jaholmes

Does the NB C4 have the same ABS setup as the C4S and TT cars. Is the ABS pump a 4-channel ABS system. Also, is the entire brake system on the C4 different then a NB C2.

Thanks,

Arena993

Jeff (InTheAir) any help?

95 C4 993

From a similar question I asked some time ago.......


The ABS/ABD (options M224 & M339) hydraulic unit part number is #993-355-955-50. However, you may also need to replace the ABS control unit depending on the production date of your 993. The Porsche part numbers have stayed the same but the units were revised so if the serial number ranges don't match you'll lose ABS functionality. If you are replacing the hydraulic pump on a MY94 or MY95 check the ABS control unit serial number for a 4-digit production date (in bold below)

ABS-Control Unit (993-618-125-00)
DI015193XXXX

ABS/ABD-Control Unit (993-618-126-00)
DK094593XXXX

If you have a 3-digit production date (in bold below) you have the old style control unit and will need to also replace that.

ABS-Control Unit
DI013720XXXX

ABS/ABD-Control Unit
DK093710XXXX

if you are replacing with a newer style hydraulic unit. The newer style units have a serial number greater than (in bold below)

ABS Hydraulic Unit (993-355-955-00)
462/502372

ABS/ABD-Hydraulic Unit (993-355-955-50)
463/505058

InTheAir

The NB C4 (and C4S for that matter) does in fact have the same braking system as the Turbo, which is different from the C2. However, the difference lies in the brake booster setup--the C2 has a vacuum brake booster and the C4 & Turbo have the hydraulic brake booster.

The C4 & Turbo come with ABS and ABD (automatic brake differential) and, because of this, have two brake power controllers versus the single brake power controller in the C2.

Arena993

See the "Mighty One" comes through. Jeff to clarify. The C4 does have the same brake system as the Turbo, but the calipers are C2 type. Right? Just wondering.

Mike

InTheAir

That's correct--the NB C4 has the same calipers as the NB C2.

pcar964

What about C2s with ABD?

InTheAir

They have the two brake power controllers, but I believe still have the vacuum booster.

Arena993

Thanks for the clarification

RallyJon

Except for the smaller rear pistons for some strange reason.

InTheAir

Correct--the piston diameter inside the caliper is smaller on the rear in the C4.

jaholmes

Yes I did see this in the thread about making a C4S into a C2S. But it didn't make a lot of sense to me.

I have been thinking about a NB 993 and doing an RS Clone track car, and others have pointed out that the C4 is a good starting point because the ABS is the same as the RS.

I know it doesn't make sense to make a C4S 2wd, but a C4 might be not as bad. Plus I don't want to get into the arguement about RWD vs. AWD.

The other issue is that the C4 doesn't have the big brakes to back it up, and if you do big brakes fall into the preped category.

Thanks everyone for the quick response. It is kinda strange that all the C4 responses are Cabs.

mborkow

the C4 caliper is also silver rather than black (or red)