997gt3north

- part arrived today and gets installed tomorrow along with the cup 8/32nds r&p
- this is the 4340 cromoly 50/80 diff
- useless factoid is that besides being oily, it weighs 21#

- what may be of more interest to people is that I will be installing the stiffer rear sway bar from the new 997gt2
- i have been in discussions with a fellow rennlister who with a few others in the UK are testing this as a possible cure for the excessive front push that reveals itself on short tracks with lower speed turns
- i won't speak for others but i will do my own testing
- porsche engineers have confirmed that the updated rear sway bar in the middle of the 3 holes is 20% stiffer than the stiffest setting that our cars come with

paul

leif997

looking forward to your data results in both regards

996FLT6

I'm getting the 50/80 GT lsd(oem fried) for my 6gt3 also had the r/p(copans) done awhile back. Can someone elaborate what kinda advantages it has on the track? Regards Mike

sharkster

paul not useless at all and well.. car **** for folks like us. I love what you're doing... When the weather clears up I can't wait to see what you make of it. I believe the new GT2 sway is still "hollow", right? All of Porsche's sways are and have been for a while. Wish they were solid (even though it's heavier).

Crazy Canuck

interesting

03-turbo911

Looking forward to your impressions!

OldGuy

I like the way you photographed it all dreamy like. Like a 1950's pic of Lauren Becall or something.
with that sheen to it.
like the old classy **** pics.

997gt3north

It was sent directly to the shop - will find out in the next few days and let you know.
Why I think there is definitely something to it is that the weight of 2 turbos and the little bit of extra plumbing surely wasn't enough to alone require a stiffer bar than that on the 997gt3/rs versus the 997gt2.
Thus, I can only conclude (besides the obvious pushing nature of the car even though it was delivered on full rear stiff) that even the lawyers allowed the engineers to at least stiffen the rear a wee bit more.
If it works, it sure will be a nice relatively cheap solution for all the track junkies - this doesn't negate the fact that I think more front tire can still be used for better braking.


Paul

997gt3north

I stole a few lines from the Guardtransmission site that explain my primary reason for my decision, but basically mine was fried and i was getting very highspeed braking instability (not fun) and I want to further exploit the gt3s amazing braking

From the website
- Limited-slip differentials provide lock-up on both acceleration and deceleration. Lock-up on deceleration allows aggressive entry into a turn and late braking, reasons why all Pro race teams (that we are aware of) utilize LSDs, rather than TBDs.

(in english, if you brake late and are trail braking, the car will want to start rotating like a top, the LSD actives like throwing an anchor out the back of the car and keeps the rear end much more planted as it is forcing the rear wheels to rotate at the same rate even though you are turning the stearing wheel
)

- A torque-biasing differential (TBD) performs like an open diff whenever one of the two drive wheels lifts off the ground. Lock-up and traction are lost until both drive wheels are again planted firmly on the ground.

(in english, this is a benefit of a LSD over a TBD in that if the inside rear wheel is slipping the LSD will lock and the power will get put to the ground better)

There can be a negative of a very high lockup rate LSD versus a TBD
- Torque-biasing differentials provide lock-up on acceleration only. The amount of lock-up (5-80%) increases as the amount of torque increases. On deceleration, lock-up is negligible, making the TBD the ideal diff for the slower speed turns of autocross. (In the same slower-speed turns, an 80% LSD would most certainly cause understeer.)


To answer your gearing question
- basically a trackcar through gearing (a multiplier of tq) wants to maximize the amount of time the car can be in it's natural power band
- a 4.0 r&p plus slightly different 3-6 gears results in slightly better acceleration on the gt3 motor
- obviously there are downsides like increased tranny wear because of increased gear changes and the gt3s power band 5500rpm - 8000rpms isn't exactly wife friendly daily driving territory nor the gas friendly range

paul

smlporsche

Congrats on the Gaurd unit.
I installed one on my S2 and it has completely transformed the car under threshold braking as well as hooking up coming out of the corner.
You won't be dissapointed...