demetan

I'm planning on eventualy putting drilled rotors on my S4 when I'm ready to change my brakes. I read that some of you swapped for GTS brakes. Are'nt they Brembos like the S4? Is it really worth it?

Madturk

The gts brakes are same as big reds. They are nice. I doubt you'll feel a big difference on regular sprited driving.

demetan

That's what I tought. Even on track I don't think you get better braking by just changing calipers & disks of the approximate same size & not changing or modifying anything else.

ammonman

The GTS rear brakes are identical to S4 brakes. The fronts use larger diameter rotors than the S4 and appropriately sized calipers. If you do choose GTS fronts you have to go to a 17" wheel for clearance.

Mike

Gary Knox

You can achieve about 80% of the 'upgrade' from S4/GT brakes to GTS without buying the GTS calipers, which are the real cost item. Just buy a set of GTS rotors, then make two 10mm thick aluminum bar spacers (with appropriately located holes) to put between your S4/GT calipers and the mounting brackets on the hub. Also, four mounting bolts for the GTS calipers, which are 10 mm longer than the S4/GT bolts. Voila, you've added 10 mm of outer diameter for heat transfer and clamping torque, and you only lose the inside 10mm of the rotor contact with brake pads. Again, you will need to have 17inch or larger wheels.

Ducman82

you wont see to much of a difference while street driving. i had the early S brakes on my 81, and the swap to GTS was nice. but i dont do track racing or super spirited driving, so it was kinda a waste of cash. and ya, i had to get new wheels... found that out after the fact when i could not install the ones i had.. LOL

demetan

Nice to know. But just to add a centimeter...I still like my 16in 10 holes & the tires are new from this spring.

By the way Gary, I hope you don't have to change ALL your car's tire the same year (not to mention winter rubbers...)

mark kibort

I did this and it worked phenomenally! however, you need to grind the calipers a bit. you get F50 caliperss (stock S4 is the same) and bigger rotors. there is really no difference in doing this vs the GTS system, but the gts system has larger calipers which can dissipate more heat in extreme situations. but, i have done this for years now with no heat issues using more clamping force, and being able to shed about 10% more heat due to increased rotor mass, which is the benefit.
i then went to the C2turbo calipers, which are S4 identical, but radiused for bigger rotors and went to a true 330mm rotor vs the 322 of the GTS.
the finess of the change is the type of spacers you make or use . i had aluminum spacers machined for both changes

Randy V

Just noticed that a 928 OC Officer doesn't own a 928?

atb

I have the big reds at all four corners. On the track, they provide literally fade free performance. Not true with the stock S4 brakes. For street performance, while it may be arguable whether or not they provide more stopping power, I can tell you that the brake modulation sublime. The brake feel in my S4 is unparalled by any other car I've driven. Other's may have more stopping power, but just the sheer control all the way to where the ABS kicks in is awesome!

the flyin' scotsman

Im fortunate to have both a S4 and a GTS...........I would spend the money on better pads for the S4 if your really going for it.

I drive fairly hard and dont feel the need to upgrade either systems, on the street....IMHO

Ninespub

Better off spending the money on new fuel lines, motor mounts, PK tensioner, intake refresh, X-pipe, etc., etc., etc.....................................

FredR

On my late S4 I used the Hawk Street Plus pad set- a noticeable improvement for minimal bucks. However on the track i managed to boil my brake fluid without really trying and that made me wonder if more needs to be done to dissipate additional heat. I also wondered if my wider wheels restricted air flow into the brake area.

Later on I did some back to back tests with my auto GTS and my friend's S4 manual [stock brakes]. I really thought there was something wrong with the S4 brakes as the difference breaking wise was night and day type of thing.

Rgds

Fred

Rgds

Fred

jcorenman

The real question for bigger brakes is "how much horsepower?"

A secondary consideration might be driving style, but let's assume you drive the car as it is intended which includes hauling the car down from very high velocities, and "spirited" drives on twisty mountain roads and braking hard for every corner.

Stock brakes are fine for stock horsepower. Porsche knows how to design this stuff, and you can only add so much energy between corners. The stock brakes can handle that.

Now add horsepower, and you can easily overheat the brakes. It's simple physics: More power means more velocity (i.e. energy) between corners, which the brakes have to absorb and dissipate. For the GTS the engine displacement and horsepower went up around 8%, and the brakes went from 302 to 322mm. Porsche gets it.

Kibort swapped his engine for a stroker and started having problems with his S4 brakes, no surprise there.

Our S4 is fine with stock brakes, but we repeatedly cooked the brakes on our GT (headers, cams, Sharktuned) and warped the rotors until Jeff (Speedtoys here) pointed us towards some better pads.

Superchargers, turbo kits, strokers should all come with bigger brakes IMO.

Personally I would skip the drilled rotors, they look cool but weaken the rotor and tend to develop cracks.

Cheers,

mark kibort

that just about sums it up... everyone always gets the hp thing confused , even for braking. actually, you really dont get any more power with the bigger brakes... stock brakes have the same power... thats limited by the tire and the brakes ability to slow at the limit of the tires (%slip). the question is how long and for what duration can the stock brakes work, and that happens really at the track over repeated threshold braking activities. if you get fade (and its not driver induced ), you need more themal mass..... the GTS brakes give the increased thermal dissipation capabilities that just works out for the increased engine HP for repeated stops or slow downs.

the feel might be better due to less pressure to slow at a given rate, but becuse that rotor speed is faster at the clamping point, the power is the same and heat generated is the same as well.