Christer

Since there are a few people talking about this, I thought I would start a new thread.

First of all information. According to what I read, the RS uses the same 4 piston caliper rear with same size disc as the standard later Carrera models. The front however is a 322x32 as opposed to the standard car's 298x28. The calipers and pads are therefore also larger. Is this correct so far? If so, why does design911 sell RS rear discs for almost twice the cost of standard discs? Or is the RS disc the same size, but cross drilled or something in the rear (or is this a ripoff)?

I thought it might be an idea to discuss this in more detail and get the fact straight.

Cupcar

The RS front setup is the same as 1991 Turbo and uses the same perforated 322 X 32 disc and the same caliper with 44 and 36 mm pistons.

The RS rear calipers are the same in outside dimension as the standard C2 caliper but the pistons are larger at 30 and 34 mm.

The RS rear disc is the same as the M030 968 and therefore has a 951 part number: 951.352.041.91. It is perforated but otherwise the same dimensions as the normal C2 disc. I don't think it is twice the price at Porsche dealers. <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />

ThomasC2

They are crossdrilled, and named "RS" which always seems to increase the price! They are
still 24 mm thick.

Bill Gregory

FWIW, the RS rear calipers have been superceded by the 993 rear calipers,which have the same 34/30 pistons.

Christer

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Bill Gregory:
<strong>FWIW, the RS rear calipers have been superceded by the 993 rear calipers,which have the same 34/30 pistons.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">and these are also bolt-on replacements potentially?

So far, we have the 1991 C2 Turbo set up as far as calipers, discs/rotors and pads on the front. In the rear we have effectively the 993 rear caliper and the cross drilled RS disc. What about the rear pad? Is this now effectively a 993 rear pad?

thanks!

Mr. C4

Bill,

Don't shoot me for this but I thought the Euro RS set up was 3.6 turbo (Same as 928S4??) discs and caliper up front while the rear was the 964 Carrera front calipers but mounted on the rear with Euro RS specific drilled discs.

What about brake bias valve?

Ciao,

Johannes

ThomasC2

If you want red calipers the set up is as follows:
Front: Turbo 3.6 calipers and discs from 3.6 or 3.3 turbo. It's the same calipers as the 993 TT/RS, and you need adapters.

Rear: Use the 3.6 Turbo caliper. It's the same as the 3.3 or RS, except for the colour. Just bolt on. You could possibly use the 993 TT/RS caliper but then you have to use adapters I think. The rear discs are the RS discs as said above. The rear pads are the same size as late C2,C4,RS and Turbos.

Also change the break bias valve to the 3.6 turbo version.

I did this upgrade a couple a months ago and it works really well, and it looks great to!

Christer

I think we are getting a little bit off the point here. I may consider Big Reds or whatever if the RS brakes cannot easily be acquired, but I don't want complete overkill with great big heavy calipers etc.

Also, we seem to have alot of ambiguity as to which calipers/discs/pads need to be used - so far we have 3.3 Turbo front discs/calipers/pads with 993 rear parts. Or 3.6 Turbo/993TT fronts (which doesn't sound right to me) with my existing fronts calipers moved to the rear but using rear RS discs with RS pads???

AAAAAAAAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRGGGGGGGGGGHHHHHHHHHHHHH.

And I thought this would be straightforward.

Bugger.

<img border="0" alt="[crying]" title="" src="graemlins/crying.gif" />

kahuna

You might want to look <a href="http://www.pelicanparts.com/MotorCity/wmv/brakes.htm" target="_blank">this page</a> over for clarification

John Boggiano

<img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" />

ThomasC2

Christer, it's not that complicated. I don't know if you read the "911 & Porsche world" magazine. But I think that in the two latest issues there have been articles about a grey 964 which has been upgraded with 3,8L, big breaks etc, and a blue one with the same setup as I described. You can also buy the parts as a kit from many of the independent part dealers. The frontcaliper of the 3.6 turbo is replaced with a 993-partnumber.I'll think that your old front calipers will be a little to much in the rear, but maybe someone else can clarify that.

Cupcar

The 3.6 Turbo does not have the same brakes as the 964 RS and the RS does not use normal C2 front calipers in the rear, the pistons are way too large and you would have too much rear braking effect.

The 1992 RS/1991 3.3 Turbo uses the 928 S4 caliper and the 3.6 Turbo uses the later 928 GTS caliper which is also the same as the so called "Big Red". The GTS/Big RED uses a larger pad which is associated with a 322 mm diameter disc which has the annulus of contact extended 10 mm toward the center of the disc, hence the Big Red system has a larger front pad with more swept area in a package still using a 322 mm disc.

To my mind there are 2 trick set ups for a normal 964 using the 928 GTS/Big RED Turbo front calipers:

1. "Big Black" 928GTS front caliper based system using 928 GTS front calipers with the cross over lines and brake bleeders flipped so the calipers are in the correct direction as far as the piston stagger, since they mount in a different position on the 928. You will need the same caliper adaptors to install this system on the front of a normal C2 that is required for Big Reds described below.

For the rear use 993 rear calipers and the RS rear discs.

This will give you a system with 322 X 32 front discs that are identical to a Big Red front system. The rear system will be identical to Euro RS with 299 X 24 mm.

2. "Big Red" system from the 3.6 Turbo will bolt directly on with only caliper adaptors and no modification to the calipers in the front of a normal C2.

Also 3.6 Big Reds and Turbo disc a direct bolt on in the rear. This will give you the same system as Big Black above but with Red painted calipers front and rear with THICKER Turbo rear discs that are 299 X 28 mm.

So there you have it: Big Black with 24 mm rear discs as in a Euro RS or Big Red with 28 mm thick Turbo rear discs. Pick your color, use a 55 bar proportioning valve from a Turbo 3.6 and the brakes work great.

*Note that the above installations will only work with 17" or larger wheels*.

As for me I had the Euro RS set up originally installed at the factory and added the modified 928 calipers and 3.6 Turbo front discs to upgrade my system and keep the calipers the same color as the RS rears I had, works great with better brake feel than the original S4 size caliper. <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />

Bill Gregory

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"><strong> use a 55 bar proportioning valve from a Turbo 3.6 </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Not to nitpick, but isn't the Turbo bias valve 60 bar?

General comment: Kahuna posted a link to Bill Verburg's most excellent compendium of brake specs. Very useful for answering many questions.

Cupcar

Yep, you are right 60 bar my memory was wrong again! <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Bill Gregory

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"><strong>my memory was wrong again!</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Heck, sometimes I have trouble remembering yesterday! <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />