My mechanic is recommending a gt3 cup lsd for my rwd 996tt. He says its a bit more aggressive than the gt2 lsd at 60% vs 40% lock up and also much more robust. Has anyone here done this or know anything about it?

 

60% imho is too much for the street...

 

yeah, he said I would notice it in parking lots. But maybe its easy to get used to? What would make it too much in your opinion?

 

for what it's worth..i have a factory LSD in my 99 and as i recall its a 40% locking unit. It is noticable....the 60% may be too aggressive for the street imo. I have a high tolerence for aggressive cars..but you may have different tolerences.

cheers.

 

What does 60/40 mean? max 60% torque to any one side?

 

im confused aswell
how does a 40 vs 60 differ ?
and why would you notice it in a parking lot ?

 

Anyone? I'd love to learn about this!

 

http://members.aol.com/agspeed/LSD-lock.htm

 

Even better....

http://www.guardtransmission.com/velocity.htm

In short, the two numbers are the lockup amount under acceleration/deceleration. Therefore, a 60/40 will be 60% lockup under acceleration and 40% under deceleration (including braking). The article link above goes into much more detail and explains it better than I can here. Enjoy.

 

Thx scott,
Are you running an LSD in your protomotive 996tt? When I talked to Todd K. about it he thought an open diff was OK for big HP.

 

No, I'm not running one and I don't believe Markski is either.

The thing is....open diffs apply power evenly to both tires when they both have adequate traction (like on the street or dragstrip). However, when only one wheel has traction, such as on ice or snow...the wheel with the least traction will spin. Since I don't drive my car on ice or snow...I haven't any problems thus far.

LSD's will also provide more traction on a roadcourse in turns (when the inside wheel lifts)...but for my type of driving with this car...it's a non-issue.

 

It will understeer like a b%tch.

 

I upgraded my GT2 w/ Guard LSD 50/80. I highly recommended to anyone that has 2rwd. You must have suspension set up for the the LSD to avoid oversteering. Even launching in straight line my car hook up so much better due limited wheelspin and straight rear. I can exit the corners much faster without worrying the inside rear snapping on me upon WOT. Even in the rain the car is much more stable now than before the upgrades. I prefer it over PSM/TC.

 

Cars without LSD and enough hp tend to break axles easier. Then again, the Cup LSD isn't a billet unit like the RSR unit.

 

how about doing something to the center coupling to get more power to the front tires, the four wheel drive on these 996tt's only gets like 10% realistically and only if your spinning the back wheels, which you cant do without making the car "hop" !! i drift it a little out onto main roads at nite and if the back is sliding i guess then the front helps pull it back into a str8 line... but like the audi 50/50 is very aggressive and you can launch those better !!