4S to RWD which LSD

So, after a year and a half of DEs I'm feeling I want just RWD. The car feels sluggish coming out of corners, is noticeably slower than ce 996s of similar specs. So if I'm going to got to RWD which lad is right for a DE/street car? Wavetrac, Quaife, Guard. I'm keeping the G96.31 tranny, not sure I gain anything going to the .01. I prefer actual experience over probabilities. If someone has done this let me hear it. I can do the conversion to RWD I. An afternoon and put it back in slightly more time. It's the LSD that's throwing me.

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Sounds like for your intended use a Wavetrac would be sufficient. the "right" LSD depends on your priorities and intended use. Either low-maintenance, street-friendly helical gear designs (Wavetrac and Quaife) or more aggressive, race-oriented, higher-maintenance clutch-type design Guard. jmo

If you are going to track the car, I would go with Guard. It will provide the balance and stability you need during braking, as well as putting the power down while accelerating out of a turn. But you will need to give Guard a call to discuss your options. They have a program that will supply the internals.

Now this is a 2WD conversion I can get behind!

Let me answer one more question you will eventually have. Is s Guard LSD streetable. Absolutely. It works great on the street. You will appreciate the cars stability in lousy weather conditions. You want the 40/60.

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Second vote for that Guard 40/60. Good call doing the RWD conversion! Only upside there.

Just spoke with Matt at Guard Transmission. He said they have the internal parts for any 996 differential to turn into a LSD. Just give him a call. You can DIY the project if you have the skill or he can give you a name of a local indy to do it if your doesn't have the capability.

Another vote for Guard. The 996 C4S is fairly impressive and I've seen quite a few do very well on track compared to 996 C2. Admittedly, there is a purity in the RWD platform. What run group are you in and tracks are you frequenting? I'll be at VIR Nov 1-2 with Audi and if you're there hopefully we can catch up and chat. -KJ

Thanks guys, I'll call guard later this week and discuss my options. I've built clutch pack diffs in the past so I'll see how tough this is. I'm currently running intermediate solo. It's not in my head that I'm slower, it's just how it is. Whether it's a 190k engine or drag from the front diff, I don't know. But this is the cheapest way for me to find out. I want to have a hartech rebuild at some point, but I'm not burning oil, no boredcore, so convincing the wife of a "need' to add 500cc to my motor is a hard no. I'm not running again until December with TSCC at VIR, so I have some time.

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I wouldnt sweat the run group nor car. It takes years to learn how to balance the car and carry speed around the track. No question, your car will be a heck of alot more nimble with RWD and good LSD. With 320 hp, its tough to keep up with the newer Porsche models on the straights, but you will be able to hold your own in the braking zone, corners and exit. There is a benefit to the lightness of the 996. For sure, an extra 80 hp/tq from a top rebuild in our 996s will level the playing field to the new models on the track rather dramatically. I am with you, sometime in the next few years i will get an elective rebuild as well. Right now i am enjoying the rennasaince that's occurring with m96 parts and rebuild enhancements. The future is pretty bright for the Classic 996.

I run a quaife in my rwd 996 4s, I chose it because of price (I'm in the UK and it's cheap here) and my usage - just a road car. For track I'd have a clutch or hybrid system like wavetrack, but for road / occasional track use I'm very happy. It was pretty easy to fit really, I just needed one size thicker a shim to get the backlash perfect but it would have been fine just reusing what was there.

any one done this upgrade without removing the trans? I have access to a 4 post or even my quik-jack.

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Here is Guards website. I would give Matt a call at Guard [phone removed] and he can fill you in. You will see a list of all the Porsche race shops that use Guard internals on the website, which will give you a pretty good idea of where you can go to get it done, or how to do it. Impressive list. Limited Slip Differentials | Guard Transmission https://share.google/YGmj1Y9V9JTVFa57a

This car benefits from more front camber, letting you lay on the throttle early. What�s your current alignment values?

I've spoken with guard and it's not just an upgrade. It's a full pull trans, replace the diff and perform a setup with some pretty tight tolerances. Gonna have to think about this. Not any dealers near my neck of the deep dark woods.

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Yep. Its a major project and worth it if you want stability on the track and street. The other lower priced options are great for the street, but suboptimal for the track. To put it another way, back end stability during high speed braking, rotating the car thru a turn and getting on the gas is a huge benefit. Many speak highly of Giken as another option to Guard, but you may be in the same predicament. Makes sense to spend some time understanding the limitations of Wavetrac and Quaife on the track. Hate to see any 996 owner outgrow the capabilities of an expensive parts decision quickly. As a side note, I have found no limitations on the track or street with a 40/60 Guard LSD.

I was removing the trans when I did the quaife but if I recall correctly I more or less did all of the diff work with it on the car as it was easier than on the ground! I can't for other products that may need machining etc, but for the quaife there was nothing that couldn't be done in situ, the only bit that was tricky doing in situ was setting up the dial gauge to measure backlash.

quaife pumpkin with cw and bearings fitted Full access with trans in situ

Did you replace differential carrier bearings when you installed Quaife? If so how did you remove inner bearing race?

The easiest way to remove the old race is to use a welder and weld a bead around the old race bearing face and it will almost fall out with very little resistance, when installing the new race, freeze the new race in freezer overnight and install.

Outer race? Once the pumpkin is out you can (slit it etc and) knock it out through the casing, and the other side obviously you have the casing off the car so can easily be dealt with: To remove the existing carrier bearings, use a bearing puller (if you use it carefully you can pull from the inner race so it comes out as one):

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Nice work, did Quaife give any instructions/ specs for the install?

They gave a technical drawing and instructions on how to chamfer the output flanges (needed to install, quite easily done). The porsche repair instructions gave me the rest that I needed. Quaife weren't particularly helpful in truth, a long story but due to a **** up on my end (ordered the wrong diff for snap ring output flanges not bolted), I called them to see if they could confirm some measurements for the output flange for me and they said they'd pull up the cad drawings and confirm but I never heard back. Chamfered output flange below:

@n559br , I see you put your C4S up for sale. I hope we didn't scare you away and you are going to look for a 996C2 instead for the street and track?

Actually I'm thinking about a 718 cayman gts. Not scared of the LSD, but I have some funding available for a different track car and am looking at my options.

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Great car for the track. Good luck with it. Looks like you did quite a bit of refreshing and upgrades on your C4S. It will make the new owner a happy owner.

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I agree with this sentiment. In addition, a soft sway bar setting up front and a stiff setting in the rear allows you to take advantage of the AWD system. I get the desire to transform the car to rear wheel only but the C4S can be driven hard on track.