To best understand how the Wavetrac® is truly different from the other gear differentials on the market, you
first have to understand the primary problem that the Wavetrac® solves.
The problem: Loss of drive during zero or near-zero axle-load conditions.
Zero axle-load is a condition that occurs during normal driving,
but creates the most noticeable problems when driving in extreme
conditions. Zero or near-zero axle-load is the condition that exists
when there is ‘no-load’ applied through the drivetrain, when one drive
wheel is nearly or completely lifted (often in aggressive cornering). It
also occurs during the transition from engine driving a vehicle to
engine braking and back, even with both drive wheels firmly on the
ground.
Here’s how that loss of drive hurts you:
1) If you lift a wheel, all gear diffs except Wavetrac®, will NOT power the other wheel.
2) During the transition from accel to decel, all gear diffs except Wavetrac®, do nothing.
Why does this happen?
All gear LSDs (including Torsen®, Truetrac®, Quaife®, Peloquin,
OBX, etc.) work in basically the same manner: they divide the drive
torque between the two axles, applying drive to each side, up to the
available grip of each tire. The amount of drive torque one wheel can
get over the other is described as the bias ratio, a measure of the torque split across the axle.
Standard, open differentials have a bias ratio of 1:1. They can
only apply as much drive torque as there is available traction at one
wheel. When one wheel loses grip, the total available drive is lost as
well (at a 1:1 ratio). All your power goes out the slipping wheel -
along the path of least resistance.
Torque biasing differentials offer increased bias ratios over
open differentials. For example, if a diff has a bias ratio of 2.5:1,
then it can apply drive torque to the wheel with the most traction
(gripping wheel) at 2.5 times the traction limit of the wheel with the
least traction (slipping wheel). This is a significant improvement over
an open diff… most of the time.
The problem is that when one tire has LITTLE or NO grip (zero axle-load), the other wheel gets ZERO DRIVE, because (basic math here): 2.5 x 0 = 0.
Lift a wheel (or substantially unload a wheel) and you get zero
axle-load on that side - that means that during the time the wheel is
unloaded, the typical diff will NOT power the wheel that’s still on the ground. No matter how high the bias ratio, you get no power to the ground.
During the transition from accel to decel, where you have near
zero torque on the axle, even if the wheels are on the ground, the
typical diff is unable to begin applying drive torque until AFTER the
zero torque condition is over. While this condition is generally
short-lived, the fact that most diffs can do nothing during that time
means that there will be a delay once the zero torque condition stops -
creating a reaction time in the driveline.
The Wavetrac®, however, is different:
The innovative, patent-pending, Wavetrac® device in
the center of the diff responds during these exact conditions when zero
or near-zero axle-load occurs. At or near zero axle-load, the axles
(and therefore each side gear in the diff) start to turn at different
speeds.
This speed differential causes the Wavetrac® device to step into action:
Precisely engineered wave profiles are placed on
one side gear and its mating preload hub. As the two side gears rotate
relative to each other, each wave surface climbs the other, causing them
to move apart.
Very quickly, this creates enough internal load within the Wavetrac® to STOP the zero axle-load condition.
The zero axle-load condition is halted, and the
drive torque is applied to the wheel on the ground (the gripping wheel)…
keeping the power down.
Some gear differentials rely solely on preload
springs to combat loss of drive. The drawback is that you can’t add
enough preload to prevent loss of drive without creating tremendous
handling and wear problems at the same time.
So, to avoid these problems, the preload from ordinary
spring packs must be reduced to a level that renders them ineffective
at preventing loss of drive. The Wavetrac® is the only differential that
can automatically add more load internally when it’s required.
In the case where both wheels are on the ground
during zero axle load, such as during a transition to deceleration, the
Wavetrac® device is able to prepare the drivetrain for when the zero
torque condition stops, eliminating the delay seen with ordinary gear
diffs.
What this means for you as a driver is that power
is delivered to the gripping wheels for more time and in a more constant
manner – making you faster and improving stability.
The Wavetrac® truly is different - and its innovative features can make a real difference in your car’s performance.
Here’s something else you won’t find in any other design:

The Wavetrac® diff’s behavior can be altered in the field to suit your needs. It comes standard with carbon-fiber bias plates
for the best all around performance and lifetime durability. Changeable
plates using materials with different friction coefficients to
fine-tune the bias ratio are sold separately.
These bias plates provide a mechanism to tune the response of
the differential as a function of applied torque load. The applied
torque load manifests itself as an axial load from the differential
pinions into the housing. This axial force is then considered a normal
force into the bias plate, and as a function of the effective
coefficient of friction, provide a resistive torque to the rotational
motion of the differential pinions. The resistive torque will add to the
resistance of relative rotation of all components within the
differential. The resistive force, however, is non-uniform since it is a
function of the axial load from the differential pinions. The unbalance
of the resistive torque will manifest as non-uniform energy absorption
within the differential causing a bias ratio.
Here are more features that make Wavetrac® even better:
The new Wavetrac® Differential brings current gear technology to the market.
Internally, its gear tooth forms are optimized for strength and improved oil film retention over competitive designs.
Our gear package is smaller, reducing overall mass, yet is
more durable since particular attention was paid to the tooth strength -
optimized for high torque conditions.
Attention was also paid to the side gear/axle interface,
putting as much material thickness as possible in this critical area -
most important when power levels get high.
Each Wavetrac® Differential is crafted from the highest quality materials available.
The internal gears are made from high strength 9310 alloy steel.
The diff bodies are machined from case-hardened steel billet.
To complete the package, every Wavetrac® differential is
built exclusively using high quality, high strength fasteners from ARP®,
the world leader in fastener technology.