Diff Rebuild Service - 3 Clutches or Wavetrac?

[jbfrancis3]

Its time for a rear diff rebuild and I will use diffsonline.com. I'm between a 3 clutch system or the Wavetrac.

Wavetrac seems like a no-brainer, given strong remarks around performance AND its cheaper than 3 clutch system

Diffsonline has rosier comments around the Wavetrac as compared to their 3 clutch: https://diffsonline.com/bmw-differen...formation.html
Hack Engineering praises the wavetrac: https://www.hackengineering.co.uk/wavetrac-explained/
I called a local shop RRT Performance: they preferred the 3 clutch over the Wavetrac, so that was a different view

Diffsonline - Wavetrac: $2,799
Diffsonline - 3 clutch: $3,099
Metric Mechanic - 3 clutch - $2,695 [for comparison purposes]

Am I missing anything?

[Obioban]

I went wavetrac because it has no clutches to wear out— so mile 300,000 performance should be the same as mile 1 performance.

[jbfrancis3]

I went wavetrac because it has no clutches to wear out— so mile 300,000 performance should be the same as mile 1 performance.

Even more of a no-brainer, then

[jbfrancis3]

Aha, finally found some downsides quoted. Per Bimmerworld

Several helical non-clutch type LSDs are also available. Wavetrac and Quaife both make a helical-style LSD that are more expensive but offer advantages in wear resistance and performance. Helical diffs use multiple sets of gears instead of clutch discs and plates. They are always engaged and have quicker and smoother response and are less affected by heat than a conventional clutch. There are a few downsides to helical diffs: if one wheel becomes airborne (hopping a curb on track or lifting the inside wheel during cornering) the lockup goes away. There is also additional upfront cost and some slightly higher gear whine than a traditional clutch LSD.

https://www.bimmerworld.com/E46-M3-Diffsonline-Custom-Performance-Differential.html

[elbert]

The Wavetrac is supposed to lock up if a wheel is unloaded. The locking mechanism is wave shaped (sinusoidal), hence the name.
I'm waiting for Obioban's on-track review

[Obioban]

^yep. Every helical except wavetrac becomes open if you lift a wheel. The wavetrac does not.

[Sharocks]

I have a 3 clutch Diffsonline unit.

I really really really like it. I was considering an OS Giken unit but decided against it because Diffsonline is local to me and if my car is broken, I don't wanna wait on Japan.

[jbfrancis3]

The Wavetrac is supposed to lock up if a wheel is unloaded. The locking mechanism is wave shaped (sinusoidal), hence the name.
I'm waiting for Obioban's on-track review

^yep. Every helical except wavetrac becomes open if you lift a wheel. The wavetrac does not.

Thanks

I have a 3 clutch Diffsonline unit.

I really really really like it. I was considering an OS Giken unit but decided against it because Diffsonline is local to me and if my car is broken, I don't wanna wait on Japan.

Wavetrac wasn't considered?

[zivagolee]

I have the diffsonline 3-clutch diff as well. I wanted the wavetrac, however, it was hard to find any in-stock at the time for our cars (even at diffsonline). Hopefully, they fixed their supply issues by now.

[Sharocks]

Wavetrac wasn't considered?

I built this diff years ago. Like 2014 ish. I had heard about Wavetrac but Dan wasn't offering them so I didn't bring it up. Also my car isn't a full track car so I didn't think I needed a clutchless diff.

The Diffsonline unit has been super stout. I'm very happy with it.

The other company I considered going to slightly was Blanton but again I know Dan personally and he's super local and shipping a diff is heavy lol

[elbert]

The other company I considered going to slightly was Blanton but again I know Dan personally and he's super local and shipping a diff is heavy lol

Probably a good thing. Blanton went rogue a couple years ago and screwed some people over.

[STAATS]

Something I want to understand about the wavetrac (as a curiosity being a previous driveline engineer for an FSAE car) is how the locking works and how it acts... their technical data and description is very limited, being IP, which is fine, but it doesn't instill me with confidence and I haven't seen any very good reviews other than "it feels great" (which is compared to a flogged out stock diff so the same could be said for any core replacement). Their limited technical data, showing the wave operation make it seem like the locking would be a intermittent application... it just looks like an intermittent clutch operation... as the other option which is locking through increase diff pressure seems unlikely as they don't recommend a specific Diff Oil, just use OEM or not Redline basically.

The maintenance free operation is very appealing and I am looking forward to a review from Obioban as I know it should go into significantly more details than most others i have read so may hopefully answer some of my questions haha

[elbert]

Their limited technical data, showing the wave operation make it seem like the locking would be a intermittent application...

The actual differential mechanism is basically like a Quaife. My understanding is the wave portion is to provide preload, so that the worm gears (which provide the torque biasing) will continue to work when a wheel is lifted.

[jbfrancis3]

Something I want to understand about the wavetrac (as a curiosity being a previous driveline engineer for an FSAE car) is how the locking works and how it acts... their technical data and description is very limited, being IP, which is fine, but it doesn't instill me with confidence and I haven't seen any very good reviews other than "it feels great" (which is compared to a flogged out stock diff so the same could be said for any core replacement). Their limited technical data, showing the wave operation make it seem like the locking would be a intermittent application... it just looks like an intermittent clutch operation... as the other option which is locking through increase diff pressure seems unlikely as they don't recommend a specific Diff Oil, just use OEM or not Redline basically.

The maintenance free operation is very appealing and I am looking forward to a review from Obioban as I know it should go into significantly more details than most others i have read so may hopefully answer some of my questions haha

The Hack Engineering link I posted gives perhaps a medium-level dive into the workings.

Actually Diffsonline does recommend Redline in 75W110 spec for this unit.

[STAATS]

The actual differential mechanism is basically like a Quaife. My understanding is the wave portion is to provide preload, so that the worm gears (which provide the torque biasing) will continue to work when a wheel is lifted.

I understand it has the same inner workings as a Quaife... I ran a TORSEN diff on our FSAE car until issues with wheel hop and we transitioned to a Drexler Clutch pack diff... I am more interested into how exactly the wave mechanism creates a load that transfers to the other wheel when one is unloaded. It looks like it works like a fluid coupling type operation like the torque converter in an automatic car... so how much torque can it transfer in this "locking" operation? I think I partially answered my own question by making the realisation that it is likely a fluid coupling type arrangement... which is pretty genius when I think about it...