mark kibort

Looks like RB.com has really improved their aready good rotor rings. the cooling design before looked not as efficient as their new design. the metalurgy held up and just blew me away with using one set of rotors for an entire season.

pads were PFC11s and they are fantastic too. they didnt crumble and decintegrate like the pagid black RS-14s

the big change was the new (black paint below) cooling vain design... looks better than the brembo they replaced. maybe the drilled brembo uses a different design, but the RB.com uses a very nice vain design.

the air foil design change is the second to last picture below... old vs new RB.com

RacingBrake

Hi Mark,

Thanks for sharing your experience on RB replacement rotor rings. As we discussed I can't emphasize enough for the importance of rotor hat and how they are attached to the disc.

Our rings are made to replace Brembo 13" (332x32) rotor rings so it's assume a customer would bolt these rings to the original hats w/o any issue or concern.

However to the benefit of Porsche racing community I like to share with you for a proper hat design. Essentially we want to keep the disc slides out and in during heat cycles, so the disc mounting tabs have oblong slots while the hat has round hole.

When a two piece rotor is properly assembled together, all nuts s/b tightly against the hardware shoulder with as very little twist angle and all mounting points should be all even, this will assure the disc is assembled "concentrically" to the hat.



View of the hardware in hat section, the nut sit inside the hat round mounting hole snugly without a play.


Disc mounting tab has oblong hole, and the nut sits towards outer edge of the hole.



When it refers to PCD, we rather to call it out where the bolt center is than the center diameter of the oblong hole


So when the disc is heated up it expands outward, and the bolt ends up positioned around the center of the oblong hole. These oblong holes allow the disc to extend & shrink without stressing the rotor hat, thus keep the disc/rotor from warping and cracking.

I have seen some two piece rotors simply bolt together with round holes in hat and "disc" which severs no functionality of this heat stress and are destined to failure.

Inside the disc is our patented "Convergent Vanes" for a more efficient cooling than conventional van design as detailed in this thread.

https://rennlist.com/forums/991-gt3-...l#post13069941





Learn more about our simple and easy hardware with self-lock feature etc.

http://www.racingbrake.com/product-p/fk5-10.htm

mark kibort

learning more all the time.. the products look amazing. I do understand the point about the nut body not rotating.. i did notice the oblong hole vertically for expansion, but didnt thing about the rotation factor of the nut causing any concentricity issues. the only way to torque them down was to have the nut body catch the edge of the hat shoulder. Looks like it did the job, but probably not as optimial as an original Brembo HAT, so those with brembos, will have an even better design.

Looking forward to reporting the good news toward half the season with these brake.

Thanks again for the help and advice on my set up and amazingly quick responses and shipping!

Best,

Mark

Next go around, do you have a 13.5" ( 345mm) rotor ring that fits this same Hat design? I think my calipers can fit this, and all ill need is spacers and longer mounting studs to do it.

RacingBrake

Our next size from 332mm up are (Surface mount disc only):

• [INDENT]345x30 VW R32/Golf
• 348x32 EVO 10 front replacement
• 350x34 Porsche Brembo replacement
• 355x32 Dodge Viper replacement
• 372x32 Dodge Viper BBK
• 380x32 Nissan GTR Rear replacement
• 380x34 Nissan GTR/Mustang GT500 front replacement
• 390x34 Nissan GTR 2012+ Front replacement[/INDENT

Center mount design rotors are what we good at; with over 200 sizes from 290mm up to 432mm for more than 400 applications.

mark kibort

looks like the evo 348mn would be the direct fit and my calipers should be able to handle it. i would only need to push out the calipers .35" and need .35" longer bolts. seems like a slam dunk for near 14" rotors!!

lets see how these do and make the changes next season!

thanks

Mark

RacingBrake

Here are some real two piece rotors just assembled for shipment.





These are of center mount design, and you can see how tight and uniform of these hardware nuts against the shoulder. Each rotor hat is lazed with P/N for positive identification of application and their respective replacement rotor rings.

H704-22A is for Mazda RX8 front RB BBK (332x26mm)
H704-16 is for Mazda RX8 rear two piece stock upgrade (303x22mm)

onefastviking

Mark, So what happened with the KE ?

Regardless of your answer MK, I'm glad your brake issue is solved and that you are running newer pads and new, non cracked, rotors now.

mark kibort

Thanks...
as expected, i had 5% more surface area . that coupled with the way heat is dissipated with the aluminum hat, and that solved the problem. the problem is gone as the brakes dont go into themal runaway and fade the pads look amazing at 5mm thickness, whereas before, the pads were turned into crusted dirt clods that broke apart. There is not the fade in that one 100 ft section of two spots in northern californium. Approach to turn 2 at laguna and approach to turn 13 at thunderhill. there is less thermal mass, but more surface area, and much better heat sheding material, along with better cooling vanes.
i started the season out with the new stuff (the brembos were cracking from the start of the experiment) if it wasnt for the cracking i have now, i wouldnt have changed them out. interestingly, they didnt get any worse.... could have been due to a centering problem originally, that i fixed after a couple of weekends. the pads had at least another weekend on them, but 5mm is a good spot to change.. plus, i always like to bed new rotors with new pads.

mark kibort

i was thinking about you at the track and measured the temps at the hat and the rotor. i had a pit area , right off the track. actually, the first time in a long time to pull in from the track, and get good tire temps and brake temps.
the rotors were well over 500 degrees, but the hats were only 250F.. amazing. usualy, the stock rotors were always just a little cooler than the rotor surface.
the calipers were 350F. the temp paint on the rotor showed a distinct line betwen the had and the rotor surface near 1400 degrees or greater.

this is the diff. the hats now dissipate MUCH more heat , much more efficiently.

mark kibort

Who would be interested in a 928 custom HAT from RacingBrakes.com.????
i think the costs are in the $800 range for a set of hats, but the rotors will last , 2-3 times as long as the stock solid rotors, PLUS, you also save about 7 lbs per rotor by going to a 2 piece.

this rotor hat would allow you to run the GTS diameter rotor, or slightly larger, 13" rotor, and with a GTS caliper or 964T caliper, (small short pad), you can bolt on the 13.5" rotor (348mm). running the GTS diameter rotor (322mm) is easy as making .3" spacers that go under the calipers and then all you need is the GTS mounting bolts. (2 each caliper for the radial mounts)

Im talking to RB.com now and they are interested in making them for us, if we are interested. any takers?? this would be for 928 or 964T owners!

Mark

below a pic of my custom hat from wrightwood, but those are not avaialble and might not be as optimal as what RB.com can make.

onefastviking

So are you now saying that the lighter / lesser mass rotor hat is able to dissipate more heat ?
I'm not going to go back digging but as I remember it I believe you were suggesting otherwise in the past.

No worries either way, what you have found out thru your testing is nothing new to me or many others on here.
I'm just glad you got your brake issues worked out.

RacingBrake

When dealing with brake heat, the rotor is acting like a heat ex-changer with two things to consider:

1. How large is the thermal capacity, this is directly related to the mass 9size) of the brake rotor, the heavier (larger) the better, in order to keep the heat under threshold.

2. How fast a rotor can dissipate the heat (move the heat out of the system)

I always like to refer the brake rotor as a heat sink - Just like your bathroom sink. The size of a sink (rotor) and the how fast it can drain the water (heat) determines how much heat you can put into the rotor w/o causing rotor to warp/crack (sink overflows).

For high speed track cars, you don't want to carry too big a sink, but you want it to drain the heat fast vs. heavy & low speed truck/trailer which you need a huge sink (mostly drum brake) to hold the heat because the low speed means poor heat exchange.

I hope this explains why Mark's new brake set up makes sense - A lighter rotor but with better design to cool the rotor faster still can perform better than a heavier rotor.

I have a discussion detailing the brake design in other section in case you are interested to learn more.

Racing Brake rotors vs AP Racing J hooks

mark kibort

That was my worry... but as i started to think about why the 2 piece rotors were performing much better, i had to think about it again. turns out, i forgot most of what i learned back in the day. no one suggested this, including you, and if you did, i would have been all over this a year earlier! even though there is less mass, aluminum transfers heat at a much fastrer rate and now the hubs, hats and subsequently rotors shed heat better. that added to the RB.com new cooling vanes and you have a really great product at a lower cost than the other alternatives.
when i came into the hot pits, the hats never got above 250f, while even the calipers were 350F (and rotors between 1400F and soon after, 500F by the time we got into the padock)

Yes, im glad too and thanks for that. the fact that you save 5lbs per side is also a nice bonus too!

definitely worth the price of admission! '

now, i wonder if the center mount rotors do the same, as the entire surface area of the rotor only transfers heat to the tabs to the hats.. thoughts on that?

mark kibort

great description.

winders

The RacingBrake dude and his product seems to get thoroughly shamed in that thread mentioned at the end of his post. Based on what I just read, I would never buy one of the Racing Brake setups!