Any of you running a Wavetrac LSD? Here's some info on what makes 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 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. Wavetrac®: Designed from a clean sheet using state-of-the-art knowledge and engineering to be a better differential than any other. It uses a patent pending design to improve grip in low traction conditions. Wavetrac®: Gives you quicker acceleration and faster cornering by driving both drive wheels instead of just one. And, it offers improved no-load performance when compared to other helical gear differentials on the market. http://www.youtube.com/watch?v=GiIeGH121mM
Wavetrac is awesome. Darn, why did I get a 9" ARB air locker rearend that can only be used in a straight line?
I don't under this part. What's the condition we're trying to avoid or the performance loss? What does Wavetrac do in this condition?
I assume it means there is no deceleration load transferred from the rear axles back to the diff gears or tranny. ..
From the reading I did I think it's this: There is no torque transfered if there is zero load on 1 wheel. So in some instant between acceleration and deceleration there is zero load. The effect is a slight lag in throttle resonse. Like if you lift off the gas just to where it's not accelerating and not decelerating and then you get on the gas again there will be momentary lag until you get out of the momentary zero torque condition. I'm not sure I buy that but that's what they're saying. How much power do you lose to a viscous (speed differential) LSD?
I'm not a hi tech guy. So I will not jump in to that soap. But I'll tell ya this..... This $hit hooks up something nice!!
Looks like Wavetrac might be the very best of the torque type LSDs for sure. I get the impression that there are two basic types (maybe more) of LSDs. Torque differential and speed differential. Basically what makes them "lock up" and transfer power to the side that has more traction. Seems like the common speed difference type is viscous -- uses some sort of heavy/thck (viscous) fluid with disks. When one side starts turning faster than the other it transfers power to the slower side. I get the impression that viscous would be more of what you want but it robs power. Something like that. I'm interested in understanding this now.
Sorry missed this... None yet....but I design/troubleshoot industrial electrical/mechanical drive systems so I "sort of", after 30 years of it, understand the principals. When I do get an LSD... it will probably be a Getrag 3.73 rear end. I am only plannig to be aiimng at the low-mid 500rwtq in regards to what the rear end really cares about. I think the Getrag rear end with axles is cheaper than changing to the stringer '09 6-speed axles and installing a Wavetrac. Mechanical drives (not fluid drives) are pretty good in design to eleminate loss (because this amplifies heat and wear) but noise is usually a by-product. Look at how good a clutch connection is to a flywheel, or the synchros working on a high speed shift in a manual tranny. Now to LSD. Howevr at low speed the connection is not quite as good (slipping the clutch...etc) Now as to how the Wavetrac does it...It moves the gears by utilizing a "wave shape" between the gears. I will follow with a great explanation for the Wavetrac. A little more detailed as to why Flex likes it so much. .. ..
Here you go... WAVETRAC IN DETAIL: Enhanced No-Load Bias Ratio via its Wave Design Center Pack: One of the known shortcomings of a typical torque biasing differential is its loss of drive (behaving much like an open diff) under zero or near-zero torque conditions (for example, when there is 'no-load' applied through the drivetrain, either at vehicle stationary and/or transition from engine driving vehicle to engine braking and back). The Wavetrac differential uses a patent pending design to improve grip in low traction conditions. Precisely engineered, converging / diverging 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. This imparts an increased normal force through the side gears, increasing the bias ratio as a function of load. This increase occurs automatically only when conditions find it necessary, and it 'reverts' back to its nominal bias ratio quickly and seamlessly, maintaining optimal drivability and performance at all times. It's like having two differentials in one: you get the benefit of a higher bias ratio when needed without detriment to the car's handling. Interchangeable Friction Plates Provide Controlled Bias Interchangeable Friction Plates Provide Controlled Bias. 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. Interchangeable plates using materials with different friction coefficients to fine-tune the bias ratio are sold separately. These friction 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 friction plate, and as a function of the effective coefficient of friction, will 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. Superior Design, Materials, and Construction: Designed from a clean sheet, 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. 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. .
... still didn't explain why Wavetrac is superior for the acell->decell->acell situation (when both wheels have traction). They said the other LSDs don't do anything in that situation implying that Wavetrac does do something in that situation. I understand the wave profiles "climbing" over each other for the condition of unequal traction but what does it do for the other case?
Sounds like you need to get in a car that has a Wavetrac in it. I think you will understand then...:hug:
I assume they mean (because of the design in how their "limited slip" operates) the gears that are on the axles are actually fully disengaged from the differental gears for a very brief period of time... preventing what may be called a "jolt". The WaveTrac is taking the load insted of sending the "jolt" back up the drive train. I believe the "carbon discs" are taking the load. Maybe in other LSD designs the gears do not fully desengage each axle so the force is transferred to the diff gers ausing the "jolt" you feel.
I found it! "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." Here you Go I wish I could paste the whole page but it has imbedded pics. Here is the link. http://www.wavetrac.net/technical.htm ..
I read that before. Ok, all gear diffs except Wavetrac, do nothing. but what does Wavetrac do? I couldn't see where they explained that. They are very detailed about what and how Wavetrac handles 1). Maybe I missed something?
