O.S. Giken "DualCore" LSD

OptionZero

Haven't seen this discussed here; seems like discussion has centered on the 1.5 Way (plus cooling)

Apparently OS Giken makes version called "DualCore" which is a Torsen combined with a clutch-type diff. With wheels on the ground, it acts like a Torsen; if a wheel lifts, it locks and becomes a clutch type:

https://www.osgiken.co.jp/DualCoreLSD/

It is listed as available for Z34 (if i'm reading this correctly)
https://www.osgiken.co.jp/pro_lsd/nissan.php

Almost new reviews available in English

Thoughts on this?

It may simply come down to whether it locks hard enough on power, but in theory this seems good for cars that see track/street duty.

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Rusty

This is news to me. Sounds like a good idea.

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Rjk370z

Sounds like someone is shopping for a lsd.

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Tractionless

How often does a wheel lift?

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filip00

If you push it, basically on every tight hairpin.

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DarkJak

So this is suggesting the normal OSG will have less than 100% lock if a wheel is lifted. It hasn't bothered me, but seems like it'd add just a tad more consistency.

The only time I've noticed wheel slip under wheel lift is low load lift like angling up a driveway. At the track, I think the lift has been short enough that I can't tell I'm spinning the inside slightly, because I'm still getting power to the outer wheel.

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OptionZero

If i'm reading you correctly, you're saying the normal OSG 1.5 way clutch type won't lock at low speed situations?

but this Dualcore version will, due to its gear type engagement on acceleration?

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Spooler

No, it locks all the time. That's what I saw at the Tail of the Dragon. Now, If you have 900whp you can have the 1.5way tuned by OS Giken in the states. I had my last diff tuned by them for 900whp. It is only $150 to have it done. It is tuned in California. Why did I have it tuned? Because my old 3.69 OS Giken diff would one wheel peal on me in the right conditions. The only downside is the OS Giken diff fluid won't help the LSD shuffle under tight turns. You got to give to get sometimes.

filip00

As a 1.5 OSG owner let me chime in.

At super slow speeds, doing a parking lot turn, the inner wheel sometimes locks up and chirps. Not often, but sometimes.

If it's a normal corner, drifting is easy, controllable, both wheels lock up as they should, all good.

BUT. There is a situation where the OSG is not acting well.....namely, uphill hairpins. Whenever I was driving an uphill hairpin, and if I approach it normally, slightly too quickly and want to just powerslide through it, the inner wheel WILL SPIN for a brief second, after which it locks up, and spins the outside wheel, acting normally. But this will happen. And I tried and tested it over and over. It's just how it acts.

My preload is factory:

338kg of negative preload (Pressure preventing lockup)
25/38 degrees ramps (coast/accelerate) Angle of 10 active clutch plate sets.

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Tractionless

Good to know, I'll have to keep my eye out for some pics!
It actually happened to me this weekend in a parking garage with a large ramp elevation change and the OE LSD pulled the Z up on the LHS side wheel without issue haha.

At 102k miles on the OE LSD i'm figuring on it needing replacement in the near future but the subject OS Giken unit seems like overkill for spirited mountain corner carving.

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OptionZero

Filtering through Japanese sites and advertisements, here is the best description I could find. Unfortunately, it is from 2014, and it's from OS Giken USA's Corvette build:

https://www.corvetteforum.com/forums...ln-2015-a.html

What is the benefit of Dual Core?

Improved Turn-in
. When converted to a one-way configuration turn-in ability improves due to the decrease in static decel lock from the pressure ring. The benefit of the variable deceleration lock provides the stability under trail braking and corner entry.

Variable Deceleration lock
. Decel lock is now determined through the difference in
wheel speed. This compensates for the lack of initial decel ramp angle by going to a one-way configuration and allowing the helical side gears to engage the differential lock during cornering. The greater the wheel speed difference, the more the differential will provide locking. This lock can start at 0% utilizing our new zero preload option for Dual Core use.

Smoother Acceleration Lock
. The transition from deceleration locking to
acceleration lock is seamless. This is due to the helical side gears being active during cornering. As there is difference in wheel speed; the clutch plates are locking mid-corner at about 30% total lock. As you pick up throttle there is no abrupt action caused by differential locking. On some Super Lock applications slight wheel spin may occur during curb hopping maneuvers or when one wheel is off the racing surface. The Dual Core cures that and stays locked even when the vehicle is temporarily airborne.

***Our LSD's are fully tune-able; however, I must disclose that all tuning is done in house here at OS Giken USA. This is similar to how one would submit their shock absorbers (Penske, Moton, etc) in for service. Tuning parts are not sold to the general public. The reason for this is for the customer's ease of mind. We have the experience and data to be able to achieve the characteristics you want from your differential. Also the complexity of reassembly is much more than your typical clutch type differential. There are many little details that need to be followed in order to have a proper working diff. We have seen many units come back to us due to improper tuning that we would like to protect our customers by providing a service linked to the us directly. We want our customers to be fully satisfied with their unit and tuning is a daunting task especially for our units.***

MSRP for LSD Tune when purchasing a new differential is $150. MSRP for LSD upgrade will be $150 plus cost of parts. Please note that Dual Core will be available for the C5/C6 sometime late in the year transitioning to 2016 once full development and extensive testing (Track and Autocross) has been performed.

We are still in the process of firming up applications with Japan. At this time we do not have a set cost on upgrading LSD units to Dual Core at this time as we are still in testing phase. You will see release of various applications towards the end of the year and enter 2016.

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Tractionless

Good info. but seems like overkill for a canyon carver. In which case what would the member base recommend for streetability but proper lockup when mountain driving?

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Rusty

Wavetrac.

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Spooler

I enjoyed my OS Giken on the Tail of the Dragon. It's worth it in my opinion. Paying them $150 to tune my new one was money well spent. No more one wheel peels at 764whp and up. If my car spins now it goes straight. I have no more issues with it stepping out.

OptionZero

The OS Giken needs a cooler, though, which is another $1,000

I believe the Wavetrac doesn't need one. That's a big advantage


Speak of which

Since the "Dual Core" is a mix of helical and clutch . . . . do we think it will need a cooler?

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