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Porsche front brake conversion questions

8K views 17 replies 10 participants last post by  Ontrack 
#1 ·
Hello, well i am in process of rebuilding my suspension and i was thinking about putting Porsche 993 Carrera, black brembo brakes on my 1995 Audi S6. Here's what i have in the list so far:

Porsche calipers - $400
Apikol RS2 Bracket with all hardware - $259
323mm Zimmerman rotors for an Audi A8 - $46.99 x 2

What brake pads would i use and what would be the cost? Also, what lines should i get? Is there others thing that i am going to need? Any other suggestions? Also, i was looking at a Stoptech brake kit, but those go around for $1700 brand new..
 
#2 ·
As long as the hose connections at the caliper is the same, you can probably use factory lines. Otherwise, a good DOT approved S.S. line will have less expansion under heavy application than the factory rubber lines. The S.S./teflon is also less forgiving than the rubber lines, I had a set kink on me when I ran 993C2 calipers on my old CQ.

As far as pads, I have run Pagid (endurance race compound), Textar (OE) and Jurrid (OE). An OEM pad will be the nicest on the street, which I suspect is where this will see the most use.
 
#3 ·
#4 ·
What brembo calipers are they ?

17z or 18z ?

You could look into Carbotech pads they have always been my fav (around $150).

As for hoses just get some Stoptech ones for an S6 from Rockauto like $45 for the pair.
 
#5 ·
#6 ·
Personally, I like Carbotech pads. I use one set for the street and another set for the track.

The stock CQ line, from the strut to the caliper, will be too short for use with a Porsche caliper, at least they are with the 996s, I used. The stock strut to caliper line is 160mm. You can replace it with a stock rear CQ line which is 250mm line. These lines are NLA from Audi, but you can get aftermarket. Centric comes to mind. I personally don't like SS lines are they have a tendency to fail at the crimps, especially on lines that are flexed a lot. You also don't know what grad of SS is used in making the lines. SS is rust resistant, not rust proof. The poorer grades of SS with less Nickel will rust sooner. Just my 2 cents.

Greg W.
 
#7 ·
The 993C2 caliper is slightly different than the 993S/tt calipers, and require a slightly smaller rotor diameter from what I remember. I ran a 12x1.25" (aka 305x32) Coleman rotor with custom hats. The caliper brackets were also custom, but I believe were the same critical dimensions as the RS2 bracket.

My new setup uses Q7 Brembo rear calipers with Wilwood rotors and hats (I had the hats machined locally). I do not have it on the car yet because I need to go through the suspension at the same time. The 993C2's worked very well, but for various reasons I had trouble (not because of the type of caliper, but that the guy that made the kit for me used too short of flex line, so both sides kinked, then he used non-anodized aluminum for the hats and brackets, so they corroded terribly, and then to top if off he used two calipers off the same side of the car, so the piston sizes were backwards on one side but correct on the other side). I'm going to be using rubber lines this time around and since I've done all the design work and parts sourcing myself, I can control the outcome.
 
#8 ·
The 993 (non-turbo) are 'medium' brembos. They're the same as an RS2 caliper. Designed for a 304mm rotor, but will fit up to 332mm with some slight shaving and spacers. You might be able to use the standard A8 323mm rotor without shaving, but you'll need to add a few mm of washers/spacers radially to space out the caliper for the larger rotor.

I've got the same calipers that I plan on using with 312mm 2pc 4x108 rotors (and later with 323mm 5x112). I actually have two pairs and paid $100-150/set. You can find them for cheap from Porsche guys (928S4, 951S, 951/968 M030, 993) because they all upgrade to 'big' (993tt/928gts) calipers.

Lots of options for pads for them, all depends on what kind of driving you're going to do. You can also modify the 'medium' calipers to fit the larger 'big' caliper pads with the 'big' caliper pad holders and slight mods.
 
#9 ·
Other things to think about, the old-style brembos require a LOT of spoke clearance as they're very wide. The newer monoblock style are thinner and are pretty cheap nowadays too. I'd personally look into Boxster S/996 calipers unless you get a set of the earlier calipers for cheap or free. I certainly wouldn't pay $400.
 
#10 ·
So from what i understand these would be the better option: http://www.ebay.com/itm/PORSCHE-911...b2afcf75b:g:sG0AAOSwzaJX25jd&vxp=mtr#viTabs_0 What would be a fair price to pay for them? As i understand with 996 calipers i would need this bracket: http://www.apikol.com/index.php/products/braking/urs4-s6-boxster-s-brake-brackets.html and stock Audi A8 rotors would do fine? Also when looking for brake pads i would just specify that they are for a 2003 Porsche 911 non-turbo?? Also, would my stock 16" Avus wheels fit over them?
 
#11 ·
OOOOGT said:
The 993 (non-turbo) are 'medium' brembos. They're the same as an RS2 caliper. Designed for a 304mm rotor, but will fit up to 332mm with some slight shaving and spacers. You might be able to use the standard A8 323mm rotor without shaving, but you'll need to add a few mm of washers/spacers radially to space out the caliper for the larger rotor.

I've got the same calipers that I plan on using with 312mm 2pc 4x108 rotors (and later with 323mm 5x112). I actually have two pairs and paid $100-150/set. You can find them for cheap from Porsche guys (928S4, 951S, 951/968 M030, 993) because they all upgrade to 'big' (993tt/928gts) calipers.

Lots of options for pads for them, all depends on what kind of driving you're going to do. You can also modify the 'medium' calipers to fit the larger 'big' caliper pads with the 'big' caliper pad holders and slight mods.
Alex, the RS2 uses 322x32mm rotors from the factory and a different caliper with increased mounting surface offset. It is not a 928/993/968 caliper meant for 304x32 rotors. Caveat - there IS a part number for the 304x32 rotor and caliper to go with it for the RS2. The 322mm setup lists as "17 wheels only", which makes sense. I think most RS2's had the 17" Cup wheel option and therefore the 322 diameter rotor.
 
#13 ·
cuatrokoop said:
OOOOGT said:
The 993 (non-turbo) are 'medium' brembos. They're the same as an RS2 caliper. Designed for a 304mm rotor, but will fit up to 332mm with some slight shaving and spacers. You might be able to use the standard A8 323mm rotor without shaving, but you'll need to add a few mm of washers/spacers radially to space out the caliper for the larger rotor.

I've got the same calipers that I plan on using with 312mm 2pc 4x108 rotors (and later with 323mm 5x112). I actually have two pairs and paid $100-150/set. You can find them for cheap from Porsche guys (928S4, 951S, 951/968 M030, 993) because they all upgrade to 'big' (993tt/928gts) calipers.

Lots of options for pads for them, all depends on what kind of driving you're going to do. You can also modify the 'medium' calipers to fit the larger 'big' caliper pads with the 'big' caliper pad holders and slight mods.
Alex, the RS2 uses 322x32mm rotors from the factory and a different caliper with increased mounting surface offset. It is not a 928/993/968 caliper meant for 304x32 rotors. Caveat - there IS a part number for the 304x32 rotor and caliper to go with it for the RS2. The 322mm setup lists as "17 wheels only", which makes sense. I think most RS2's had the 17" Cup wheel option and therefore the 322 diameter rotor.
Ah, thanks for the correction!
 
#14 ·
cuatrokoop said:
Alex, the RS2 uses 322x32mm rotors from the factory and a different caliper with increased mounting surface offset. It is not a 928/993/968 caliper meant for 304x32 rotors. Caveat - there IS a part number for the 304x32 rotor and caliper to go with it for the RS2. The 322mm setup lists as "17 wheels only", which makes sense. I think most RS2's had the 17" Cup wheel option and therefore the 322 diameter rotor.
It's been a while but I have to correct this.

RS2 used 304mm rotor stock with red painted 928 S4/951S calipers.
Optional were the 322mm rotors and that setup used red painted Big Black calipers from 928 GTS.
MOST RS2 out there have the 304mm rotor setup.

The only difference between 928 GTS and 993TT Big calipers is the leading or trailing orientation of the caliper on the car... you just have to swap the bleeder/crossover tube and you can make Big Blacks from Big Reds and vice versa.
On B4 chassis you need the 928 orientation, on UrS you need the 993 orientation.

Hope this helps
 
#17 ·
Hmmm...my father is using that Apikol setup on his '84 4Kq with 2-piece strut upgrade, but it required him to dump the 15x7" Cabrio rims and move to 16x7" aftermarket rims. I don't believe it was spoke interference, but radial interference. It seems like the 15x8" rims are particularly good for large brakes.
 
#18 ·
Mentosman42 said:
Yeah the common upgrade on the URQ if you want to keep the 15x8's is boxster calipers with 300mm(if i remember correctly) rotors.

This is the setup my car has, got the bracket and rotors from apikol and sources the boxster calipers myself.
My recollection is that the urq uses the same brackets as the 1990's A4. apikol doesn't list brake brackets for the urq, but does list the bracket and rotor combo you mentioned for the A4 using boxster calipers.
 
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