.pdf
You'll have some reading to do, but this should be a good guide to get you going
https://www.cusco.co.jp/en/pdf/LSD%20Guide%20Final.pdf
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From: Japanabama
I haven't played around with it much to make it the fastest setup as possible, but I have had good success on track with my Cusco RS 1.5way set to 100% torque setting.
You'll have some reading to do, but this should be a good guide to get you going
https://www.cusco.co.jp/en/pdf/LSD%20Guide%20Final.pdf
You'll have some reading to do, but this should be a good guide to get you going
https://www.cusco.co.jp/en/pdf/LSD%20Guide%20Final.pdf
Installed back in 2005, I don't have the measurements before install. I am generally good with documentation but not that good
To get you in the ballpark, the initial torque setting on the RS 1.5way is a range of 51-65 ft-lbs
To get you in the ballpark, the initial torque setting on the RS 1.5way is a range of 51-65 ft-lbs
Senior Member
Joined: Oct 2006
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From: SoCal
Never go full lock on these japanese LSDs.
Some good info here:
https://motoiq.com/project-nsx-part-...-differential/
https://motoiq.com/watch-how-the-os-...ow-to-tune-it/
Some good info here:
https://motoiq.com/project-nsx-part-...-differential/
https://motoiq.com/watch-how-the-os-...ow-to-tune-it/
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From: Japanabama
There's a used 1/2-way Kaaz I could snag for about $300 about an hour away, but I wonder if I wouldn't regret it after pulling the thing apart for a rebuild, given that labor will cost more than the diff itself.
A new one would cost about $700-800, and in that case I would get a 1.5-way.
The accepted ultimate is OS Giken Super Lock LSD and we in usa purchase the usa locking spec part number for our style driving (less drift biased).
The OS Giken super lock has the highest # of clutch platesof any diff so it can operate in the "grey" area (not fully locked) the best.
My experience-
I hated my FC stock clutch type because it locked hard and gave on throttle understeer unless you powered over into oversteer.
I swapped it out for an FD Torsen for autox. That worked well at 300ftlbs torque, but when I went EFR and 400ftlbs torque the bias ratio was not high enough and it drove like an open diff. Which would kick to the less loaded side on the freeway- sketch.
So for my FD, I put usa spec OS Giken super lock in. It is amazing. One can get on the gas before the apex and drive through the corner with no understeer. Very controllable throttle steer.
I hate understeer and carefully tune my FD so it never understeers.
My FD specs are 0 toe F/R, -2.5 deg F camber, - 1.4 R. Stock R1 rear swaybar, lightest available Tripoint F bar (they told me it is lower rate than stock R1 bar), ohlins 11k/11k and 295-315 front tire 9n 18x11 +45 and same rear.
With OS Giken I will have to add some rear camber now because you get full power to the rear wheel still on the ground (when you are 2 wheeling transitions) instead of the torsen bias ratio slip limiting rear weight transfer/accel.
The OS Giken super lock has the highest # of clutch platesof any diff so it can operate in the "grey" area (not fully locked) the best.
My experience-
I hated my FC stock clutch type because it locked hard and gave on throttle understeer unless you powered over into oversteer.
I swapped it out for an FD Torsen for autox. That worked well at 300ftlbs torque, but when I went EFR and 400ftlbs torque the bias ratio was not high enough and it drove like an open diff. Which would kick to the less loaded side on the freeway- sketch.
So for my FD, I put usa spec OS Giken super lock in. It is amazing. One can get on the gas before the apex and drive through the corner with no understeer. Very controllable throttle steer.
I hate understeer and carefully tune my FD so it never understeers.
My FD specs are 0 toe F/R, -2.5 deg F camber, - 1.4 R. Stock R1 rear swaybar, lightest available Tripoint F bar (they told me it is lower rate than stock R1 bar), ohlins 11k/11k and 295-315 front tire 9n 18x11 +45 and same rear.
With OS Giken I will have to add some rear camber now because you get full power to the rear wheel still on the ground (when you are 2 wheeling transitions) instead of the torsen bias ratio slip limiting rear weight transfer/accel.
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Thread Starter
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From: Japanabama
The accepted ultimate is OS Giken Super Lock LSD and we in usa purchase the usa locking spec part number for our style driving (less drift biased).
The OS Giken super lock has the highest # of clutch platesof any diff so it can operate in the "grey" area (not fully locked) the best.
My experience-
I hated my FC stock clutch type because it locked hard and gave on throttle understeer unless you powered over into oversteer.
I swapped it out for an FD Torsen for autox. That worked well at 300ftlbs torque, but when I went EFR and 400ftlbs torque the bias ratio was not high enough and it drove like an open diff. Which would kick to the less loaded side on the freeway- sketch.
So for my FD, I put usa spec OS Giken super lock in. It is amazing. One can get on the gas before the apex and drive through the corner with no understeer. Very controllable throttle steer.
I hate understeer and carefully tune my FD so it never understeers.
My FD specs are 0 toe F/R, -2.5 deg F camber, - 1.4 R. Stock R1 rear swaybar, lightest available Tripoint F bar (they told me it is lower rate than stock R1 bar), ohlins 11k/11k and 295-315 front tire 9n 18x11 +45 and same rear.
With OS Giken I will have to add some rear camber now because you get full power to the rear wheel still on the ground (when you are 2 wheeling transitions) instead of the torsen bias ratio slip limiting rear weight transfer/accel.
The OS Giken super lock has the highest # of clutch platesof any diff so it can operate in the "grey" area (not fully locked) the best.
My experience-
I hated my FC stock clutch type because it locked hard and gave on throttle understeer unless you powered over into oversteer.
I swapped it out for an FD Torsen for autox. That worked well at 300ftlbs torque, but when I went EFR and 400ftlbs torque the bias ratio was not high enough and it drove like an open diff. Which would kick to the less loaded side on the freeway- sketch.
So for my FD, I put usa spec OS Giken super lock in. It is amazing. One can get on the gas before the apex and drive through the corner with no understeer. Very controllable throttle steer.
I hate understeer and carefully tune my FD so it never understeers.
My FD specs are 0 toe F/R, -2.5 deg F camber, - 1.4 R. Stock R1 rear swaybar, lightest available Tripoint F bar (they told me it is lower rate than stock R1 bar), ohlins 11k/11k and 295-315 front tire 9n 18x11 +45 and same rear.
With OS Giken I will have to add some rear camber now because you get full power to the rear wheel still on the ground (when you are 2 wheeling transitions) instead of the torsen bias ratio slip limiting rear weight transfer/accel.
Rotary Freak
Joined: Jun 2005
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From: sydney
What's a 1/2 way, understood there's 1, 1 1/2 and 2 ways? Kazz units are probably the most popular over here for circuit work - mainly due to local support - less an issue there I'm sure!
I see a 1 1/2 out of a late car is on yahoo now and has dropped about 7k yen in the last week or two after having no takers for months. We bought one for 24k some years ago, plates were fine....if predominantly used by boy racers on the street as most of them are, might be worth a punt.
I see a 1 1/2 out of a late car is on yahoo now and has dropped about 7k yen in the last week or two after having no takers for months. We bought one for 24k some years ago, plates were fine....if predominantly used by boy racers on the street as most of them are, might be worth a punt.
Thread Starter
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Joined: Oct 2004
Posts: 5,176
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From: Japanabama
What's a 1/2 way, understood there's 1, 1 1/2 and 2 ways? Kazz units are probably the most popular over here for circuit work - mainly due to local support - less an issue there I'm sure!
I see a 1 1/2 out of a late car is on yahoo now and has dropped about 7k yen in the last week or two after having no takers for months. We bought one for 24k some years ago, plates were fine....if predominantly used by boy racers on the street as most of them are, might be worth a punt.
I see a 1 1/2 out of a late car is on yahoo now and has dropped about 7k yen in the last week or two after having no takers for months. We bought one for 24k some years ago, plates were fine....if predominantly used by boy racers on the street as most of them are, might be worth a punt.
The accepted ultimate is OS Giken Super Lock LSD and we in usa purchase the usa locking spec part number for our style driving (less drift biased).
The OS Giken super lock has the highest # of clutch platesof any diff so it can operate in the "grey" area (not fully locked) the best.
My experience-
I hated my FC stock clutch type because it locked hard and gave on throttle understeer unless you powered over into oversteer.
I swapped it out for an FD Torsen for autox. That worked well at 300ftlbs torque, but when I went EFR and 400ftlbs torque the bias ratio was not high enough and it drove like an open diff. Which would kick to the less loaded side on the freeway- sketch.
So for my FD, I put usa spec OS Giken super lock in. It is amazing. One can get on the gas before the apex and drive through the corner with no understeer. Very controllable throttle steer.
I hate understeer and carefully tune my FD so it never understeers.
My FD specs are 0 toe F/R, -2.5 deg F camber, - 1.4 R. Stock R1 rear swaybar, lightest available Tripoint F bar (they told me it is lower rate than stock R1 bar), ohlins 11k/11k and 295-315 front tire 9n 18x11 +45 and same rear.
With OS Giken I will have to add some rear camber now because you get full power to the rear wheel still on the ground (when you are 2 wheeling transitions) instead of the torsen bias ratio slip limiting rear weight transfer/accel.
The OS Giken super lock has the highest # of clutch platesof any diff so it can operate in the "grey" area (not fully locked) the best.
My experience-
I hated my FC stock clutch type because it locked hard and gave on throttle understeer unless you powered over into oversteer.
I swapped it out for an FD Torsen for autox. That worked well at 300ftlbs torque, but when I went EFR and 400ftlbs torque the bias ratio was not high enough and it drove like an open diff. Which would kick to the less loaded side on the freeway- sketch.
So for my FD, I put usa spec OS Giken super lock in. It is amazing. One can get on the gas before the apex and drive through the corner with no understeer. Very controllable throttle steer.
I hate understeer and carefully tune my FD so it never understeers.
My FD specs are 0 toe F/R, -2.5 deg F camber, - 1.4 R. Stock R1 rear swaybar, lightest available Tripoint F bar (they told me it is lower rate than stock R1 bar), ohlins 11k/11k and 295-315 front tire 9n 18x11 +45 and same rear.
With OS Giken I will have to add some rear camber now because you get full power to the rear wheel still on the ground (when you are 2 wheeling transitions) instead of the torsen bias ratio slip limiting rear weight transfer/accel.
How noisy is the OS Giken?
I've had my Tomei 1.5 set at full lock since install and it has always been a pain on the street and I've regretted going with it.
I'm even considering going back to the stock torsen for now.
I've had my Tomei 1.5 set at full lock since install and it has always been a pain on the street and I've regretted going with it.
I'm even considering going back to the stock torsen for now.
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Joined: Oct 2006
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From: SoCal
OSG and Carbonetics are more steeetable and "clunk" significantly less than Kaaz, Cusco, Tomei. All of which should be set and have at least one set of clutch plates deactivated to reduce lock for road course and especially street use.
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From: SoCal
Shortly after switching to the carbonetics i ordered an osg and i am currently planning to install it soon. The carbonetics has been on the car for about 4 months.
i hope that answers your question
I have been using the redline 80w-140 the green one. I had originally imported the 80w-250 from os giken.
first time i cracked the pumpkin os giken usa suggested the redline as the os giken oil is only available in japan
first time i cracked the pumpkin os giken usa suggested the redline as the os giken oil is only available in japan
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Joined: Oct 2006
Posts: 440
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From: SoCal
How many miles is 4 months and have you changed the fluid after you broke in the Carbonetics?
iirc, carbonetics recommends their 80W90 or similar weight for the initial break-in, and many people have had success with Motul Limited Slip 90PA.
Theyve been quieter than OSG in many S2000, 350Z and RSXs that I've driven.
iirc, carbonetics recommends their 80W90 or similar weight for the initial break-in, and many people have had success with Motul Limited Slip 90PA.
Theyve been quieter than OSG in many S2000, 350Z and RSXs that I've driven.
Last edited by Billj747; Jan 11, 2023 at 05:31 PM.
I was going to say, if you think the os giken diff is expensive wait till you have to buy the os giken diff fluid. And you do have to buy it.
I originally installed my os giken with motul as that is what came with it and os giken says you can use it in a pinch (2nd hand diff, but new/unused in box).
TeamRX8 pointed out how superior the os giken fluid spec is for viscocity with heat and all those clutch plates generate a lot of heat.
It drove better with OS Giken fluid, it had a stronger lsd feel.
How noisy is the OS Giken?
When I back out of a parking spot with the steering wheel turned hard one way it does clunk and frienda say the inside wheel locks/unlocks.
Other than that there are no noises/downsides. Nothing in forward gears.
I originally installed my os giken with motul as that is what came with it and os giken says you can use it in a pinch (2nd hand diff, but new/unused in box).
TeamRX8 pointed out how superior the os giken fluid spec is for viscocity with heat and all those clutch plates generate a lot of heat.
It drove better with OS Giken fluid, it had a stronger lsd feel.
How noisy is the OS Giken?
When I back out of a parking spot with the steering wheel turned hard one way it does clunk and frienda say the inside wheel locks/unlocks.
Other than that there are no noises/downsides. Nothing in forward gears.
