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Limited Slip Differential (L.S.D.) FAQ by KAAZ U.S.A.

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  • Limited Slip Differential (L.S.D.) FAQ by KAAZ U.S.A.

    Frequently Asked Questions

    General Questions:
    • Why should I buy a Kaaz Limited Slip Differential?
    • What is the difference between 1.5-way or 2-way L.S.D.?
    • Where does the L.S.D. mount on the vehicle?
    • What type of gear oil should I use?
    • Why is break-in important?

    Trouble Shooting Questions:
    • What is the noise I'm hearing in my new Kaaz L.S.D.?
    • Why does this noise occur?
    • How do I fix the chattering noise?
    ________________________________________
    General Questions:

    Why should I buy a Kaaz Limited Slip Differential?
    You might think, "Why should I buy a Kaaz unit when I can buy from the car manufacturer themselves?" Well, we'll show you below.

    The following diagram shows the KAAZ clutch plate compared with another typical brand.




    See the difference in size. If you'd like, you can view an exploded view photo of the Kaaz L.S.D. that helps to show the overall construction. The most important factor of an L.S.D. is the friction between the clutch plates. The plates cannot slip when they are not meant to, otherwise the L.S.D. is of no use. A bigger plate will have larger surface contact area and provides better grip between plates. Since friction causes heat, our L.S.D. utilizes maximum allowable plate sizes in order to distribute the heat evenly so the plates don’t overheat and cause problems.
    Besides the larger size, our plates are made from special materials to improve the effectiveness of our L.S.D.
    Back to General Questions Index | Back to Trouble Shooting Questions Index
    ________________________________________

    What is the difference between 1.5-way or 2-way L.S.D.?
    Sometimes you will hear these terms used in the business of L.S.D. trading and the racing department, etc. but what does it mean? As we mentioned before, when the accelerator is stepped on, the L.S.D. comes into use. But what if you are braking through a turn? 1-Way L.S.D. means that only when the accelerator is stepped on, the L.S.D. comes into use. The 1.5-Way L.S.D. means that when the car is braking, there is little L.S.D. effect and the 2-Way L.S.D. means that either when the car is accelerating or braking the L.S.D. is always active. The difference between these are the shaping of the cam into different shapes for the pinion to fit. The diagram below shows how the 2-way version of the Kaaz L.S.D. operates.



    ________________________________________
    [/B]Where does the L.S.D. mount on the vehicle?[/B]

    For every different type of car, the L.S.D. is fitted on different places. As we all know, the cars are separated into following categories: FR, FF, MR, RR and 4WD. Basically the L.S.D. is fitted between the 2 wheels that the drivetrain uses to propel the car. On 4WD cars, 3 L.S.D. are fitted. One in the front, one in the center and one at the rear of the car.
    ________________________________________
    What type of gear oil should I use?

    A special blend oil made by KAAZ named "PowerTrain Gear Oil" can be used to keep your L.S.D. running for long hours under the best condition. The oil helps the clutch plates to grip and slip when needed.



    KAAZ PowerTrain Gear Oil works for all transmission/L.S.D. uses.
    1. Our gear oil can be used on front drive manual transmission and rear drive final gear.

    2. Our gear oil has the capability of improving your L.S.D.’s performance, giving your L.S.D. a longer lasting life and removing unnecessary noises form the L.S.D.

    3. Unlike some other gear oil, at normal temperature, our gear oil flows fluently between the gears in order to decrease friction loss from the beginning of your drive. This not only will give you a comfortable drive but also help save fuel consumption.

    4. Our gear oil has the characteristic of low friction loss and at the same time provides high lubrication.

    KAAZ PowerTrain Gear Oil is available in 2 liter containers.

    CAUTION!!! Do not use the KAAZ PowerTrain gear oil on automatic transmission vehicles.

    Why is break-in important?

    When the L.S.D. comes out of the factory, it has been thoroughly washed, but some iron dust and dirt particles may still exist in between the clutch plates. The clutch plates do not fit perfectly from the very beginning, therefore this causes some jumping effect. Applying too much torque when the unit is new will cause damage to the clutch plates and may result in plates forming an angle fit. Once these plates forms an angle fit, the L.S.D. is unable to function at 100% efficiency. Damaging the clutch plates will decrease it’s lifetime.

    When the break in is done properly and the clutch plates form a perfect fit, not only the L.S.D. can be functioning at 100% efficiency but the lifetime of the unit will be longer than expected. Just like fitting a new brake pads, if you floor the brake pedal right away the brake pad’s ability to stop the car will decrease. Therefore, you have to let the brake pads and the brake disc rub and form a good fit before hard use. L.S.D. is the same way, initial form fitting is very important.

    Information about the break in is found in the instruction booklet that comes with each unit. Every manufacturer of L.S.D. has their own way of break in procedures. Please follow the instructions that come with each unit. After the initial break in procedure, L.S.D. oil must be changed. Check the oil drained after the break in, you will find lots of iron grains from the friction of the plates rubbing to form a good fit. You can then visually see the importance of the break in and oil change.

    [/B]Trouble Shooting Questions:[/B]

    What is the noise I'm hearing in my new Kaaz L.S.D.?

    When a new mechanical L.S.D. is installed, it usually gives out strange noise. This noise comes from the different friction forces of the clutch plates.

    Why does this noise occur?

    The noise occurs when the L.S.D. is effective and the clutch plates are rubbing against each other. The vibration of the friction produces this noise. The noise is most likely produced when driving at low speed or backing into the garage. When the clutch plates rub together for some time it will form a perfect fit between plates and the noise will disappear.

    Some new and larger L.S.D.s we make are made with larger plates to maintain more torque. Some of these larger L.S.D.s will produce some chattering noise even after the initial break in. Please do not think that chattering noise is normal when using a mechanical L.S.D. If you follow the correct installation and break-in procedures, the noise will be gone from your L.S.D. in no time.

    How do I fix the chattering noise?

    We understand that most car owners who use the mechanical L.S.D. are very disturbed by the chattering noise. As mentioned previously, the chattering noise comes from the friction between the clutch plates. This situation is normally caused by not doing enough break in and bad angle fit between the clutch plates.
    The best to break in and remove the noise is by driving in a “figure 8” pattern as shown below for about 30 minutes and let the plates rub in to form a good fit. If this initial break in is not performed and too much torque is applied to the L.S.D. at once, the plates will form strange angles. Then the chattering noise will continue and may even cause damage to the L.S.D.



    The oil used in the L.S.D. could also contribute to the noise problem. Poor quality oils contain large amount of tiny grains of metal which cause chattering noises. If noise still occurs after break in, try changing the L.S.D. oil. This usually eliminates or reduces the noise. Oil which contains large amount of added chemicals will cause noise too. Users who are especially concerned about the chattering noise could think about changing to a better quality oil such as KAAZ Powertrain Gear Oil.
    ________________________________________

    KAAZ U.S.A.
    (949) 631-0990
    (888) 522-KAAZ
    fax at (949) 631-0909
    newportcars@kaazusa.com

  • #2
    very informative!

    Comment


    • #3
      indeed.

      Comment


      • #4
        where do you drive fiugre8s at?

        i guess install it at midnight and find a shopping center...

        Comment


        • #5
          Thanks for the information!

          Comment


          • #6
            One thing to note: Kaaz LSDs do NOT like synthetic oils like Redline or many other store bought oils. THough it may seem like they want you to keep giving them money for no reason, BUY KAAZ fluid for those types of Diffs. NIsmo on the other hand comes with their own fluid when you buy a kit. On the tin it says "Full Synthetic". I use Redline Synthetic in my Nismo S.S.S. diff, for reference.

            ALso, take care of your diff. I broke mine in last November, changed the oil to the Nismo fluid in the begining of December, and did not change it to Redline until August!!!!!! BAD! That was with plenty of street/mountain drifting and a couple of track drift events per month!!!!!!!

            Luckily I bought my diff brand new, so there was no noticeable damage and i did a good job breaking it in and there were no metal shavings or residue in the oil, it was all the same consistency, not chunky, it was just darker than new fluid. I consider myself lucky. Rule of thumb is every couple track events (if you go) change the fluid. Or what... like 3,000 miles or so.

            Also, pick an LSD that fits your drifting style. For instance Hariguchi (yellow BN Sports FC3S RX7... you've all seen it) has a 1 way LSD. He uses a lot of feint and clutch kick drifts, meaning he needs good turning response. (no locking under braking or weight shift forward), then clutch kick and a lot of power on means diff is locked when accelerating through drift.

            Koguchi uses a 2 way LSD, since his style is more rounded and uses a lot of shift lock or braking drift/weight transfer to initiate.

            Just some examples. I personally drive more like Hariguchi or Miki (1.5 way) but my S.S.S. is 2-way right now. Since i can, i will change the casing to be 1.5 way (on S.S.S. and G.T. Pro Nismo diffs the casing is cut to both 2 and 1.5-way patterns, all you do is disassemble it an rotate the cage 45 degrees, then reinstall).

            Hope this helps.

            Comment


            • #7
              Question on acceleration note in illustration.

              So, is that "accelerate through a range of 20 km per hour per gear" - in a 5 speed, that's topping out at about 60 mph or 100 km per hour, then hitting the brakes and turning at the end of the figure eight.

              If so, then I gotta find a BIG place to do this next spring when I get my new diff....

              Comment


              • #8
                they need to make a kazz for the supramk2

                Comment


                • #9
                  Good Stuff

                  I was just gonna post a question about all this stuff... but the Kaaz guy read my mind.

                  My questions:

                  Is a Kaaz also adjustable from 2 to 1.5?

                  Is a 2 way fully locked almost all the time? i.e., is a 2-way locked and 1-way more like stock? Someone please expand on this area.

                  Thanks.

                  Comment


                  • #10
                    One more question...

                    What is the better style diff for newbies?

                    Which one requires more skill to handle?

                    Comment


                    • #11
                      Re: One more question...

                      Originally posted by mjk180
                      What is the better style diff for newbies?

                      Which one requires more skill to handle?

                      everyone is gonna tell you 1.5 is good for newbies and 2 way requires more skill to handle, but 90% of those people have never even driven 2 way so take that with a grain of salt.

                      Comment


                      • #12
                        Something i wrote a while ago for the Zilvia.net archive and FAQ:

                        "There are various types of LSDs. For our cars, there are Viscous, which uses a fluid filled sac that expands with heat (Fritction) to lock the output shafts, and then there are mechanical. Mechanical means that the LSD in engaged or not due to interaction between 2 (or more) set, mechanical parts. This category inclused CLUTCH and HELICAL type LSDs.

                        For road racing, Helical type is more desirable, because it acts like an open diff while turning in and such. If I am not mistaken, it does not lock the two output shafts to spin at the same rate, but rather it biases torque to the wheel with more grip up to 80%. Shiet, you know what, its been a while. If I weren't on a slow *Censored**Censored**Censored* computer running Windows 95 i would search google for QUAIFFE or HELICAL LSDs and dig up some diagrams and a more in depth explanation.

                        Ok, other type of Mechanical LSD, clutch type. Clutch type LSDs use a center cam that moves under torque changes within a casing. The casing is 2 parts (L and R) and is symetrical in that sense. However, the cuts in the casing making the notches for the cam to slide in are not. That determines 1, 1.5, or 2 way LSD. As the cam slids in the notch it pushes the casing outward, which engages a series of clutch discs, some attached to the casing, some to the output shafts. When engaged, both output shafts will rotate at the speed of the casing, making both axles, and subsequently, wheels, rotate at the same speed.

                        Now back to the notches:

                        A 1 way notch is cut like an upside down triangle. While the cam can push backward against the tapered edges, expanding the casing, it cannot push forward against the flat surface. Therefore under acceleration torque (cam rotating backwards) it will lock, and under deceleration torque, when the cam is forced to rotate forward due to forces from braking, engine braking, etc.. it will just contact a flat "wall" and the casing will not expand.

                        A 1.5 way notch is like an upside down triangle with a more flat trangle on top of it. During acceleration it will expand the casing at one rate, and during deceleration, it will still expand the casing, but due ot the cuts' higher angles, it will require more force to move the casing apart. Therefore, only during Very hard braking will it have enough force pushing it forward to expand the casing.

                        Need it be said that a 2 way then is shaped just about like a diamond? Where it requires almost the same amount of acceleration or deceleration to force the casing apart. Usually, the top cuts are slightly more dramatic, making the 2 way still require slighlty more deceleration force to push the cam to expand the casing.

                        Ok, there is more. The more the casing expands, the more clutches contact each other, and the more the output shafts get locked into the same rotation. Now there are adjustable diffs (like Nismo SSS and GT Pro)where you can set a breakaway torque. That means that the cluch discs get moved closer together or further apart to dictate the SOFT, MED, or HARD setting. The closer the clutch plates are to each other, the sooner the output shafts, and thus the wheels, will spin in sync.



                        *I didnt edit any gramatical or spelling errors. Yes, i know they are there. Deal with it."

                        Cliffnotes: Under decel, 1-way will act like open diff... 1.5 will take longer to lock the wheels into the same rotations, and 2 way is almost instantaneous (good for drifting, not terrible for grip once you get used to it... i grip my car a lot since i drive mountain roads everyday...)

                        While in a parking lot or making a U-turn or whatever, 1 and 1.5 way diffs will usually act like open diff. With 2-way LSD it will sometimes actually have enough acceleration to lock. Thus making a skipping or clunking and scaring the little old ladies at Von's Supermarket. LOL. Of course if any clutch-type diff is packed tight enough or on a hard setting it should do this as well.




                        As for which one is best for beginners? Well, 2 way is harder to get used to, as it actually makes you understeer more during certain circumstances. It all depends on your style though... if youa re smooth a 2 way is a must. If you are like me and are into feint, clutchkick, side brake, etc etc a 1.5 is actually a little more helpful because it allows you a little bit more turning without sliding. But hey, I use a 2-way and I love it. I think i could do just as good with 1.5 but I don't feel liek taking my SSS casing apart to align the cam with the 1.5 way cuts (Nismo SSS and GT Pro are cut to be changeable between 1.5 and 2 way as well as adjust breakaway torque setting).

                        What it comes down to: get a mechanical, clutch type diff for drifting. Anything is good, you will learn how to use it. If a 1.5 way is $300 and a 2-way is $900 (there is no difference in price, when new this is just an example), get the 1.5 way since in this case it will save you loads of money. Even if you "want" a 2 wya. The differences aren't so noticeable that you will suck with one, and run D1 with the other....

                        As for 1 way, these are usually for FF cars where you don't want any locking under deceleration while turning because they already have enough understeer and locking the drive and TURNING wheels into the same rotational speed is suicide! Nothing but understeer (FF sucks for sports driving haha). Sometimes you'll see 1 way diffs used on RWD cars (good for grip i suppose) but for drifting, I like the 1.5 and 2-way because during off throttle or throttle modulation on/off it keeps the whels spinning. Soemtimes in a 1 way this would make the wheels roatate at their own speed and you can grip/lose drift if this happens. Whatever works though...

                        Comment


                        • #13
                          Damn that's one hell of a post *applause*.

                          Comment


                          • #14
                            Thanks!

                            Great post. Just what I was looking for...

                            Comment


                            • #15
                              exelent explination. I was waz looking into kazz and lsd's for a while and this has actuall been the most help.

                              also nice post _pg_

                              dudes got knolage

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