(310) 986-6620
Rebel Rock Racing - Grand Am
Porsche 996 GTS

We at Rebel Rock Racing would like to thank OS Giken and Gbox for a great partnership this season! The OS Giken differential that we used in our 997 GTS performed flawlessly all year long and proved it's durability. The unique design of this differential also made for great drivability on the track and helped tremendously with setup as it removed the typical understeer characteristics of a more traditional differential that we have experienced in the past. This has been a great addition to our race car and we look forward to a continued partnership in the future!

Kory Deason - NASA GTS-3
BMW M3 (E36)

Despite weather conditions and mechanical troubles, Korey Deason and his team competing in the NASA GTS-3 class with their OS Giken equipped BMW M3 (E36) were able to finish the weekend with an overall win for GTS class, and a new GTS-3 lap record!

Although starting at the pole and then re-acquiring the lead on day 1 by utilizing the faster corner exits possible with OS LSD, suspension problems ended up with tire failure and some repair work to be undertaken before the next day's qualifier and race. Thanks to the help of Kevin Deason and Kerry Mock, the car was repaired and prepped for Sunday's event and the weather cleared up as well!

Once again, the M3 took pole position in the qualifier (by an almost 2.5 second margin vs. the closest GTS-3 car!). For race day, Korey started at the pole and never lost position, landing him top podium spot and a new GTS-3 lap record of 1.25.064.

Congrats to the team on a stellar performance!

Vimeo video: Sunday race with win and GTS-3 course record


MiniDeck Motorsports (Rich Peterson) - USTCC
2004 Mini Cooper S R53

"The MINIDeck Motorsports #58 was entered in the 2nd round of the USTCC at Thunderhill Raceway Park in Willows, Ca. This was a 2 hour race scheduled for Sunday Morning in conjunction with the Western Endurance Race Championship.

The driver duties were split between team owner Rich Peterson and prior USTCC BMW driver Andy Chittum. Qualifying was Rich Petersons duties but was also his first time on track at Thunderhill. Andy will be driving the full two hours on Sunday with one pit stop planned.

As our qualifying was not up to the other drivers we were to start in 15th on the grid. Andy was able to get the #58 Mini with the new OS Giken limited slip differential up to 5th place but the MINI was penalized for excessive noise. We went back out and fought our way back uip but after ten laps again we were black flagged for excessive noise. Andy came into the pits and we made modifications to the exhaust and sent him back out. Andy fought and gained ground but around the 1 hour mark the 58 MINI was black flag, again for noise. The MINI was brought in and the exhaust pipe was hammered almost closed. This time it work and Andy start fighting his way might forward. By the end of the day we finished a respectable 5th. If not for the penalties for noise we should have finished on the podium.

Our lap times were comparable to the leaders, We attribute this to the new OS Giken LSD as well as the new OS Giken clutch. The car was real easy to point where we wanted it to go and then put the power down."

-Rich Peterson

Stewart Leask - XDC Series
1991 Nissan 240SX S13

"As I work more on my car setup and continue the chassis and suspension development it becomes more and more clear to me the work this specific differential does. I've always had to grown accustomed to other 1.5s and 2 ways that upon kicking immediately sail the car outwards - they're very sharp and abrupt. The way you have this differential setup for me allows me to calmly plant my car at an aggressive fast line via clutch kicking or absolutely toss it out with as much angle as it can hold. It all varies on my inputs and reacts and responds correctly to my every movement. I cannot thank OS Giken enough for choosing to work with me for the 2012 season. I feel as if you guys are a very integral part of this new-found aggressiveness the chassis has presented and I'm very grateful!"

-Stewart Leask

Justin Tsang - SCCA STX Class
2007 Mazdaspeed 3

"Mazdaspeed 3 has a huge problem getting traction out of the corner. Even removing the front sway bar and adding a big rear sway bar, the car still struggles to get out of the slow corners.

I was in need of a solution, and the OS Giken Super Lock LSD was the answer. With the OS Giken LSD I am able to get on the gas much earlier without spinning the tires. The OS Giken LSD also can pull the front end into the corner even when you are on the throttle, allowing you to stay on the gas throughout the turns. At first, I was worried that a clutch type differential would have a negative effect on the turn in, but the OS Giken LSD with its smooth engagement of the clutch plates allows the car to turn in freely. The OS Giken LSD also works great in the street; it is quieter than the OEM unit and does not make any sound even at full lock.

Overall, the OS Giken Super Lock LSD improved the performance of the car substantially. On an autocross course, this probably improved lap times by around 0.5 secs, which can be the difference between first place and mid-pack in autocross. In my opinion, this is a must if you are serious in competing in any form of racing with the Mazdaspeed 3."

Youtube: Justin Tsang

Media Racing Team - Canadian Touring Car
2011 Scion tC

Drivers Luc Lesage and Jocelyn Fecteau have been competing in the Canadian Touring Car Championship with OS Giken LSD-equipped 2010 Scion tC's. Despite the new tC going into this series as a new entry with no prior racing history, the team has been able to finish their events in the top tiers, with little/no mechanical problems.

Especially at tracks like the Circuit Gilles-Villeneuve which is particularly demanding on the cars, the tC was able to finish in the Top 7 while many of the other teams suffered from mechanical issues during the race.

As the season progresses on and the team gains valuable data and more experience, look to see them climbing up the ranks with the OS LSD providing reliable and consistent traction through the corners!

Keep updated on their progess via their Facebook page:


Orion Performance (Chile) - Rally Mobil
2010 Mitsubishi Lancer ES

OS Giken LSD is equipped to the Orion Performance Mitsubishi Lancer which is competing in the Rally Mobil series in Chile. They have taken first place in many of the rounds in the series, and are serious contender for series champion. Special congrats to Team Orion and Speed Addicted for all their efforts:

Another ORION's YouTube link: de Gavardo & Huidobro



Jarret Tamaye - NorCal Regional Champion 2010 (NASA PTE/TTE)
Mazda Miata

"Last year (2009), without the OS LSD I competed in just Time Trials and was able to get a regional win and place 3rd in Nationals. After installing the LSD in the off season, I was able to drop my laptimes significantly.
I've averaged about 3sec improvents in laptimes from last year to this. Granted I've made some other upgrades as well, but the LSD definitely has played a part.

The ability to put the power down under just about any circumstance AND be able to control it no matter how much grip or lack thereof has been a godsend.
This has also played a huge part in race situations where going into corners offline and getting as big a jump out of them are crucial to complete a pass. Being able to put the power down and easily control the car at the limit has helped immensely.
All of this helped me wrap up the Norcal Region PTE Championship this past weekend. My final race was in the rain and the car handled beautifully. I was even able to keep up with and eventually pass another Miata who was on Hoosier wets while I was on full tread RA-1's!

Thank you for a wonderful product and be sure to thank Bill Wilner of MiataRoadster for sponsoring me and showing me how much the LSD would help. It has done that and more!"

Mark Lin - CSCC Solo Sprint
2004 Acura RSX

OS Giken Racing Multi-Plate TS2A Clutch
(Pressed Steel Cover, Twin Plate, 184mm Clutch Disks)

"On July 20 event of the 2009 Mobil 1 Solo Sprint Series, I ran into some unforeseen problems.

Only having ran 10 minutes into the warm-up session, my car suddenly became very difficult to shift and soon after, became impossible to shift while the vehicle was on. My first instinct was that my friction disk broke allowing the clutch spring to pop out and jam between the pressure plate.

Upon pulling the transmission, I noticed that my assumption was correct. I needed a new clutch and fast seeing as I had a 2-day event coming up in just 2 weeks. OS Giken was able to provide me with support and rush shipping to get my car put together in time for my next event. I was assured that despite the clutch being a twin plate and unsprung, it would be fairly easy to drive while capable of holding much more power than I currently make on my K24A2 motor. I thought this would be a good route to take considering that if I decide to add forced induction; at least I would not have to worry about upgrading my clutch in the future. Of course, I was hesitant about using the clutch since my car happens to be my daily driver as well as my track car.

After the OS Giken twin plate clutch was installed on my car I took it out for a drive to break in the clutch and ensure everything was working properly. During the test drive, I was shocked. The pedal feel was only a little bit firmer than stock although having a much higher clamping ability. Also, unlike every other twin disk unsprung clutch I've driven, the clutch was easy to drive, easy to feather and had virtually no clutch chatter whatsoever. Here was a clutch that I could live with driving through rush hour traffic and capable of tolerating track abuse. The best part is now I don't have to risk popping out the clutch spring and ruining another track day. I would highly recommend anybody shopping for a performance clutch in any build stage for their car because the OS Giken clutch is both street-able and capable for the track.

When racing with the OS Giken twin plate clutch, it is very easy to rev-match and perform a smooth downshift. This is due to the characteristic of the clutch providing a positive feel and allowing the driver to feather the clutch resulting in smoother shifts to prevent unsettling the car's balance in a competition situation."

Super Lock LSD Spec-S

"Where do I start? I set a new personal best at Stratotech Park by 1.2 seconds. My old personal best set back in July 5 was 1:08.9 and my new personal best on August 3 was 1:07.7. The same timing system was used and for those who are curious, we used transponders with each driver having their own assigned transponder number.

To be perfectly fair and honest, several things was been changed since my previous personal best which was set 2 months ago. I recently got bigger tires (255/40-17 Dunlop Direzza Sport Z1 Star Specs) instead of my (245/40-17 Bridgestone RE-01R). The weather during the event was also cooler by 10 degrees Celsius and I had a slight change in alignment to make my car more stable. I ran the Star Specs with nearly full tread depth (9/32) and when I ran on my RE-01Rs, they were at about 4/32 tread depth.

Now the fun begins, how much time was gained with the OS Giken Super Lock LSD? Assuming that having tires 1 size larger, a cooler track day and a small change in alignment resulted in a 1 second difference in time, there is still a 0.2 second improvement. I don't know what other people think the recent changes account for in time, but I for one personally think the gains of changing to the OS Giken Super Lock LSD to be closer to 0.5 seconds.

When I was running on this differential, just like the clutch, I was very impressed and surprised at the same time. The OS Giken clutch-type LSD has one of the most clutch plates in the LSD on the market. The clutch operates smoothly and quietly just like OS Giken's clutch and the limit is easy to feel. One of the best characteristics of the Super Lock LSD, other than the quiet operation and smooth engagement, is under normal driving conditions and upon entering corners during competition, the LSD feels like the original OEM open-differential and does not cause the car to push upon corner entry.

The OS Giken LSD replaced my Quaife LSD and the gains are almost as significant as my Quaife LSD over the OEM open differential. One thing I noticed for sure was improved grip levels when I'm rolling onto the gas past neutral throttle. I was able to apply power sooner and harder and use the Super Lock LSD to help me hold my desired line while I unwind the wheel for corner exit. Another thing I noticed with the OS Giken LSD is it gives me the choice of running slightly different lines as the car would not push out as much under power. For certain corners, if I wanted the car to hold a tighter line, the LSD would allow me to do so. Although the OS Giken LSD costs more than my Quaife, the gains are well worth it and I'm glad I made the jump to upgrade to an OS Giken Super Lock LSD.

I would like to thank OS Giken for sponsoring me as the first driver and car in Canada. I would also like to thank VEX Performance for helping me with the installation. VEX Performance is located in Red Deer, ALberta, and is an OS Giken Dealer."

For more product information, contact OS Giken or VEX Performance. Some products are available but not listed so please inquire! To place a product order, contact VEX Performance. Shipping is available in Canada and the U.S.

Y. Matsuda - Porsche Club of America (PCA) competitor
1989 Porsche 911 Carrera Coupe

"In the past someone told me that since the 911 has the engine in the back, rear traction is excellent so you don’t need an LSD. I believed that Porsche designed the car with that in mind, and being an avid fan of the 911 I also believed an LSD was unnecessary. However, in 2006 when I started competing in Autocross with PCA, I gradually started to doubt that statement. Full brake turn-in on slow/moderate speed corners caused the rear to become unstable, and on tight corner exits the inside tires would lift, causing wheelspin and giving me a feeling that the car was not moving forward enough.

Whatever someone said to me about not needing an LSD was untrue.

Until then I had installed fresh shocks and a large torsion bar for suspension tuning, which helped to reduce roll and pitch. However, these additions did not change the basic handling characteristics. This continued to cause troubles for me for a while, and then I found out that a famous aftermarket LSD company called OS Giken was now available in the US. I decided that it would be a good time to try the SuperLock LSD during my next transmission overhaul.

The key point for me in choosing to go with OS was that the unit was constructed with very strong materials (heat-treated, matte finish steel case just like the ones used for pure race) and the fact that OS uses more friction plates than any other brand. In any case, after installing the unit, running at autocross and on track (Streets of Willow) proved to be excellent! Especially on track it is very noticeable that throttle can be applied much earlier on corner exits. Additionally, the attitude of the car on corner entry is much more stable on turn in, and it feels like I can safely push the car harder and deeper in the corners. Another benefit which was not expected is that my tire pressures don't climb as quickly throughout my runs, making air pressure management easier.

Since my 911 is daily driven, the quietness of the SuperLock during everyday use was really surprising, in a very good way. In Japan, I used to compete in a Datsun for gymkana events and I used a different companies clutch-type LSD. However, on any low-speed turns the diff would chatter and if I had a passenger in the car they would always ask if my car was broken! With the OS SuperLock, even on U-turns I get no chattering or noise from the diff, so it's been great both on the street and on the track!

I am very happy with my OS SuperLock; if I would have known how much of an improvement it would provide I would have installed it much sooner! So, to all 911 fans I would like to say that even though rear traction is excellent on our rear-engine cars, an LSD like the OS SuperLock is definitely necessary for high-performance.
And to all my competitors, I would like to say… Don't listen to me!"

Dan Gardner/Scott Web - NASA Pro WERC, SCCA World Challenge
Scion tC

"We selected OS Giken and the Super Lock LSD because of their reputation, especially in Japan. They don't believe in 1.5-way units for FWD applications, as that will cause the car to push on turn-in. This is the last thing you want in a FWD car. For FWD applications, the units are 1.1-way, meaning they are open on turn-in, and only go to lock once power is applied. OS also uses more clutch plates than just about anyone in the world. Unlike other clutch-type diffs, there is no need for them to be rebuilt and no need to break them in; once it is installed it is ready to race!

Under spirited driving, this diff is second to none. It has virtually eliminated wheelspin in our Scion tC road race car. In a FWD car, getting the power to the ground is one of the most important elements for going fast. With the OS Super Lock, throttle can be applied earlier and to a greater degree, which results in very real laptime reductions. The car is a rocket out of the corners, and the power just gets down to the ground once locked up. Hills, rises, tight hairpins, nothing seems to affect the diff. It just works! Unlike some other diffs, when the inside or unloaded tire lifts in the air or gets light, the diff still remains locked, sending power to the outside tire that has grip. Some other LSDs will just go back to an open configuration under this condition, and plenty of wheelspin is the sole result.

OS is a great engineering company. Hardcore racers know their name, and their products are geared towards those who are truly seeking to get the best performance out of their vehicle. This is a huge performance upgrade over the stock tC diff. The forced induction crowd really shouldn't be without it, and even NA cars can benefit significantly. Even if you're not a die-hard racer, this diff will help you put the power down during spirited drives and AutoX outings as well."

Dan Gardner
Driver and Team Manager
Jackson-Dawson Road Race Scion tC
NASA Performance Touring National Champion 2009

"When I first joined the Jackson-Dawson team Dan Gardner and I sat down to discuss the characteristics of the car. One component he brought to my attention was the OS Giken Super Lock LSD. He mentioned that they had done considerable development to get it just right, and that I would be impressed with its ability to enable early and aggressive power delivery. Having driven several front wheel drive race cars before, I didn't think much of it until I started getting up to speed in the car. I don't know what kind of special sauce OS Giken puts into that diff, but boy am I impressed! In the middle of my stint at Thunderhill I found myself bemused at just how amazing the car behaved at the exit of Turn 9 (running clockwise) where the road falls away beneath you after the braking zone. Whereas most FWD cars would understeer with an aggressive application of throttle, our Scion tC would actually tighten its line. It's like magic, and makes the car so much more capable and fun to drive. Well done!"

Scott Webb
Co-Driver, Scion tC Road Race Car
WERC Endurance Series, E1 Class

Cheston Chiu - Sports Compact Car Ultimate Street Car Shoot Out '08
Nissan 350Z Z33

"When preparing my twin-turbo Nissan 350Z for Sport Compact Car Magazine's Ultimate Street Car Challenge, I wanted a robust and durable clutch system that would be able to sustain the abuses from the various performance tests. OS Giken's TR2CD Twin Plate Racing Clutch performed flawlessly for me. The TR2CD weighs lighter than the OEM stock clutch & flywheel assembly and has a similar pedal feel which resulted in easy driving around town and noticeably faster engine revs on the track without slippage when max boost pressure was engaged.

With little or no clutch chatter noise and the holding power, the TR2CD is ideal for high horsepower, high torque cars that are meant for both street and track duties. Along with the TR2CD, I also invested in the OS Giken Super-Lock 1.5 way LSD. The multi-plate design of the Super-Lock LSD is truly fantastic! It allows for super quiet operations (i.e. NO ping/popping noises) during low-speed, high angle turns and fairly predictable differential locking during hard acceleration and deceleration on turns during the lap time battle (in which the Z won, and I credit partially to the superior designs of the OS Giken Parts). With the wide variability in the adjustment of lock amount, the Super-Lock LSD can be customized to whatever motoring event I plan on doing, either Time-Attack or Drift-- having one unit that can be adapted to multiple uses is not only an economical choice, but also practicality.

I am very pleased with the manufacturing quality and installed performance of my OS Giken parts I have in my 350z. Thank you for helping bring my Z to the podium!!!"

Justin Pawlak - Formula D Pro
Mazda RX7 FC3S

"I'm very excited to be working with OS Giken this season! After switching to the OS super lock differential I realized how much of a difference a "tunable" differential makes. Being able to make changes to the locking time in the diff, helps give me an added advantage over the competition. It's very easy to change the differential from either a 2-way or a 1.5-way lock up.

After making adjustments to the differential it's nice to actually be able to "feel" the changes made, and to be able to "tune" it for each course and competition. Compared to other differentials I've driven on, the timing consistency of lock-up is very predictable based on how I've "tuned" it to be. Overall, the build quality compared to other differentials I've used is over and above the others, the quality and precision of each component is amazing and before I even used the differential I could tell it was going to be a quality product.

Also, I've been using a OS Giken twin disc clutch since 2004, since I began drifting. I have just recently rebuilt the original clutch that lasted over 3 years, being abused weekly, along with being driven daily for two of the years. I'm definitely amazed on how much abuse this clutch has taken, and how long it has lasted. Even though the clutch can hold over 450whp the pedal feel is much like stock, and the engagement is very smooth and consistent. Also the engine response is quicker because of weight of the clutch/flywheel assembly.

I would like to thank the OS Giken team for helping me out this season, and providing me with quality components to improve my drift program. These quality parts have helped me, in my rookie season, place in several top 16 positions, along with recently winning the Formula D Mexico event and placing 3rd in the championship event in Irwindale, CA."


Taka Aono - Formula D Pro
Toyota Corolla AE86

"For this season the Falken AE86 used 1.5 way diff and went through four different final drive gear sets(4.9, 3.9, 4.1, and 4.5 ). Every time when we open the diff carrier, we inspected LSD unit and did not find any sing of wear or issues. These disc plates thickness did not change, and inner spring length stay the same as new springs. When I was driving, I could not feel any loss of performance from LSD operation which is commonly able to feel from conventional LSD unit after 2~3 events.

Performance of Super Lock LSD on track is, as usual, the best! Consistency of the lock capability and timing is the key for professional drift competition and OS diff always promise me the consistency. (Some top team has to run welded diff to get the consistency!!!)

The ability to change lock timing is the very useful feature on Super Lock Diff too. By playing with lock timing, we were able to set up the car for different configuration of track layout.

Driftpro started program called Drift 102 which is the school for beginners and offers use of a rental drift car. For the rental drift car, we picked the AE86 chassis and used Super Lock LSD (from 2003). The same unit had been used on my Formula D car from 2004 though half of the 2007 season. Prior to installation, we inspected the unit and found no sign of wear and tear in side the diff! This was amazing, because the Drift 101 car (which uses another brand LSD), required to have its LSD overhauled every season!

From these experiences, I can say that the Super Lock LSD is the best LSD in our field!

Since 2004, I used OS Giken multi-plate racing clutch. The clutch I have been using is twin plate type. Even though it was race clutch, the pedal effort was almost the low as a sport level clutch (like a "Stage 1") from other companies, yet still able to hold 400hp. Engagement is smooth and easy. Durability is also impressive, as we overhauled the clutch in the mid season as just a precaution. From our inspection I can guess that if it weren't for the fact that this clutch was being used by a professional race team with established maintenance guidelines, we should have been able to use the same clutch throughout the season and more!

Also, I found engine response to be perfect! From one of my teammates, I have learned that too light of a flywheel can have a very negative effect on drifting (i.e. stall, under-steer on initiation of drift, and etc.), yet if flywheel is too heavy, performance of the car will be lost. The flywheel paired OS Giken clutch kit has very nice balance and is perfect weight for drift use."

Hiro Sumida - Formula D Pro
Lexus IS350, Toyota Chaser, and Toyota Corolla AE86

"I have been using OS Giken Super Single clutch since just before Formula D began in 2004. I switched from the previous clutch brand because I wanted more clamping force from the clutch at initiation and ever since I started to use the OS Giken Super Single in my AE86, I was able to pin point the timing to clutch-kick to initiate my drift. The Super Single clutch had a solid bite at clutch kick,but at the same time,it was also very gentle to my transmission components.

I have drifted my AE86 for more than 3 years, but I have never broken a single transmission. Since the Formula D 2005 season, I have been using the OS Giken Twin Plate on my 1994 Toyota Chaser. This car has been known as the famous "zombie" Chaser because the outer shell has been beaten down to hell from me hitting the walls so many times. However, despite how it looked from the outside, the mechanical components were very sound. I was able to take the 3rd place podium finish at the Formula D 2006 season in New Jersey and this was probably the most beat up car that has podiumed in Formula D history. I believe this accomplishment only came from the consistent performance of the OS Giken Twin Plate clutch which has never slipped or broken any of the other transmission components, while my competitors consistently had to swap clutch, tranny, and axle shafts. And to add to this amazement, I have never serviced the clutch even till this day..., which is well over 4 years of competitive drifting!

I began using the OS Giken Super Lock LSD at the same time I used the OS Giken Twin Plate in the Formula D 2005 season with my Toyota Chaser. This was the first time to see the vast choice of different setup the driver can choose from a single LSD system. Not only there was the different kinds of cone plates to set the initial torque, but the small springs inside the LSD unit to intentionally choose the speed of the plates opening up to lock the diff components. And after finding the sweet-spot for my Chaser, all I needed was a routine oil change. I have never opened it up for over 4 years, and the Super Lock LSD still works like it just came right out of the box.

Since Formula D 2007 season, I was driving the Falken/Discount IS350 and with the development of a brand new car, you really have to worry about every single component of the car, but I knew that we did not have to worry about the diff because we were using the OS Giken Super Lock LSD. For the last two years, the car was consistently pushing over 650hp to the wheels, but we have not had a single issue with the LSD unit. And of course, we have never broken a single axle shaft too!

Overall, my personal impression of the OS Giken clutch and LSD is that they are very strong and crisp in their performance, yet they are also very gentle to protect the other transmission components like the engine, transmission, driveshaft, and axle shafts. And nothing comes close to OS Giken products in terms of endurance performance."

Berk Technology - Global Time Attack
"The Berk Technology Time Attack Race Team made the switch to an OS Giken Super Lock Limited Slip Differential for the 2010 Redline Time Attack season and as one of the leading teams developing the BMW 135i chassis in the US, we could not be happier with the results.

The class we run our car in requires the use of 140+ tread wear traditional street tires so being able to put all 400 horsepower down to the ground without the help of sticky R-Compound tires is essential in our success. We have tried a few different limited slip differential setups on our BMW 135i and the OS Giken Super Lock LSD stands far and above the rest. The car launches out of each corner now like its being pushed!

In our first event of the 2010 season, with the new OS Giken Super Lock LSD, we were not only able to shave three seconds off of our previous best lap time, but also set a new track record in our class, and took the event win!

Aside from being the best performing limited slip differential we have tried, the OS Giken Super Lock LSD is actually shockingly quiet and smooth under street driving conditions straight out of the box! Through our many years of making street driven track cars, we had come to accept that having a good performing LSD would mean sacrificing drivability on the street as they were noisy and lurchy in situations like turning into a parking spot.

This is absolutely not the case with the OS Giken Super Lock LSD. Under mild street driving conditions there is no noise and none of the lurching motions that you get with other LSDs.

OS Giken makes an exceptional product for anybody from the daily driver that sees occasional track time, to the full blown race car!"

Randall Smalley/RSR Motorsports - Continental Tire Challenge Series / Grand-Am
Mini Cooper S R53

"Mini Coopers have a unique problem when attempting to put their engine power to the ground. The front wheel drive Mini's have a very short wheelbase. To keep the front end compliant, soft spring settings are a must. Excessive weight shifting is the result, unloading the front suspension under acceleration and causing excessive wheel spin. The OS Giken Superlock LSD Differential effectively control this spin. Through testing, some trial and error and with the help of the engineering staff at OS Giken, we have eliminated this problem. The cars turn in quickly, with predictability, maintain their 'set' to the apex and it's full throttle through the turn exit.

RSR motorsports races both the Supercharged and the Turbo versions of the Mini Cooper S. The Superlock LSD has proven to be the best in controlling the sudden acceleration of the supercharged model and the smoother but higher torque of the turbo model.
RSR has tested ATB (automatic torque Biasing) style LSD units and other brands of plated differentials. We have found the OS Giken units to be far superior in both performance and adjustability. They have also proven to be extremely durable. All four of our team's cars are equipped with OS Giken Superlock Differentials. I also have one in my street car."

Chris Musante / Musante Motorsports
Porsche 964

"OS Giken makes precision products for both vintage and new Porsche models. Having raced and tuned Porsche cars for 25 years, we have had the opportunity to test all the popular styles of differentials including open differentials, torque biasing differentials, locked spools and limited slip differentials.

OS Giken limited slip differentials install nicely and work well in both Porsche street cars and Porsche racing cars. We have installed OS Giken limited slip differentials in Porsche cars ranging from lower power early 911's to higher power applications like 993/996 Turbo and 996 GT3. Every limited slip installed well and worked perfectly.

Knowledgeable and experienced drivers have only praised the performance and the durability has been second to none. The Japanese made OS Giken parts are extremely well made with close tolerances. On the track they perform flawlessly with smooth and predictable engagement and disengagement. For the street they are quiet. For road racing, the high percent lockup during deceleration allows deep and effective trail braking and better overall braking. On power exiting of corners is smooth and precise due to the increasing lockup percentage during acceleration.
This makes for very fast and predictable corner exit.

We have run the OS Giken units as delivered right out of the box with excellent results, however, if it is necessary to change the characteristics they are easily tuned to provide different deceleration, neutral throttle and accel characteristics. Due to the tuning capability the OS Giken could be run in any application with great success. There are other well made differentials on the market but I would have to say that OS Giken has an advantage due to the large number of plate friction surfaces and longer service life."

David Smart - SCCA National Solo Series
"The Lotus Elise/Exige platform is instilled with excellent handling traits that make it a favorite for track/autocross competitors. It was introduced to the US in 2005 with an open differential. Hardcore drivers required more and by year-end Lotus began offering a Torsen unit. At that point, I had raced my Lotus with the open differential for an entire year. One word...frustrating. Massive wheel spin at mid-phase leading to understeer at exit (induced by inside wheel thrust).
In 2007 I installed the Torsen unit...better.
In 2010 I moved to the OS Giken Super Lock...AMAZING!

Choosing OS Giken was an easy choice based on solid recommendations from fellow race drivers and excellent US-based technical support. Installation was drop in and go. I raced the very next weekend and drove the car to a 1st in class and top PAX finish. Straight out of the box it has been good for a streak of Regional, Division, and National Tour wins. This differential has given my Lotus Exige S the ability to put the power down under full lock while still allowing a crisp turn-in. Rotation in tight turns and stability in high speed sweepers is now "on demand". Although difficult to quantify the improvement (due to unique Solo course configurations) I would estimate a 0.300 to 0.600 second advantage on a 50 second course. An ETERNITY in Solo and a must have for any serious competitor or weekend warrior.

Huge thanks to the engineers in Japan for making the Super Lock available to Lotus Elise/Exige drivers. This is the differential that Lotus should have installed from the factory. It retains the quiet operation and durability required by OEM manufacturers and the performance to put competitors on the top step of the podium."

Sean Tillinghast - NASA Driver(GTS Challenge GTS-3)
BMW E36 M3 #001

"The OS Giken Super Lock differential took the performance of my BMW to the next level. Having run a custom-built, limited slip differential for several years, I was skeptical of how much advantage would be realized by changing to a locking unit. After one race with the OS Giken Super Lock I was convinced as the control of the car through and out of corners was amazing. The Super Lock eliminated all inside rear wheel spin which had been problematic at courses with quick transitions and elevation changes such as Mid-Ohio.

The OS Giken differential further allowed more aggressive use of curbing without sacrificing acceleration through the apex. The unit opened quickly on deceleration as the rear was very neutral under breaking and did not over respond if I jumped off the throttle.

The Super Lock is great for the weekend race warrior. My mechanic installed the differential and I raced it the next weekend; no difficult setup, no break-in. The locking effect reduces heat generation within the diff and eliminates the need for finned covers, coolers, and frequent diff oil changes. The Super Lock offers outstanding performance, durability, and ease of use."

Ian Stewart - SCCA T3 Class Driver
Honda S2000

"I was very impressed with the OS Giken unit. We instantly noticed the difference from our previous unit because of the smooth engagement. Almost no clunks when pulling around in paddock. On track that smooth engagement is noticed both on corner entry and corner exit as the unit made it very easy to apply power on corner exit. Another on track tendency that disappeared when going to the OS Giken was the snap over-steer on corner entry.

Instead it was a very progressive and controllable over-steer allowing me to get the front of the car right down to the apex easily and most important consistently. This was something that was most noticed in the Grassroots Magazine test. Our lap times were better with the OS Giken unit but they were also consistent. Far more consistent than any of the previous units. This did not change through out 45 minutes of racing at the runoffs, again a quality I very much liked. I did however notice that after each track session when the unit was very hot we did get some clunking moving it around in the paddock. I'm not sure the cause of this or if the fluid (non-OS Giken gear oil) in the housing was breaking down due to the heat. Most important to me this did not change how well the differential worked on the track.

Overall I'm very impressed with the OS Giken Differential. You guys make an excellent product and I'm very happy to have it in our car."

Scott Berkowitz - NASA Driver(GTS Challenge GTS-3 2008 National Champion)
BMW E36 M3 #88

"For years I have suffered with driveline problems in my BMW M3 GTS racecar. I've had issues with premature clutch wear and slipping using both stock parts and various other high performance manufacturers. I've also had problems with my highly modified BMW limited slip differential, such as extreme wheel spin from the unloaded inside wheel which prevents me from getting full power down when most important.

Since switching to the OS Giken Super Single clutch and flywheel kit, my clutch problems have disappeared. The feel is great and it stays consistent through out the race. I've also installed the OS Giken Super Lock LSD and the performance change is awesome. I can now get excellent power down in fast or slow corners and the wheel spin has effectively been eliminated. All this has allowed me to turn faster and much more consistent lap times. I truly believe that the combination of the OS Giken driveline products have taken my car to a higher level."