If you have wandered over to the suspension section you may have seen my recent thread entitled “Twin master cylinder manual brake system project underway.”

I have owned my FD since 99 and after lots and lots of mods (including a twin Garrett T04 turbosystem) am finally getting around to re-visiting the brake system.

I say re-visit because I did put the M2 AP racing CP5200 4 piston calipers on w a 13 by 1.15 rotor. I also deep sixed my ABS. Result was the car stopped really well… on the front brakes. Every now and then I would yank my wheels to wash the insides and funny thing, there wasn’t a lot of (EBC) brake dust on the rear wheels.

My 22 seasons of serious GT3 racing made me really appreciate how fast you can go w great brakes. Really appreciate.

So I thought this Wisconsin winter I would straighten out the brakes. I plan to do some track sessions at Road America and run the Silver State Classic in Nevada next September.

I figured I had the front knocked, I would slip a set of 13 inch by 1.1 rotors on the rear w a nice 4 piston Wilwood FSL caliper. I would dump my big fat power brake system and replace it w a couple of Tilton master cylinders and a (bias) balance bar.

So I read up on things and started to line up the ducks.

I had shopped around and figured i’d go w Coleman building me a couple of aluminum hats and I would use a set of their rotors. Nascar stuff is good enough for me.

In the meantime I had stumbled across a very nice site that seemed to offer (they all “seem” to offer) the possibility of a custom piece. They ask you to post to a New Product Development part of their forum… so I did and sort of forgot about it.

Until they posted dimensional drawings and a CAD picture. And it looked like no other rotor I had ever seen before.



All that was two weeks ago. I have subsequently spent lots of telephone time w Warren Lin, President of RacingBrake. He is 60, an engineer w a distinguished career and decided he had some ideas about making great(er) brakes so instead of retiring w a comfortable life ahead he did what any red blooded person would do: he started a new company.

Result? 3 major pending patents and brakes that set the mark as to performance.

While I thought I was pretty dialed as to brake engineering I have learned a lot from Warren.

My understanding as to brake upgrade was that rotor mass was where it’s at.

Not necessarily.

Warren contends that it is as much about rotor material ( I thought they all looked/were the same) and rotor design as mass.

Racetrack results tend to be supportive.

In order to produce the rotors he wanted, Warren had to start w a clean sheet of paper. RacingBrake does it all from scratch and therefore controls all aspects of the design and manufacture. Even the fasteners are proprietary …

The sole purpose is performance, after all, the name of the company is RacingBrake.


Let’s get into rotor tech.

Rotor material may be one of the single-most important, yet least appreciated, performance determinants.

It all looks the same!

Many rotors produced for the “high performance” market are bought as blanks and then drilled, slotted and machined. Often, the material is not even up to OEM spec..

RacingBreak does not buy blanks.

RB knows material engineering pays performance dividends and has created it’s own array of proprietary scratch engineered alloyed rotor materials, each to suit a particular high performance/race use.


Proprietary material along w a special heat treating process to stress relieve and promote thermal stability is the building block upon which the following break-thru designs are based.

The other design aspects may appear more sexy but do not discount the advantage of a purpose built foundation.

Generally when we think brake upgrades we think of a two piece rotor. Since the hub is generally made from aluminum there often is a 12-16% weight reduction in the assembly despite there being more rotor ring frictional mass. Win, win.

The rotor ring is bolted to the aluminum hub. If you will look carefully at most two piece rotor assemblies you will see that the rotor attaching tabs are a cast surface that is in the same lateral plane as either the outer or inner frictional surface.

Everything in the Coleman catalog including their Nextel Cup rotors and my high dollar M2 rotors are designed in such a manner.

Warren felt that the mounting function should not key off of one of the two frictional surfaces as it would lead to uneven heat dissipation as well as unequal brake torque stress transfer. The surface with the mount tabs would run cooler than the other surface. Since all of the braking torque is transmitted thru the rotor ring mount to hub the Center Mount transmits this torque evenly between the outer and inner frictional surface thus eliminating the standard mount mismatch stress.



Another major benefit of the center mount is airflow. Think of the inner ring of your rotor as the air intake and the outer ring as the exhaust. Compare air intakes.

I did. Here’s what I found from an inspection of my M2 setup:

My aluminum rotor mounting hub/hat bolts to the outside frictional rotor surface. There are NO air intake holes, it is sealed! The inner rotor intake is effectively sealed w the inner brake dust shield! Yes, there is a small scoop but for most of the open area the shield functions to exclude cooling intake air.

Contrast this w the virtually unobstructed air intake provided by the Center Mount design…

Bigtime air intake versus mainly obstructed intake. T25 V GT42.

The Center Mount has a patent pending.


Warren talks rotors and AIRFLOW, sort of like we do w turbos.

So now that Warren has the air intake nailed he addressed getting it through the rotor to maximize cooling.

End result is: the Convergent Vane, patent pending.



Of course most of our rotors have cooling vanes. Beyond that I really didn’t give the subject much thought. I knew there were straight vanes and curved vanes.

I didn’t know, for example that on most curved vaned rotors the vane runs the wrong direction on one side of the car. That’s because in order to have them running correctly two molds must be made and more inventory must be stocked. It is both humorous and sad to learn that in many instances the vanes are only cast one way but the slots or holes are drilled to give the illusion that there are a right and a left!

Of course RB does it correctly by casting a true right and left thus achieving maximum airflow.

We have opened up the intake w the Center Mount design, now let’s talk airflow through the rotor:

Warren talks of rotors as they were a kitchen sink.

The heat enters the sink like water through the faucet. The sink is of a particular size, just like a specific rotor mass. Whether the sink overflows in the medium term relates greatly to the inflow thru the facet versus the drain flow.

Warren has spent lots of time on the drain. If you can effectively increase the drain-flow you can keep the sink from overflowing.

Starting w the most basic aspect of vanes:

The inner ring (air intake area) is smaller than the outer diameter (exhaust).

If you look in the Coleman catalog to see a diagram of their curved vanes you will note that the intake openings, because of the smaller inner rotor diameter, are smaller than the exhaust!

This is upside down as to the heat removal needs and is one of the prime reasons for disc warpage and cracking. Warren’s Convergent Vanes design solves the mini intake problem thus promoting increased flow, decreased overall rotor temperature and evening out disc temperatures across the radius.

Rotors run hotter towards the outside edge. In addition to lowering the overall rotor temperature Warren’s Convergent Vane design is engineered to solve this problem. His Convergent design employs 36 inner vanes and 54 outer vanes.



Finally there is the full floating aspect of Warrens design…

Cast Iron and Aluminum, perhaps two materials couldn’t be much different. Cast iron absorbs and holds heat. Aluminum conveys heat.

Now we are going to bolt them together? Enter the floating rotor in the hub concept.

As the rotor gets hot, maybe 1300 degrees, it is going to expand but not at the same rate as the aluminum hat.

My M2 setup is just bolted together with no provision for different expansion rates. Warren engineered a floating system employing elongated holes, proprietary 10.9 grade crimp locking hardware that unlike others employs no prone to rattle lockwashers rather DACRO crinp locking hardware that does not lose torque when heat cycled. The rotor can expand and contract without stressing or cracking.

So RacingBrake has the right stuff.

The capper to all this is that they have shown a great interest is SOLUTIONS relating to specific cars.

THINK FD...

For instance they have cast a caliper mounting bracket for the rear of the 350Z so as to relocate the rear OEM single piston emergency braked caliper to fit a larger disc. I don’t know of a company that has done that.

Warren is really big on simple solutions. Instead of 6 piston this and that as the immediate solution he has redesigned our stock sized rotors so they work as bigger rotors. There may be no need to relocate calipers to get what we want. If there is a need for a larger rotor he does the front and rear so they balance using the stock ABS master cylinder.

How good are his brakes?

2 piece nsx rotors for oem calipers

I have just returned from an HSR race at Daytona and want to comment on this Racing Brake BBK setup as it seems my car was the test mule for this new kit. I logged over 4 hours and 300 miles of track time last weekend under RACE conditions and I can categorically say that this setup is fantastic! I installed this new kit myself in only a couple of hours for all four wheels and I was really impressed with the strength and manufacturing quality of both the brackets and the two-piece rotors. The factory two piston front and single rear calipers are more than up to the task with a strong solid pedal and zero fade! I was able to brake with just about any car out there save for the prototypes...i.e. Audi R8, Lola's, Riley & Scott..etc. I really have to thank Warren at Racingbrake as he has been great with all of help and support. I have the final race of the year in two weeks at Sebring and I can say that after the race weekend at Daytona that the brakes look ready for an entire full season still. Pad wear is great and the rotors show no wear or appearance of hairline cracks. Daytona is murder on a braking system as I have to slow from about 170 down to about 45 for turn one and I did this for over 85 laps last weekend.

Re: 2 piece nsx rotors for oem calipers

Ok I can only speak from my own experiences but what I can tell you is this...As long as a caliper has sufficient and even clamping forces without distortion or binding and it is able to hold a pad of a large enough surface material it will work just fine in all situations whether it be for racing, occasional track use or primarily for the street. The larger rotors are a definite step forward in performance to the smaller two piece rotors which I used before. The pads are the same so I do have a direct comparison. The larger rotor surface is able to dissipate heat better and distribute it over a greater surface area hence cooler brake temps. The kit also includes new brake lines which are extremely high quality as well. My brother races in my group with a Carrera RSR 3.0 liter with 996 Turbo brakes and 10" front and 12" rear slicks. I was right with him at all braking points and he is a semi pro driver with 25 years continous racing experience. In fact I outqualified him at Daytona and also beat him in the race ...for the very FIRST time...The new brakes gave me much needed confidence...and they really look great inside my 17" wheels!!!!!!!!!

I am indeed using the bigger rotors front and rear and have noticed no problems in brake bias and I still am using the factory ABS setup. I am using the original calipers on my 92 and yes they are slightly heavier than an aluminum caliper but they have been trouble free and I do use high temp grease after every race on the slide pins..a five minute job at most. One of the problems I have always noticed in my years of repairing, modifying and racing automobiles is that many people tend to overcomplicate things by replacing unnecessary parts. I like the look performance and PRICE of the original caliper..plus it has that great NSX logo already on it!

I agree, and I have posted before re the same. I have had over 15 track days on the very first set and I still have a few more track days left, this after turning them once. Hairline cracks are there but then they are expected after some 50 sessions on the same rotors.

Just an fyi, running cooler rotors has huge benefits. A few months ago I took my 96 RL to the track for the first time - as it was a rainy and cold day so I said I might as well since I committed to help. I was having great fun and laughing passing all the other "sports" cars on the track in my session While the joke amongst our local weekend boy racers is that I use my pyrometer too much, suffice it to say that the temps on my OEM front rotors were 800F on this cool and rainy day The rotors warped and the lifespan of the OEM pads were toast; good thing I had Valvoline brake fluid. The hottest I have gotten my RB rotors on the the track is 500F and that is 100F-150F cooler than the OEM rotors I used to run under the same settings/conditions/track.

http://www.nsxprime.com/forums/showthread.php?t=80162
1st Place in Class 4 hours of Sebring!

Just wanted to let all of my fellow NSX'ers know that at last weekends final HSR race of the year at Sebring my 1992 NSX won first in class in the four hour enduro on Sunday! Other cars in my class include BMW M3 GTR's and Porsche Cup cars. Many thanks to Racing Brake for giving me the consistent and safe stopping power

Posted: Wed Mar 01, 2006 12:58 pm Post subject:

Arnie, GOTO:Racing has been using RB rotors on all of our race cars with excellant results. Excellant brake performance and fantastic longevity. We recently ran one set of RB rotors for the entire 25 Hours of Thunderhill. While we had to change pads, the rotors not only went the entire race but they were still good enough to race the first sprint race of the year at Sears Point.

///////the above is both a the end of my post and perhaps the beginning of an FD relationship w RacingBrake. there is additional info on their site along w a forum where you are free to browse and pose questions. RB already is a known quantity at RX8club as Warren makes a full lineup for the car.

here's an RX8 RB corner:



my purpose is to raise awareness upon the proper occasion of new products that might upgrade our cars. i am not commercially affiliated w RB. i will be buying their rotors for my FD no matter what rear calipers i decide upon. i will be selling my M2 rotors and caliper mounting brackets when i get around to it.

BTW, i believe Rishie represents RB so you might contact him if you wish to purchase.

here's a picture of what you will find on my car in 07...



respectfully submitted FYI,

howard coleman

 

Those look beautiful.

Good point about the directional vanes. I haven't seen a stock rotor yet with directional vanes that were stamped "left" and "right".

The $20,000 question is what are these going to sell for?

 

RB currently offers both a single piece FD rotor for the front and rear. the front rotor is a real directional (as in left and a right) so they had to make two molds.

the one piece is made from their uprated proprietary.

prices are on their site. i suggest you contact Rishie

howard

 

Fantastic stuff as usual, Howard! Thanks for taking the time to do some legwork and write this up for us!

I think they're on to something as far as intelligent rotor cooling design. Very neat stuff!

Dale

 

SUPERB info HC. I think i'm gonna have to print it out though so I can really read thru it and highlight the key points. Superb. thanks a lot for the breakdown.

YES OF COURSE WE ARE ALWAYS Hooking up the Rotary Brothers. Just shoot me a PM. Our subforum has ads currently for Racingbrake. Howard's informative post is just what we needed to get the knowledge out there. I try to pursue products that are better and unique in comparison to their competitors. RB is one of them and are very open to engineering and producing new items. i.e. 2 piece FD rear rotors.

Thanks, Rishie

 

Awesome work Howard!!!! GREAT find!

 

Looks like really good info.

I might have to go with them for the track car.

 

I've always wondered about that myself. I did chalk it up to production tooling costs, but I still thought it was pretty self-defeating.

Yet another aspect that I've always wondered about. Sportbikes have been using full floating rotors for years because of this. I think car rotors haven't done this in the past because of the difficulty in making the cast floating pin area strong enough to handle the loads imposed. Casting techniques have come a long way in the past few years. Many foundries are now able to precision die-cast pieces that are lighter and stronger in the right places over conventional extrusion or machining.

 

Floating rotors have been around for years, but real innovation as I see it is the mounting design with mounting tab from both sides of the rotor. This must help with the over all strength and rigidity of the rotor as well as the heat dissipation. Thanks for the post Mr. Coleman!

 

It's simpler on bikes because the hat and rotor are coplanar. On cars the rotor and hat are offset from eachother so a car hat has to carry bending loads that a motorcyle hat doesn't see. Many true auto racing pieces use two piece rotors with floating hats as motorcycles do. You also see car hats often have thin slices cut through them between the mounting ears. This is to allow the ears on the hat to distort some as the rotor expands and contracts, thus preventing stress concentration and warping of the hat.

2 piece rotor with floating rotor:



2 piece rotor with fixed rotor and stress relief slots in hat:

 

Do they have complete kit for FD?

 

Little more clarification:

Are you referring to a complete rear kit, larger rotor, with caliper?
Or talking about front and rear two piece rotors?

If you can specify a little more I can better answer your question.

As a heads up, what I think howard and I are working on and ultimately like to see happen is this:

1. Two piece rear rotor, RZ Size, with Caliper relocation bracket for the US Spec Caliper
A Nice OEM minor upgrade to mate with 99 spec front brakes.

2. Even Larger Rotor, like what howard is doing, with a caliper relocation to reuse the factory caliper. An Ideal mate with any Front Big Brake system.

The only issue with using an aftermarket rear caliper is you will 99% of the time lose your ebrake function/handbrake because we do not use a drum style ebrake mechanism.

Rishie

 

Nice read! As always, when Howard says something, I listen

 

Very interesting. I'd certainly be interested in an OE Caliper Brake Kit if they were to offer one for the FD.

 

Sweet, that's exactly what I wanted to hear.

I'm going to start a GI thread asking what size would be most ideal for an upgraded rotor diameter, aside from the HC 13" version for the BBK.

Thanks, Rishie

 

Not necessarily. Most of the current bikes now have fairly coplanar hats (we call them "carriers") and discs because the wheel casting technology has allowed manufacturers to almost build the carrier/hat into the construction of the wheel hub, reducing component size and weight. In the past however, the majority of carriers/hats had an offset not too far from those pictured in your post, due to older casting technology that forced the carriers/hats to attach closer to the axle.

However, we do agree that the loads a car disc will see are far greater than those on a bike, due to the difference in mass...

 

I say...it is time for a brake kit faceoff!!!

Stoptech vs RacingBrake!!!

 

This is exactly what I am looking for. Thumbs up

 

We're on it. Really trying to make this happen quickly. RB has been great in producing products in quick turn around time. It's amazing to work with this company.

Rishie

 

Wow, thanks for a great writeup with pics so that the technically challenged could understand.

 

2nd.

I'd like them to produce something that is properly balanced with this on the front too. I'm looking to upgrade all 4 corners in a balanced manner (assuming all stock booster/abs hardware) if possible.

My previous idea was:
RS/RZ Rears
Stoptech 'Race' kit front (designed to balance with rs/rz rears)
Hawk HT-10 pads on all four corners to start

 

Please let us know what you find as far as development goes for potential kits or costs. thanks for everything.

 

Good stuff but I'm suck a cheap SOB I'll probably just stick with the traditional approach.

 

Oh come on Fritz. You're not cheap. Shiet. We're trying to make a CHEAP upgrade hehe. Don't rain on our parade. lolz.

So i've been emailing warren back and forth all day today. We're working thru the details, sizes and all that good stuff. I or Howard will keep you posted.

Just comes down to caliper brackets.

Looks like they have the ROTOR RINGS in stock for FRONT and REAR 99 SPEC FD Rotors. WOOT WOOT. Just need hats and brackets. We're good to go.

Peace, Rishie

 

FYI, Howard might not be around for a couple days.

I think he's having minor surgery so just wanted all of us to give him our best and hope that he recovers quickly. You're in our thoughts Howard. WE'll talk to ya when you return with a vengence.