Ghia

Hi,
I've just spend the last hour trenching through 17 pages of search material regarding 928S4 calipers and 993TT/928GTS calipers.
I have learnt a fair amount fairly quickly, thanks for all the info

But... I haven't managed to find the answer to my question.

Can you fit 993TT/928GTS pads into 928S4 calipers? I know that they're 10mm deeper/taller but other wise are the same size.

If you can't fit them, is it possible to modify the calipers to accept the larger pad?

Thanks in advance.

MG

User 41221

When it comes to brakes, I seriously doubt you want to do too much re-engineering. The Big red/black pads are not designed to fit the smaller 951S/S4 calipers, altho I do not know what the specific fitment differences are between them. I was of the understanding that there is a difference in surface area to allow for clamping force and heat dissapation and I don't know how modifying the S4 caliper will affect its ability to carry the stress loads. I think it would be a lot easier to just buy the right pads and be done with it.

I don't mind modifying other systems on cars, but I want to know that smarter people than me made sure the car will stop properly! Let us know what you find out if you pursue this.

Regards,

Ghia

Thanks, has anyone actually tried to do this?
MG

Riff

+1 on what Scott wrote. What is the benefit of fitting a bigger pad than will fit into the caliper? The rotor of the S4 will also be a mis-match for the pad.

Ghia

I'll be using different discs which will suit the larger pad. I'm using the calipers on an upgrade and need a slightly deeper pad.
I know about what should and shouldn't be done, I'll not be taking any risks with the structure of the calipers, any machining will be carefully done on a mill if need be.
I just wanted to know if anyone has done this. I don't have a spare grand for another pair of calipers.
MG

pcar928fan

They won't fit... Why would you want to do that anyway... Get some aftermarket pads for $125 and call it day. You might get them for less than that even... Sounds like you might have S4 brakes but some GTS/TT pads... I think when I was at the race track I paid $150 for a set of front S4 pads and there are not many "DEALS" on site at a race track... The point of the difference between the GTS caliper and the S4 caliper was so you COULD PUT A BIGGER PAD IN... Bigger in ALL dimensions for better friction and heat dissipation.

YMMV!
James

caster951

Length wise the pads are the same, but the width/height is larger for the Big Blacks/Reds. As stated above, they will not fit.

RyanPerrella

No the larger pads wont fit in the S4 calipers

The Big black pads are also available from fewer manufacturers and are in general 2x the cost. If you have S4 calipers, stick with those pads. Also if your rotor isnt large enough the outer pard of the pad wont contact the disc and you will quickly develop an odd wear pattern. But its a mute point, they physically WONT fit, the spring would have to be modified somehow.

Ghia

I won't be using them on S4 discs, they're for a completetly different vehicle so I have choice over what discs I use in diameter and thickness etc.
If the pads are the same length then it's just the stops which the pads sit against which need modifying so the pads will sit in further.
Remember this is NOT going onto a Porsche or anything standard. I just wanted to know if it was possible for the pads to fit into the calipers.
MG

PorscheDoc

Yes the pads will physically fit in the caliper (length wise they are the same), but they are taller to accommodate the larger rotor of the 993TT, so you won't be able to use them like that.

Robby

What PorscheDoc said...

I went through months of trying to "reinvent the wheel" for my Turbo S- I've looked at Big Reds, etc- turns out, they are about the most cost-effective way to get more pad- same length, but taller- essentially, the BR's are more of a square while S4's are more of a rectanegle. BR's fit perfectly onto the almost 7/10" larger rotor. Now, for your application, it's anyone's guess, since you're talking about doing something different altogether, it sounds like.

Also, I've found that pads are very similar in price b/t BR's & S4's, but then, BR calipers are a lot cheaper than S4 Calipers. If my S4 calipers go, I'll probably go to BR's. I just don't really want the extra weight- mine's a street car so I doubt I'd benefit much from the extra rotor & I'm pretty sure the extra unsprung weight will be felt over bumps, etc.

Ghia

They fit!
I've modified the pad holders to allow the pad to slip further down into the caliper. They're only 8mm taller than the S4 pads but it's a worth while mod without the expense of buying new calipers.
MG