Originally Posted by trophy

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Next would be the A-arms, you already have the Walrods in the front, I would replace the super soft rubber bushing in the rear a-arm (the rear a-arm has a monoball at the front of the arm already and a rubber one at the rear, this is to allow the Kinematic toe effect for the rear end). What this will do is eliminate the Kinematic toe effect in the rear of the car, makes it more balanced and predictable when pushed.

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Originally Posted by Bill Verburg

To eliminate KT you need to use a spherical joint(aka monoball) on the rear of the rear A-arm and use toe links w/ spherical joint ends.
PS I'd be very interested in learning the ET of the 9" front wheels that you are using w/ the 255/35 tires

Originally Posted by utkinpol

If you have nice clean 993 with full interior I doubt the rationale to convert it into track only car. As of what to do - 993 can be done to run faster than stock RS car, you need full track conversion - strip it, put in full cage to make it stiff, replace front fenders to fit wider rims, roll rear fenders and put rsr like aero kit.
There are cars like this on a track.
Imho nice mint 993 car is a collectable item, it is worth more in its stock form than in a track only, but it is up to you.
It also may cost less now to buy 996 cup car than to build 993 street car into 993 'rsr' replica.

Originally Posted by mhm993

I dunno. You don't even have a cage yet. Take the conversion slowly since each step can significantly change the car. Get used to the incremental alterations and make sure that everything works together. I've seen way to many cars that have taken giant steps in mods and then go, boom!

You can make a 993 into a great 993 but if you need a GT3-RS you are going to have to buy one.

-- mindy

Originally Posted by trophy

I edited my previous post, I forgot to put replace the soft rubber bushing with a monoball.....

I will measure the wheels for you Bill, I think you have asked before and I forgot about it... Running the 255's on the front was an experiment that really didn't work as well as expected. Way too much front grip that was difficult to dial out.

Originally Posted by Flying Finn

Well of course it is.

Originally Posted by Steve Weiner-Rennsport Systems

The very LAST thing on a handling improvement program would be seam-welding. You won't feel the difference compared to all the other items on my list of upgrades. A proper cage will certainly help and thats noticeable, however proper dampers are tops on the list.

EVO uprights and tie-rods are needed to correct bump steer issues found at RS ride height and thats where your car should be.

I did prioritize my list of suggestions to make assessment easier and thats where to begin. You can install monoball cartridges, however the ERP adjustable links are MUCH better as they permit a wider range of adjustability. This is critical for bump-steering the rear suspension to get better kinematics.

Originally Posted by trophy

Hey Paul,

Some good advice here all around. A good starting point would be to get rid of the rubber in the suspension, it moves around alot and doesn't allow you springs and shocks to work effectively, namely;

ERP links (toe, Kinematic Toe and Camber link), As Steve says this will ensure you can get an accurate alignment that will hold.

To get the height and geometry right at a good low height (RS or lower) you will need to get a set of RS/GT2 uprights and GT2 Tie Rods. This will correct the bumpsteer you are experiencing when you go lower.

Next would be the A-arms, you already have the Walrods in the front, I would replace the super soft rubber bushing in the rear a-arm with a monoball (the rear a-arm has a monoball at the front of the arm already and a rubber one at the rear, this is to allow the Kinematic toe effect for the rear end). What this will do is eliminate the Kinematic toe effect in the rear of the car, makes it more balanced and predictable when pushed.

The last bit would be solid side members, this will then eliminate the movement in the rear suspension carrier, further planting the rear of the car.

Next step would be to get a good track specific wheel alignment:

Camber: Will be dependent on the tires you run, less on street tires more or R-Comps etc, the resulting camber settings will depend on tire temperatures, this will be a trial and error process. Even with my car running -3+ on the front and -2.6 on the rear I actually get pretty even tire wear. (last sept I drove 1500km to Salt lake city, 900km on the track and 1500 km back with the above alignment and perfectly even wear)

Toe: As has been said, 0 on the front and some toe in on the rear. I run 0.7 degrees toe-in each side and has worked very well for my car. These cars need toe on on the rear or they can be quite diabolical. Especially the way you have it set now with 0 toe and stock rubber links.

The above will get you quite a long way to matching the performance of a GT3 in the corners, you could do this with your current JIC's and notice an amazing improvement. After this would then be some dedicated track coilovers, as per Steve's suggestion, however the above will be very noticeable.

A note on Tires: The Sumi's are a great tire, for the street. If you are wanting to match your brother you will have to select a better tire. If you are stuck with a street/track type tire I have always had great success with the Dunlop Star Specs, wear pretty well, stick well, and pretty easy to set the car up on. Sizes Front 235 40 r 18, Rear 265 35r 18. These cars can run some pretty wide rubber without modification to the body. (there is no need to put wider front fenders on these cars I have had 255 35 r 18 on the front of my car on 9" rims with absolutely no rubbing at below RS height).

If you want to go to a dedicated track tire like the Hoosier then I would go for the 245 35r18 front and 285/295 30r 18 on the back.

Of course the alignment settings for camber will be different between the Dunlops and the Hoosiers.

Oh, get your diff fixed with parts from Matt at Guard

Hope this helps.

Originally Posted by Bill Verburg

To eliminate KT you need to use a spherical joint(aka monoball) on the rear of the rear A-arm and use toe links w/ spherical joint ends. You can buy RSR rear A-arms which come w/ some very nice large spherical joint in the rear leg and nice new ball joint at the outer end. The leading leg of the rear A arm has a spherical joint like connection. I'm curious as to the possible differences in the stiffness of this joint. All the ones I've tested that have been removed from a stock chassis 993 have been quite loose and sloppy, the RS rear A-arm that I used was extremely stiff and tight by comparison and the same seems to be said for the RSR versions. Unfortunately I have not had the opportunity to test a new stock one to see if they are any better new than at the high milages I've seen.

but just reducing KT by the use of RS hardness rubber is a nice way to go that still leaves the car streetable.

If you really want the car to handle at it's best you do need to eliminate all the rubber suspension pieces and utilize some great adjustable shocks.

An interesting option for all the spherical joints are the sealed versions that have recently been coming on the market, the older style which are exposed to the elements really don't last all that long. The factory has always used a sealing gasket on the RS shock tops but the sealed A-arm(both front and rear) and rear control arm versions seem like a very attractive way to go. Of course if the ball joints are in need of replacement factory RSR parts are the way to go.

PS I'd be very interested in learning the ET of the 9" front wheels that you are using w/ the 255/35 tires

The other advantage of the RSR type front end besides the wheel/tire setup that is possible is the wider track, The factory engineers have lobbied for wider track front ends on the RS/RSR lines for years, finally getting the go ahead on the 997GT3RS .2 versions and the newer 991

Originally Posted by GTgears

Just a little bit of inspirational viewing...
http://www.youtube.com/watch?v=eyjLmrHk3_s

Originally Posted by bobt993

I can tell you that the 997 GT3 with still out-handle a well sorted 993 unless you do an extensive job on the aero setup and change the geometry on the suspension. Keep in mind Porsche was really just getting started with the multiink suspension when the 993 and has only improved it along the way.