Mine clunks at very slow turning speeds. It is a custom tuned OS Giken for autocross. Everywhere else it makes no noise

i thought that is what all LIMITED slip diffs did, which is why they are limited and not locking. have i been wrong this whole time?

Yes.

@justinco, congratulations - I think you’re going to love the differential. My OS Giken 1.5 way LSD was an awesome upgrade, and right up there with my ACE Type-A 350 header and my MCS 1WNR single adjustable coilovers as one of my favorite modifications so far. The OS Giken unit just transformed the back of the car and made it so much more fun to drive. As for modifications, you and I have travelled similar paths, huh? I haven’t made it through the video yet so cut me some slack if you mentioned this, but did you go with 1.5 way unit, too?

It’s cool you’re working so closely with the guys at @CounterSpace Garage - I did the same, and they were fantastic to work with and have given me a ton of support long after the sale.

The twins with lockers set up for tracking that I have been in clunk at sharp slow turns, less so when warm, and are fantastic on the track compared to stock.
Much less tire scrub etc. than with the old clutch, hydraulic and gear lockers I use to race with off road, before the Jeep Cup days.
:thumbsup:

Watched with popcorn ㅋㅋㅋ

Going to watch this later.... for education purposes:popcorn:

Justinco, any feedback on the LSD over the past few months of driving? How it’s behaved differently than the Torsen in AX, track, and street situations? Thanks!

Just to followup on this. Once I switched to the OS Giken OS250R fluids the low speed clunking went away. I had Motul fluids in there before for the first 1k miles, per OSG.

The biggest difference I have noticed (autox and track) is the car is much more smooth and controllable on corner exit power down situations. It will slip and slide (tire grip), but very predictably while still accelerating. Versus the torsen, where grip would break away more abruptly and be harder to keep under control. No real difference on the street cause I drive like a grandma.

@justinco You mentioned the backlash with the ring gear and pinion gear, but were you also told that you didn't need to measure the bearing preload and/or adjust shims (that you called washers in the video)? I've been bitten by not checking preload and adjusting shims!

That's right. Per OS Giken it is a drop in upgrade for our cars. Obviously if something is horribly out of wack you don't want to go forward with the install.

Really curious how this would change the corner exit dynamics in a track setting. I've been thinking about upgrading the diff in the next year or two. Sounds like it makes a big difference!

Hey Justin, did you have to change the side bearing shims at all? I'm assuming not by the video. I'm actually installing the diff into a 3.91 rear diff from an IS350 which is the same as in the BRZ, and when re-installing the LSD the shims seem a bit too tight. I'm afraid if I drive the one into place with a drift I won't be able to get the diff back out. I pressed the bearings on and they are definitely pressed on all the way.

The stock non-LSD in the unit wasn't too hard to remove it just kind of fell out so my I ordered 4 smaller shims, 2 for each side and then I'll measure the backlash.

Now that I'm writing this I should really just measure the width of the two units and figure out if there really is a width difference or not.

Everything I read including other install articles for the Giken show and mention that backlash is checked and may need adjustment yet you installed yours without, apparently, checking backlash whatsoever. Is there any whine or noise, apart from chatter when cornering, at all? Is it as silent as the OEM? Tossing up between the Giken and the Cusco but if the Giken is a DIY v Cusco being a pro instal job, I could spend the extra the on buying Giken and instal myself.

Also; does the Giken negate the need to use Whiteline style diff inserts to stiffen the mounts? Now that I think about it I think I saw you had them in fitted in your car during the Giken install. Is the NVH any worse with the Giken and Diff mount inserts?