Just for those who don't know the history of the Helical/Torque Biasing differential, it was invented by Gleason and known as the Torsen (Torque Sensing).
Quaife
History - Reverse engineered the Torsen design (yes, Quaife is a copy) and took out a worthless patent (which has long expired) to make their company look like the almighty and scare away other companies in Europe, and it worked. So much so that 90% of the global population think Quaife invented the Helical LSD.
Function - Torque Biasing, with bias ratio of 2.1:1, which means approx. 66% of torque can be transferred to one wheel
Construction - "Billet" (hate that word, as it is inaccurate. See
here) Case & Internal Gears
Warranty - Lifetime warranty in Europe. Other countries depending upon Distributor (i.e if distributor says no, you're out of luck) and sales are region-locked, which means, if you did not purchase from an Authorised distributor in your country, you will not have a warranty. FYI, several of the large BMW Diff Specialists in the US back-door their LSD's from Europe, which means you
do not have an official US warranty, and the European trader that broke the territorial sales rules may not assist due to having to keep things under the table. Be wary of this when purchasing a Quaife within the US, as a lot of traders are not even aware of this and just think "lifetime warranty" because it's a Quaife. Non-transferable warranty, so if you did not purchase a brand new unit from an Authorised distributor, again, you will not have a warranty
Guarantee - None
Wavetrac
History - Manufactured by Autotech Driveline, who were the US Quaife Distributor up until around 2007 before they decided to drop Quaife and reverse engineer their own. During 2007 (before the Motovicity changeover), warranty claims were up in the air as Autotech would only warranty parts they had left in stock, therefore a lot of owners got burned
Function - Torque Biasing, with bias ratio of 2.1:1, which means approx. 66% of torque can be transferred to one wheel. However, they do have an additional "centre wave-design" and "friction plates" which pre-load the gears and allow continual power even under no-load conditions (i.e one wheel in the air, or broken axle)
Construction - "Billet" (hate that word, as it is inaccurate. See
here) Case & Internal Gears
Warranty - Lifetime warranty worldwide regardless of who you purchased it from (warranty card/sales proof required), as sales are not
region-locked and are
transferable between owners
Guarantee - None
MFactory
History - We started offering our Helical LSD's in 2007 during the "Quaife Crisis". As with Quaife and Wavetrac before us, we took the Torsen and reversed engineered it to make it better. Our main goal was to simply offer the best value Helical LSD on the market (of which we succeeded)
Function - Torque Biasing, with bias ratio of 2.1:1, which means approx. 66% of torque can be transferred to one wheel
Construction - "Forged" Case & Internal Gears. This is what makes our LSD
Stronger, Lighter & Lower Cost than our competition. Others are more expensive because they are "Billet" (i.e inefficient manufacturing when done in bulk) and you are paying "Brand-name Tax"
Warranty - Lifetime warranty worldwide regardless of who you purchased it from (warranty card/sales proof required), as sales are not
region-locked and are
transferable between owners
Guarantee - 30-day Money Back Guarantee (exc. shipping costs). We want you to be fully satisfied with your new purchase and are the only Manufacturer to offer this
No Load Issue
Yes, under no-load conditions (i.e one wheel in the air, or broken axle) a Helical LSD will act like an open-diff (100% on Quaife/MFactory, 50/50 with the Wavetrac), however, this does not mean that Helical LSD's are bad like proponents of Plate/Clutch style LSD's will tell you. The main market for the Helical LSD is the street car (with occasional track use). Unless you are serious with your circuit/rally racing (not drag racing), 99% of the time you will never be in the situation where you would lift a wheel off the ground, and even if you did, all you need to do is apply a little brake to simulate a loaded-condition and you have power again. And if you break an axle under high speed (like on the drag strip), would you rather your car coast to a stop, or continue to be powered, thus putting you into the wall? In conclusion, for the everyday driver, a Helical LSD is easier and safer to drive (more predictable), maintenance free (fit-and-forget) and, if you ever do get a no-load situation, just apply a little brake with your left foot (no need for special wave designs or friction plates that wear out
)
Please Note: The above only applies to our Helical LSD's. For serious track racing (circuit/rally) applications, we very much recommend a Plate type LSD such as the MFactory Metal Plate LSD, Cusco RS LSD or OS Giken (we don't recommend any other brand as the others all use old cone-washer technology and are inferior/obsolete, including the BMW M's and the custom Plate LSD's offered by most BMW Diff Specialists. I'm not saying they are bad, far from it. Just that they are old technology)