Achieve optimum performance with increased control and more flexibility using the Kaaz LSD. With a stable differential locking ability, the driver's accelerator input will give smooth and positive power transfer. Enjoy "pure sports driving" as only Kaaz can offer!

Kaaz Corporation is the top brand name manufacturer and supplier of Limited Slip Differentials (LSD) for racing and street performance in Japan. In 1998, Kaaz USA was established to supply the same high quality parts to the North American market. Today, Kaaz product is recognized as one of the top brand name from Japan in the U.S. racing and performance industry. Many top teams in various racing categories from drifting to road racing use our LSD units for their team cars. Especially in the drifting scene, Kaaz Solid LSD is considered the top choice LSD from beginners to professionals.

Kaaz LSD is known in the automotive industry as “Mechanical L.S.D.”, also referred to as “Multi-Plate L.S.D.”

Features of Kaaz LSD
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Kaaz LSD is the pioneer in the large sized clutch plate design (Figure 1). It's effectiveness and durability has been proven at the race scene throughout the world.

Figure 1.

Kaaz "Basic" and our new "Solid LSD" models react fast without fail and have a wide range of adjustments available to suit different drivng conditons. We use the largest friction plates size possible and also increase the number of plates to gain maximum performance. As a result, when compared with other LSD brands, you will find that a Kaaz LSD offers the following advantages:

• The sensitive LSD will work even when the slightest torque is applied.
• Increased ability to transfer power from the engine to the ground without loss.
• The power acting on the plates is reduced so that abrasion on the plates are protected.
• Increased number of friction plates greatly improves abrasion efficiency and heat capacitance of the plates. Longer plate wear life.
• Not only the friction plates, but all parts of our LSD have been improved and made larger, so the overall strength of the main body is increased.

These merits gives the LSD near perfect efficiency, stable operation and long lasting outstanding control for you. For a better understanding, you can view the exploded view photo of the Kaaz LSD to see the overall product construction.

Smooth locking ability and stable drivability

Kaaz has noticed a great advantage in the use of cone springs to apply the initial torque to the clutch plates. For this reason, we still use the cone spring design like the day our first production run was made. This is a long proven design.

The cone spring is generally known to provide pressure when compressed. Normally the initial resistance is soft but as more pressure is applied the resistance increases quickly. Understanding this cone spring's character and pressure build up, our engineers have achieved a unique design to provide the smoothest engagement and locking ability into our LSD units.

In general, there is a misunderstanding that "High Initial Torque = More Effective LSD". Kaaz design is based on the LSD's overall locking characteristics and not to depend on the initial torque setting only. This makes for much smoother driver control. By controlling the LSD's effectiveness based on the accelerator input, the driver can always feel superb stability while driving. Kaaz LSD's most unique feature is the smoothness between the lock to free transfer due to it's superb design.

Material and Special Processing

A newly developed "RS" type clutch plates are utilized on all our new "Solid LSD" models. These new plates are uniquely designed to improve gripping while reducing wear. All of our pinon gears and side gears are made from top quality steel and special heat treatment to obtain maximum strength. The differential casings are all machined from top quality material to withstand the abuse of high horsepower input and high temperature inherent in performance driving. Precise fitment is assured with strict quality control management.

Kaaz Powertain Gear Oil

Kaaz Powertrain Gear Oil works for all transmission/differential uses. Our gear oil can be used on front drive manual transmission and rear drive final gears. Our gear oil has the capability of improving your LSD's performance, giving your LSD a longer lasting life and reducing unnecessary noises from the LSD unit. Our gear oil has the characteristic of low friction loss and at the same time provides high lubrication "Caution" Do not use the Kaaz Powertrain Gear Oil on automatic transmission vehicles.

The Normal Differential

As we well know, a race car driver wins races from shaving lap times by cornering faster. Because of this many teams and constructors try to make their cars that can maintain higher cornering speeds.

On every car a basic differential is fitted to distribute the engine's power to the driving wheels. The basic differential gear (Figure 1) supplies the power to the wheels which is/are loaded with least resistance. This allows the car's wheels to run at different speeds in a turn with least resistance.

Figure 1.
 

However, when a car is cornering close to it's limit, the car will exhibit roll, a leaning to one side, causing the inside tire(s) to lose forward traction and lateral grip. The wheels lift and cause excessive spin because of lack of downward force or weight distribution. This wheel spin is useless for acceleration until the tire(s) regain traction and start to translate the power to the ground. Limited Slip Differential (LSD) is needed to alleviate this wheelspin.

Limited Slip Differential

An LSD is constructed slimilarly to the normal differential (Figure 2).

As you can see, the pressure plate rings have the side gear, the pinion and the pinion gears locked inside and behind each pressure rings are a number of clutch plates. When torque is applied to the differential, the differential case will rotate and throw the pinion into the pressure ring cam. The pressure ring is then pushed out against the clutch plates thereby squeezing them together. This in turn causes the wheels to gradually lock together, depending on the power applied. This effect limits the wheel spin during hard cornering and applies power to the wheels evenly when more power is applied. On acceleration and deceleration, it provides even grip and on neutral power, it frees up for less drag and easier turning.

Figure 2.

Different Type of LSD Configurations (1 Way, 1.5 Way & 2 Way)

Some manufacturers make LSD's in different configurations and are commonly classified as 1 way, 1.5 way and 2 way. This designation reflects the design of the cam groove which enables the LSD to function differently under different loads. A 1 way differential means that the cam is shaped in such way as to have positive lock only when accelerating. The 2 way is constructed in a way to have positive lock motion in both acceleration and deceleration mode (Figure 3). The 1.5 way functions almost same as a 2 way but provides less lock when decelerating. The 1.5 way can provide more forgiving balance when braking than a full 2 way setup, although it is less effective for true racing applications, it provides easier operation for beginners in throttle off conditions. 1.5 way is also very effective for front wheel drive cars which need extra stability during braking.

Figure 3.
            
 

A Comparison of LSD

There are many brands and grades of LSD in today's market.

The OEM supplied LSD, standard and optional on many cars today are 2 pinions. This design has very low positive lock and it is designed to provide some sporty feel to the showroom cars. Because of the nature of this low lock design, it is just slightly more effective than not having one at all. Not a choice for true performance drivers.

A performance LSD should have at least 4 pinions. This is the design used for racing and rallies around the world. The positive lock ratio and linear lock characteristics are determined by a number of components. The cam profile, clutch plate quantity and size, initial torque of the preload springs and the lubricants.

A viscous type, torsen type and helical type are some of other designs used as OEM equipment or optional LSD unit. These designs are commonly used since they are less aggressive and easier to maintain than the clutch type racing LSD unit. In order to achieve the maximum traction control, most OEM performance divisions and aftermarket manufactures use the clutch type design for their LSD unit.

Breaking Procedure of new Kaaz LSD

All new Kaaz LSD needs to be broken-in to seat the clutch plates. Applying too much torque when the unit is new will cause damage to the clutch plates and may result in plates forming a angle fit. Once these plates form an angle fit, the LSD is unable to function at 100% efficiency. This will also result in more chattering noise under low speed turns. It is very IMPORTANT to perform the breaking procedure as described below.

Chattering Noise.

All clutch type LSD's make chattering noise under low speed turns. This is normal for these types of LSD. The reason for this chattering noise under low speed turns is that the clutch plates are rubbing against each other thus giving you the limited slip action. If the breaking procedure is completed according to the diagram above and proper maintenance of the LSD is performed, the chattering noise will gradually decrease after accumalating some miles.

Oil for Kaaz LSD

It is important to use 80W/90 GL-5 specification gear oil on Kaaz LSD. We highly recommend using our own Kaaz LSD fluid.

DO NOT USE SYNTHETIC BASE OIL ON KAAZ LSD. Kaaz LSD may not function smoothly.

Differential Oil Change

When one has a Kaaz LSD, it is important to do routine maintenance of LSD Oil. We recommend to change LSD oil every 5000 miles for daily driven and occassional track use vehicles. If the vehicle is full race,we recommend more frequent oil change.

By changing the LSD Oil , Kaaz LSD will give you a long life span. Take care of it just like your engine.