So, I ordered a 3:63 torsen from them.
Initially I received a wounded 4:10 torsen, to replace the wounded 4:10 torsen i already had.
After MONTHS of back and forth, they finally sent me another diff. Which i promptly left in the corner for about a year, as the car was down. Until I got it out today.
I'm not sure what i have. It's NOT a torsen.
I THINK it's a 3.63 and limited slip, but want confirmation.
Based on this website screenshot and partial part number.
But what kind of diff?
Anything I need to do while it's on the bench? Should I even use it for the limited slip in my turbo miata after the challenge?
That's an open diff with a Phantom Grip like device in it.
Real Mazda limited slips have a two piece case with the split in the ring gear flange, and you can't see any side gears. They have four spider gears on a cross, and the cross works on components inside the case. And Torsens are Torsens.
The ring gear looks thinner than I'm used to seeing, which is a good sign at least. Spin the thing around and look for a pair of numbers like 41 10 that would indicate the tooth count on the ring and pinion gears (4.10 ratio in that case). Or just count the teeth if it isn't stamped. Should be 40 ring gear teeth and 11 pinion teeth.
Gears almost always have at least one gear with a prime number, so that every tooth on one gear eventually wears against every tooth on the other gear. Prevents weird patterns from forming.
Pete. (l33t FS) said:
That's an open diff with a Phantom Grip like device in it.
You just described the Tochigi-Fuji Super LSD found in the later NB, NC, and ND. That's a factory diff. The springs push the cones against the clutches.
In reply to red_stapler :
Agreed, factory Tochigi-Fuji. It's basically a preloaded helical iirc.
So, is there anything I need to do to this differential? Maintenance, rebuild clutch packs, etc?
And ill try counting teeth. At least ring gear side. No idea how to count the pinion.
In reply to red_stapler :
Yuck. Mazda way cheaped out, then.
One huge advantage of the earlier type was that you couldn't have a spider gears grab the pin and break it, at which point the unpinned half would sling out and hit the pinion gear...
In reply to Pete. (l33t FS) :
It's intended to address the fact that a Torsen goes open if you have a badly unloaded wheel, I believe. They've been reliable.
Keith Tanner said:
They've been reliable
On the street, absolutely. They tend to break tabs off the friction cones under shock loads like road course curbs, prosolo and drag strip launches, etc. Mazda Motorsports decided to offer a Torsen for the Spec MX5 cars based on this.
Reading more about these last night while I couldn't sleep, seems the rx8 has these as well and theres rebuild kits.
I also see where guys pull the torsen from another diff and replace the blown up fuji.
Should I just run it? I can't find where these go and hurt the gears, they apparently just go open diff. Any conflicting information to that?
Also, 40 teeth were counted this morning. Google says that's the 3.63 ring gear!
So I DID get what I ordered.
It depends on your application, but I'd run it.
Dusterbd13 said:
Reading more about these last night while I couldn't sleep, seems the rx8 has these as well and theres rebuild kits.
I also see where guys pull the torsen from another diff and replace the blown up fuji.
Should I just run it? I can't find where these go and hurt the gears, they apparently just go open diff. Any conflicting information to that?
Also, 40 teeth were counted this morning. Google says that's the 3.63 ring gear!
So I DID get what I ordered.
Just a little note... the rx8 diff is bigger and uses a bigger ring gear. But yes, the diff uses the same style of limited slip. A lot of the rx8 guys swap in the FD diff internals.
