FD New Brake Options
 

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.

http://img436.imageshack.us/img436/1...rakedwgyr8.jpg

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.

http://img214.imageshack.us/img214/2...unttechlk1.jpg

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.

http://img219.imageshack.us/img219/1...enttechsw7.jpg

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.

http://img213.imageshack.us/img213/2...irrisesfl5.jpg

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:

http://img213.imageshack.us/img213/7742/rx8bbktm5.jpg

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...

http://img436.imageshack.us/img436/8...4311212ul9.jpg

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:

http://www.roadfly.com/magazine/8/pe.../2-7215151.jpg

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

http://www.gruppe-s.com/Subaru/subbrk/scrprorotors.jpg

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.

hey Rishie, you had me real scared there for a moment. actually my wife had what turned out to be minor surgery and she is now back running on all, uh, rotors. (well she does driver her own modded FD)

with that report out of the way it is back to brakes.

i have a couple of emails from warren since i posted relating to the fd...

he really did a slick deal for the 350z and wants to do something similar for the fd.

currently the co offers a significant FD upgrade w the better-material directionally-vaned (right and left) one piece rotor. designed from scratch as to material and configuration and reasonably priced.... see Rishie.

secondly, they offer stock dimensioned two piece rotors. these are about 15% lighter have the Convergent Vanes, Center Mount, FORGED aluminum hubs/hats and are made from a proprietary greatly upgraded material. these are the rotors on the NSX that won a couple of weeks ago at Daytona. they are a huge performance upgrade even though they are stock dimensions.

thirdly, warren offers a two piece 328 X 28 (12.9 inches by 1.1 inches thick) for the rear. i am going w these w a 4 piston wilwood and i will probably use a Line Lock as an emergency brake... or make a small rotor on the driveshaft yoke w a spot brake.

finally, warren is excited about making a 324 X 24 (12.8 by .95 inches thick) which he says is the max rotor for the rear to mount the stock OEM caliper and emergency brake. he would then do a 328 X 28 for the front w his 4 piston caliper. the combo would balance out and the ABS would be happy.

this would be the ultimate setup for those who want to keep the E brake, ABS and power brakes yet have Supercar Brakes.

this setup is VERY COOL. warren casts a new rear caliper mounting bracket so you can use your caliper even though the rotor is almost 13 inches. i have not seen this done anywhere before. if you go to his site and look at his package for the rear of the 350Z you will see a picture of the bracket. it is very similar to the FD rear bracket.

BTW, i forgot to mention his aluminum hubs/hats are FORGED not cast.

it just keeps getting better.

howard coleman

well, you know being married it's like you're one person anyways. hehe.

Yups that's just awesome. I've been discussing the same things with Warren and can't wait to see how quickly they respond. This company has had amazing turn around times for engineering and development. i'm so stoked.

Next i'll hit him up about doing the FC chasis. hehe. THe ones I actually own. lolz. But one thing at a time. Don't want to bombard Warren as i'm sure he's a very busy man.

Sorry for the scare. Hope it went well with the wife's surgery.

Laters, Rishie

I allways wanted to do 2-peice OEM size rotors and retain the e-brake. The only company that came close previously is Project Mu but I beleive they only offer the larger JDM sizes.

as i mentioned RB did a complete re-do for the porky 350Z. if they can stop it they can stop the FD.

here's a thread from a guy who tracks his 350Z and has warren's setup. it is lengthy so i thought i'd just post the links:

http://www.freshalloy.com/site/marke...ke/default.asp
http://forums.freshalloy.com/showpos...1876&postcount

and a picture of the front RB full tilt setup.... that retains the E brake.

http://img208.imageshack.us/img208/8382/000ux4.jpg

howard coleman

here's the RB key to running 12.8 inch killer rotors on the rear w OEM calipers and E brake:

a band new purpose cast caliper mounting bracket! this one is for the 350Z

http://img205.imageshack.us/img205/3...bracketue1.jpg

(it doesn't have to be red)

howard coleman

Figures, I ordered the 99 rear setup a few days ago :( I'm confused, are there any plans to offer the nice 2 piece rotor for 99 rears?

Wow, I never thought I'd see Howard wetting his pants over something like this... :p:

No, you didn't. :)

BTW, most aftermarket 2-piece rotors use billet aluminum hats so this isn't exactly a new development...

Which is? Most rotors are made from cast iron. How are these any different? Cryo treated? High nickel content? What?

Sounds like this might be a better match for all the existing 13.0" (330mm) front brake kits than the 'RZ-spec' 12.4 x 0.8" (314 x 20mm) rear rotors available from Mazda and Precision Brakes... if it allows retaining the OEM parking brake and balances the piston area increase front to rear...

Having matching rotor diameters is not really the problem. It's the mismatch in the piston area ratio when upgrading to an aftermarket 4- or more-piston front caliper and retaining the stock rear calipers. Even the '99-spec rear calipers don't offer increased piston area. If they can fix that, then they've got something.

We will have two piece replacement 99 spec rotors. Maybe howard got more info from RB, not sure if they are disclosing materials or not. I know the Endless rotors had a higher content of lead. Not sure what's different in these ones.

Thanks, rishie

i will check to see if the 12.2 diameter might be able to be replicated at a reasonable cost.

what are you running for front brakes? with your engine and Road America's long straights and slow corners you will need a 12.9- 13 inch rotor w 1.1 inch min thickness or you will be in the weeds in 2 laps.

howard coleman

Not sure yet on the fronts- may have a lead on a Mandeville kit, if not stoptech was the plan. Or maybe you could sell me your m2 kit for cheap :D

Thanks Rishie.

Howard, my post wasn't meant as an attack; just curiousity and a little humor about your "obvious enthusiasm". :)

hey Jim,

yes, when i typed the "i forgot to mention" re forged i was referencing my longish initial post and did forget that i had mentioned it a few paragraphs earlier... old age is creeping up.

you do raise some excellent points. i compelety agree that properly matching piston area front to rear is essential for balance. it certainly is not all about rotor sizing.

as to materials engineering... they really do know their stuff and share some of it on their site. my post was so long i decided to just make general statements. while the exact mix is proprietary they do mention they use lots of carbon. the large amount of carbon makes the casting process more difficult.

if you were to call warren i am confident you would find a comfort as to what he is up to materials-wise.

clearly the company has gone the extra mile as to design. it is my conclusion they correctly realize that material is fundamental to making a better rotor.

in addition, their convergent vane design is easy to draw and more challenging to cast. warren uses a unique vertical rather than a horizontal mold process.

as to the 324 X 24 rear rotor.... warren is figuring out a rotor size in the front to balance out the increased rear leverage and retain the stock 4 piston thus retaining the overall balance.

howard

Thanks Howard. I'll take your word that their casting methods and material are better, and obviously functioning vanes on each side (rare in cast 1-piece rotors but typical in aftermarket 2-piece rotors) is a good thing, but the best improvement of their design seems to be the alternating tabs mounting the hat to the rotor allowing more air into the center of the rotor and past the vanes, as well as equalizing the stress on the rotor and hat.

So the stock front calipers would be retained to maintain the piston area ratio front to rear? That was one of the best features of Mandeville's kit (besides price), along with the obvious increase in front rotor diameter/mass to shed heat more quickly.

Wow, some interesting new go-fast parts! Subscribing to this thread now...

I'd be very interested in anything that let's me run my collection of 16-inch wheels.

Will any of these options do that, esp. if you're running the stock front caliper with the re-location bracket ?

TIA,
:-) neil

BTW: what does Racing Brake say about brake-pad compatibility and their proprietary rotor material ? Carbotech is saying that their pads weren't designed for Racing Brake's materials. Not saying they don't work, but may not work optimally or it may shift the "sweet spot" (e.g., heat range).

Answer to Jimlab's question on RB rotor material
 

Hi, This is Warren from RacingBrake that Howard and Rishie are mentioning. Hello to everyone.

We got into this RX7 brake project through Howard’s inspiration and enthusiasm which means a lot to a relatively unknown brake company like us.

I admire the respect that Howard received from you folks and from my experience in working with him only about two weeks, the diligence and eagerness he demonstrated and the efforts he puts into this project and shared with other RX7 enthusiasts what he found proven that he is well deserved.

I have just noticed user jimlab #32 asked some questions which I like to reply as follows:


BTW, most aftermarket 2-piece rotors use billet aluminum hats so this isn't exactly a new development...

RB rotor hats are made (machined) from "Forged" aluminum blank in stead of cutting from billet (aluminum bar) which is "extruded" and readily available from aluminum mfgrs such as Alcoa or Kaiser. We have to make various "blank" tooling for different sizes of hat. This is not a new development rather it's a process that we all know costs more to make, yet has the benefit of better stiffness and strength than those made from billets that offered by most competitions. RB commits to performance brakes. More and more enthusiasts start to realize that our extra efforts are worthwhile.
http://www.racingbrake.com/main/two-...mbly.asp?i=hat

Which is? Most rotors are made from cast iron. How are these any different? Cryo treated? High nickel content? What?

RB rotors material are alloyed and heated from the base of SAE G3500 gray iron instead of G3000 which is the standard brake material for motor companies and aftermarket but unfortunately very few aftermarket brake meets this standard based on our past experience. Our rotors have higher carbon than regular gray iron for better heat handling but carbon will also weaken the strength of iron, so the alloys (Cu, Cr, Ni, Mo etc) may be added to make up the loss of strength resulting from the increase of carbon contents and enhance performance under extreme heat. But there are more important aspects than just the chemical compositions (% of elements) that predominately dictate the overall performance of a brake disc such as microstructure which deals with the formation (type and size) of graphite (carbon) and the matrix (distribution of pearlite or ferrite), that is beyond the scope of discussion here. Some reference link (scroll to Rotor Material)
http://www.racingbrake.com/main/rotor_is_important.asp

At RacingBrake we believe in the basic material science, therefore we like to heat treat our iron because when you hit the brake, the temperature surged, so we developed a process to heat up the casting higher than the highest brake temperature a rotor can reach, then cool it down. The discs are cut from these “treated’ casting which might have some sort of deformation that is not noticeable with eyes. You may consider this is a process similar to “pre-warp” the rotors then machine from those “warped” castings. This explains to our customers why RB rotors will not warp and are more resistant to wear and heat checks. More on heat treatment but again it’s beyond the scope of our discussion.

The above made us to disbelieve on Cryo treatment which some companies are marketing to teat the rotors on opposite way – cool it down. We don’t have enough experience to comment on Cryo treatment but we know from the experience we had with those companies supplying brakes to professional racing teams (NASCAR) they only use heat-treated rotors, not Cryo.

Link to Cryogenic treatment question asked by an EVO racer
http://forums.racingbrake.com/viewto...highlight=cryo

Warren, will any of the options allow me to run 16-inch wheels ?

I would like to keep my stock front calipers and use one of your OE brake-relocation kits that allows for a bigger rotor up front, yet keep the 16-inch wheel.

:-) neil

Hi Warren, and welcome to the forum. Thanks for taking the time to explain some of the metallurgy used in producing your rotors.

Me too. I think it would take me quite a while to move up from a 16" wheel, if I had a carefully designed, vaned rotor and used it in combination with a good ducting system. A Mandeville re-think might be a good way to go here.

Sorry I'm a technical man, but my budget forces me to be a bottom line kind of guy...

So I'm looking at $499.40 for an OEM FD rotor replacement... Once we start talking about a increases in caliper, that retain the e-brake functionality and ABS, which I'm both not ready to get rid of...
What are we talking about $$ wise for a "Dream Setup" and I realize that different people dream differently... but reading through this there was talk about an upgrade in caliper and rotor, and personally I don't think I'll ever go back to the stock 16" wheels, so anything that fits in 18" wheels should fit the bill....

And personally I go track racing once or twice a year, again due to budget, so I'm interested in maximizing my ability to be competitive when accelerating and breaking, but more importantly I don't want to sacrifice the other 80-90% of the time that I'm just going for a Sunday drive....

Edit: Well I guess there seems to be 2 markets those that want to retain the stock wheels due to weight and $$ to upgrade... and those that don't :D

When you form the pearlite, are you forming fine or corse pearlite? I'm only asking because like you said, adding more carbon will increase stregnth and hardness, but will reduce ductility and impact resistance, and that you are adding Cu, Cr, Ni, Mo, etc. to get back some ductility and impact resistance. I'm curious about the pearlite size because that will also affect dislocation movement, which for those who dont' know what that means, it affects ductility and hardness and toughness.

The only rotos that will allow for 16" OEM FD Wheels are the currently offerred FD Front two piece rotors. Not sure if RB will be producing a US Spec OEM Two piece rear. That's something I have not mentioned to Warren since we got side tracked on these larger upgraded kits.

If they have the rotor rings I don't see why they couldn't make it. More than likely it will use the same rotor hat as HC's rotor, or the 99 Spec one that we also want to make.

Warren thanks for chiming in. It's great to see a manuf get up on our little community board to express some knowledge.

Thanks, Rishie

I agree that if they already "hats" made for the FD, it should be easy to fit any diameter rotor.

What I'm talking about are NEW rotors to go with a brake caliper relocation kit like they did with the NSX that allows you to keep the stock wheels:

taken from: http://www.racingbrake.com/main/oe_c...it_compare.asp
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Advantage of RacingBrake OE caliper big brake kits:

1. Built to fit under stock wheels. No larger wheels, wheel spacers, or longer studs to buy and install like competitions’ aluminum caliper kits.
2. Direct bolt-on, easy to install. No additional hardware, no bleeding required.
3. Extremely affordable – Costs only a fraction of an aluminum caliper big brake kit.
4. Low maintenance cost – Retains the use of OE pads with the freedom of choice (stock or aftermarket) at a fraction of those expensive non-standard (FMSI) pads.
5. Our brackets are made of high strength ductile iron and are stronger and stiffer than aluminum bracket.
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:-) neil

There isn't a whole lot of room as is with the stock wheels and calipers. M2 used to offer a 4 pot kit that fit under stock wheels with a 12.5 rotor, but that wilwood caliper was not nearly as bulky as the stock ones are.

From my rough measurements, there should be enough room to go to a 12-inch rotor (304.8 or 305mm) with the stock caliper.

I believe the delta in square inches would be about 36.9 sq. inches.

If Racing Brake could make a 12-inch rotor that has better thermal resistance and a rotor with thicker material going inside (by reducing the spacing between the rotor faces) perhaps it would be worthwhile.

How about it Warren / Racing Brake, is a 12-inch rotor worth it up front ? If so, will you make the OE caliper big brake kit ?

I believe there are many of us with stock wheels that would love to upgrade to better brakes . . .

TIA,
:-) neil