Aussie skypig

Time for new rotors.
Having most of my experience with bikes, I went straight to considering the Girodiscs. Bigger, floating, and cast iron. Just like my bikes…
https://flat6motorsports.com/collections/987-brakes/products/girodisc-2-piece-340mm-front-rotor-upgrade-set-cayman-boxster-987

I like big brakes, and I cannot lie.

Pretty expensive though.

Any other oversized options I should consider?

18” BBS wheels.

Currently, the brakes feel fine, if lacking initial bite. New pads, rotors approaching the wear limit.

If I decide to stay with stock size, I’m leaning towards DBA slotted rotors.

Any experience with the Girodiscs or others?

Kitc2246

I run Sebro slotted with Pagid RSL 29s on 18 in Hankook RS4s on a 2013 Boxster S. I wore out Ferodo DS1.11s after six track days. Planned to move to 3.12s but can't beat the FCPEuro Lifetime warranty. I've talked with others and they have indicated no need for bigger brakes until or if I start running slicks. Girodiscs are great but $$$. Suspect your shipping would make FCPEuro prohibitive especially since you have to ship back the worn parts. Rotors cost about $55 to return.

old man neri

What master cylinder are you currently running out of curiosity? Stock or the GT3?

Aussie skypig

Hi. Stock as far as I know.
If it’s a common mod, potentially the PO has replaced it. (Car has a GT3 throttle body for eg)
How to tell? Are they different piston diameters?
I’m familiar with changing the master cylinder size for different feel/effects, on motorcycles.




Seems big brakes aren’t as common as I suspected.

Some say drilled discs are better for the road. Glaze pads less when not braking hard? Or “better” as in not best for track.
Grooved discs seem to be recommended for track use. I think my car will see infrequent track use.

Has anyone used the Girodiscs?

CaymanR99

I’ve seen a number of 987.2 with Gyrodiscs, all on track. Don’t recall seeing any on street.

When I ran a 987.2 on track (DE) I ran Sebro slotted with RSL29 pads. Slotted discs stand up to heat cycles better than discs with holes. All discs develop cracks, when the cracks get to the edge of the disc (relatively large cracks) the rotor is done. Cracks develop faster with holes vs. slotted.

Gyrodiscs are a good product. Not needed for street, the stock setup is more than adequate. But if you want the look of big brakes go for it.

GT3 master cylinder? I ran on track with the standard master cylinder. The GT3 master cylinder is bigger diameter requiring shorter travel to apply the same amount of force to the brake cylinders. You have to push the brake pedal a little harder to apply the same amount of pressure to the brakes. Some say this improves the “feel” of the brakes. YMMV.

old man neri

Common enough mod. I'm about to do it. Mine is the mail. The TRW part number is PMN166, surprisingly economical. I'm only doing it for feel and for kicks. I doubt it will increase actual performance numbers nor do I have the knowledge or experience to talk about that. I'm not sure how to externally tell the difference between the two.

harveyf

When my wife bought her 2006 Cayman S new, her favorite party trick used to be to take out unsuspecting passengers and do a serious acceleraton run followed by a brake check (on a nearby lightly travelled road), hurling them forward against their shoulder belts. Only to say that the stock brakes, in new condition, are very impressive.

jscott82

AP Racing, PFC, Brembo all make big brakes kits (or at least have the parts you need).

But let's be honest, big brakes don't make you stop any faster... Stock brakes can lockup the tire (or get into ABS) even on slicks, so you dont need more stopping power.

What larger brakes buy you is a bigger heat sink for repeated threshold brake stops in sucession. If you find yourself doing multiple successive emergency stops on the street maybe avoid that street because.... damn....

They do look cool though, a stock brakes just don't fill up an 18in wheel.

If you want to adjust the "feel" of the brakes.
GT3 MC will shorten the pedal stroke giving a better feel, albeit wit more effort.
996 Tubo booster will give you less boost, better feel, while again increasing effort.
steel braided (Teflon lined) brake lines increase line stiffness reducing pedal stroke and giving better feel. But the teflon is a wear item and MUST be replaced every few years
if you want more initial bite, that is a function of pad material. I don't know what to recommend for a street car though. Stock pads really are the best IMHO...

as far as drilled/slotted... Drilled looks the best and is the lightest but they do not stand up to repeated high heat cycling.

KCShelby

When I was reading obsessively and researching the purchase of my 2008 Boxster S, I came across a Car & Driver Magazine 40,000-mile long-term test of the 2005 Boxster S. They optioned the super-duper ceramic brakes for their test car, but they found...

>>As for that $8150 brake system, the advantage of six-piston calipers (up from four in front) is perfect brake feel, and the benefit of the bigger rotors (13.8 inches front and rear) is fade-free braking even after many high-speed stops, a huge asset at the track. But in everyday driving, our tests showed that the expensive brakes bested the standard ones by just eight feet in 70-to-standstill stops. As far as stopping distances are concerned, both the base brakes and the mondo-costly ones are so strong that they are limited only by the grip of the tires, not the clamping force of the brakes. So unless your Boxster is destined for several weekends of racing, it might be a better idea to leave the substantial cash for these ceramic-composite brakes in the kids' college fund.<<

Aussie skypig

Thanks everyone.
Some great, useful info.
While I’m keen on the “look” of bigger rotors, this is a low priority.
Sounds like; unless I start spending more time on the track than I currently plan, I should replace the rotors with stock size. Probably stock style, or slotted DBA (Disc Brake AUSTRALIA )
(I spend a fair bit of time at the track, but it’s racing my bikes)

I had a fantastic drive in the hills on the weekend and the brakes are not working very hard in this environment. (Vision/Safety/Licence preservation, rather than brake performance are the limiting factor)
I think the “lack of initial bite” feels like a bigger MC effect, and helps my amateur “heel toe” efforts to be smoother. No lack of brake power when required. Matches the “Man’s Clutch” effort (Compared to my Corolla!)

Again - really appreciate the effort/info.
Any feedback on the DBA rotors compared to Zimmerman/Stock?

Zach L

What car?

Best bang for buck is Sebro slotted rotors. Many of us run them on track. I used Sebro and swap back and forth between track/street pads. 987 has the easiest pad swap of any car I've ever seen.

Aussie skypig

Cayman S 2006 987.1
What pads are you using?

harveyf

For a more detailed look at my stockish rebuild, see the article linked below. I only tracked the car once but I did make an 8000 mile road trip, including long twisty sections on the Pacific Coast Highway. No issues.

https://newhillgarage.com/2021/08/16...n-s-brake-job/

KNSBrakes

We have AP Racing BBK's on sale this month if you're looking for an easy way to go 6 piston front without changing uprights to GT3's..

Depending on what options (and kit) you go with you're in the ~$4k+ range for fronts only.

Of course that includes 2 piece rotor, lines, calipers, pads etc.

Just throwing that out there as an option. Send us a PM if interested in getting a quote or give us a call.

We also have Girodisc front rotors which will grow your front rotors in diameter. These include longer bolts and spacers for your stock calipers.

--Aaron

jbx2

I'm going to consider this option for my next front brake refresh: