[BAC5.2]

You'd need the DCCD from a newer 5MT DCCD trans (post-99) if you want that swap to be easier. Finding that setup will be challenging though. As for ABS not liking it, you could easily wire up a relay that opens the DCCD when the ABS engages.

PPG makes a helical center differential, but actually obtaining one is challenging as well. They make a front diff that's readily available, but the center requires a few phone calls and no lack of dollars ready to spend. The helical rear diff is a similar situation to the center. Available if you make the right calls and have the money to spend. That said, 3 helical LSD's drives like a Humvee. Any slippage, just drag the brakes. 3-wheels on ice, one on dry works like a charm!

 

[BAC5.2]

Peter, that is only for the automatic transmission.

Simon, Just because both fronts are spinning, doesn't mean there will be no benefit from a front LSD.

The transfer gears changed in 99, and an old style diff won't fit a new style transfer gear. The easiest thing to do, supposing the DCCD units have 1:1 transfer gears like you do, is to swap the whole back-half of the transmission (so the rear cover and the transfer gears). If you do that, model year doesn't matter.

Finding one cheap will be difficult, but not impossible. I'd keep your eyes open and see if you don't come across a good deal on e-bay. Remember, if you find a 5-speed DCCD box in good shape, the gearset is worth a lot to kids in America who think STi 5MT gears are worlds stronger than what they have. You can probably break even!

The Audi diff is unlikely to work. I'd be shocked if the spline count and bearing surfaces were even close to the same.

 

[BAC5.2]

Hey Simon....you can always put a phase I tail section on your trans (if you can score a 12kg diff).

Speaking of which....any trans gurus know if phase I transfer gears will work in the phase II case? I'm working on a potential swap deal and I'll need new teeth should I pick up the parts.

On the DCCD subject, you could always use the "Spiider DCCD controller" or rig up a 12v switch similar to the torqumada lite mod..... 40/60 when you want the tail to be comin 'round, then flip a switch to lock it up to pull you the rest of the way through!!!

The early transfer gears won't work in a new case. Well, I say that because the new-style transfer gears won't bolt into the old style cap.

I wouldn't bother with a 20KG center diff. Having driven one, it's attrocious.

Go DCCD.

 

[BAC5.2]

Here I thought you had a front LSD all this time.

As Jeff Foxworthy would say.... "well there's yer sign...." !!!! The OBX front LSD is a cabon copy of the Quaife and is worth every penny of $400-ish on fleabay. I've been running an OBX for a couple years now, other I know have been using it longer than I have, with turbo power. Some report noise from a lack of preload on the worm gears. Others report hardware issues. I report quicker corner speeds and quicker lap times.

The OBX isn't a carbon copy of the Quaife. If you look at them side-by-side, you'll notice a TON of differences. Still, if you don't want to spend a lot of cash, it's alright for a knock-off.

 

[BAC5.2]

I edited your post to read a little closer. You should know that it's a little too much work to remove a front diff just to look at them side by side. They feel and function identically when I step out of one car and get into the other. Aside from the lack of radius on the stubshafts, which like to rollover the axle seals upon installation, I would say teh OBX is a little better than just "alright" for a knockoff...... Many of the OBX parts pushed on ebay are not up to the quality of other brand name parts....but they got it right with the front diff.

If you DO happen to have both next to eachother, the differences are apparent. You might not notice a difference driving two cars back-to-back, but there are many differences.

I'd compare the OBX diff to an STi helical differential. Few worms that look rather spindly, and an overall construction clearly never intended to see high-horsepower race-duty loads.

 

[BAC5.2]

The OEM JDM Subaru LSD is ~$1000USD. They are available from Subaru of Japan, but I don't have a part number on me right now. I'll try to find it.

Re: OBX. I was doing some more looking around, and apparently straight from the box you need to invest ~$35 in new hardware to get any semblance of durability out of the unit. The OEM bolts, apparently, are of dismal quality and often strip. Similarly, the worms are preloaded with beville washers made of tin-foil.

I don't think I'd trust something in a gearbox whose Spec'd hardwear isn't up to snuff.

Looking at the "torn apart" pictures of the OBX diff, it looks like it's made from some heat-treated mid-carbon steel. The Quaife, by comparison, looks to be made from some heat-treated high-alloy steel.