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I was hoping that you could produce one sized hat, and then the purchaser could choose his rotor size. Does each rotor size have to have a hat made specific to the rotor's diameter?
thats a great question... i was thinking that i could use a 330rotor on my custom hat, that is a brembo cross, and bolt a 348mm rotor on it if i wanted.
what makes me question that , is that the S4 pad is an exact fit from inner diameter to outer, so in other words, you could never put a 304mm rotor on the hat i have... be interesting to hear how this all works.
for our cars , i think what im using is ideal, maybe make it around the 322mm which is GTS rotor. you get a lighter rotor and hat set up that looks cooler and probably ends up being cooler too.
the S4 calipers are stretched to work at 330, but with a little grinding can work on 322 easily. some have moved the pad stops in the calipers to push out the pads further without using caliper spacers and longer bolts.
be interesting to see what is most popular with this group
With 304mm OD it leaves only 52mm annulus which can be marginal in fitting the brake pad unless it's trimmed.
OK for 322mm two piece (62mm annulus)
Our price for this track duty two piece rotor will be below $700 which is similar to our two piece rotor for Toyota Supra turbo (RB is the only supplier).
304mm is too small for a two piece rotor due to no room for hardware.
322mm and up would be OK.
The way I understand is that you are using 993 Turbo caliper and its rotor 322x32mm for mounting to 928 spindle as BBK upgrade.
We have a rotor ring can be made to 322x32 (or 332x32) and both sizes of rotor can use the same hat (@180mm pcd).
322x32 with 61mm annuls
Our price for this heavy track duty two piece rotor will be below $700 which is similar to our two piece rotor for Toyota Supra (RB is the only supplier) which is still a very popular old fashion race car like Porsche 928.
We treat all car makes the same, and never charge Porsche tax like others.
Above is something we can come up with - Let me know if you have any question and suggestion.
the calipers we are using are from the 964 turbo (965T).. dont know if the 993 turbo uses the same caliper. but the offset is for SURE the 964Turbo (C2) not the 993 turbo for the hat. i think the 322mm is a good place to start as its a common rotor and its the same as the upgrade in diameter that gets the S4 928 to the GTS levels. however, i went one step further and used the 330mm rotor rings. (also with the C2Turbo calipers)..... the S4 caliper uses the same pad but isnt radiused for the larger rotor (designed for the 304mm rotor).
(it also has slightly larger foot pads to increase the radius of the caliper.
With 304mm OD it leaves only 52mm annulus which can be marginal in fitting the brake pad unless it's trimmed.
OK for 322mm two piece (62mm annulus)
Our price for this track duty two piece rotor will be below $700 which is similar to our two piece rotor for Toyota Supra turbo (RB is the only supplier).
With 304mm OD it leaves only 52mm annulus which can be marginal in fitting the brake pad unless it's trimmed.
OK for 322mm two piece (62mm annulus)
Our price for this track duty two piece rotor will be below $700 which is similar to our two piece rotor for Toyota Supra turbo (RB is the only supplier).
Let us know if you have any question and suggestion.
There are two products that I think would make sense:
1) 304 x 32mm ring and hat. This is a direct fit for for '86.5-91 S4/GTs, and a good upgrade path for older cars (with S4 calipers). A 52mm annulus is fine, I just measured a set of factory pads at 51mm width.
2) 322 x 32mm with 62mm annulus, used on '92-95 GTS. This is also a good upgrade path for big-horsepower 87-91 cars, GTS calipers are available and bolt directly to 86.5-91 spindles (although a bit pricey and used ones are rare).
The 318 x 28mm Boxster setup falls between those, I don't see that as being a particularly attractive choice.
The 355 x 32mm Brembo big-brake kit is the next upgrade step, not many around (other than racing) because of cost.
The 928 hats are deeper than the 993TT you pictured above, your 71.75mm measures 77.10 on a new factory 322x32 GTS rotor. I believe that is unique to the 928. The "step" on the ID (shown in your drawing) is critical for hub-centric mounting, that is missing on some of the hats that have been made for the 928 (as Kibort mentioned at the beginning).
I've got GTS calipers and rotors going onto the front of our '90GT in the next week or two, if you want to try anything.
I guess I find it hard to take that a lot of the new performance cars are coming out with massive brakes, and these aren't sports cars.
Let's put this in perspective - In about 3 months you will be able to buy a Ford Focus (RS) with 350mm front discs. Oh the shame...
There are two products that I think would make sense:
1) 304 x 32mm ring and hat. This is a direct fit for for '86.5-91 S4/GTs, and a good upgrade path for older cars (with S4 calipers). A 52mm annulus is fine, I just measured a set of factory pads at 51mm width.
2) 322 x 32mm with 62mm annulus, used on '92-95 GTS. This is also a good upgrade path for big-horsepower 87-91 cars, GTS calipers are available and bolt directly to 86.5-91 spindles (although a bit pricey and used ones are rare).
The 318 x 28mm Boxster setup falls between those, I don't see that as being a particularly attractive choice.
The 355 x 32mm Brembo big-brake kit is the next upgrade step, not many around (other than racing) because of cost.
The 928 hats are deeper than the 993TT you pictured above, your 71.75mm measures 77.10 on a new factory 322x32 GTS rotor. I believe that is unique to the 928. The "step" on the ID (shown in your drawing) is critical for hub-centric mounting, that is missing on some of the hats that have been made for the 928 (as Kibort mentioned at the beginning).
I've got GTS calipers and rotors going onto the front of our '90GT in the next week or two, if you want to try anything.
Thank you for the insight. I read your post several times just tried to gain some idea of what we should make for the community.
However we like to propose using 322x30, which is the same as our rotor ring for Cayenne 17Z brake kit that are very popular upgrade for VW/Audi guys, as shown in the dwgs below (keeping the same OE offse of course).
It will be more economical if we don't have to make a new ring while keep the weight down, in fact you can see from the weight estimate, 322mm is still a few ounces lighter than 304mm. Our purpose for this larger rotor kit is to improve the mechanical advantage w/o the weight penalty.
Dimensions shown are for reference only not a production dwg.
Status of availability:
Both hats - New (6 weeks)
304x32 - New ring (6-8 weeks)
322x30 - In stock
Last edited by RacingBrake; 03-12-2016 at 11:11 AM.
I guess I find it hard to take that a lot of the new performance cars are coming out with massive brakes, and these aren't sports cars.
Let's put this in perspective - In about 3 months you will be able to buy a Ford Focus (RS) with 350mm front discs. Oh the shame...
Totally agree. 355x32mm is the stock size rotor for Corvette Z06 (500+ HP track car), on top of that GM uses the same rotor for both left and right, so we first introduced our light weight two piece rotors with substantial weight saving and still going strong today. http://www.racingbrake.com/ProductDe...Code=GM-IRK-02
355x32 is also the stock size rotor for Viper G3-G5.
03-10-2016, 07:41 PM
