GTgears

Hello,
I typed out a response and the board ate it. I am going to repost with just some bullet points since I've got a lot to do today.

1. Here's what the factory LSD looks like inside:
http://www.planet-9.com/987-cayman-b...dissected.html

2. There is no such thing as Porsche motorsports compnents for the factory LSD.

3. "Regular maintenance" on a GT LSD is generally 4-5 years for a DE driver. It is 2-3 seasons for a club racer and 1-2 seasons for the pros. Not one of the Napleton Interseries LSDs has yet required a rebuild. The regular maintenance is often presented as a knock against the LSD because people think it is frequent. It isn't and frequently exceeds the amount of time one of us will own a car before moving on to the next one.

4. My PDK development partner is not unnamed. It is BGB Motorsports. The LSD exists and is being put through the paces by them before they will start selling.

5. We made the PDK LSD because BGB wanted it. We make parts for racecars, not street rods. BGB had the vision to see that PDKs were being built as racecars and moved on it. They will reap the rewards of that foresight as they own the product that we made.

6. Gains on track are generally 1-3 seconds a lap. Lime Rock would be a 1 second track because it is short. LS and SP are 2-3 second tracks.

7. Change your gear oil every 5-6 track events.

That's all for now. I'll come back tonight and chat more when I am not under the gun.

Regards,

Matt

Marine Blue

Matt,

Thanks for the link and all of the details. Being a street driven car I don't think I'll need a rebuild anytime soon but when I do I know exactly where I'm getting the parts.

Do you know if any other changes are required to the rear end to handle the added stress of a properly working LSD?

stevecolletti

Thanks, Matt

I absolutely love the LSD, and really appreciate your help in getting the setup right for me.

I'll be ordering two more LSDs.. one to replace the dead one in the RS, and another one for my wife's 986 Boxster S (6-speed) - though I'm not sure which will be first.

And thank you for the lap time deltas (#6). It's great to see that the gains are as dramatic as they seemed (and that I'm not crazy).

Is the PDK LSD in the 987s the same as in the 997s? and what are the lockup percentages for the stock PDK LSD?

Again, thank you!

sharkster

Sorry I'm going to have to send you a 4.0 factor LSD to do this week too

the_vetman

Matt, thanks for the excellent info. When I heard you speak last year, it was still an "un-named race team". Guess that's changed since!

I agree that BGB will reap the rewards. Many PDK owners are inquiring into better LSDs! (I said "some" previously to be.. uh, politically correct )

Z356

Lewis: Could you elaborate re: your suggestion (in quote above). My understanding is that Shark Werks & many other shops sends client's OEM gt3 LSD's that fail (which is often) to GT Gears for them to rebuild using Guard components and Matt doesn't believe Porsche Motorsports components can be used to rebuild a factory gt3 LSD! So I am just trying to understand what you know re: 'replacement of factory components with Motorsport components'

Matt: That is a great link to your writings at Planet 9 and I appreciate all the work you put in explaining the different LSD's Porsche is using (past & present) on its various models! It is quite a 'primer' on this interesting topic and I strongly recommend the reading to all. I hope you continue to contribute often to our forum here on Rennlist 987/981...since we have many guys that are tracking their Boxsters, Caymans, Spyders and Cayman R's and are thirsty for this kind of know-how & information!

For the rest of you reading this thread, let me end this post with an example of Matt's distinctive writing on the subject at hand:

"I think part of what we are seeing here is Porsche's continued push away from really high performance automobiles and more towards GT cars that are safe and comfortable, that still perform well, but not stellar. I don't think when they put together the specification on this LSD that they ever intended it to see the track. There's a number of street drivers who are perfectly satisfied with the performance of this differential, especially when you leave all the various electronic traction control items engaged. It's being developed as an integrated system and the practical reality is the LSD isn't expected to do as much as it once did because the brakes are automatically more involved than they were in the past.

But then you take the car to the track. And you turn off the electric babysitters so that you can really feel the car and drive it at the limit without the computers stepping in and saving your **** when you push it too far. It's just too much for this little LSD. Or in some instance they get in your way because you and the car can go closer to the edge than they will let you and they step in and pull you back, making you slower but safer. Heck, it's too much for the street GT3 LSDs which are having a catastrophical failure rate when taken to the track. Even Porsche's flagship trackday special is ill equipped for use on the track in this department. And if the new TT model (only offered with a PDK & electronic differential) is any indication they are just going to go further to the side of electronics in the road cars going forward. Technology is a double edged sword here. The cars keep getting safer and more comfortable, but at the same time we keep getting further removed from them and the real control of the driving experience. Just look at how they are advertising the newest GT3R. They are openly calling it a racecar that's easier to drive for a gentleman racer that doesn't need the skills of professional.

Porsche has been systematically making their LSDs less aggressive on all their cars for a while now. IIRC, the current GT3 is 28/40 locking versus the 40/60 they used on the 996 variant. The GT2s have used the lower locking percentages since the 996 version of that car. It stands to reason that they would go low on the Cayman as well. It makes the cars more forgiving and basically makes it harder for the street driver to catastrophically fail and do something really stupid that kills or maims people because they pushed it too far. But for the people racing and tracking the cars, it disables them. This is why there will always be a healthy aftermarket for Porsches, because people will always want to race them no matter what Porsche does with the product line."

Saludos,
Eduardo

stevecolletti

This month's 'Excellence' magazine (#209) has a GT Gears advertisement for the PDK LSD (available January 2013) - "exclusively through BGB"... sounds real or, at least, imminent.

GTgears

Eduardo,

I was commenting that there are no motorsports components for a Cayman LSD. Porsche Motorsports Cup Car internals are completely compatible with the street GT3 LSD.

Steve,
Yes, they exist, though Excellence was supposed to have that ad running a couple of months ago. Something broke down in the communication(probably my fault) and it didn't come out until just now, which is the May issue hitting homes middle of March.

Also, I want to thank you for the patience on your LSD install. Your car threw all of us a curveball. For whatever reason, Porsche made some changes to the 2012 6MT without telling anyone. Thankfully they didn't change the ring gear offset in the process, but they did change the mounting depth of the ring gear and the length of the bolts. Now we know for future 2012 customers.

Not the first time or the last they do that sort of thing. We had something similar with the 986 Boxster when they changed the sidecover bearing size without notice. And more recently we've had some issues with the PDK. We used a factory LSD for dimensions on our own LSD for the 987/997. Unfortunately someone thought they needed to make two different castings and two different differentials for the PDK. The open PDK gearboxes use a differential that is 4mm smaller than the LSD. We are now in the process of making a 2nd PDK model that will fit the smaller gearboxes. And this doesn't even address the 997 turbo PDK and the soon to be released 991 GT3 PDK, which we are told is different. It is never ending.

stevecolletti

Not a problem, Matt. I'm glad it was so easily resolved - ok, not for Alex and James @ SW (thanks, guys!).

As I mentioned in my post, it really completes the car.

GTgears

Just spoke to John Tecce at BGB. He's got the PDK LSD in their 991 and is running around town in it. Going to put the car on track on Monday/Tuesday and will have one in a Cayman early next week as well.