WaveTrac Automatic Torque Biasing Differential for BMW [E82/E88/E90/E91/E92]

Description
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Are you ready to take your BMW to the next step in drive train performance? Wavetrac has finally released their Automatic Torque Biasing Differential (ATB)for the E90/E91/E92 3 series and E82/E88 1 series. The OEM differential was never designed for high horsepower out put or track use. This ATB Wavetrac diff was specially designed to handle as much horsepower as the N54 engine can put out, and is guaranteed to last longer then your vehicle. The OEM differential is an open diff, where one wheel is able to spin freely if it is lifted off the ground, giving the other wheel absolutely no power to the ground. Wavetrac has patented their one of a kind design that is able to keep the power to the ground no matter what kind of situation it faces. Be the first to have the latest drive train technology in your BMW with the Wavetrac Automatic Torque Biasing Differential.

Please Note: Wavetrack now makes an application for the 2010+ 135i N55 and the 2011+ 335is

RECOMMENDED BY THE EXPERTS!

""When I had my E92 335i, I did a lot of performance mods. It was fast and I had every bolt on out there. It was tuned well and produced good power. I felt like something was missing though, I would drive it aggressively but it wasn't confidence inspiring. It was easy to lose traction and cornering wasn't the best. I got some expert advice from a person who is a fellow car enthusiast and professional racecar driver. He loves cars and mods everything he owns. The first question I got asked was does the car have an LSD (Limited Slip Differential). My answer was a sad no, it wasn't a well researched topic on the forum. It didn't really seem like a DIY job and I was terrified of doing it.

I still made the call, talked to some experts and got their advice on what to do. A week later, there was a box at my door with my new Wavetrac unit in it. It was packaged well and arrived quick. Sometimes it helps to talk to the expert and get their input on the best way to go. I took it to my local shop to get it installed. When the LSD was installed, I took it out on the street and there was an instant difference. That confidence was back, my car could handle the increased power I had given it finally. Taking corners was fun now and when I lost traction it wasn't terrifying anymore. It was a lot more controlled. Why did BMW not put an LSD in this car from factory? It is a true performance car that should come with an LSD. Well I am glad I found this MOD and would happily recommend it to everyone. If I had to do it all over again, I would make this one of my first mods!""

- Sean Singh, Mod Expert, E9X 335i Alumni & E92 M3 Owner

PLEASE NOTE: Ring gears are welded to the differential on the 1 and 3 series vehicles made after March of 2007. This means you will have to purchase a new ring gear from BMW to use with the Wavetrac diff or have an installer take the ring gear off your BMW diff and use it with the Wavetrac. Also BMW does not sell the bearings for the Differential separately. Please Use caution or the correct tools while removing the bearings. This has only been confirmed for the 540i, call your local dealer to check on bearing availability.

Applications

Model	Wavetrac P/N	Install
335i M/T up to 3/2007	30.309.170WK	Direct
335i A/T up to 3/2007	30.309.170WK	Direct
335i M/T from 3/2007	30.309.170WK	Requires Install kit
335i A/T 3/2007- 9/2007	30.309.170WK	Requires Install kit
135i M/T	30.309.170WK	Requires Install kit
335i A/T from 9/2007	30.309.175WK	Direct
135i A/T	30.309.175WK	Direct
2011+ E9X 335is DCT	30.309.173WK	Requires Install kit
2010+ E8X 135i N55	30.309.173WK	Requires Install kit

Wavetrac At A Glance:

Innovation: Patent pending Wavetrac design automatically improves grip in low traction conditions. This feature is truly innovative and unlike any other torque biasing diff design.
Superior Materials: 9310 steel gears run in case-hardened billet steel bodies. ARP fasteners used throughout.
Maintenance Free: As supplied new, the Wavetrac differential will perform a lifetime of service without maintenance or rebuilds.
Customizable: If desired, you can alter the diff’s behavior to suit your needs using optional components.
Limited LIFETIME Warranty: All Wavetrac differentials include a transferable, Limited Lifetime Warranty.

Customer Reviews
After sitting on the fence for a while around what my next mod would be I sourced a WaveTrac differential for my 07 bolted diff earlier this year from Alan @ ModBargains.I was stunned by the transformation: a night and day transformation in both off the line and cornering performance. Power was put down smoothly and evenly in the straight and corners. I have to admit it's been hard to keep my foot off the gas and my rear in a clean line.If anyone's on the fence about a differential, or considering it among a number of mods. Get the Limited Slip!
uniter@E90post.com

What makes a Wavetrac Different?

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 drive train, 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 drive train 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.

Mod Category:

Drivetrain

Mod Subcategory:

Differentials