agdamis

Have the wise men decided which is the best aftermarket slippy diff set up for the 997S?

Quaife, Guards......................................

Thoughts?

ECS

Very interested in the responses. The Porsche OEM one is only about $500. The Guards closer to $1500. I am debating myself.

agdamis

ECS - I believe the Porsche one use "pressure plates" or "clutch plates" which wear out. The Quaife or Guards units I believe last forever.

996toomey

I am not a tech so please do not ask me to explain the differences but you are not talking about a true LSD.

The Guard unit for $1500 and the Quaife are Torque Biasing and only have lock up under acceleration and not under braking. A true LSD has lock up under acceleration and deceleration.

These units are probably a good choice for street and auto-X.

The Guard Pro Unit about $3200 is a true locking LSD and can be set on initial install for your driving needs. This is more of a track unit but still capable on the street.

I talked with Paul Guard via e-mail and for track use he recommends this unit set at a loose 60/40.

agdamis

I think I have read and discussed the same thing and you are 100% correct but I will happily take the $1,500 unit vs. nothing now as I think it is ridiculous that a car of this caliber does not already have it. I am interested most in what works best with our cars both mechanically and electronically.

Dave07997S

I agree with you 150% about the car already should have it for the 997.1 cars and it does...just the ROTW cars not US cars. The Quaife is an excellent unit and some auto manafacturers use Quaife diffy's.

It's just a shame it will cost near $3k in parts and labor to put a LSD in the car...something a $25k Mustang gets stock.

Dave

RonCT

Depends on what you are using the car for. If road courses, then the Guard is the way to go from my research. He even has an option of using his pressure plates to create custom configurations in an OEM Motorsports housing to save some $.

ECS

Great thread. Does the LSD that comes with the 997.2 have lock-up under braking as well as accel? And....not sure I get the benefit of a true LSD under braking. Less lock-up therefore more grip? But doesn't the ABS deal with that if you are too hard into the brakes? Thus, would you have to disconnect the ABS? Looking for some education.. Thanks.

roberga

Quaife: great for Autocrossing

Guard: can not be beat for tracking.

agdamis

I knew the professor would appear on this post. In my case we are looking at 75% spirited street and 25% track. I seem to partial to the Guards simple unit.

agdamis

ECS - As I have started this post, I will do the right thing and compile some of our questions for a good friend of mine who is a Bosch special project engineer, and whose area of expertise is ESP, Traction control systems and so on. This would be right up his alley. He is also a amateur racer in the spec miata series and many times he has been my instructor.

f4 plt

I just put a Guard true locking LSD in my '83 Sc and very happy with the results. The quality of construction of the Guard is outstanding, and as a previous post noted you can select the locking ratio you want as you install it. IF I still had my Cayman s I would install a Guard unit in it. My 997.2 Carrera S has the factory LSD and so far I'm satisfied with it.

RonCT

Guard will build you whatever you want just by adjusting the discs they use. You can start with a Motorsports unit and create what you want or start with their upgraded unit.

Moderato

How does the OEM Porsche LSD compare to the Gaurd?

Has the OEM LSD been changed at all, for the 997.2 vs. the one available in Europe for the 997.1?

I've been told that under normal "spirited but legal" street driving conditions an LSD can actually hurt turn-in and cause some understeer. Is this true and any reason why Porsche might have not made it an option in the USA for the 997.1?

Dr. Car

Comments please on the different effects of the various units on the car while decelerating ... is balance affected? My general belief is that for LSD to be active you'd have to be on the gas pretty hard for it to engage. Which is not what people usually do at turn in. However, some units will lock and affect weight transfer under deceleration, right? One hopes the LSD is not affecting balance during corner entry ... it should only cause understeer if it's correcting wheel slip, and the car is putting down more power. That's a good thing, and can be dealt with by modulating the throttle. I believe a good LSD mostly makes itself noticed in corner exit, as the driver goes to WOT.

Good question about why it was not an option on the 997.1. Probably because very few buyers have any use for it, and do the Germans consider American buyers mostly poseurs? As a RWD car with a rear engine, the 911 puts power down very well with an open diff. Perhaps the absence of LSD on the 997.1 was intended to aid continued sale of the 996 GT3 in 2005? Some buyers might have (rightly) figured that a 2005 S with PCCB and LSD would be a match for the GT3, and a more utilitarian car to boot.