RED SHARK 1990

Ok, now what is the verdict on this ? To go with GTS conversions or stick with s4 calipers and upgrade to bigger rotors? Anything else guys....

mark kibort

You tell me. Its race proven to go with the GTS rotors, or even better styling with the 965T hole'd rotors. why do a conversion when the S4 calipers are plenty capable for ANYTHING you can toss at it?
It would be an entirely different discussion if you were talking big reds, where you get the "red" color calipers which is very cool and looks great on a street car. But, its looks only. S4 calipers work just as well, by any matrix you could judge them by.

mark kibort

most all racing pads are 51mm thick from outer edge to inner edge.
Here is an example. this is the S4 pad, Ferarri F50 pad, and ST40 pad. (all the exact same pad).
below, is the ST60 caliper pad that the ALMS GT3RS and WCGT porsches use
Notice that the pad thickness is the same. Still think they are dumb?
Im sure the could all have designed a pad like the GTS big red, but NONE of them have. why, that inner diameter just generates heat and not much stopping power!

mark kibort

If that is the 965T offset, then that would be the solution! BUT, man thats some pricey stuff! $1000 for a set of rotors and hats! $500 every time I dump a rotor?

I think Ill stay with the used GTS rotors that I have turned and bolted on my car for about $20 bucks for the set! even If I buy the rotors new, GTS or 965T, I think the cost is around $250-300 for both. Heck, they last 4 weekends before they start to crack and warp.

Jon B.

On a more awesome note, I am now registered on Pelican Parts after reading this thread.

pcar928fan

I saw you post over there! YEE HA! Now I can really keep tabs on you!

rb4_Porsche

Do you have the exact difference in pad thickness between S4 and GTS.

Thanks

mark kibort

you mean the width? i think it was about .25" or something, i posted it before, let me see if I can find it. the length of both pads are the same, so there really is not much difference. most all the diff is in the diameter of the rotor.

rb4_Porsche

Here is an example. this is the S4 pad, Ferarri F50 pad, and ST40 pad. (all the exact same pad)
According to the illustration it's 51mm for S4 pad, and I was wondering what's for GTS.

Vilhuer

60mm or little under it.

rb4_Porsche

Thanks.
The stock rotors for S front is 304x32mm w/51mm pad so if it's upgraded to 14" rotor (350x34mm that is the same as 997 GT3?) why can't we just use the same stock pads (presumably we can use the original caliper + adapter) to save the trouble and cost.

tveltman

My advice is to take the stock S4 calipers off, degrease and strip them, paint 'em red, then sand down the "PORSCHE" lettering to bare aluminum. Clear coat if you like (I didn't bother, calipers still look great after 5 years and ~25k miles). Put whatever rotors on it you want. Increase the rear bias to 33, and the car will nosedive a lot less under normal street driving, and from the bulk of the thread, apparently won't adversely affect your braking on any track driving unless you have significantly doctored your engine. If you're asking about the brakes, my guess is that isn't your situation, so dont worry about it

cobalt

I think the point most everyone is missing is that despite the increased pad and rotor dia both the S4 and GTS calipers use the same 44/36 pistons.

You can swap the 3.3l turbo calipers aka S4 calipers and the 94 turbo big reds without changing bias. I don't see why you would need to on a 928. It is not like adding the big calipers to a C2 which runs the same size pad as the turbo in the rear which uses 34/30 pistons instead of the C2's 30/28. IIRC the rears of an S4 and GTS are the same sized pad and pistons.

BTW if anyone is interested Cup Car on the forum has big blacks and 965 turbo rotors for sale. The bleed and feeds have been swapped but can be swapped back I think he was asking $750 for the 2 calipers and set of cross drilled rotors.

He is also an excellent source for braking info. IIRC he wrote a nice article in one of the panorama issues about brake upgrades.

rb4_Porsche

It seems staying with stock set up is ideal for most of us w/o all these swapping and still keep the brake under 16" wheel
So upgrading brake pad and rotor is perhaps all it needs and worthwhile at this point.

Is there a two piece rotors available?

pcar928fan

Go to a 33bar rear bias bar so your rear brakes actually start doing some work and put some aggressive pads on the car and an S4 will pop your eye ***** out of your head when you hit the brakes! My S4 brakes WAY better than either of my GTS's! The only difference (well, the only change I have made anyway) is the 33bar 911 Turbo (I think) bias bar to get the rear brakes doing some work. I used to run racing pads on the car when I was tracking it all the time, but they are to noisy for the street but they made the car stop even better!