Diff Rebuild Service - 3 Clutches or Wavetrac?

[STAATS]

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.

Thanks I'll check that out

Fair point on the redline - I dont have a reference and i am only going on memory so could be wrong but i thought it was Wavetracs own recommendations that advised against redline...

[STAATS]

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

I do just want to point out that whilst generally your statement is correct it isn't entirely true. 300,000 mile performance will 100% be different to mile 1 performance... Wavetrac themselves even vaguely allude to this in their vague technical information...

Quoting their information "The Wavetrac diff’s behavior can be altered in the field to suit your needs. It comes standard with carbon-fibre bias plates for the best all around performance and lifetime durability. All other ATB LSDs like the Quaife run the helical gears on the diff casing, meaning the gears/housings can polish theirselves or transfer material, making for inconsistent performance. Changeable plates using materials with different friction coefficients to fine-tune the bias ratio are sold separately."

Essentially the Torque Bias Ratio which is the key to the whole function of a helical diff is reliant on internal friction so there is 100% parts to wear out... the difference is with the helical setup the wear faces receive drastically less load due to the design vs the direct large torque loads applied to clutch plates in a clutch pack diff. This is why Wavetrac refer to the fact they use a friction plate whereas Torsen for instant doesn't... so Tosen's get sloppy over time... The Wavetrac setup shouldn't get sloppy as quickly and plates can be changes out to adjust that internal friction and hence change the TBR. As a helical diff gets sloppy the TBR should reduce... so a brand new wavetrac may have a TBR of 2.5, whereas a 300,000 mile Wavetrac may have a TBR of 2.0... assuming you stick to the maintenance free operation. So in general this isn't really an issue, the diff still functions and still provides a locking functionality... but it will act differently... as the TBR will have changed... I am not experienced enough to quantify what that change would be like for the driver... i just know it will be there... in trawling other message boards to figure out how the wavetrac function worked I came across guys who were replacing helical diffs and accepting it as par for the course... they were Quaife style without the locking mechanism or changeable friction plates... maybe the wavetrac locking mechanism will mask the changes in TBR... not sure... but the changeable friction plates would stop you flogging your diff carrier so you could replace plates instead of the whole diff if you ever got to that point of wear...

[bingmobo]

Good day all.
About to pull the trigger on the single biggest and most expensive upgrade to my car yet (not counting the "Big Three" or any large maintenance items).
I have an E46 M3 Convertible (fat ass) and I am planning on going with a 3.85 ring gear (a little spunkier for said fat ass than the 3.62) and the 3-clutch 35/60 LSD from DiffsOnline.
Is it really worth the $2500 to go with theirs over the original M-Variable LSD? All told this will cost me just under $6k assuming I can swap it out fast enough for the core refund.
Thoughts on this endeavor?
Thanks all.

[George Hill]

I've installed a few DiffsOnline diffs into fast street cars and track cars, no one has ever said they bought to much diff.

With that said I'm not sure a Wavetrac wouldn't be something to consider for your situation. I'm not a diff expert but I would think the benefits of Dan's 3 clutch 35/60 ramp setup would be much more noticeable on track than the street. And to be honest just a fresh diff from him works pretty well as is on a street car.

[bingmobo]

...And to be honest just a fresh diff from him works pretty well as is on a street car.

See this is also on my mind. Perhaps the 3.85 gear with the normal M-Variable would be a good solution?
I think my budget can do one or the other; a faster ring gear or a better LSD, not both. LOL.

[George Hill]

See this is also on my mind. Perhaps the 3.85 gear with the normal M-Variable would be a good solution?
I think my budget can do one or the other; a faster ring gear or a better LSD, not both. LOL.

Stock rebuild with 3.85 ratio.

If down the road you feel like the LSD is lacking swap in a Wavetrac.

[t3ddftw]

I've been thinking about a Wavetrac diff -- does it change the driving characteristics of the car too much? I.e. does it over-steer any differently, etc?

[Obioban]

I've been thinking about a Wavetrac diff -- does it change the driving characteristics of the car too much? I.e. does it over-steer any differently, etc?

I feels exactly like a new stock M variable lock.

... and it should stay that way forever, as no clutches to wear.

[bigjae46]

Does a wavetrac lock up under deceleration? I didn't think torque biasing/helical gear differentials did.

[R3VM3UP]

Can’t speak to the wavetrac specifically but helical torque biasing differentials do indeed provide biasing on decel. The bias ratio on accel is referred to as the drive ratio and the bias ratio in the decel direction is called the coast ratio. Some offer different bias ratios in the drive and coast directions.

Traditionally helical diffs won’t bias torque when you lift a wheel, but wavetracs and other like the T2R include a friction element that can aid in these scenarios.

[bigjae46]

Probably going to be hard to find someone who's driven different $3000 diffs to compare. The ZF clutch diff (3 or 4) with 35/60 ramps is the tried and true setup. I also know that tried and true doesn't always mean optimal (spring rates anyone?).

The wavetrac does sound interesting.

[Obioban]

Probably going to be hard to find someone who's driven different $3000 diffs to compare. The ZF clutch diff (3 or 4) with 35/60 ramps is the tried and true setup. I also know that tried and true doesn't always mean optimal (spring rates anyone?).

The wavetrac does sound interesting.

As someone who has and likes the wavetrac… I don’t think it’s the diff for you, at least in your e46. It’s leaving performance on the table for sure, compared to an aggressively ramped clutch based setup. I got it because my car is/will be as street as it is track, so I care about street driving dynamics and NHV (and not needing rebuilds is hugely appealing to me).

[Lee_Enfield]

What involves installing the wavetrac carrier if it was purchased seperatly? I was planning on rebuilding mine with a racing diffs clutch kit but this is interesting.

[sapote]

What involves installing the wavetrac carrier if it was purchased seperatly? I was planning on rebuilding mine with a racing diffs clutch kit but this is interesting.

It’s a total difference carrier compared to the original LSD dimensions, so you need to shim the output bearings for correct plays and ring/pinion mesh pattern.

[cornerbalanced]

Any consideration towards Drexler GT4? Drove an E92 with a Drexler GT4 and was seriously blown away, even compared to cars I’ve driven with Wavetrack & OSG (very limited experience albeit).

Grip was pretty incredible with the Drexler GT4, and when the rear end eventually would step out, it was incredibly linear/progressive, and correcting felt like second nature. I’m sure the Wavetrac should feel similar, anyone able to chime in?