And you know from experience that the OSgiken is inferior to the Guards and Motorsports?????

I have run the OSgiken in 2 different cars, Honda S2000 SCCA T3 race car/996GT2 OLOA/UTCC, and couldn't be happier. I will also state that I have no experience with Guards/Motorsports LSD builds.


80shilling,

Sounds a lot like 930mans GT2 build, I would only comment that for track work 400/600 is going to be mushy. I run 600/800# springs and the ride is acceptable on the street.

Peter

 

Peter, I think 400/600 is good for what I want to do with it, bearing in mind that I will be using added gas pressure in the remote canisters on the Car for additional spring rate support at the track. When I'm finished at the track, I remove the added pressure and BINGO! comfy street manners. If you are right though and I DO think it's too mushy at the track, I will just have to change out the springs to the 600/800 setup that you have and see how I like it.. at very little additional cost.

I am choosing the OS Giken, because it's something different, I have had some really good feedback from a couple of local racers who use it and it seems to overcome the understeer/push issue the Guards and Motorsports LSD's have on corner exit because it doesn't instantly lock, it gradually applies locking force.. If I hate it, I can always go with the Guard.

Thanks for all the great information and feedback this thread has generated, I really appreciate all the support. I will make sure to let everyone know how this turns out.

 

thanks for sharing, great thread.

 

You won't hate the OSgiken, it is very progressive on lockup and not pushy @ all. That is the beauty of the OSgiken diff. The price doesn't hurt either. If I remember correctly 100#'s of pressure equals app 33#'s of spring rate which is good for tuning. But you are right, changing spring rates is one of the most reasonable $$ things to do.

Peter

 

Yes... This thread has turned into a VERY informative exchange of ideas.. really productive..

 

Just because it hasn't run ALMS doesn't mean it can't. Notice I haven't said anything bad about Guards, just that from my personal experience the OSgiken works very well and IMHO it is a viable alternative.

http://www.osgiken.net/products/superlock.html

Peter

 

Thanks for that explanation.. DAMN! these Cars get expensive when you really want to do it right.. I might call Kevin Buckler at TRG and see if he has any interesting parts lying around.. I've known him for 15+ years and maybe I can sweet talk him into giving me some of the good stuff at a decent price...

 

Believe me it wasn't easy being a Guinea Pig It is a large leap of faith and $$$ for the install on a Porsche vs the tried and true Guards/Motorsports/Repacked OEM LSD. If I hadn't used an OSgiken in my S2000 and been very impressed I doubt I would have installed 1 in the GT2.

Peter

 

So... after a frustrating month, my suspension project is finished and the results were well worth it...

There was an issue with one of the shocks not working correctly, so I had all 4 rebuilt from scratch.. New seals, new ss lines, new valves, new fluid etc.

We settled on -1.5 degrees camber in the front and -2.0 degrees in the rear, caster of 8.2 in front, 1/32 toe OUT in front, 1/8th toe IN in the rear. The ride height is set at 25-3/8 front and 25 1/2 rear.

The Car is transformed... The ride over rough, broken surfaces is 100% better.. the wheels no longer lose their composure and the car stays planted, whereas before the car would literally leap around from bump to bump.. The ride is substantially improved over the stock harshness, yet the slightly stiffer springs control the car better in high speed situations and even on the freeway there is a marked improvement in stability in a straight line over stock. Most of this is attributable to the additional high speed damping circuits that are used to tune the shocks to absorb the high speed shock shaft movements (sharp bumps that accelerate the shaft very fast)...

In tight, twisty situations, the car turns in more immediately and is now quite phenomenal, with less body roll and no nervousness. The rear end is planted and follows the front like it's on rails. The previous sensation the car had of the rear end almost "falling" into the corner in a sloppy, uncontrolled fashion is completely gone, replaced by precise movement. Once the car is in the turn, it's on rails.. even midcorner bumps fail to dislodge it from it's intended path... It takes a set and then doesn't move.. no porpoising, unwanted movement, nervousness, squirming; it just digs in once and then stays set until you change the steering input.

On corner exit, I can apply the power earlier and harder, due to the rear end squatting less which means there is less weight transfer from front to rear.. this means that the front end doesn't get light under power, causing understeer as it did stock. The rear end grips incredibly well and just digs in and fires me out of the corner while the front end grips and goes where I have pointed the car.

In mid to high speed corners, the car is just phenomenal... I have a favourite road in the middle of nowhere that I test all my cars and Motorcycles on that has a bit of everything on it.. Tight twisties that are smooth and also have some diabolical rough patches, mid speed corners and some 100+ mph sweepers, some that you hit 140+ through if you have the car to do it.

After a couple of passes, I had the car in a beautiful 4 wheel drift at about 80 mph through one particular corner.. just freaking sublime... It's one of those driving moments of nirvana where you hit everything just right.. the car does what you want it to do and you have it balanced right on the edge, but all under control.. I was laughing like a maniac, giggling like an 8 year old it was such a revelation.

All-in-all, I have to thank Rob King at S-Car-Go for seeing this project through and dealing with my perfectionist nit-picking.. I'm sure he got entirely sick of me asking him to tweak this and change that until it was spot-on. The results were ENTIRELY worth the hassle and extra work we had to do. The combination of components and settings are amazing...

The big test will be when I get the car out to Laguna, Sears/Infineon and Thunderhill.. Then I will know if I have to increase the spring rates or not.

Now I can honestly say that this is by FAR the best car I have ever owned.. The stock suspension is definitely the area the car falls down on, but once it's fixed..... Stupendously amazing car..

 

As with Peter, we both have 600/800 springs and I FEEL it's the lowest I would go , but for what you want it should suffice!

I have your setup just about done, do you still want it to compare to mine? I told you I would do it for you, sent it around to a few people and what you sent me setup wise, and finally received info back.. I'll compile it all together and send it to you in a little bit.

On a brighter note though, glad you found some sort of resolution with your setup, as from what you told me before it was never ending like with my car/setup, in search for that SOLID setup!

 

Thanks for your input and support while I was dealing with this, I really appreciate knowing that you were there as a resource if it all went pear-shaped..

I would be really interested in seeing what your setup is and compare to to mine, as I am always willing to tweak and prod something until I feel it is close to perfect. I think I am going do dial in ONE more click of rebound damping in the front and see what that does, as I think it might further refine the behavior of the front end.

As you say, I might get to the track and find my spring rates to be too soft. I can always change springs for a nominal amount of money.

I will be driving the snot out of the car for a month or two, finding out what if anything needs tweaked for the road. Once I finalize the settings, I can track the car and as you know, what works perfectly on the street, can be entirely inadequate for the track.

The tracks I run are so different, that I usually have a different setup for each track. Sears/Infineon is where you need a softer setup and I will be able to also set the left side of the car up slightly firmer than the right, to deal with turns 2, 4, 5, 7 and 10 where I traditionally end up with slight understeer (especially turn 4 which is off camber). Thunderhill and Laguna are smoother surfaces.. Laguna is quite low grip compared to the other tracks and I tend to concentrate on setting the car up to be very fast and neutral through turn 4 and also to make sure the brakes are biased correctly to avoid swapping ends under hard braking into turn 2.

I look forward to getting your input and settings. Thanks again for your support and knowledge.

 

FWIW people run stiffer springs so they can hold the car up under cornering and give you more flexibility with the dampening rates. If your springs are too soft, you will roll them under cornering loads and have to run stiffer dampening rates. Stiffer spring allow less clicks of stiffness on the dampers.

People that buy coilovers and report that the car jumps over small bumps (uncommonly misrepresented as bump-steer which it is NOT) are suffering from riding the dampers and not the springs. Soft springs = too much body roll, so you have to run stiffer dampening to hold the car up because the springs are too soft.

Personally, I think a high speed, high load (I.E. low speed bump requiring) track like Infineon will completely overwhelm your springs. These car are heavy! If the tracks is baby butt smooth, i's not a problem, just up the bump rates. But if it's bumpy you need stiffer spring rates for cornering.


However I would like to know what the aftermarket drag/trailing arm does. better than stock other than reduce deflection under load.

 

These new coilovers have done the exact thing I wanted, which was the REVERSE of the stock suspensions terrible behaviour over broken surfaces. They have made the ride downright cushy compared to stock, because the high speed damping circuits allow the shocks to absorb the small, sharp bumps that the stock shocks/springs couldn't deal with.

Sears needs softer spring rates because you need more suspension travel as well as more weight transfer... Having spent 7 years racing my 550 HP 944 Turbo there, I went through 7 or 8 sets of springs and eventually settled on a set that were only 100 lbs stiffer than stock (non progressive). The surface at Sears is far short of the smoothness of Laguna or Thunderhill, plus the need for weight transfer there is different than most tracks you will run.

I quizzed the top suspension gurus at TRG (Kevin Buckler's group) and the Nascar and Southwest Tour suspension guys and got some really great information from them regarding how they set their cars up differently for Sears. They go with the softest spring rate they can without causing clearance/grounding issues at Sears for precisely those reasons.... Travel and weight transfer. It completely screws you up for aero effects (too much travel/ more ride height allows air under the car) , but Sears is a mechanical grip circuit for most cars, not an aero circuit.

Again, I have to have this car remain civilized for the street, since I use it for weekend getaways with my Girlfriend and want to retain a civilized ride... I have a friend that has a 944 turbo that's setup for the track that was built for him by Andial.. full cup suspension 800 lb springs front, 1000 lb springs rear.. that car is undriveable on anything but billiard smooth surfaces.. it launches itself into the air over even small bumps on back roads. Even MY 944 turbo was unbearable on city streets and country roads. The GT2 is most definitely a compromise car for me.. I don't need it to be a dedicated track weapon.. it needs to be good enough for both environments.... I will be happy if I can turn 1:38's again at Laguna and 1:49's - 1:50's at Sears... If the car is capable of that, then I will be happy, as that's what my 944 Turbo would run on Hoosier R6's... only that 944 Turbo ceased to be useful to me as a street car because of the suspension being too track focused at the end.

 

I will put this up here for everyone to see. All of this info was sent to me after opinions from Vic (VA122) on rennlist, Lex at Moton and Vic I believe spoke to Sofronas at GMG! It transformed my car..... Hope it helps!

"I'm still waiting for Lex at moton to call me back, he was racing.

Here goes
-center steering wheel first and lock in place (seriously no one does this for some reason.)
-Camber for DOT-Rs 2.6/2.4 f/r with shims or you'll lose your caster
-Caster 8.5
-toe 0/-2mm (toe in) per side f/r
-bar middle/1 from full soft f/r
-adjust rear dog bones for kinematic toe in (not out) if they don't know what i'm talking about leave go somewhere else.
-adjust rear toe links for 0 bump as above if they don't know what i'm talking about leave go somewhere else.
-springs 6in with 3 in helper (0-150 weight) visually it should be completely compressed when wheels are on the ground.
-600/800 or 600/900 up to 800/1000 more and you'll need slicks.
-rear locking plate for toe links help depending on what brand you have.
-re-corner balance the car with your weight in the drivers seat with sand bags. ( a LOT of shops forget the weight part)
-front bump kit is a must if you lower more then 20mm from stock
-rake/chassis height- 100/120 f/r or that ratio if you want to go lower, but too low you need the cup uprights
-canister pressure 150/175 f/r

you should be good to go from there and the rest is shock tuning. I'll get you the baseline from lex, depends on the springs you use (eibach)


"Wooo Hoo, Just talked to lex.

here we go,

yuo want a 4-5" min spring up front 600-700lbs with a 4" 150lb tender

In the rear you want a 5-6" main 800-900lbs and a 4" 150lb tender.

Canister pressure:
Front 150-psi
Rear 175 if you have the 22mm diameter shafts and 250 if you have the 14mm diameter. You have 22mm in front so you can compare to figure out which ones you have.

Shock settings.

F compression (on the shock body) 4-5 from 0
F Rebound (cans) 4 from 0
R Bump(compression) 4
R Rebound 5 from 0

From there you should be good to go, and let em know if you want to plug a pro in the car and sort her out once and for all. "

 

dude when i finished the suspension in my Gt2 it beat the hell out of the 996 cups!!! with carpet ac and radio... i would drive it home from the track!