powdrhound

I just wanted to do a quick post on my impression of the recently installed Guard GT Club 40/60 LSD in my car. My decision to install the LSD in my car was the fact that I had trouble putting power down coming out of corners at my local track (HPR). I was running my car with PSM switched OFF (with the dash switch) in AWD form with the stock open diff on Nitto NT01 235/315 Rcompound tires and putting down about 550-600hp. My alignment specs are -2.2 camber front, -2.1 camber rear. Toe is 1mm total front and 1.5mm total rear. Spring rates are 600F/800R. Once I started running the car aggressively in the upper run groups I started having issues with spinning the inside rear tire when powering out of turns. It didn't matter if I was AWD, the car just does NOT have the ability to transfer much meaningful power / torque to the front via the viscous coupler. There are a number of guys here that will claim that an LSD is a waste of money for these cars in AWD due to our "abundance" of traction but my experience shows other wise.

When I initially had the LSD installed I decided to retain the AWD system to gauge what difference the LSD would make. The only other change I made was to have my shop totally disconnect the PSM system on the car thus taking it completely out of the equation. I still have ABS so the car is basically set up as a GT2. Right off the bat, I could tell a difference in the car in the way it powered out of the turns. The car now hooks up beautifully and just rockets out of corners. It feels more stable under hard acceleration than before, it tracks "straighter", if you will. One of the things that surprised me was the fact that the "push" of the car mid corner was reduced as the car now was much more eager to have the tail of the car step out, the rate of which could easily be modulated with the throttle. It is now actually very easy to drift the car if you just wanted to play a bit. This was impossible before with the open diff.

The one HUGE difference of the LSD however is one that I did not really anticipate prior to the install. What I am talking about is how the car now behaves under hard braking and how much easier it is to trail brake the car with precision. Prior to the LSD install, whenever I would enter the braking zone and brake HARD, I could feel a bit of nervousness to the car that is hard to describe. Under hard braking the car felt like the rear end would get very light and lightly wag it's tail from side to side, enough that small corrections would need to be made. Also, it was very easy to have the tail of the car step out during trail braking and I would have to be real careful to keep the back end in check. After the LSD install, all this "nervousness" disappeared. The car is now dead solid under hard braking and I brake hard, generally just to the threshold of where the ABS would occasionally start to cycle. The car now just squats down and comes in dead straight. I think this is a result of the Guard LSD being set up with abound a 50 lb. preload which ties the two rear wheels together inducing this "stability". In addition, it is now much easier to trail brake later into the turn without the back of the car feeling like it wants to come around. All in all, it feels easier to to drive the car harder into the turns now.

I must also mention that the notion that the car will push on corner entry with the install of the LSD is a huge myth, at least not with the LSD set up I have. I detected absolutely zero difference in the corner entry compared to my prior open diff. Maybe this is because I can trail brake later and more aggressively but the car does not push any more than before.

Another item of note is how smooth and progressive the Guard CLUB LSD is especially now that I have done 10 track sessions and changed the gear oil. I fully anticipated more of an ON/OFF type feeling but it is just not there. The lock up both under braking and accel is seamless. Initially in turn 12 at HPR where the car accelerates hard and unloads a bit as it crests the hill I could feel the LSD lock and try to induce a bit of push but this is now completely gone after the break in. On the street the LSD is totally transparent with out any noise except when I am backing up and turning where you can hear a bit of a clicking which I assume is the clutch packs. When moving forward the LSD is dead quiet. I ran 3 sessions at HPR with the new LSD and then did some timed runs and took close to 2 seconds off my normal time while still running fairly conservatively trying to relearn the car. Not bad, I am sold.

The other thing I was considering was going to RWD and after speaking with Chris Cervelli who highly recommended it I decided to take the plunge. I removed all the 70+ lbs. of components from the car, added a touch more rake and had it aligned and corner balanced again. As an aside, removing the components shifted the balance spit from 38.5/61.5% to 37.6/62.4%, so less than one percent. I am very impressed and happy with how it turned out. The car is now RWD with LSD and no PSM but with ABS. Basically what I ran before minus the FWD. The difference is now is VERY VERY subtle and by no means huge. It feels a touch more nimbler and really seems to turn in even better. Any push that may have been there is gone as far as I can tell. I think you have to respect the car a little more and be ready to catch the back end from stepping out with a quick stab of counter steer. With my 550+hp traction is not an issue on R compound 315s anymore than it was in AWD. This really just reaffirms my belief that the FWD system does not have the ability to transfer much meaningful power to the front.

I did a few session at the track in RWD but with traffic did not have a chance to do any timed runs to compare it to AWD. I do believe that the car will be marginally quicker than AWD due to the fact that the car is a touch lighter thus allowing slightly faster cornering speeds and some power is freed up from the reduction in drag. I did gain about 2 mph at the end of the straight at HPR. My seat of the pants dyno tell me 20-30 hp. As I said, the car now does feel a bit quicker and more tossable. I like it and look forward to really relearning the car getting the most out of this setup.

In summary, I am very happy with the results of this set up and see this as a "must" for anyone that seriously wants to track their 996tt. In my opinion, for what it's worth, the addition of a properly set up LSD along with a deletion of PSM is a huge benefit to the AWD system that will give you quantifiable benefits when the car is driven hard. In my book, the LSD benefit is almost greater under braking than accelaration. For a RWD turbo an LSD is a virtual necessity in a track environment or if you want to drive the car hard in the twisties. It is beyond me how anyone could be happy with the performance of one of these cars in RWD mode with an open diff unless they only go in a straight line.

I would like to thank Matt Monson of GUARD for taking the time to answer all my questions as well as showing me around his shop, and taking the time to pick out the right product for my needs. I looked at many options when looking for an LSD and Matt was one of the only guys I spoke with that did not bad mouth his competitors in order to make a sale. And in the end, that sold me. I addition my thanks must go to Chris Cervelli for properly setting up the LSD in my gearbox and to 3zero3 for putting this all together.

996tnz

^^^^Thanks for having taken the time to post this LSD info back then PowderHound. A friend only just pointed me to it as we were discussing my 996Ts backside dancing around on corner entry. Very relevant. How has your LSD held up over time - do they take much maintenance?

Tuxiemama

I must also mention that the notion that the car will push on corner entry with the install of the LSD is a huge myth, at least not with the LSD set up I have. I detected absolutely zero difference in the corner entry compared to my prior open diff. Maybe this is because I can trail brake later and more aggressively but the car does not push any more than before.


Excellent stuff, thanks for taking the time to write this up as I am about to enter you territory with my TTS RWD... brilliant stuff

powdrhound

Talk about a blast from the past thread. I have 159 track sessions on the Guard Club LSD at this point which is roughly 40 track days or 50-55 track hours. I also have a few thousand miles of street driving thrown into the mix. Zero issues. No noise or clunkiness, nothing. It just works seamlessly and it's been flawless. My only maintenance is that I change the change the gearbox fluid every 6-8 track days with M1 Delvac 75w90. Probably a bit of an over kill but I change it while doing the engine oil since it's all right there. Oil is cheap... I do have a gearbox cooler which probably helps in the long run.

cbracerx

Great review, glad this resurfaced. I'm a WaveTrac guy but only because of costs, Guard makes excellent stuff.

z06801

Great write up and follow up! thank you. I'm headed this way with mine and confirms my thoughts. Mine isn't my primary track car but seems to end up there quite a bit

"02996ttx50

i also am sold on the wavetrac. had it a cpl months and suits my wants/needs to a t. i think it's the rear wheel lock that matters, less so trail braking etc etc. but that's just me. not tracking, just hillclimbing and apexes.

either way, any "lsd" is an awesome must have mod

blockhed

my car came with wavetrac so hey it is what it is

"02996ttx50

haha the poor mans lsd

Tuxiemama

If the Feebies monitor this site they're going to be looking for drugs called "Guards" and "Wavetrack" as pseudonyms for LSD

"02996ttx50

oh im sure im already on some list... somewhere

Bernie930

Wavetrac is NOT a limited slip diff. It is a torque biasing diff. Not saying its bad but its not what they make u believe it is. Still better then some of those offshore diff's though, lol.

"02996ttx50

it is "commonly" and i believe accurately referred to as a "torque biasing" lsd for the purpose of identifying its use and application. though it is not in the purest technical definition of the term, a LIMITED SLIP DIFFERENTIAL, it does much the same thing and is described in the same category as other lsd's.

that distinction has not been lost on me. i guess that's why people say "it is what it is". lol

rs10

So for the same price, you'd go for Guard? What do you see as the advantages of Guard/disadvantages of Wavetrac?

Thanks!

"02996ttx50