We do not tolerate personal attacks and we also do not tolerate shills for parts or services suppliers. Your style of posting has led some members to "smell a rat" so to speak, rightly or wrongly, and while I don't want to see someone called something they are not, you did sorta dig a hole for yourself in how you first posted here. I would ask all of our members to remember we don't allow personal attacks.

Well now I have to question whether or not the person with the Motons just wanted to sell you some Motons. Suspension tuning is a black art as most shops, even race shops, cannot afford the equipment to really do it right in real time. It could have been that your install of the PSS9 was not correct or not setup properly vs. a well tuned Moton setup. If you want to see the reverse, do a search for Cayman Viper Turbo and watch me outdrive a 996 Twin Turbo (not just a 996) on a set of Motons using only my lowly Cayman and PSS Damptronic suspension. I suspect my suspension was tuned better than his, that doesn't mean I would recommend he throw away his Motons and get Bilstein instead, I'd recommend he get some help getting his car set up right and some additional seat time. Paying more does NOT guarantee anything other than a lighter wallet.

The price differential between the discounted Quaife unit (we are getting a deal through Motordrive) and other LSDs has nothing to do with the quality of the units and everything to do with buying units in bulk. As has already been stated in some situations a TBD is better than a clutch type LSD, in others a clutch type is better, but for the vast majority of drivers they don't have the skill level to exploit the differences to their fullest potential.

With regard to dropping the transmission, my shop told me they could check backlash but not preload without dropping the tranny (unless I have that backwards but I don't think I do). They also checked the contact patch between the ring and pinion. They also stand behind their work as Allan stands behind the Quaife units that he sells. Evidently the one car that had a problem did not purchase their unit through Allan so we don't know anything about the unit or the installation that was performed. FWIW I know of a Stasis unit in a Cayman that had a problem as well and had to come out, but I don't label their units as "cheap".

If my Quaife unit is installed properly and within tolerances there is NO long term risk as you suggest, my unit may well outlast the factory diff it replaced.

Why not ask Paul Guard himself? He goes by Geary here on the site and is a Cayman Club sponsor. I am privy to information about his LSD units that he has asked me not to share yet so I'll let him say whatever he wants to say.

Farnbacher is also a sponsor here and I've driven the Stasis unit first hand and I can tell you there was no discernable difference between it any my Quaife unit on the track, both were solid. I have head that the Guard LSD will have different lock-up choices, and that the Stasis unit does not, but that could have changed. If I understand the supply chain correctly it is Guard -> Stasis -> Farnbacher Loles, typically the more people in a supply chain the more expensive an item is, not because it is better, but because each party is in business to make money. I suppose I could buy a unit from Farnbacher and resell it for $5,000 but that wouldn't make it any better, just more expensive.

Hmm the RUF Cayman I drove in October had NO LSD in it at all, does that mean RUF was afraid to put one in because it might break? or that RUF did not yet have a solution? or that RUF didn't think it needed one? I suppose I could conjure up all sorts of reasons why and at least one would support some argument I am trying to make.

In short I *think* you are trying to say "You get what you pay for" and for the most part that is true and for the most part people understand that. However, that does not necessarily make any given part any better than any other given part or any part any less or more risky than another without something more to go on than the retail price being charged for an item.

I think people here are smart enough to understand the risks inherent with tuning their cars and I don't see anyone rushing into anything lightly, so given that we all pretty much understand your point, what is it that you are trying to convince us of exactly?

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K-Man S

Exactly ........

Answered here:

This is a problem that would plague any differential that is installed improperly. Basically, if the ring and pinion gear end up disintegrating, they will turn the gear oil into liquid sandpaper.

It's made by Getrag. It has nothing to do with Audi.

VMAN,

I don't mean to beat up on you, I really don't. But I can understand that you may get defensive to what I am about to write, based on the previous tone of this thread. I think it's unfortunate that you ended up in this mix up so early on in your Cayman Club experience. You will learn your way, give it time.

That in mind, I would like to ask what Audi has to do with the transmission made by Getrag for Porsche? Why would Porsche need to go to Audi? Why not go directly to Getrag to source the part? I've seen many statements about the Cayman using Audi or VW transmissions, yet Audi and VW don't even make transmissions. They source them to suppliers just like everyone else. In fact, does any car manufacturer actually make their own transmission?

I am not saying this to discredit or attack you Vman. I am saying this because in this situation, if I someone doesn't clarify this point, I/we will be correcting hundreds of the post in the year to come in which members who read it here will be claiming that the Cayman has an Audi transmission. I do not believe this to be the case.

I may be wrong and you may provide proof of the claim, and if you can I am all ears and very interested. But what I suspect you mean is that the Getrag transmission made for Porsche is similar to one of the Getrags made for Audi and that there is a limited slip differential provided to Audi that will fit into the Cayman transmission because of those similarities.

Back on the original topic, I think there is a wealth of information in our forums that clearly compares the strengths and weaknesses of the Quaife TBD to the clutch type differentials (http://www.caymanclub.net/cayman-mod...al-vs-tbd.html). I will not restate those benefit, but one needs to be pointed out. Thanks to Tess, Quaife was the only solution that was readily available and somewhat affordable. Sure, F/L had the very customized Stasis unit, but it has been priced more than twice the cost of the Quaife and availability has been very limited. We are all anxiously awaiting more news from Guard Transmission.

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Tess,

Just tell me when I can expect to get my unit..........

Well, I'll say it again: if you look under your car the diff cover has a very distinctive logo featuring 4 interlocked rings, and the seal I bought for the half shaft on the other side of the tranny was described to me as an Audi part by the Porsche parts guy at the dealership.

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I appreciate that Tess stepped up and provided a solution for early adopters, but for people about to buy a new differential the cons of the TBD solution should not be buried because it may upset Tess or other forum members who have already bought such a differential.

I will try and objectively list pros and cons of both differential options as I see them, take it for what you will:

Quaife TBD
Pros
- Cheapest to buy $1,400 to $1,500, thanks to Tess and the group buy out of the UK they are readily available
- 50 guys who run them like them
- Quick and cheap $500 install seems to work (ie without dropping transmission from the car)
- Lockup only on acceleration so car should act more like an open diff at turn in.
- No parasitic drag under braking, because no decal lockup
- Lower maintenance requirements than clutch LSD.
Cons

- Quaife may not have the best name in the Porsche industry for providing durable high quality products or high quality product support. Although initial member review of the new product seem that may have changed.
- Inconsistent lockup with a high horsepower car may not provide you with as consistent corner exit as a clutch type LSD, still better than no differential.
- TBD’s have not decal lockup so you can’t brake as deep into corner as a clutch type LSD.
- Quick and cheap install $500, without dropping transmission from car may lead to the differential failing in the long term as backlash and other tolerances cannot be accurately measured without dropping the transmission during install (which turns the install into a $1500 proposition).
- 50 installs of Quaife ATB differential, so far only one failure, not sure if failure due to install or differential, so realize you are taking product development risk.
- When you open your transmission to install a differential, you add another point of failure/risk, if that differential fails you may destroy a $10,000 transmission or your car.




Clutch Type LSD (Stasis-Farnbacher, Guard, Factory Audi)

Pros
- Likely to be best solution on the track for a midengine car with high horsepower as it will allow consistent lockup on corner exit and provide you with some decal lockup under braking to drive deeper into corners.
- Vendors that offer the product have strong reputation for quality in the Porsche industry and their other Porsche products have been used extensively by professional racing team.

Cons
- Still remains to be proven with real data if LSD is better than TBD ie. (Cayman S with street tires and DOT R tires, a pro level driver, one with an LSD and suspension setup for the LSD and one with an TBD with suspension setup optimized for TBD differential on closed street course and open road with back to back test drives.)
- Must do more expensive $1,500 transmission drop install and cost of LSD’s are going to be between $2,100 to $3,000, much higher than TBD
- Factory Audi and Farnbacher solution not readily available from suppliers, seems like a work in progress or one you have to call specialty shops like GBox or Farnbacher to get your hands on.
- Guard LSD unit for Cayman S is stuck in customs, don’t know if it will be days or weeks before it is released.
- No factory LSD solution, so realize you are taking product development risk by installing a differential.
- Clutch type LSD’s need to be maintained and checked every season if racing and every couple of years otherwise.
- When you open your transmission to install a differential, you add another point of failure/risk, if that differential fails you may destroy a $10,000 transmission or your car.