Geoffrey

I began the installation of the brake system tonight. It is an ABS-5 system from a 993 C4S/TT. This is a true 4 channel system, unlike the 3 channel system the comes on the 964. One of the cool things I found along the way was a factory racing brain from a 1998 GT2 and I was able to scrounge around for a front harness from which I cut the ABS wiring and relays out. I should be able to wire this up as a stand alone system and will include an ON/OFF switch similar to the 964 Cup car.

I got it mostly installed with the exception of some soft lines which I'll want to replace with new ones.

bhensarl

Dude, you must be some sort of a genius. I can't even rewire my new stereo (believe me, I've tried ). Great work once again!
Brian

NineMeister

Geoffrey,
Obviously you have sold the family to the slave trade to pay for all these goodies, so I'll treat you to a new pair of temporary bonnet rams if you like so that you don't have to ruin that lovely paint by using a plank to hold up the hood.
Great work - I wish I had the dedication to take my RSR apart and do likewise to the same standards -keep it up.

hawk911

Now that's just showing off.

Geoffrey

Hey Colin, thanks for the offer. I do have the factory RS aluminum prop rod in a box somewhere, I just haven't found it yet. What you don't see is the high tech old shop rags protecting the paint...

I just happened across the brain on eBay one day so I guess I just got lucky. I didn't sell my family, but I did sell my very nice 700hp 89 Turbo 911 for this project.

Trust me, I'm no genius. All you need is one of these and some patience to cut apart the front wiring harness to extract only the ABS specific wiring, relays, and fuses. Porsche wiring diagrams are great.

Indycam

3 channel vs 4 channel ? What this ?

NineMeister

The standard 964C2 ABS system has three channels controlling front left, front right and rear brakes as a pair. The 964RS (and 964C4?) & Motorsport ABS systems have 4 channels which obviously control all 4 wheels independently.

I believe that the Motorsport ABS ecus also have different control parameters to allow higher levels of slip on individual wheels, perhaps someone with more info could enlighten us?

Geoffrey

Hi Colin, I believe all of the 964s came with 3 channel ABS, including the factory RSRs, at least that is what I'm seeing in the parts manuals. I think the 4 channel ABS came out in the street turbo in 96 and on the RSR/GT2 of that era.

The chips inside the brain have a sticker written "Cup" on them indicating that they are different from the production ABS. Those that have driven with the racing brain say that it is much better than the street brain in terms of speed and allowing more slip out of the wheels before kicking in. I believe.

NineMeister

I think you may be right over the 964 models, I have to admit that I had my head firmly in the 993 box when I mentioned the differences between the C2 and C4/RS/Turbo.
Interestingly we have a 964C2 arriving in a couple of weeks to fit a complete 993 turbo ABS system because the standard system will not cope with Big Red brakes and sticky tyres on track. Similar job to your's I would imagine.

Geoffrey

Yes, and I believe the racing brain and the street brains to be interchangable. Coping with slicks and allowing for some wheel hop on rough track surfaces due to stiffer suspension is what the racing brain allows for. Too bad you were not here, I'd send you the brain to try. Furthermore, my final plan is to fit the car with the dual adjustable master cylinder which will allow for brake bias to be moved around. That and the electric power steering are two projects I'll tackle after the car is up and running.

tonytaylor

Does the 993RS and RS clubsport use the same ABS ECU as the 993tt ?

Geoffrey

Front brakes all bolted up. There is an endurance setup that uses 380mm rotors and 1" thick pads, but that would be just overkill on this car. Brake rotors are 332x32 with alumunum hats which are slightly larger than 993TT/C4S/RS rotors which are 322x32 and have steel hats. Calipers are the same.

Centerlocks again.

Cupcar#12

Geoffery
Can you send me pictures of the trunk as you do this - i'll be right behind you in installing my system.
hopefully i can find either an RS ABS brain or salvage the chips from mine (which was crushed)
My car should be delivered in a day or two (after 2+ years )
I can send you my email
thanks

Geoffrey

Rob,

No problem, I can send you any pictures you want. I believe the 964 Cup used the same street car brain. I have several friends with Euro cup cars and I can verify that later this week when I see one of them. In fact, if they are the same, I may have the factory ABS brain still.

Bill Verburg

Outstanding job on this car,

please post full details of the vac. to hyd. swap. It is a very desireable mod IMHO