fwd lsd

Posted by chadillac2820, May 2, 2012
Drivetrain Tech - 4G63 transmission, clutch, flywheel, driveshaft, gears, differentials, transfer case, shifter, etc.

  1. chadillac2820

    chadillac2820 Proven Member

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    newnan, Georgia
    What fwd lsd are you guys running? Pros and cons? Most importantly, price?
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  2. pyanac711

    pyanac711 Proven Member

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    I'm running the quaife LSD and having no problems at all daily driven. It will run you $800-$1000 with a life time warranty and claim they will take anything you can throw at it.
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  3. chadillac2820

    chadillac2820 Proven Member

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    Yea Ive heard the quaife units are great but I'm not sure I want to spend that much money on one for a fwd when i plan on getting an awd ASAP.
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  4. Pipnorcali

    Pipnorcali Proven Member

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    If you going awd don't bother but it's a must have for fwd ( the quaife) the cheaper inserts don't work as well ( search LSD inserts for more info)
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  5. crimsondragon

    crimsondragon Proven Member

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    Piscataway, New_Jersey
    I only know of 4 types of LSDs that are popular. There's the typical insert type like the RipGrip which are known to be weak but they're cheap.

    Kaaz and Quaifes are torque based and are of clutch and helical gears design respectively.

    The newest one to the market is the Wavetrac which is also of a gear design but consist of wave discs in the center to eliminate zero-axle load conditions. Read more here: Wavetrac® Differential - A torque biasing differential with a difference

    Quaife's are great for DD, road racing, and autocross since they consist of turns but their slow to lock design is terrible for drag. If you want to drag race, go with a Kaaz. Not to say Kaaz isn't DD-able. It just takes getting used to and is more noticeable. Any car can benefit from an LSD, especially FWD. AWD can still spin one side or the other if you make enough power to do so. In turns, you can eliminate power-on understeer with a Quaife. Read more here: http://farnorthracing.com/tech_quaife.html
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  6. chadillac2820

    chadillac2820 Proven Member

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    Yea i searched LSD before posting this. I guess I was wanting some real world experience on the inserts. I knew everyone would say quaife and i don't blame them. I'll be running slicks and was wondering if a cheaper option LSD would get me by.
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  7. chadillac2820

    chadillac2820 Proven Member

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    Exactly what I am looking for!
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  8. jtmcinder

    jtmcinder DSM Wiseman

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    Great post by CrimsonDragon. One quibble:

    While the above is true, the way that torque makes these lock is very different. A Kaaz, being a modified clutch-pack, locks as a function of total transmitted torque. A Quaife, being a T2 helical, locks as a function of the difference in torque that is being transmitted to the two outputs. This is why a Quaife is better for anything involving turning, while a Kaaz is better for going straight ahead. The Quaife doesn't lock until right before you need it to lock. The Kaaz is locked long in advance.

    If you haven't already: http://www.dsmtuners.com/forums/drivetrain-tech/251295-diffs-lsds.html
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  9. daren_p

    daren_p DSM Wiseman

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    Newmarket, ON_Canada
    Like most things, you get what you pay for. Want a "real" LSD, it will cost you. An insert may help (have read mixed reviews) but you still have a weak stock diff, which can easily explode with some wheel hop.

    I use to run a Quaife when I was fwd. Its expensive, but it was defently worth it as. Though I would take the awd "mod" over a real LSD in a fwd anyday.
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  10. chadillac2820

    chadillac2820 Proven Member

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    I would be lying if I said I was doing an awd mod LOL. I don't have the patience for that type of task. I will be buying an awd soon. I just got a great deal on this fwd and wanted to play a bit.
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  11. chadillac2820

    chadillac2820 Proven Member

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    Play competitively I should say.
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  12. crimsondragon

    crimsondragon Proven Member

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    I kinda explained the difference between the two but wasn't entirely sure how they worked the way they did. Thanks for the info. Kaaz's seem similar in operation to the lunchbox lockers in the offroad and domestic world such as Aussie, Lockrite, Spartan, and Powertrak just to name a few except they don't use clutch packs but replace the side gears with housings that have ridges that lock to the center housing when it senses torque and unlock through turns.
    #12
  13. jtmcinder

    jtmcinder DSM Wiseman

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    There are two general ways that diffs lock as a function of (total) transmitted torque. Modified clutch-packs (aka Salisbury diffs) lock by having the legs on the spider pry open the casing, causing plates to come into contact, similar to a multiplate clutch. The other trick is to use the fact that the spider gears not only turn the side gears, but also push them outwards, which can wedge them against the walls of the casing or against ridges for even more friction. In either case, these diffs are designed to lock as transmitted torque increases, such that they are hopefully locked pretty hard before one of the outputs exceeds available grip. In contrast, helicals only start to lock when one output stops "reflecting" as much torque because it is already exceeding available grip. The "automatic torque sensing" part of the name Quaife uses is accurate. (The "automatic torque biasing" part of the name, in contrast, it highly misleading; locked is locked. Nothing special there.)

    One correction to my own post: when I said that a Quaife is better than a Kaaz for anything involving turning, please note that this thread is about a FWD so it's about front diffs. In the rear, I'd go with a 1.5-way Kaaz or Cusco, regardless of type of driving.
    #13

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