Limited SLip Differential

Anyone Looking for a LSD for GDB/GRB?,

i have this brand new, not even open, OS Giken LSD sitting in my warehouse. customer flaked off on me. retail is $1590 USD. any one interested? this is for the rear LSD of GDB/GRB (EJ25). let me know if you are and i will get you a quote shortly.make sure to leave your email address if anyone is willing to leave a comment.

i will give you a OS t-shirt and a OS license plate frame with it!! lol

also, i still have those SARD RD-1 in my hands. let me know if anyone is interested as well.

USED GIAS Sport for Sale

damn i have a lot of seats in that corner lol

stock 350Z seats, the STRADIA Maziora test seats, leather ERGO II, and a GIAS Sport. o yea Kentz, 英語だとGANTZみたいw。そのうちクッション持って来てッw。昨日ジムの後言うの忘れたよ。ってなわけで宜しく。also there is ALFA ROMEO clutch from OS Giken too lol dont know why i have that clutch here. i think the flywheel is different though. gotta count the splines… and there’s a  Lamborghini’s movement alteration kit. o yea, and a 240SX LSD.

that GIAS Sport is for sale from my buddy. he had the seat for about 2 years now i think. the cushions are missing on the pic but no worries. he took it home to wash it real quick. there is a rip on the left bolster. heres a pic.

also, i didnt take pic of the shell, but there are some scratches. by the way, the shell is FRP. not the all black FRP fake Taiwan made motha fuckas.

is anyone interested? leave comment and your email addy so i can get back to you.

i’m currently selling those leather ERGO II and the red PROS as well and the 240SX LSD.


starting a day with a mechi-katsu sandwich, a clam chowder, and a ice coffee from MamMoth Bakery inside the Redondo Marukai 🙂

一日を始めるために、レドンド沿いのマルカイ内にあるマンモスベーカリーよりメンチカツサンド、クラムチャウダー、そしてアイスコーヒーをゲット 🙂

MamMoth Bakery

1620 W Redondo Beach Blvd

Gardena, CA 90247


and now on the 2 freeway, heading to Chevy Chase Dr. in Glendale. why? cuz i got the OS Giken LSD installed 🙂 take it out for a drive.

そして、高速道路の2号線に乗って、グレンデールにあるチェビーチェイス・ドライブに向かってます。なんでって?OS技研のデフが入ったからこれから試運転も兼ねて峠で遊んでくるとこッス 🙂

arrived at Chevy Chase Dr.


and here i go!!


poooooooowerrrrrrrrrrr shiiiiiiiiiiiiiiiiftttttttt!!! lol


gotta watch out for deers,


and horse-riders.


cigarette break on the side 🙂 lots of people were here i guess… lotta skid doughnut marks.

横でタバコ休憩 🙂 結構人が溜まってたんだろうね…定常円かましたタイヤマークがイッパイ。

went to go get some gas now, changed my camera settings to Tv. and Rd. 2!!


poooooooowerrrrrrrrrrr shiiiiiiiiiiiiiiiiftttttttt!!! again, lol


i hate this turn… arghhh


hahahha i look so fast… lol thanks to the OS Giken LSD, the car feels much more fun 🙂 unlike the other LSDs, the locking is smooth. the car will have its head inward and turns with the accel pedal control. i will something more detailed soon.

ウケる、俺超速そうじゃん…笑。OSのデフに感謝ですねぇ。車が全然楽しくなったよ 🙂 他のデフと違ってロックがガツンって効かないからいいね。車はアクセルのコントロールで頭入る感じになってきたし。もっと細かい事はそのウチ書きます。

on the way back, found a dog sticking his head out from the window.


a fun Sunday it was.



OS Giken Review

here is a quick email from OS Giken a while back.


If you have a chance, please check out the Feb. 09 issue of Grassroots Motorsports. An article concerning differentials is in there, comparing performance of the OS SuperLock, Kaaz, and the stock Torsen on an S2000. Needless to say, the SuperLock outperformed the competition and was the editors’ favorite of the 3.

Some highlights of the article:

“Essentially, the OS Giken provided the best of the two other differentials…”

“…he posted the fastest lap of the day when running the OS Giken…”

“Its very progressive lockup was just what our duo desired.”


Some things about the OS SuperLock that are not mentioned in the article:

          no break-in period required

          no need for rebuilds (with regular maintenance)

          as smooth as an open diff at low speed (no diff chatter), but still able to lock up to 100% under throttle

          no expense spared during manufacturing (raw-forged gears, heat-treated components, unique patented design)

OS Giken Limited Slip Differential

so why choose a OS Giken LSD? well, lets take a look at the picture below first.


***Courtesy of OS Giken/OS Giken USA***

and here is a random LSD i found online. i had to crop the name off since i will be talking shmack about it… lol hahahha well, i will save the shmack talking for later. please take a look at the picture below.


***Courtesy of Google Image Finder*** …lol

now do you see the difference? yes the number of the clutch plates, also known as the friction plates. OS Giken has twice the number of the plates inside the differential. and its springs in the pressure ring is to pull the two rings together unlike the others where it tries to keep it open as much as possible. with all the patent received mechanism, OS Giken’s LSD for lock 100%. below is the simple steps of how the OS Giken LSD works.


1.) the spring inside the pressure ring will switch from free to lock in split second.

2.) the drive force thats been flown from the engine to transmission will revolve the differential case, and at the same time, spins the pressure ring simultaneously.

3.) the pinion gears and the cross shaft will push open the pressure ring.

4.) the stretched open pressure ring will push out the pressure plates to lock.

5.) the pressure plate locks perfectly to rotate the side gear which is hot forged.

6.) the drive force will be transmitted to the drive shaft upon the rotation of the side gear. 


1.) プレッシャーリング内のスプリングがオープンとロックの状態を瞬時に切り替えます。

2.) エンジンからミッションを通って来た駆動力がデフケースを公転させてプレッシャーリングを回転させます。

3.) ピニオンと十字軸がプレッシャーリングを押し広げます。

4.) 広げられたプレッシャーリングがプレッシャープレートを押し広げてロックします。

5.) 確実にロックされたプレッシャープレートがサイドギア(熱間精密鍛造加工済み)を回転させます。

6.) 回転したサイドギアがドライブシャフトに駆動力を送ります。

one of the LSD out in the market is the same type as the OS Giken LSD since they use the OS LSD as for OEM. i’m not sure if they still do OEMs. i believe some people do know which company i am talking about. but still, the mechanism within the LSD is different. there is this one company that tried to make it like the OS Giken. not mentioning who though.. and this guys is the one i would like to bash on lol. here is how the story goes. one of the engineers went to this lawn mower factory in Okayama Japan with all the blue prints memorized (not completely though since he was doing minor works) and made a mock up of the differential. but of course the product was a complete fail. just kept on breaking. and yes they been doing more and more research. then one of te engineers have took all the tech info and started his own company. to fill in gaps of the quality, they used carbon fibers for clutches and differentials. not gonna mention who though… hahha this was long time ago. i bet some people do know about this pretty famous john dory in the industry. well, copy is only a copy even though they added their originality. they cannot copy the mechanism of their STSG (Spline Through Side Gear) and the LTCS (Lock Timing Control System). the number of the pressure plate and the diameter size is one and only from OS Giken. that is the reason why i recommend OS Giken LSD.

OSのデフと近い構造の物がマーケット内にあります。今はどうかわかりませんけど、以前はOSさんがOEMで卸していたので。知ってる人も多分多いでしょうねそのメーカーがどこなのか。でもやっぱ本物のOSの機構は違いますね。誰とは言いませんが一社似せようとした奴等が居ますねぇ。そこまで言いませんけどね(笑。話はこんな感じです。開発陣の一人が設計図を丸暗記して(完璧に覚えれなかった様ですねぇ)岡山県にある某芝刈り機の専門工場に駆け込んだらしいです。そこで似せたデフを作り始めたそうです。まぁ当たり前ですけど、失敗に終りました。それでも開発などを続けて行くウチに独立したそうです。技術の足りない部分は素材で補おうって事でカーボンを使用し始めたそうで。誰とは言いませんがねぇ…笑。もぅかなり昔の話らしいですよ。知ってる人も意外と多いでしょうねこの業界内はかなり狭いので。まぁ、所詮コピーはコピーです。OSの機構は簡単には真似出来ないでしょう。STSG(Spline Through Side Gear)やLTCS(Lock Timing Contorl System)とか。プレッシャープレートの枚数や直径の大きさはOSが群を抜いています。それが僕がOS技研をお勧めする理由です。