David J Marguglio

It has been suggested to me that the programing for the RSR ABS brain is markedly different than the stock 993. As I have access to both units, is it possible to copy the "chip" in the RSR unit to upgrade the stock unit? If so, is that something I should persue?

Geoffrey

David,

I have been wondering this exact same thing. The system hardware between a 993TT / 993C4S and one found in the RSR is exactly the same. Noting that you have a C2S, you'd need to make sure the hardware is the same. The AWD cars have the master cylinder in the trunk along with the pump and accumulator. I don't know about the 993 2WD models, but the older 964s have it up under the car where the AWD front diff sits. The brains are interchangeable between the AWD and RSR, and the "Hammer" works both systems. I have access to a RSR brain, but no C4S brain to compare. I would first start by looking at the inside to see if the processor board looks the same. If I didn't own the RSR brain, I would get access to an EEPROM programmer and copy it to a blank chip so I had it for the future, then install either the copy or the original into the 993 brain and locate a "Hammer" and go through the test to ensure the system is operating properly. If so, then I would very carefully road test the swap. The thing you don't want to happen is to have the ABS system not workproperly. Not working wouldn't be as big an issue, however, not working properly could be catastrophic. As an aside note, there is probably some legal thing about copying the chip, blah, blah, blah...

DCLee

Short answer: I don't think so. The racing ABS for the GT2 Evo and RSR cost upwards of $10k from the factory. I believe it was four-channel ABS (like in a T-T) not the three-channel street 993 setup. Somebody correct me if I'm wrong.

No easy answers here, I'm afraid...

Lee in D.C.
Lee

ngoldrich

Geoffrey,

Is the "hammer" you are referring to an ABS test unit ? If so, where can I get one ?
My race car has 3 channel ABS and I have thought about upgrading to 4 channel. But like you said, I do not want to risk it since I will have to modify the harness to work. I want to know all circuits are correct and functioning properly before I drive it.

Thx,
Norm

Geoffrey

The 993AWD (TT and 4S) and RSR systems are the same from a hardware perspective. The brains are interchangable. Both are 4 channel systems.

Norm, yes, the "hammer" is an ABS test tool, not sure where to get it since I borrow it, but it isn't all that expensive, about $1200 or so. You can get a harness and cut out just the ABS wiring and install it as a separate system without the ECU and Chassis wiring. This is what I'm doing in my 964 project.

Bill Gregory

993 2WD's are just like the 964's, with the MC and vacuum cannister where the AWD differential goes.

MJR911

Anyone know how easily and cost effective it is to upgrade the ABS unit for 964Turbo system? I would like to go from the street system to a better race setup. Any help would be appreciated.

Geoffrey

All of the 3 channel systems are pretty terrible, including 964 Cup and 964T so it wouldn't be an upgrade. The upgrade is as mentioned in this thread, true 4 channel from the 993 C4S or TT,and a racing brain which is available from PMNA for about $1300 (pricing courtesy of Norm).

MJR911

Sorry for my ignorance, but does the racing brain from PMNA a direct swap from the 964 system?

ngoldrich

Mitch,

No, this racing brain is 4 channel ABS. The 964 is 3 channel. From what I hear, you need to change the whole ABS hydraulic controller, tubing, 4 port bulkhead connector, wiring harness & brain

Norm

MJR911

Thank you Norm and Geoff, exactly what I wanted!

Geoffrey

Here is the ABS hydraulic pump you need to work with the Racing brain

Dave in Chicago

Mitch -

There was a racing ABS for the 964 RSR, good article from years gone by in Pano, I think I still have it in an issue of Up Fixin der Porsche. Jurgen Barth, then Director of Customer Racing, is interviewed and says the '93 964 RSR 3.8 "has the same ABS system as the 911 Turbo GT Le Mans. It is a racing ABS system with different hardware and software. It's a much more effective system because with the normal ABS their are long intervals before it reacts and returns to standard again, which means the amplitudes or cycles are long. The racing ABS cycles are short. It enables you to brake much later, deeper in the corner than you could with normal ABS, or even with your foot. The racing ABS was developed for the RSR and used at the same time on the 911 Turbo GT Le Mans. The RSR actually came first."

For what it's worth, there's at least one of these RSR's in the region, though I have not examined the ABS bits.

Julian Allen

I think that's a hydro-boost pump for the power brakes, not the ABS pump which should be self contained with the valves and solenoids: 4 channel ABS should have two lines in (F & R) and four lines out (one to each wheel).

Geoffrey

Yes, it is the hydro pump which is ONE of the 6 major components you need to convert to the system that is compatible with the Racing ABS brain.

Master cylinder
Reservoir
Pressure accumulator
Hydro pump
ABS controller
ABS brain