GR Yaris (Gen 2) Cusco rear LSD vs. Quaife rear LSD

Fred

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May 17, 2024
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Southern Germany
I've fitted a Cusco 1 (1way) together with the "Kalle 50/50 gear set".
Performance-wise it's a very nice improvement. The car behaves much more like a traditional 4x4 and understeers less.
You can step on the gas much earlier and get a nice touch of oversteer.
However I don't know if the set has been installed correctly.
Even after almost 2.000km and two oil changes the Cusco still makes creaking noises under acceleration in curves.
I don't think this is normal!

Has anyone here experience with the Cusco rear LSD?
And, how does it compare to a Quaife rear LSD?
I wouldn't like to return to the OEM torsen diff. ...
Thanks for your input
 
I've fitted a Cusco 1 (1way) together with the "Kalle 50/50 gear set".
Performance-wise it's a very nice improvement. The car behaves much more like a traditional 4x4 and understeers less.
Can‘t answer your question unfortunately, but that’s Interesting - can you please provide a link to the „Kalle 50/50 gear set“ and say if it has any downsides?

I am also thinking about a proper LSD and happy to hear you wouldn‘t like to go back anymore…
 
at least on full blast friction LSD outperforms the torsen as it doesn't loose the drive even inner wheel lifts off. Downside is that it requires more maintenance. the GRMN is equipped with friction disc lsd from factory but diff's 've got 5tkm maintenance interval IIRC.
 
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Not entirely sure if the noise you're hearing is from the clutch plates engaging, incorrect preload/backlash setup, or just not fully broken in yet — but in general, plate-type LSDs are definitely noisier than Torsen-style diffs.

I recently upgraded my rear diff with an OS Giken unit. I'm currently working on installing an equal-ratio transfer gear set, so I haven’t had the chance to test how it feels or sounds yet.

That said, getting the shimming right during installation was a tedious process — but it's crucial if you want the LSD to perform properly and avoid unnecessary wear or noise.

20250530_151604.webp
 
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Quaife ATB is similar to Torsen.

I found the Torsen doesn’t loose traction as often in the dry when putting in oil without friction modifier, which increases the torque bias ratio and thus effective locking. Also rally style suspensions with lots of droop travel with quick extension help maintain traction by not lifting the inner wheel.
Plated diff will always lock, ideally also in the front because if the front inner lifts you can still loose the rear if front traction disappears - this is for very sideways relatively high grip situations, i.e. actual rally or some form of controlled event.
 
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Can‘t answer your question unfortunately, but that’s Interesting - can you please provide a link to the „Kalle 50/50 gear set“ and say if it has any downsides?

I am also thinking about a proper LSD and happy to hear you wouldn‘t like to go back anymore…
I have no "direct information" regarding the Kalle gear set since it was ordered directly in Japan from a friend.
But IRC in Austria is offering the same components:
IRC Performance
Motorsport Parts Builds Support
Unteramt 129, 3264 Gresten, Austria
Mobile: +43 650 71 33 143
Web: www.ircperformance.com
 
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Not entirely sure if the noise you're hearing is from the clutch plates engaging, incorrect preload/backlash setup, or just not fully broken in yet — but in general, plate-type LSDs are definitely noisier than Torsen-style diffs.

I recently upgraded my rear diff with an OS Giken unit. I'm currently working on installing an equal-ratio transfer gear set, so I haven’t had the chance to test how it feels or sounds yet.

That said, getting the shimming right during installation was a tedious process — but it's crucial if you want the LSD to perform properly and avoid unnecessary wear or noise.

View attachment 36255
Thanks! The not correctly performed shimming is also my suscpicion. I will have to control it.
 
Quaife LSD in the rear axle here -
Performs as quietly as stock, no strange noises. The differential didn’t require shimming - preload/backlash was in specification when measured. Are your diff oil changes relatively clean (no sparkly bits etc)?
 
Another alternative is the Wavetrac Torsen LSD. Their claim to fame is no loss of traction if an inside wheel lifts.

 
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Quaife LSD in the rear axle here -
Performs as quietly as stock, no strange noises. The differential didn’t require shimming - preload/backlash was in specification when measured. Are your diff oil changes relatively clean (no sparkly bits etc)?
Yes, the last two changes were quite clean.
I will check better the next one.
 
Im pretty sure what youre hearing is supposed to be normal.
The Cusco diff most likely has a high preload thats why its so loud.
Torsen diffs are known to be quiet but there are also Clutch Plate LSD's with a low preload that are known to quiet (Drexler for example).

If the bearing preload would be too tight or too loose you would hear it also on the straights not just the turns and the noise would be louder with higher speeds.
 
Im pretty sure what youre hearing is supposed to be normal.
The Cusco diff most likely has a high preload thats why its so loud.
Torsen diffs are known to be quiet but there are also Clutch Plate LSD's with a low preload that are known to quiet (Drexler for example).

If the bearing preload would be too tight or too loose you would hear it also on the straights not just the turns and the noise would be louder with higher speeds.
Thank you, that sounds comprehensible.
 
Quaife LSD in the rear axle here -
Performs as quietly as stock, no strange noises. The differential didn’t require shimming - preload/backlash was in specification when measured. Are your diff oil changes relatively clean (no sparkly bits etc)?
How's the Quaife in comparison to the original Torsen?
 
@Fred
I couldn’t honestly tell you as I upgraded from an open differential on a Convenience Pack. Quaife seem to keep their gear ratios a closely guarded secret but I’d think there would be at least a slight difference between the OEM Torsen LSD & Quaifes biasing ratios.
 
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