LSD and gearbox options for DE 996 C2

looking to set up a C2 to use mostly as a fun car for DEs. im nearly there with it but want to get an LSD in there, the idea of tracking without one doesnt fill me with enthusiasm. anyone gone down this path and care to share any advice. i assume i cant just stick a G96 box from a GT3 complete with LSD into the C2. that really would be a nice and simple option but since ive never read about anyone doing it i have to assume its not happening at the bellhousing. anyone seen both out of the cars? since you would be able to tell with a simple glance over each maybe anyone used to doing clutch jobs could jump in. discounting the fanciful option above, as far as i can see it my options are: M220 retrofit Quaife ATB type Guard Transmissions as things stand the M220 is a 22/40% split so doesnt seem especially positive. can these be rebuilt or respec'd to use motorsport clutch plates or do they use a special, all to themselves setup and so i'll be stuck with this forever. ATB offers a very cost effective solution but tbh im not keen to get on a track with hard suspension and one of these in. Guard Transmission would be first port of call but i cant see that they make an option for the G96 box in the C2 though with their site under construction its hard to see. for those who also didnt want to stick with the open diff what route did you go down?

I club race mine and it still has an open diff. It's pretty quick and a blast to drive. Where are you located? Unless you're racing and chasing that last tenth of a second, I honestly don't know that the LSD is that necessary. Just my �.02 -KJ

thats interesting to hear, maybe im just used to them and so feel it should be there when i dont need it. gearbox is out of the car for other work so i can essentially have it installed free which was pressing me to come up with a solution. in texas

if the gear box is out, yeah, it makes sense. I'd ask on the racing & DE forum. A couple guys there have some some crazy fast 996s. I'd also consider building the car to Spec 996 requirements. If you decide to race it's good to go and if you decide to sell you'll have a decent market. Just a thought. -KJ

I can only answer the OEM M220. Yes it can be rebuild and re-ramped for different lockup. I have a spare one that I don't need, it just needs new friction disks. Found that is simply uses G50 disks aka Cup gearbox. Other than at 10/10ths or in the rain you may not really need it. Gearbox doesn't even need to come out of the car to put the LSD in.

"Need" no. "Should", absolutely. When powering out of corners the unloaded inside tire looses traction. This slows acceleration, causes corner exit oversteer, and kills the rear tires. On some tracks a diff can gain you over a second. If you get a clutch diff with proper ramps, the diff will also help braking significantly. If you choose a Torsen type (Quaife etc) it's really only going to help under power. Diffs make a huge difference in the wet. GT3 & Motorsport diffs fit the C2 ... but the box otherwise is different.

Great idea, LSD's transform these cars. I'd spend money on a good diff before suspension. I think it's that important to a 996 based P-car.... So, Guard does make their GT unit for these tranny's, IIRC it's their 993 diff. I have one in my 996 now and swear by it. I couldn't imaging trying to brake from 160 or so without one which is exactly what I'll be doing tomorrow at Cal Speedway. You can also use a GT3 cup diff for about the same price. Alternatives are the Kaaz diff and the Giken diff, both are about $800. cheaper than the Guard. I had the Kaaz in a 2.7 Boxster I built and it worked just fine. I only ran if for a few months before I went to the 996 so I don't know about it's longevity. Guard of course has many advocates here on RL.... Bill from Apex has it right. Diffs are good for at least a second ifnot more. It's all about learning to use one to it's fullest potential....

The Giken is about $1900-$2000 now and pretty slick with 0-100% lockup on accel and braking. Any low speed corners in my car just spin the inside wheel, so it should make a big difference. The Giken fits the C2 996 tranny with no issues after you grind off the internal web on the engine side of the transmission. The Giken is a big, thick cylinder opposite the ring gear, whereas the original open differential is very skinny on the right side. A little grinding and it fits right in there.

So what are the benefits/drawbacks with a Gikken over a Guard LSD? +longevity +price -?

Wow... raced with the Giken last weekend in my 02 996 - world of difference!! One plus: 3 seconds a lap faster than my prior best!! Nuts! Giken goes to 100% lockup in both directions (accel and brake) - not sure if Guard goes to 100%.

Quotes source post: 7550788

What track was that?

I just put a Giken in my 996 Spec car. The biggest difference I notice is under heavy braking. Previously the car was pretty unstable in the high speed braking zones. You had to work a bit to keep the back end under control. Now the back end is planted. I'm finding I'm having issues now with even more overslowing than I had before. I'm not sure I would put the LSD before the suspension. I'd do the shocks, control arms, sways first. But there's no question that a good LSD will help the car considerably. Very happy so far with the Giken, and my wrench tells me that is should require less maintenance than the Guard. Just my $.02