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Hi All,
My friend just bought an used 2011 987.2 Cayman S with PDK.
i helped him did a vin check and it seems his Cayman S came with Limited Slip Diff from the factory (option code 220).
However his mechanic is telling him his car does not seem to act like it has LSD when it was out in the hoist, both wheels do not rotate the same direction. Ok I am no expert but I don’t know if this is the right way to check it the car has LSD or not.

Is there a way to know? Other than taking the whole trans and diff apart?

Also I saw on previous posts it seems Porsche 40% differential LSD is prone to worn out quickly and loses its locking function. What would be recommended? Guards? Porsche OEM?
Any feedback would be much appreciated!
 

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Wavetrac hands down. The mechanical function allows just enough rotation of the inside wheel to go around sharp corners without causing understeer, yet when pushing the throttle on hard, both wheels put the right amount of traction down preventing snap oversteer. On threshold braking, the ATB LSD tracks straight without any back end wobble. Even in the slalom feature of autocross, this LSD keeps both rear wheels driving, yet does not interfere with tunin or weight transfer. I have found I can use the Porsche PSM on most of the time except on very bumpy sharp uphill corners with a lot of throttle will tigger the nanny.

Works for the life of the car. Does not make clicking noises, but it does transfer power to the outside wheel with the inside wheel lifted off the ground.
 

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Wavetrac hands down. The mechanical function allows just enough rotation of the inside wheel to go around sharp corners without causing understeer, yet when pushing the throttle on hard, both wheels put the right amount of traction down preventing snap oversteer. On threshold braking, the ATB LSD tracks straight without any back end wobble. Even in the slalom feature of autocross, this LSD keeps both rear wheels driving, yet does not interfere with tunin or weight transfer. I have found I can use the Porsche PSM on most of the time except on very bumpy sharp uphill corners with a lot of throttle will tigger the nanny.

Works for the life of the car. Does not make clicking noises, but it does transfer power to the outside wheel with the inside wheel lifted off the ground.
Do you have any data or links for cars that do not have LSD fitted from factory and what kind of set up would it be?


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i helped him did a vin check and it seems his Cayman S came with Limited Slip Diff from the factory (option code 220).
However his mechanic is telling him his car does not seem to act like it has LSD when it was out in the hoist, both wheels do not rotate the same direction. Ok I am no expert but I don’t know if this is the right way to check it the car has LSD or not.
You can't really test a clutch type LSD that way. They only lock up under load.

The tests I've seen involve putting the car in neutral, jacking up only one rear wheel, and measuring the torque required to spin it. But unless it's set up with a lot of preload (which generally you wouldn't want for a street car) then the torque spec is pretty low and it's hard to tell how worn the LSD is.

Unless you're racing I'd probably just assume it's fine and not worry about it.
 

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Do you have any data or links for cars that do not have LSD fitted from factory and what kind of set up would it be?
Yes, mine! I used Cantrell Motor Sports as my install shop. I had no LSD with my Cayman as it had inside wheel spin, even with wide RE71R rear tires. What I found was that the Wavetrac transfers power much better/smoother to the outside tire at the traction limit. This transfer of power without upsetting the front turnin or changing the understeer/oversteer balance is what makes this mod predictable and smooth. Also, there are no preload clutches to wear out or ramps to figure out, just get a small box from Wavetrac or their suppliers and have your mechanic install it. Two weights of Motul transaxle oil are available, standard 75W90 and race 75W140.

That's it. Works as advertised, two black Hoosier A7 tire strips at the start, smooth delievery of power at each apex and predictable trail braking performance.
 
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Yes, mine! I used Cantrell Motor Sports as my install shop. I had no LSD with my Cayman as had inside wheel spin, even with wide RE71R rear tires. What I found was that this LSD transfers power much better to the tires traction limit. This action without upsetting the front turnin or changing the understeer/oversteer balance. Also, no clutches to wear out or ramps to figure out.
I knew I asked the right guy!!

Any additional cooling solutions required?
Or supporting upgrades to keep it reliable?


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I'll just put this right here:

As far as cooling mods an external oil cooler that returns to the pinion would be a good mod at the same time. Requires machine work to the case and an external pump.
 

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Croc987S friends car is PDK equipped. Guard does not make a PDK application according to the above Guard link, only manual.
 

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They do make a PDK diff, they don't really advertise it though since you can't get internal parts for the PDK transmission. It's not serviceable as far as Porsche is concerned. Call Matt, he'll set you up. You have to reuse the carrier bearings.
 

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I've designed a set up but don't have much to share until I finish my car. I've seen a few pictures but nothing detailed on web.

Basically you need to add a pickup to the bottom of the tail housing. Use a Tilton or similar pump, Setrab cooler and add a return on the top of the case to return cool oil to the pinion. The trans is prone to oil buildup in the tail housing in racing conditions, which results in starvation at the pinion.
 

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Croc'd has one for a manual 08 Boxster S. I just found it now from 5 months ago. Its a full on description with a set of drawings with measurements for the WaveTac LSD. The problem is the PDK/manual 6 speed have slightly different parts. No oil cooler here.

LN does have a description on their web site of a PDK external cooler and transaxle cooler. Please call LN for gear pump details that really makes this cooler work.

Post 7250 in What have you done to your 987 Cayman today, please review Dave's details.


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Turning a wheel and observing the direction the other turns is not a completely reliable test, alas. This is especially the case when the LSD has significant wear and loses its break-away torque limit. Popping the side cover off the transmission to see what's in there is pretty easy.

In terms of alternatives to the factory, the Guard LSD is the class act. Wavetrac is a Torsen aka. Gleason design worm-gear differential. It provides locking under accel, but does nothing under braking. The Salisbury clutch plate design of the factory and Guard LSDs providing locking under both accel and decel. On the track and in rain / snow, it's certainly a benefit to have the differential working for you under braking as well as acceleration. Cheers,
 

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So the Option 220 "Limited Slip Rear Differential Lock" is a real LSD?
 

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So the Option 220 "Limited Slip Rear Differential Lock" is a real LSD?
As far as I am aware, the only time the factory ever used a Torsen-type LSD was for some of the production years of the 968. So yeah, otherwise 220 = Salisbury style "real" LSD.
 

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So, Porsche will not allow any repair parts for their PDK transaxle per post #9 which means no rebuild, so a useless LSD. That's worse than Guard that can be rebuild, allowing for removal, rebuild and install of the rebuilt unit. Wavetrac works for the life of the car. It also has braking stabilization, like a 1.5 style LSD. This allows for use in tortuous tracks and no real effect on understeer from the preload or oversteer from the lockup as happens to clutch style LSD 2.0. Below is a picture deplicting the wave locker action that allows transfer of power when the inside wheel is lifted off the ground, which is different than other Torsen-ATB's.

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Quote:
Originally Posted by 32krazy! View Post
lifetime warrenty and able to handle 1000 hp to the wheels. its been used for yrs on corvettes bmw m/b mustang and others for both road and drag duty. for the street you will barely notice its there. i have one in mine took 2 hrs 2 shims and a new bearing on the d/s havent looked back. rwd with a tbd is the mack daddy! like a porsche should be
please consider this my annual agreement that the wavetrac TBD lsd is far and away the most rewarding mod i have done to the car.. and it DOES "lock" contrary to what some report to the contrary.

it willl allow you to "drift" and "throttle steer" your car while running rwd in ways that are just not possible with the awd setup. all for 1200 bucks with a lifetime guarantee, and no plates to ever need replacing.

at the very least, it is worth further investigation if your attempting to go rwd and do not want to end up being ONE wheel drive lol. trans does need to be dropped to re-shim and set the lash spec.

it will totally transfom the car.

add: it does NOT allow or contribute to "fishtail or "tailwag" under extreme braking. in my experience.


Last edited by '02996ttx50; 11-14-2017 at 02:12 PM.
 
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With PDKs you just need to be careful during the rebuild and re-use parts. It's not useless, just not as easy as other transmissions.

You're not going to find a better diff for our car than Guard. I know you like your Wavetrac but it's not a real racing diff, it's a street diff. Porsche Motorsports (or almost all forms of racing) doesn't use torsen diffs for a reason. If maintenance free torsen diffs worked just as well, race cars would use them. Lift a tire with a torsen and you have no wheel drive. Torsen is a great street diff. If you're going racing talk to Matt at Guard, simple as that.

So, Porsche will not allow any repair parts for their PDK transaxle per post #9 which means no rebuild, so a useless LSD. That's worse than Guard that can be rebuild, allowing for removal, rebuild and install of the rebuilt unit. Wavetrac works for the life of the car. It also has braking stabilization, like a 1.5 style LSD. This allows for use in tortuous tracks and no real effect on understeer from the preload or oversteer from the lockup as happens to clutch style LSD 2.0.

View attachment 267942

Quote:
Originally Posted by 32krazy! View Post
lifetime warrenty and able to handle 1000 hp to the wheels. its been used for yrs on corvettes bmw m/b mustang and others for both road and drag duty. for the street you will barely notice its there. i have one in mine took 2 hrs 2 shims and a new bearing on the d/s havent looked back. rwd with a tbd is the mack daddy! like a porsche should be
please consider this my annual agreement that the wavetrac TBD lsd is far and away the most rewarding mod i have done to the car.. and it DOES "lock" contrary to what some report to the contrary.

it willl allow you to "drift" and "throttle steer" your car while running rwd in ways that are just not possible with the awd setup. all for 1200 bucks with a lifetime guarantee, and no plates to ever need replacing.

at the very least, it is worth further investigation if your attempting to go rwd and do not want to end up being ONE wheel drive lol. trans does need to be dropped to re-shim and set the lash spec.

it will totally transfom the car.

add: it does NOT allow or contribute to "fishtail or "tailwag" under extreme braking. in my experience.


Last edited by '02996ttx50; 11-14-2017 at 02:12 PM.
 

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Ok, a trailered race car, Guard. Street / some race as in no trailer, no slicks or wings, Wavetrac. Slightly different applications. Lifetime warranty for the Wavetrac. The Wavetrac does not lockup as tight as a built Guard would, meaning a benefit for slalom or tight corners, as Cantrell says the Wavetrac seemed tight for a ATB LSD.

Go Guard with the recommendations from all of the heavy hitting race team's with unlimited rebuild budgets. I had the opportunity to buy a Guard, but for my street 85% race 15% application, the Wavetrac seemed a better fit and no clicking noise during deceleration as in stop and go freeway action.

Cantrell did replace all the ring bolts with new Porsche spec'ed special order bolts-$12.00 ea. which is mandatory do to the required torque.
 

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I don't have an unlimited budget. Guard diffs are in hundreds if not thousands of street cars.

I'm not bagging on you for going Wavetrac, it probably does make sense for what you're doing. I'm just saying if you want the best diff, one that is designed specifically for our cars, Guard is it.
Wavetrac makes diffs for everything; trucks, cars, jeeps and Porsche. Guard Transmission does Porsche. Matt goes to the races and works with teams to supply the ultimate product.

Ok, a trailered race car, Guard. Street - some race as in no trailer or GT4 wings, Wavetrac. Slightly different applications. Lifetime warranty for the Wavetrac, but it does not lockup as tight as a built Guard would. Cantrell says the Wavetrac seemed tight for a ATB LSD, meaning its approaching the Guard but without the recommendations from all of the heavy hitting race team's with unlimited rebuild budgets, go Guard. I had the opportunity to go Guard, but for my street 85% race 15% application, the Wavetrac seemed a better fit and no clicking noise during deceleration. Cantrell did replace all the ring bolts with new Porsche spec'ed special order bolts-$12.00 ea.
 

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They do make a PDK diff, they don't really advertise it though since you can't get internal parts for the PDK transmission. It's not serviceable as far as Porsche is concerned. Call Matt, he'll set you up. You have to reuse the carrier bearings.
I've had a chat with Matt and he's been kind to let me know that Guard no longer builds LSD for Open Diff PDK applications.

It's positioned as a Motorsports product and have not been able to get cooling of the transmission at the highest possible standards he expects and has decided not to pursue this product line.

I respect his integrity to not put out a product that works only partially to his expected levels. Might revisit Guard in the future with a different car down the road.


So at the moment I'm exploring both Wavetrac and OS Giken open diff replacement LSD.
 
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