FBIII

What's the caliper bolt spacing on the 951 front spindle? I suspect its 93mm and the 928S front spindle is quite a bit greater somewhere around 5 inches or approximately 126mm. Maybe the early 928 spindle has the same spacing.

Vilhuer

4.5L and S brakes are single piston setup very similar to what was used in NA 944 and 944 S but they are not exact same.

Its long gone. This one is 900 Turbo which has very little to do with original model.

nine-28

The Saab in question will be equipped with BMW 345mm rotors and rear wheel driven mechanics, Saab engine though. If you have an idea of the task at hand you know the guy is either crazy or crafty or both.

conc. brakes: As Erkka already mentioned (and Olli SHOULD know ) fitting GT2/Turbo or Cayenne 6-piston calipers on 928S4/GT/GTS/951S is practically impossible without raping the spindle(or is it hub?).

If I get my hands on a 380mm rotor I will make an effort to arrange an adapter for it. And there is always the issue of the disc offset: If it is close to original offset the caliper will collide with tie rod end. With Cayenne rotors (there should be a 380mm version also?) the offset is smaller, hence more space between caliper and tie rod end. If the offset is too large there's always possibility to stuff a spacer underneath the disk but ...

Olli Snellman

Teemu,
i know i should know, but i know hardly nothing of 928 models.928 & GT2 brakes seems to be even tougher thing to than 951 S with the same caliper.
I surely would like to see that Saab. Saab's have a place in my heart, my dad used to own a lot of these fine Finnish(Swedish) cars

slate blue

Olli and others, firstly fine work there, I would like to put forward my thoughts which may or may not be relevent. I did a 355 mm rotor conversion to my 928. I was pretty easy in the end, I did get lucky, I acknowledge that when I bought an F50 setup of Ebay that was designed for the 993 twin turbo.

This is a great setup for a couple of reasons, you have miles of clearance around the disc, the disc itself is very light, it is a hg or so lighter that the GTS discs, pretty sure it is 2 kgs lighter but I would like to check. You don't need to modify anything. It literally bolted on. I did have the early spindles with adaptors that allowed this however.

For my next project I would like to use the caliper you guys are using, can this fit a 380 mm disc? That is the size I want to run, I would only run a two piece disc though, those cayenne discs look mighty heavy and will act like flywheels, that is bad for accel and decel. So you might want to consider that before you buy a 380 mm cayenne disc. Stoptech make a 380 two piece disc that is quite affordable. I mean really quite affordable and your system will look all Porsche as you have the Porsche (brembo) caliper.

If you are not aware there is a kit that uses the GT8 caliper which is an 8 piston caliper that uses the 380 mm disc, I would be happy with the 6 piston one aslong as you can use the 380 disc but just letting you know just in case. The GT8 caliper I think uses four sets of pads from what I have been told but maybe you should check that.

Good Luck

Greg

P.S where did you get your calipers?

Fabio421

Could you elaborate on this please. What do you mean that it was "made for a 993 TT? If its an F-50 setup, wouldn't it have been "made" for an F-50? Is the F-50 designation just a reference to its similarity in size to the brakes used on the F-50?

Thanks

slate blue

Hacker, the term F50 is one used by Brembo to desribe the caliper, it is very similar to the GTS caliper i.e same bolt patern. So what I have is a F50 brake package that was made by Brembo to suit the Porsche 993 twin turbo. A recent sale on Ebay of F50 calipers went for about $685 for a brand new pair. I bought mine used for $1000 with everything. The pads are Pagid RS4-4 and are brilliant, what's more is that they are quite except for when it is 10 c or below.

Greg

nine-28

Greg,

interesting viewpoint you have there. So the F50 calipers bolted on directly to early 928 spindles? I presume that the attaching bolt holes are to the axial direction as with the early spindles?
Secondly, are F50 calipers designed to be used with 355mm rotors? With Porsche the common rotor sizes are 322mm (Big red/Big black), 330mm (996GT3), 350mm (996GT/GT2) and 380mm (GT2) as far as I know. Sure those Cayenne rotors are heavy so if you can post a link to a site offering affordable discs in sizes of 350mm and 380mm I would be pleased.

Vilhuer

IIRR F50 calipers are direct bolt on to S4/GT/GTS spindle. This because they will bolt directly in place of 993 TT big reds which obviously are basically same as 928 GTS big blacks. They can also be bolted to early 928 spindle using same adapters as 928 S4 etc.

Does F50 brakes use exact same disk offset as 993 TT stock brakes? Probably yes since they should be direct bolt on. This means different ET disk center is needed for them and one lindsey offers should work.

sportscarclassics

Are there any kits to mount the Cayenne S calipers to a 928 GT? 6 piston front calipers.

VT928

I am a fan of great brakes. The first rule of go fast is to make sure you can stop. For street use there are two factors that limit the effectiveness of a cars brakes, the size of the cars front tires and the tires coefficent of friction. The increased leverage the caliper being a greater distance from the wheels rotational center can easily overpower the cars front tires. Once the tire stops rolling and begins sliding the brake effectivness decreases. Most race cars have front tires that are far wider (305's and larger) and far softer (stickier) than the tires that most people run on the street. 928's were undertired from the factory and most street driven 928's still are, most commonly running a tire that is between 225 and 245mm wide on the front with a hardness in the 200's or above. Simply put the front tires on our cars serve to negate most of the benefits of larger brakes. I currently run 255's and have run 265's which about the largest tire that will fit under a lightly modified (rolled) front fender. The S4 brakes with Hawke HP+ pads on my 1980 Euro S will over power the fronts with ease. Remember brakes slow the wheel/tire unit but it is the tire that decelerates the car, therefor thier limits are the true determinent as to stopping ability. I must admit that the look of a large rotor filling the rim is one I like. Appearence is a more than enough justification for the mod in my opinion, but appearence will not change physics.

Paul

1980 Euro S Red/Blk Lea

tv

Bigfoot928

F50 front brakes should work well with the 275's I'm running now... I installed the 993 tt rear brakes to keep the ratio of front to rear bias within limits....