Rhinoceroscity

Hey all,

So I just recently did my 4th track day in my 2018 GT-R, and I'm pretty sure I warped at least one of my rotors. Car has 27k miles on it anyways, so I figure maybe its time to replace and possibly step up to a better one. I'm looking to track the car more frequently and wanted to get people's opinions on what aftermarket setup to go with. I have the stock irons right now, no carbon ceramics.

On the advice of MG1422 and bish, I did put TIKT cooling ducts on all 4 corners before doing any track days, but otherwise the car is stock. I'm looking to go to something that won't heat soak so badly and will be more warp resistant, without doing carbon ceramics because I just cannot justify the cost vs just replacing iron brakes as they wear out over time.

What are my options? I did some searching and it looks like Girodisc are fairly popular on here, but they have a couple different sizes and I'm not sure which will fit and which won't (big vs slightly smaller). I think the 390mm is what I'm after, and I think these are lighter than OEM as well? I've also looked at RacingBrake but it looks like they only do carbon ceramics for the GT unless I'm just being dumb. If people have recommendations that'd be great, looking to replace all 4 corners with new discs and pads.

Any info would be appreciated, thanks!

Stenzel-Germany

Hi,

If you have steel discs as standard, the 390mm are the right ones.

The 402mm discs are intended as a conversion kit for the MB 402mm ceramic discs.

Kind regards.

Stenzel

Rhinoceroscity

Awesome, thanks very much for the clarification! Right now the front runners are the Giro 390mm and 360mm for rears then, with some Cobalt or Pagid pads or something.

G. P

Hi,

I replaced my OEM rotors, pads, brake fluid and brake lines with the following:

Brakes Rotors - Front (Set) GiroDisc A1-123
Brakes Rotors - Rear (Set) GiroDisc A2-148
Brakes Pads - Front (Set) Pagid 8238 RSL 29
Brakes Pads - Rear (Set) Pagid 8246 RSL 29
Brake Lines - Flex Steel RennTech 42.190.0391
Brakes Fluid Castrol React SRF Racing
I track the car 5-6 times a year and have no more heating issues.
The Pagid RSL29 are "street friendly" since they are not very aggressive when running at cooler temps and feel like the OEM pads. They get aggressive when heated on the track.
The only issue with the RSL29 is if you live a colder area that get below 40F, you will get brake squeal.

Rhinoceroscity

@G. P Thanks for the detailed info! That matches the setup I've been considering, and 6 track days a year is about what I'd be looking at. I live in SoCal so the temps shouldn't be an issue.

user33

Do you have enough usage to be able to share some longevity data?

G. P

I actually do.

First, I was surprised to find that the RSL29 longevity is longer than what I have expected. It’s probably related to my personal driving style, which I think is medium to medium-aggressive on the brakes.

For the last 12 months I have driven about 9000 miles on this setup, of which about 270 miles were on track in racing mode. Most track driving was at about 160-170MPH down to 100-100 mph turns (Pocono Raceway, PA), and some 120MPH down to 60MPH (Thompson, CT), all late-brake with some tail-braking (corner dependent). For street braking, I mostly use downshifts and quick last-minute brake. So, in general, not heavy brake use. That will explain the following data:

The original pad material thickness of the PAGID RSL29 8238 (front) pads was 10.6mm, now it’s down to about 8mm. The PAGID RSL29 8246 (rear) original pad material thickness was 12.6, now it’s about 10mm. At this rate it looks like it will last 3 seasons 😊. Time will tell.

The Girodisc thickness show minor reduction. It’s recommended to replace the pads at 4mm in order to keep the rotor life to max.

As for temperatures, since installing the TIKT cooling ducts, on 80F day running 20min sessions, the rotors hardly hit 450F, calipers 370F and pads 550F.

I hope this help.

Rhinoceroscity

@G. P Those are very encouraging stats. Out of curiosity did you notice any improvements in handling after going to girodisc rotors, given that they're lighter?

G. P

Not that I can tell for sure. I am not sure the weight difference is that significant, but that is above my expertise grade

MG1422

I run the girodisc with cobalt XR1 pads and tikt ducts (front only) and slick tires on my GTR and I think it is a great set up. The XR1 pads are not necessarily street friendly but i don't mind running them on the street.

My home track is COTA so its tough on brakes and its hot but I found that this set up works great and no more fade thanks to the ducts. Longevity is great as long as you do some proper cool down laps.

As for weight difference between girodisc and stock just from picking them up they are about the same. I think my race shop weighed them and it came down to a couple of ounces of weight difference.

amgeethx

Brake rotors don't warp. If you are getting vibration under braking, it is likely the result of uneven brake pad deposits in your rotors (aka a hot spot). This can occur from improper bedding, sitting on your brakes while they are super hot at a stand still, or using your parking brake after a track session. That being said, some brake pads are more susceptible to this issue than others. If you haven't changed your pads, I have had very good luck with Pagid RSL29's using the OEM rotors and Tikt ducts. Also, make sure to use a racing brake fluid if you haven't changed to that already. One benefit to sticking with the OEM steel rotors is that FCP euro has them and offers unlimited free replacements.

det000

Are you seeing that weardown rate for inner pads or outer pads? My inner pads (OEM) went from full thickness to 3mm after just two track days. The outer pads still have quite a bit of meat left. If you're only looking at the outer pads, you might want to check the inner ones. I'm hoping the RSL 29s do better (I have them going on the car soon).

G. P

You are correct, the inner pads wear down more than the outer. I rotate pads every few months and/or when I change from daily tires to my CUP2s track tires. So the number I gave here are just an average and are really relate more to my driving style, tracks used and length of runs. The PAGID RSL29 are better than the OEM on the track, they are probably (and I don't have any supporting data to this) similar to the Cobalt XR3. If you find that they wear too fast, you may want to consider race pads like Cobalt XR1 or PAGID RSL1 , or many others which probably will require a caliper replacement.

Ago54

Hi. I have Paragon Performance rotors and EBC Bluestuff pads, TIKT pertformance cooling ducts, Motul 700 fluid.
I was two days in Germany Nürburgring Nordschleife at AMG Experience Advanced driving days.
Couple of other track days also here in Finland.
Brakes are working just fine
Check Paragon web site (https://paragonbrakes.com/2-piece-ro...-gt-gt-s-c190/)

ppgtrpro

Hello, with which measuring device did you get these temperatures? Did you take them when you arrived at the psite tours?

G. P

All measurements were done immediately as I came to the pitstop. I am taking 3 measurements at each wheel: rotor, caliper and pad. These are measured with a non-contact pyrometer Laser thermometer gun which allow to test these 12 points within 1 minute after stop. Of course, this method does not give you an exact accurate measurement of peak temperatures, but at least you can find the range you are in. To verify the caliper peak range, I also added a thermal strip to each caliper to verify the strip does not show higher limit then the thermal gun.

user33

FWIW, these temps are similar to what I've measured, except
- I've not measured pad temps (don't know why no, but I will start doing it)
- rotor temps measured using a temp gun upon returning to pits after cool-down lap(s)
- caliper temps are max/peak temps via stick-ons
- my most local track is extremely hard on brakes and I'm quite aggressive, there
- my GTR Pro has TiKT brake-cooling ducts front and rear
- I've done multiple track days with temps in the 28-30 deg C (82-86 deg F) range

My current caliper-sticker readings, which show a "greater than but not more than" peak temp range:

==============================================
Caliper Position| Top: deg C | Bottom: deg C |
================+============|===============|
Driver Front | 166 - 187 | 166 - 187 |
----------------+------------+---------------+
Passenger Front | 166 - 187 | 188 - 209 |
----------------+------------+---------------+
Driver Rear | 143 - 165 | |
----------------+------------+---------------+
Passenger Rear | 143 - 165 | |
----------------+------------+---------------+

[marked the chart as "code" and it shows correctly in entry but the fixed-width font source formatting gets lost when posted ... sigh]

G. P

One of the advantages that I saw in taking the pads temperature is to know how much temperature margin I have or don’t have with the pads.
If you look at the coefficient of friction of the RSL29 pad compound and the temperature you are measuring (**) , you can see if you can or cannot push the pad farther and gain/ loose grip.





** since my pad measurement were done on the outer pad on its side surface, I must assume that the actual pad's center facing the rotor could be higher by maybe 100C? ( does anyone have more info about what can be the center temp increase vs the side?). Regardless of the accuracy here, one can see that in our measurement the center pad temp could be at about 400C ( (550F = 287C)+100C) ,and the max grip of the pad it at 500C. That means it can be pushed father. FWIW. ( and of course your foot feel, of the brakes pedal, is the final judge of the pad performance regardless of any scientific bs)