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Discussion Starter · #1 ·
I have been tracking my CGTS for a little over a year now and am going through pads like crazy (tried Pagid Yellow, PFC, Hawk, etc). However, I expected to go through pads quickly from experience with prior cars. The one thing I didn't expect was to be changing rotors every 2-3 events. I by no means am easy on my car on the track and anytime an instructor or fellow driver rides along they say "you are getting everything out of this car." But, going through rotors every 2-3 events is crazy in my opinion. I run them till they crack all the way to the edge (yes I know this is not the safest) The main reason for going through rotors so quickly is that they are drilled (terrible for tracking a car). So this leads me to my question:

I'd like to gauge the level of interest in an affordable (50% or less the price of girodisk) slotted rotor as my fellow track friend is willing to engineer them but would like to know the interest level before undertaking this. Please let me know if you have interest. He is hopeful to have a mid-summer release if there is enough interest. Thanks!
 

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I have been tracking my CGTS for a little over a year now and am going through pads like crazy (tried Pagid Yellow, PFC, Hawk, etc). However, I expected to go through pads quickly from experience with prior cars. The one thing I didn't expect was to be changing rotors every 2-3 events. I by no means am easy on my car on the track and anytime an instructor or fellow driver rides along they say "you are getting everything out of this car." But, going through rotors every 2-3 events is crazy in my opinion. I run them till they crack all the way to the edge (yes I know this is not the safest) The main reason for going through rotors so quickly is that they are drilled (terrible for tracking a car). So this leads me to my question:

I'd like to gauge the level of interest in an affordable (50% or less the price of girodisk) slotted rotor as my fellow track friend is willing to engineer them but would like to know the interest level before undertaking this. Please let me know if you have interest. He is hopeful to have a mid-summer release if there is enough interest. Thanks!
OK, let's break this down. The tl;dr is you should get a 380mm Brembo GT-R kit all around. Yes it's $16,000. You have to pay to play. You can get a regular Brembo GT kit for about half the price. Then use the Brembo RE10 endurance pads, which are $795 each. Most serious guys tracking the 991.2 models with the 3.0L turbo are going Brembo from day 1, if they pass up on PCCB. The others are getting at least 10-12 track days out of OEM rotors.

One contributing factor is PTV may be destroying your rear rotors. You can disable PTV and swap it out for a real deal Guard LSD, for about $3000 plus labor. How grooved are your rear rotors from PTV pulsing?

The next factor is your driving. I go to the track with some pretty advanced drivers like @dii in a 981 GTS track modded to hell and they don't run through rotors in 2-3 events. It is possible you could carry a full 10 MPH more through each turn?

If you're destroying OEM rotors in 2-3 events you'll destroy a "cheap" aftermarket rotor in 1-2 days. Especially any vendor claiming to have a magically lightweight rotor. Those are the ones for street guys or drag racers, that crack at the bobbins under any kind of heat.
 

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Discussion Starter · #3 ·
To be clear I am talking about DE events. Also the reason I and many others are looking for a lower cost slotted rotor is bc we don't want to spend the thousands of dollars to buy a big brake kit. It is just shocking to me that no company has come out with a lower cost alternative. These would also only be front rotors and the hat would be manufactured in house and rotors would come for a high quality company like Wilwood or Brembo. The rears I am not having any issue with as they are lasting me about 6 weekends. Not to brag at all but I am running similar lap times in my CGTS that many club racers are running in their GT4 club sport on the same tire (Nitto NT01) so I understand increased wear is just a consequence.

Please keep this post on topic to gauge the interest for these. Thanks!
 

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You're asking for alchemy. Brembo uses superior alloys. Cheap Chinese rotors wear worse than OEM and fail spectacularly. Stay away man especially at your level of the game. It's safety equipment, go up in quality. Buy a used brembo gt kit and rebuild the seals. Rotor rings are only $900 per axle. Invest in some brake cooling also.

I probably get 9-10 days out of the pads and 20-24 days out of the rotors lapping a track car S4 about 3 seconds behind a properly driven GT4.


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I feel your pain. This month's SCCA mag had an article on this point. It's conclusion was that drilled rotors suck and the holes are primarily an aesthetic gesture. I have looked everywhere and cannot find slotted rotors for the front of my '14CS. I figure the most cost-effective upgrade would be Girodisc.

What size wheels are you using, BTW?
 

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Girodisc would be your best bet cost wise to upgrade to slotted rotors on the 981. Front 340mm versus 317mm and for the rear they are 325mm versus 298mm providing greater braking force and cooling capacity.

We have them available as individual front or rear sets or as a full kit which cost less. (Links below)

Front 340mm 2-piece Rotor Upgrade for 981 Boxster S/Cayman S

Rear 325mm 2-piece Rotor Upgrade for 981 Boxster S/Cayman S

Front/Rear 4-piece Rotor Upgrade for 981 Boxster S/Cayman S









There are also Rotora big break kits (Super Challenge), but are significantly higher in price. (Link)

 

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Discussion Starter · #7 ·
I'm running 18" wheels. Girodisk is an option but a very expensive one. If there was a slotted Zimmerman, Centric, etc that would be perfect for the weekend warrior. At about $250 a set for fronts I could use them for two weekend and then throw them out and it would still end up being cheaper than the girodisk as I highly doubt they will make it through 6 hard track weekends. Friend of mine used them and after 4 weekends came to the conclusion that they were not worth it. What we are planning to create is a hat that cost about $250 for a front set and then the rings we are targeting a cost of $400 per front set which ultimately comes out to about half the cost of Girodisk. The rings we would have manufactured by Wilwood, Brembo, etc. (i.e. A very high quality company)
 

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Nothing about tracking a $90k porsche is cheap. This thread makes no sense.


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Discussion Starter · #10 ·
I would be somewhat interested in this. I also autocross my car in super street class so installing bigger brakes isn't an option for me.
Sounds good. I have a few race teams interested due to that same reason. So far I've received 32 notes of interest so we will likely move forward if the interest continues at this rate. Thanks!
 

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Miata slot rotors conversion kit. $14 plus shipping, lasts one lap at Laguna. Shove the packing material in your throttle body to convert your GTS to the full 90whp Miata kit.




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Girodisc would be your best bet cost wise to upgrade to slotted rotors on the 981. Front 340mm versus 317mm and for the rear they are 325mm versus 298mm providing greater braking force and cooling capacity.

We have them available as individual front or rear sets or as a full kit which cost less. (Links below)

Front 340mm 2-piece Rotor Upgrade for 981 Boxster S/Cayman S

Rear 325mm 2-piece Rotor Upgrade for 981 Boxster S/Cayman S

Front/Rear 4-piece Rotor Upgrade for 981 Boxster S/Cayman S









There are also Rotora big break kits (Super Challenge), but are significantly higher in price. (Link)

Yeah, Girodisc now makes direct replacement slotted rotors for the 981 and 981 S. They are slightly larger than the stock rotors (good), lighter than stock (good), and come with the longer bolts and spacers (because of the larger diameter).

Point is, they are not the "big brake" kits I've seen for years; they do not require new calipers.

Anyway, I just bought a set and put them on. I'm told that they last twice as long as stock (cross drilled) rotors. They were a total of $2200 for all four with the hats (I have the 981 Cayman S), but considering the fact that you only have to replace the disks (not hats) the next time, the replacement cost is lower--$700 for fronts and $700 for backs.

I also go through stock fronts every 3-4 events, and twice that for backs, so it ends up being cheaper, if they do, in fact, last twice as long.

We'll see! I'm just glad someone finally makes a direct replacement slotted rotor for the 981.
 

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Discussion Starter · #14 ·
Thanks to all those who messaged me. We are moving forward with having a prototype created and expect to have something ready for full production by the end of June. Stay tuned for updates.
 

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Also extremely interested in quality slotted, OEM size rotors for the 981 S/GTS.
 

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Remind me never to share the track with anyone who participates in this thread.


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I'm just going to drop this here. FCP Euro. Lifetime replacement on any part you buy from them. Even motor oil, brakes, etc. Even if you track your car. They sell OE Porsche discs. I have no affiliation with them.

https://www.fcpeuro.com/page/lifetime-guarantee

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Remind me never to share the track with anyone who participates in this thread.


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I think there is a difference between being "cheap" an using cheap materials for a brake kit and being cost conscious where you want to have options for brake kits and not be forced into buying whatever Brembo might be selling. I would hope that those seeking options are not willing to sacrifice quality to get a lower price.

BTW I concur that if the OP is eating rotors every 2-3 events that something is wrong, either mechanically or with driving style, or something about the track he is driving such as multiple 150mph straights to 25mph corners or something that would be hard on brakes. I also disagree that an S4 is only 3 seconds behind a GT4, at least not at my track, it would be more like 5-6 seconds :) just pointing out track differences will make a difference in times as well.
 

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Discussion Starter · #19 ·
I think there is a difference between being "cheap" an using cheap materials for a brake kit and being cost conscious where you want to have options for brake kits and not be forced into buying whatever Brembo might be selling. I would hope that those seeking options are not willing to sacrifice quality to get a lower price.

BTW I concur that if the OP is eating rotors every 2-3 events that something is wrong, either mechanically or with driving style, or something about the track he is driving such as multiple 150mph straights to 25mph corners or something that would be hard on brakes. I also disagree that an S4 is only 3 seconds behind a GT4, at least not at my track, it would be more like 5-6 seconds :) just pointing out track differences will make a difference in times as well.
You raise some good points. The tracks I typically run at are NCM, VIR, Mid-OH, and Watkins Glen of which all have multiple heavy braking zones. Not to brag or be "that guy" but I am driving near the limits and am setting times less than a second off GT4 club sport being driven by seasoned racers. So I am aware that I am not the norm as many students that have CGTS whom I drive with are 5-10 seconds a lap slower. However that does not negate the issue that drilled rotors are horrible for track driving. Our prototype is set to be done next week and we plan to track it the second weekend in June. I will update you all as soon as we have tested it. Thanks!
 

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I think there is a difference between being "cheap" an using cheap materials for a brake kit and being cost conscious where you want to have options for brake kits and not be forced into buying whatever Brembo might be selling. I would hope that those seeking options are not willing to sacrifice quality to get a lower price.

BTW I concur that if the OP is eating rotors every 2-3 events that something is wrong, either mechanically or with driving style, or something about the track he is driving such as multiple 150mph straights to 25mph corners or something that would be hard on brakes. I also disagree that an S4 is only 3 seconds behind a GT4, at least not at my track, it would be more like 5-6 seconds :) just pointing out track differences will make a difference in times as well.
Absolutely. If some folks want to run $10k brakes on a base car they're underdriving that's their prerogative, but FWIW a huge portion of NASA and SCCA race cars run reputable blanks or non-OEM slotted stuff (like Zimmerman, Stoptech 1 piece, etc., for $200-300 a pair). Hell, the corvette guys still run NAPA rotors in a lot of cases with no ill effect, although they do have to replace them frequently.
 
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