Stefan964

Hi everybody,
my name is Stefan and I am driving a midnight blue 964 C2 (1991) that is meanwhile slightly modified for track events (RS suspension, big reds, Recaro-seat, RS motor mounts, MPSCs and other minor things).

I tried the search function but I dinīt find a clear answer to my question.

Here in Germany a lot of people are looking for the original 965/RS wheel carriers if they are upgrading their brakes to the 993 tt/993 C2 combo in order to avoid adapters for the mounting of the front brake calipers. Meanwhile these wheel carriers from the 965 or 964 RS are nearly priceless.

My question is: Are the 993 GT2 EVO wheel carriers an alternative?

- can they be used for 964?
- are there any additinal parts needed (besides of the tie rods)?
- which tie rods are suitable for the narrow body 964? also GT2 EVO or 993RS?
- is the mounting of the brake calipers (bigreds) directly on the wheel carrier possible?
- what braking disc has to be used afterwards (the one from the 965 turbo 3.6 as before or 993 turbo)?
- is the 964 abs sensor reusable?
- has the whole abs tooth lock washer and hub screw assembly to be changed to the 993 configuration and if yes is this still cooperating with the 964 ABS system?
- any problems with the use of 17-inch CupI-rims after the change?

I would appreciate any further details for the use on a 964 (as well as a list of the needed parts). I would like to get rid of my caliper adapters in a technically perfect way.

Thank you and best regards

Stefan

tonytaylor

I'm running the 993RS front hubs on my C2 along with the tie rods and 993RS front wishbones and 993tt front discs and calipers so I assume it will be possible to fit the 993GT2 EVO hubs as well.

Sorry I'm not very tecnically minded so I can't answer uyour questions however it may be worthwhile contacting Ninemeister who fitted the parts.

BTW it's a worthwhile upgrade IMO

Geoffrey

Yes, 993 GT2 Evo uprights can be used on any 964 or 993

You will need RS (not GT2 Evo) tie rods AND 993 inner tie rods. You will also need a front damper from a 993. The aluminum upright is 1mm thicker than the steel 964 upright so the stock dampers will not work.

993 Big red calipers are a direct bolt on with no spacers but require 993tt rotors or aftermarket equivalent.

The 964 hub, ABS ring and street screw and bolt assembly will work with the upright but needs to be kept as an assembly. 964 has 45 ABS teeth, 993 has 48 ABS teeth, you don't want to run 48 teeth. You can run the 993 RS hub, stub axle if you use the 964 street ABS ring or the optional 45 tooth motorsport ABS ring.

I don't know if a 17" wheel will fit, but a C2 Turbo has the Cup 1 wheels and 322x32 front rotors, so I would guess that it is possible.

airiscool

Excellent information Geoffrey.

I just can't wrap my head around one piece of this puzzle...

Why not machine away 1mm from the EVO upright and retain the same front 964 dampers? This would cut away much of the conversion cost! Do 964 and 993 front dampers share the same bump + rebound travel and geometry?

Geoffrey

I suppose you could machine the GT2 Evo uprights, but Porsche must have made them thicker for a reason and without stress analysis, I could never recommend that you do that.

I don't know that much about stock suspension and can't answer your question. If you move to a Moton or JRZ damper, the travel should be the same. I wouldn't see why you couldn't install a front pair of 993 dampers like from an RS, but obviously, you want the front and rear matched to the springs you are running and to the setup of your car.

chancecasey

Instead of machining the uprights, you might be able to "widen" the struts - e.g. Bilstein HDs for 964 have a sheet metal "channel" insert than can easily be removed by grinding 4 little spot welds - and I think it then fits the EVO upright. Would be interesting to see if an EVO Bilstein HD (if that exists) has this "removed" as I describe, or if it has a wider flange/insert combination. The flange metal is nearly 1/8 inch steel - more than strong enough when bolted to an upright I'd think. I would give it a try with my HD's - but I'm not necessarily saying you should.

Tom W

To me the question is why you would want to use a "stock" damper on a car where you are installing a race part. If you do one, you should be doing the other.

airiscool

I wouldn't. My car already has pricey dampers that I'd rather not have to replace. $1600 + installation sounds reasonable but to add another $1500 in dampers makes it less appealing.

Stefan964

thanks Geoffrey - excellent information.

I neither like the idea of machining the wheel carriers nor the idea of widening the struts. The best solution is definitely the switch to the 993 RS front dampers.

Unfortunately the combination of wheel carriers, tie rods and new dampers is almost as expensive as the switch to 965 wheel carriers (and my 964 RS suspension is almost new) -> I think for the moment I will further use my caliper adapters .

By the way:
Is the aluminium upright of the regular 993 wheel carrier in general 1 mm thicker than the steel version if the 964?

Thanks

Stefan

Geoffrey

Yes, 993 standard upright is the same as the GT2 Evo upright.

WIth the standard 964 suspension, you can make your own bump steer kit by modifying the upright to use a spacer on the tie rod and then replacing the tie rod end with a heim joint. This helps lower the tie rod so the toe change isn't as great.

Gus

geoff -
I know what you said about the modification is rather simple to you - but can you expand a little in detail for me as to what i need to do to make my own bump steer kit -
Modify the up right to use a spacer on the tie rod ?
Replace the tie rod end with a hemi joint?
All this is done to the bottom of the upright - I would like to make this modification but am not sure of the specifics-
Thks
Gus

Geoffrey

There are many ways to solution the issue, but the short of it is that you need to get a spherical rod end on the end of the steering rack, and it needs to be able to be adjusted for alignment. From there, you can cut the upright and weld a new bracket on, you can make a spacer and bolt the spherical rod end to the stock location.

Gus

Thanks -So mainly the objective is to lower the attachment point of the steering rack on the upright - The spacer needs to be of a length that would allow the steering rack arm to be horizontal or level on the car - as now it angles up significantly - RIGHT? Thks

Geoffrey

Yes, except you will be limited by the wheel to tie rod dimension. The larger diameter wheels, the lower you can place the tie rod. If you can get the tie rod level horizontally, AT YOUR RIDE HEIGHT, this will be the best setup for minimizing bump steer. This solution does nothing to fix the camber gain though.

Gus

Thanks for the feedback - I am running a neg 2.8 camber now - which is the maximum negative setting that I can get. I am not sure that I am understanding your ref to camber gain - thanks for the feedback