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Thanks! They look even better when you hold them up to next to more pedestrian calipers in person. People also tend to geek out a bit when they hold them in their hands and see how light they are (especially engineers or brake nerds like me).
Will there be any problem clearing the 19" Forgeline wheels that most of us run on the 991 GT3?
We don't anticipate any issues with 19" Forgelines, but we're going to look into that. We are friendly with the team at Forgeline, and our booth is across the aisle from them next week at SEMA. They are actually displaying these brakes in their booth, and we will be displaying one of their beautiful wheels in our booth! We'll get the specs and check fitment on their 991 GT3 spec wheels. A large portion of our Corvette customers run Forgelines, and Forgeline tends to build a very nice amount of caliper clearance into their wheels.
Also of note, we provide wheel fitment templates for all of our brake kits (see pic below). Our customers can check wheel clearance on any wheel they own or are considering prior to purchase. We'll provide links to fitment templates for our GT3 kits prior to the launch.
The calipers in our front and rear system won't stick out any further than the stock calipers towards the spokes. The only change is that they caliper will sit a little closer to the wheel barrel...somewhere in the neighborhood of 7mm, which is less than a third of an inch. The only thing you'd want to watch for is stick on wheel weights. You don't want those running across the tops of your calipers.
Also, the stock front brake set up has a very long hard brake line. Are there any issues with using the flexible line in terms of clearing vital components such as the springs?
We don't anticipate any issues with the flexible line. We've been producing a Spiegler line kit that uses flexible lines for these cars for a while now, and I don't know of any issues with suspension interference. We do the same on a fairly lengthy list of other applications as well. One of the nice things about the Spiegler lines is that fittings on the ends all swivel. That eliminates the binding and tension evident on lines of lesser quality. When installing you don't have to worry about clocking the lines in anticipation of tightening them down, etc. You can just rotate them to release binding tension. You can visit our Spiegler line page to see an animation of this feature. Incidentally, Spiegler is owned by a German engineer who is a Porsche/BMW nut. His daily driver is a 991 S, and he makes some extremely nice products at their HQ in Ohio. Many of their stainless steel fittings actually come from Switzerland, and the quality is second to none.
Will the brake fluid volume be affected with these calipers? Will it mess up any of the ABS calibration?
The total fluid displacement into the calipers will be very similar to stock, so the impact on system volume will be negligible. All of our front or rear applications very closely much the OEM brake torque output of a given axle. We manage that via piston sizes and disc diameter. I'll strip that down a bit:
Holding all else constant, if you increase the brake disc diameter (effective radius) on the front of the car and use the same piston sizes, you will increase the brake torque on the front of the car. The caliper is further out from the hub, and you essentially have a longer lever that can apply more torque with the same force input. Increasing piston sizes while keeping the disc size the same would accomplish the same thing in a different manner. You have greater clamping force.
Our kits are an interplay of these forces. If we go to a larger disc on a given axle, we would typically decrease the piston sizes slightly to counteract the increased brake torque of the larger disc. That would bring the overall brake torque back close to stock, and your ABS system doesn't 'know' that anything is different on the car.
With pure racing cars, the above isn't really an issue. You're starting from scratch and can manipulate other variables in the brake system...the master cylinders, pedal box, racing ABS system, etc. You have more freedom to achieve your desired brake torque output on each axle, the overall front to rear bias, how hard you want to press the pedal, when ABS steps in to assist, etc. With our aftermarket kits however, our expectation is that the customer will be keeping their OEM master cylinder, pedal assembly, and ABS system. As such, we have to keep a close eye on piston and disc sizing to ensure proper integration of the calipers and discs.
Check out our Design Process and FAQ videos. They can provide some further insight on this topic (and possibly answer some other questions):
__________________
'09 Carrera 2S, '08 Boxster LE (orange), '91 Acura NSX, Tesla Model 3 Performance, Fiesta ST
Jeff Ritter
Mgr. High Performance Division, Essex Parts Services Essex Designed AP Racing Radi-CAL Competition Brake Kits & 2-piece J Hook Discs Ferodo Racing Brake Pads Spiegler Stainless Steel Brake Lines
704-824-6030 jeff.ritter@essexparts.com
Sorry to intrude in a GT3 forum, but would this setup work on a 991.2 Turbo S? I track 50-60 days a year, and this would be a great option over Girodisc and OEM calipers that I am inches away from ordering.
Sorry to intrude in a GT3 forum, but would this setup work on a 991.2 Turbo S? I track 50-60 days a year, and this would be a great option over Girodisc and OEM calipers that I am inches away from ordering.
Randy,
We would absolutely love to release a complete front/rear kit just like this one for the Turbo S. We need to get our hands on a Turbo S for measurement first though. They unfortunately aren't exactly plentiful in our neck of the woods. If anyone can let us measure their Turbo S, we would make it worth their while! If that is a possibility for you Randy, please email me. Thanks!
Randy,
We would absolutely love to release a complete front/rear kit just like this one for the Turbo S. We need to get our hands on a Turbo S for measurement first though. They unfortunately aren't exactly plentiful in our neck of the woods. If anyone can let us measure their Turbo S, we would make it worth their while! If that is a possibility for you Randy, please email me. Thanks!
These BBKs will also be available thru Apex Performance.
In as much as I Jaw boned Jeff into getting these babies made... I hope you guys will support
the project in fold.
These calipers will eliminate all the common complaints that I have fielded over the last few years. PLus this set up will provide better braking over the current Brembo setup.
The total fluid displacement into the calipers will be very similar to stock, so the impact on system volume will be negligible. All of our front or rear applications very closely much the OEM brake torque output of a given axle. We manage that via piston sizes and disc diameter. I'll strip that down a bit:
Holding all else constant, if you increase the brake disc diameter (effective radius) on the front of the car and use the same piston sizes, you will increase the brake torque on the front of the car. The caliper is further out from the hub, and you essentially have a longer lever that can apply more torque with the same force input. Increasing piston sizes while keeping the disc size the same would accomplish the same thing in a different manner. You have greater clamping force.
Our kits are an interplay of these forces. If we go to a larger disc on a given axle, we would typically decrease the piston sizes slightly to counteract the increased brake torque of the larger disc. That would bring the overall brake torque back close to stock, and your ABS system doesn't 'know' that anything is different on the car.
With pure racing cars, the above isn't really an issue. You're starting from scratch and can manipulate other variables in the brake system...the master cylinders, pedal box, racing ABS system, etc. You have more freedom to achieve your desired brake torque output on each axle, the overall front to rear bias, how hard you want to press the pedal, when ABS steps in to assist, etc. With our aftermarket kits however, our expectation is that the customer will be keeping their OEM master cylinder, pedal assembly, and ABS system. As such, we have to keep a close eye on piston and disc sizing to ensure proper integration of the calipers and discs.
Matching stock brake bias percentage will be especially important for a 911/GT3, more so than a mid or front engined car. You don't want to be taking away rear brake bias from a GT3. That's both part of it's core strength and stability asset.
It looks like the cat's out of the bag on this project. We are now offering AP Racing iron J Hook discs in the OEM PCCB sizes. Please visit this link for all of the details.
We're back from SEMA, and trying to get caught up. I wanted to post some info about the rear calipers that we'll be using in our system. We currently use variants of this caliper in many of our systems for other vehicles such as Corvettes, M3's, etc. They have won many races and several championships during the brief time they've been in service. For the GT3 we will be using the AP Racing CP9449 Pro5000R Radi-CAL.
The CP9449 Radi-CAL weighs in at a scant 4.85 lbs. (OEM is 7.4 lbs.), and features all of the same cutting-edge features as the front CP9661...ventilated, domed-back, stainless steel pistons with anti-knockback springs, all needless weight stripped away, superior cooling, etc. As with the front CP9661, this caliper uses a very common pad shape that is available from all major pad manufactures, and the prices on this shape are typically considerably lower than the OEM pad shape. For reference, Ferodo DS1.11 in the shape for the Radi-CAL rear caliper retails for $362.51 vs. $487.49 for the OEM rear shape.
Not only is this caliper incredibly lightweight and functional, it also looks bad@ss!
10-27-2017, 09:01 AM
We'll get the specs and check fitment on their 991 GT3 spec wheels. A large portion of our Corvette customers run Forgelines, and Forgeline tends to build a very nice amount of caliper clearance into their wheels.
We are now offering AP Racing iron J Hook discs in the OEM PCCB sizes. Please visit this link for all of the details.
