TeufelHei

Any differences?

MikeN

Nope. I believe the caliper piston size changed a bit over the S4/GT years.......but generally S4/GT brakes are considered the same.

TeufelHei

I thought there was a change in the number of pistons from 2 to 4. Or was that the GTS update?

hacker-pschorr

All of the S4/GT/GTS calipers are 4-piston brembo's.

Vilhuer

Caliper piston size change happened already in '86/87 time period.

worf928

Very true. There are some subtle changes year-to-year though.

The '87-88 calipers are a few mm wider than the '89. The effect is
that some wheels that fit on an 89+ may require a very thin spacer for
'87-88. The most observable difference is that on the 'older'
calipers the directional arrow is raised - as in you can feel it with
your finger - while in the newer calipers the arrow is a
decal/coating/paint.

Also, at some point in the 89-91 range the interior diameter of the
pistons changed with the result that the noise dampers are different
sizes for what looks like exactly the same caliper.

IcemanG17

Tim
The GTS went to larger 322mm rotors (hence the "big brake" upgrade). The 86.5's & later all had the 302(or something close to that) 4 piston brembos....very good brakes, short of all out track work.

TeufelHei

The way I figure it, I can afford to make the upgrade in both wheels and brakes right now rather than saving the bajillion dollars it takes to go from S to GTS+ plus requisite 17" wheels. Savvy investment huh?

the flyin' scotsman

Tim........I considered an upgrade in brakes for my car but when I researched the WSMs and the cost involved I decided to invest in pads and fluid. The caliper piston size remains constant throughout S4, GT and GTS versions; the difference is rotor & caliper size resulting in a larger swept area. Also when researching the 'big red' brakes the substantial extra cost is the colour compared to the same GTS black brakes. Invest in the very good vaccum brake bleeder, change the brake fluid, and depending on your tolerance to noise install the most agressive pads (most agressive results in more noise and dust)

TeufelHei

For some reason I always thought the GTS Brakes had different calipers than the S4/GT brakes. I knew the rotors were larger, and with the GTS+ package you can get the two piece hat and rotor setup. As for the "Big Reds," well I think my wife put it best. "OOOhhhh pretty." That's about it.

I'm going to bleed in a full system of either Super Blue or Gold. Any reason not to go blue? I know the gold variety is labled street, but I would DE this car a few times, so I suppose it would pay off.

I'm going with Performance Friction Z-Rated pads. They aren't too aggressive, but they will stop you in a hurry. The heat range is low enough to work on the street regularly, and high enough that I should be able to make good use at the track.

Jim bailey - 928 International

GTS calipers use bigger pads AND mount out farther from the spindle to accept the larger diameter rotors. The pads surface is 75.5 sq cm for the GTS and 65.5 sq cm on the S-4 . The GTS rotor is 322 mm diameter instead of 304 mm for the S-4. The piston sizes in the caliper is the same as late S-4. Mounting the caliper farther from the spindle on a larger rotor gives the caliper more "leverage" and more swept area to transfer heat to.

Gretch

Thanks Jim, that is the most complete answer I have heard so far.

sharkmeister85

My understanding is that Blue and Gold are the same, except for color. This way when you change your fluid, you can easily tell when you have the new stuff in eg. if you are using Blue, replace with Gold and you can see when you bleed the Blue out and get Gold, you're done.
Glenn

TeufelHei

I always thought the Blue had a higher boiling temp, hence the street vs track designations.

Thanks Jim...again, you rule.