Girodisc Rotors
#91
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Join Date: Dec 2017
Location: 90 Miles East of Sonoma Raceway
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Thanks guys for chiming in, and after seeing the above, in terms of clearance, it's apparent that the extra 5mm is not a problem. So basically I can get either hat and be fine with the 85mm studs. It's more of a question on what kind of pads I want to run... GT3 vs CS stock... i take it?
I wanted to correct my previous comment. Yes the extra 5mm is not a problem but if you run the stock hat you may need longer calipers studs. Double check before ordering.
My rotors and brake fluid are inbound. It will be a few weeks before I get a change to install them though.
#92
Drifting
Extremely happy with the setup and wouldn't hesitate to go with the DS2500 pads again after this small sample size... and another shoutout to Clark at Apex, great guy/great pricing and he knows his stuff!
#93
Race Director
Vise...yikes 8 Track Days On Stock fluid? I can’t even use stock fluid...I’ll boil it in a session.
I tried out ds2500 on my GiroDisc and they worked great on the street and great the 1st 2 sessions but I noticed pad fade and by the end of the day the pad was 1/2 used up and leaving some uneven pad transfer on the rotors. By the end of the 2nd day the pads were done and only about 3mm of pad left.
Im not sure what your track is like but I was driving Sebring...instructing and driving in advanced solo. I was trying to back my braking zones up a little to go easier on the brakes....nothing helped if I wanted to maintain my track times.
Glad you liked these pads and they worked for you. I was hoping they’d work for me so I could have a quiet pad on the street and also do some track days through out the year. I was hoping I could get at least 5-6 track days and some street miles out of them. Did not work for me.
I tried out ds2500 on my GiroDisc and they worked great on the street and great the 1st 2 sessions but I noticed pad fade and by the end of the day the pad was 1/2 used up and leaving some uneven pad transfer on the rotors. By the end of the 2nd day the pads were done and only about 3mm of pad left.
Im not sure what your track is like but I was driving Sebring...instructing and driving in advanced solo. I was trying to back my braking zones up a little to go easier on the brakes....nothing helped if I wanted to maintain my track times.
Glad you liked these pads and they worked for you. I was hoping they’d work for me so I could have a quiet pad on the street and also do some track days through out the year. I was hoping I could get at least 5-6 track days and some street miles out of them. Did not work for me.
#96
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All set. Other than the brake sensors everything else was typical brake install. I’ll get a chance to check out the new setup @Thunderhill on October 1st.
Comparing the OEM S and GT3 front brake pads I guesstimate the GT3’s have at least 20% more surface area.
The new Safe Jacks worked well but I needed to put a 4x4 under the rear wheel in order to get the car high enough to get the cross piece under the car.
Comparing the OEM S and GT3 front brake pads I guesstimate the GT3’s have at least 20% more surface area.
The new Safe Jacks worked well but I needed to put a 4x4 under the rear wheel in order to get the car high enough to get the cross piece under the car.
#97
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I forgot to mention installing the Girodisc rotors wasn't as much of a diet as I had hoped. The GT3 brake pads weigh more so let's call the fronts even. I wasn't expecting a lot but here's the weights:
Carrera S 340mm Front: 23.4 lbs
Girodisc 997.2 Turbo S 350mm Front: 22.7 lbs
Carrera S 340mm Rear: 19.0 lbs
Girodisc Carrera S 350mm Rear: 19.2 lbs
Carrera S 340mm Front: 23.4 lbs
Girodisc 997.2 Turbo S 350mm Front: 22.7 lbs
Carrera S 340mm Rear: 19.0 lbs
Girodisc Carrera S 350mm Rear: 19.2 lbs
Last edited by CarreraFahrer; 09-10-2018 at 02:50 PM.
#98
Rennlist Member
I forgot to mention installing the Girodisc rotors wasn't as much of a diet as I had hoped. The GT3 brake pads weigh more so let's call it even. I wasn't expecting a lot but here's the weights:
Carrera S 340mm Front: 23.4 lbs
Girodisc 997.2 Turbo S 350mm Front: 22.7 lbs
Carrera S 340mm Rear: 19.0 lbs
Girodisc Carrera S 350mm Rear: 19.2 lbs
Carrera S 340mm Front: 23.4 lbs
Girodisc 997.2 Turbo S 350mm Front: 22.7 lbs
Carrera S 340mm Rear: 19.0 lbs
Girodisc Carrera S 350mm Rear: 19.2 lbs
#99
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Given the same overall diameter it seems strange the rears would weigh 2.5 lbs less then the fronts. The rear hats must be quite a bit bigger. (too lazy to go measure them). Laguna tuesday, looking forward to having brakes I feel confident of for the first time there in this car!
#100
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Track update: I was at Thunderhill on Monday and had a chance to get my car on track and give the brakes a good test. They worked great and I was impressed with how well the GT3 front brake pads worked and their ability to handle heat. I would say this is a nice upgrade over stock and gave me the additional braking capacity I was looking for. Of note my brakes still feel very smooth with no pad deposits. I bed in the brakes properly and there should be no worries with pad deposits. In fact I spoke with Mike and another guy from Girodisc at Rennsport last weekend and they both like the stock GT3 brake pad and thought the setup I'm running is an excellent choice for occasional track days. Now if we could find the GT3 rear brake pad compound for the rear.
I also did some instructing that day and drove a students GT350. I had forgotten how good those brakes are and the C2S brakes feel like mush in the first part of the travel. Anyone have any suggestions on how to firm up the brake pedal? I'm sure SS brake lines will help but I think they need more than brake lines. I'm using Endless brake fluid and the brakes are properly bled.
I also did some instructing that day and drove a students GT350. I had forgotten how good those brakes are and the C2S brakes feel like mush in the first part of the travel. Anyone have any suggestions on how to firm up the brake pedal? I'm sure SS brake lines will help but I think they need more than brake lines. I'm using Endless brake fluid and the brakes are properly bled.
#101
Rennlist Member
Thread Starter
Track update: I was at Thunderhill on Monday and had a chance to get my car on track and give the brakes a good test. They worked great and I was impressed with how well the GT3 front brake pads worked and their ability to handle heat. I would say this is a nice upgrade over stock and gave me the additional braking capacity I was looking for. Of note my brakes still feel very smooth with no pad deposits. I bed in the brakes properly and there should be no worries with pad deposits. In fact I spoke with Mike and another guy from Girodisc at Rennsport last weekend and they both like the stock GT3 brake pad and thought the setup I'm running is an excellent choice for occasional track days. Now if we could find the GT3 rear brake pad compound for the rear.
I also did some instructing that day and drove a students GT350. I had forgotten how good those brakes are and the C2S brakes feel like mush in the first part of the travel. Anyone have any suggestions on how to firm up the brake pedal? I'm sure SS brake lines will help but I think they need more than brake lines. I'm using Endless brake fluid and the brakes are properly bled.
I also did some instructing that day and drove a students GT350. I had forgotten how good those brakes are and the C2S brakes feel like mush in the first part of the travel. Anyone have any suggestions on how to firm up the brake pedal? I'm sure SS brake lines will help but I think they need more than brake lines. I'm using Endless brake fluid and the brakes are properly bled.
#102
Rennlist Member
the C2S brakes feel like mush in the first part of the travel. Anyone have any suggestions on how to firm up the brake pedal? I'm sure SS brake lines will help but I think they need more than brake lines. I'm using Endless brake fluid and the brakes are properly bled.
It's getting a bit better for me with each track day but it's still more temperamental then it should be IMHO.
#103
Race Director
CarreraFaher...the mushy feeling is the pad...since you’re using Endless brake fluid...highly highly doubt you’re boiling fluid. The gt3 pad is still a street pad and the gt3 has way better brake cooling than a Carrera...so you rotor and pad is getting hotter and the pad gets mushy feeling. Boiling the fluid pedal will go to the floor.
I suggest Pagid RS29 Yellow for Track use pads.
I suggest Pagid RS29 Yellow for Track use pads.
#104
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The brake pad certainly is part of this but I think the issue lies elsewhere. It's like that on the street and on the first lap out on track. I owned a GT350 that I tracked a lot and had the chance to drive a GT350R on track Monday. The GT350 has a much firmer pedal. The car I drove had the stock brake pads which I think are similar to the GT3 pad compound. I tend to think RDCR is onto something about the assistant and booster used on the car. Anyway the brakes work well I just prefer a firmer brake pedal earlier in the pedal travel.
#105
Rennlist Member
The spongy brake pedal in the first inch or so on a 991.1 isn't the brake lines, brake fluid, brake pad, or rotor. I've looked into this characteristic and the Porsche mechanics claim this "over boosting" of the braking, that gives this initial spongy feel, does this to prevent locking up the ABS on aggressive braking. (of course ABS won't lock up but it'll chirp) Those are some massive 6 piston front brakes. My 991.1 has this spongy feel when the brakes are cold and driven on the street. It isn't brake fade. On the track, with the Giro disc rotors and Pagid Yellows it does the exact same thing. No brake fade whatsoever. I've switched out brake fluids and there is no effect. My StopTech's on my old track car were dead solid after 1/8 inch of brake pedal travel. I loved that feel on the track. The 991.1 is a ton different and takes some getting used to on the track. I've used left foot braking on the track and that that helps minimize how annoying this characteristic is. Now, if you are overheating your pads on the track...then yes, it will only get worse. I'm still searching for a solution since I would really like to get back to effectively a dead solid brake pedal on the initial travel. Until that time, left foot braking.