Here's a quick survey:

1. Would you rather have lightweight rotors, or 14" sizes on the front?

2. Would you be happy with 4-piston calipers, or 6-piston units?

3. Would you pay to upgrade your rear calipers and rotors, if a kit were available which retained e-brake capabilities?

4. Would you be happy with a kit which sells for around $1300-1400 for the front? For $900 in the rear?

5. Are you more concerned with better braking performance, appearance, or weight-savings?

I have a popular retailler interested in producing a kit, and would like to have a 6-piston front setup, but I think realistically a 4-piston caliper might be the one which will work best with the OEM master cylinder. Virtually every other Brake MFG has made the same choice, with the exception of the Rotora/Greddy kit. If anyone in LA has one of those kits, email me as I'd like to know what piston sizes they use. Thanks!
Eric

 

front: 2-piece/4 pot Al calipers (stock size)
rear:2 piece/Al caliper (stock size)

...brembo type pads

 

Depends upon performance
4 piston
Yes
Yes
Performance

 

Why "stock size" rotors?

 

What's your ETA for this kit?

Personally, I'd rather go with what works best performance wise. However, I have a sneaking suspicion that lighter rotors would be the way to go for shorter braking distances rather than 14 inch rotors, especially considering the stock 12.6 inch rotors are already pretty good when it comes to fade resistance and so the lighter weight of a stock sized rotor will matter more than the extra swept area of a 14 inch rotor. Also, would 14 inch rotors fit over stock wheels? If they can't fit with stock wheels, then the kit is a no go.

I'd rather go with 4 piston calipers. It seems most kits use this setup, especially the seriously performance oriented ones. I know BMW engineers have only 2 piston front calipers for their M cars and frankly I feel the fade of trying to stuff as many pistons is more for bling. Finally, a caliper kit that improves feel or at least stiffens up the brake pedal would be greatly greatly appreciated.

Whether I will pay or not depends on how much it affects performance. I will say that if a rear kit offered serious weight savings, but stock like performance, I would be very tempted.

Your prices for the front seems very reasonable. The rears are a little higher than what I want to pay, but still in the ballpark.

This is a set of brakes. The no. 1 purpose of brakes is to stop your car as well as possible as predictably as possible. Braking performance is of course my no. 1 concern, weight savings a far no. 2 except in the case of the rear, which isn't stressed too much anyway, and appearance doesn't even factor. However, if you can offer silver calipers rather than the more popular fire engine red or black, that would be brownie points.

Keep me updated on these brakes. I'll probably be looking at replacing my brakes in the next year and right now Racing Brake is at the top of my list, but if you can demonstrate equal performance to the RB kit than I wouldn't mind giving your kit a whirl, especially since you're local in LA.

 

I'd be interested if you could use lightweight 2-piece rotors, just a little larger than stock (13" or maybe 13.2"). 14" rotors will require some big wheels I think, especially with a 6-pot caliper.

Would the rear brake kit include use for the e-brake??

Check out the K-Sport BBK- 8-pot calipers!!

 

I am doing the research and preliminary planning right now. I had another company who was going to do the kit, but they've simply not done it over the summer, and now I'm running out of time before SEMA.

I think 14" brakes may fit inside 18" wheels, but it'll be tight. Whatever I come up with MUST fit stock wheels as well as aftermarket ones, so this is a tough nut. This isn't rocket science. I've taken a peek at the numbers of the Racing Brake calipers as they relate to stock, and I've got the help of a major brake component producer, so this will all be high-quality stuff. There are other companies which produce kits using similar components from this brake company, so it's not like what I'm doing is ground-breaking. I'm just tired of the outrageous prices being charged by some of these vendors for very average components. Brembo and Stoptech aren't selling space-flight quality stuff, but their prices sure seem like they are!

My key guidelines are:
1. Performance
2. Weight
3. Price

followed by:
4. availablilty of replacement parts/pads
5. appearance

The rear kit would be close to the price of the fronts, due to the cost of the calipers, which aren't cheap. It would, however, be the first kit designed from the ground up to be a front/rear matched set. The plan is to keep the e-brake control too!

The problem with the 14" rotors is three-fold. First, they're more expensive, second, they weigh more, and third, their hardware (hats) cost more. There are some in-between 13" and 14" sizes that I'm considering, and with the jump in pad area that a 4-piston caliper can carry, and the marginal increase in brake leverage, the stopping force should increase considerably. Heat tolerance and resistance to fade for club racing would be the biggest benefits, along with the reduction in rotational weight and unsprung mass.

I doubt that they'll be provided in any other color other than black or red because, first, I love red brakes! Black is pretty much standard though. "Appearance" is far down the list, but still, I prefer red. When you outbrake someone, they should know why!

K-Sport's 8-piston calipers are overkill. They're meant for much heavier passenger cars and SUVs. They also won't meet the fluid requirements of our OEM master cylinder AND, they're heavy. Please understand that I'll only choose calipers which weigh significantly less than our stock pieces, no matter how "fancy" they might look.

**Edit** I'll take a closer look at the K-Sport calipers next week. They do weigh 5 lbs each, but since K-Sport is a sponsor of mine, perhaps they'll help. At 330mm per rotor (roughly 13") they're around the size I've been considering for the kit. Not sure they'll match the rears though.

 

I suppose another question is: How many people are interested? A solid idea of the number of people looking would help with the decision-making process.

 

i have the bremo 4 piston bbk and i thought about gettin the 6 piston rotora but i figured for a 230hp car that cant reach 150 mph i didnt need the enormous brakes. brembos were "enuff" for me. 13 inches and 4 piston calipers are fine for race duty for a stock rx8....

no need to go over 4 pistons for front and 2 piston rear.

id say performance matters most rather than cost. no one looking for bbks are on a tight budget. nor do they care if they clear the stock wheels. u think anyone spendin 2,500 on brakes is usin stock wheels and tires? no they are prolly one wider tires wrapped on wider lighter wheels....

and 14 icnhes is overkill 13 should be the limit, itd have a 13 inch lighter rotor than have a 14 inch same as stock weight rotor.

id love a rear kit WITH calipers as long as they retained the e brake. id pay maybe 1k for the rear, if it came with the usuals. pads rotors lines and calipers.


hell id buy that kit today if it were out. my rear rotors are racing brakes 2 piece slotted with endless pads and the rotors are warped as hell and its been 5k miles since i put em on.....WEAKSAUCE!

 

Please note that I was typing all of this while the 3 above posts were being made! Since your posts above PhotoMunkey, I now have a better understanding of where your desired direction is, and probably wouldn't have bothered to voice my opinions below, but anyways, here they are:

I am considering a big brake kit right now (K-sport as wafer has mentioned above) but I want the looks and no performance loss (over stock) to be number one priorities. Would be happy to see versions that would require the use of large clearance wheels (i.e. 19" plus etc.)

355-356mm drilled and slotted and coated rotors up front, 330 minimum in back

Minimal or no performance degredation from stock (difficult to do sometimes in aftermarket kits)

Big calipers up front (and in the rear) which are heavily powder coated or painted (like brembo or P-Mu) so that they are easily cleaned. I don't like the look of puny 1 pot calipers in the rear if you have big ones up front. Overall, the number of pots is not as important (more doesn't necessarily mean better by a long shot anyways) but I do want similarly sized rotors and calipers in the rear

Unsprung weight is a lost cause for me anymore with my heavy *** 19" wheels.
I just want beefy calipers made from decent material.

E-Brake integration is a must. Hell make a separate rear caliper if you have to.

Some of the new style slotted rotors look pretty cheesy in their CNC slotting designs (K-sport for example)... stay with classic brembo slots and holes, research this carefully. Rotor coatings (like gold zinc) are a nice benefit too. Two piece rotors are really nice, but I would still buy 1 piece rotors if everything else above is covered.

Ability to accept the common pads and the common medium performance pads.

Flame suit has been left at home - so please bear with me...
As you can see here, I am looking for a more affordable alternative to the great looking calipers and rotors of the $2500 (for front only) kits. If I really wanted a high performance big break kit, there are plenty of those manufactures out there that are trusted for this sort of thing and have thousands of hours of R&D.... Since you came on here to ask us what our 'druthers' would be for a kit from scratch, this is what I have suggested. I just want to make sure my RX-8 with a slightly bigger and heavier wheel package will stop nearly as good as a stock RX-8, and look 100 times better than the stock clampers. Make a safe, good looking, 4 wheel big brake kit for around $2000 and I think you will have a winner.

-C

 

...'cause I'll be using 17X9.5 and I don't see the need for oversized rotors. The stock setup are great but I'd like to lose some weight and be able to use carbon pads, that's why I wanted calipers that will take brembo type pads.

 

I am very very interested and since we live in the same basic area I'm willing to meet up sometime to talk face to face about the kit. Give me a PM if you wish to take me up on my offer. My priorities are pretty much the same as yours, though I'm a bit from the Colin Chapman minimalist school of thought; if you were going with 6 piston calipers, there better be a damn good performance reason why, or else it's just extra bling. In fact, my performance based priorities are as follows:

1. Brake feel and modulation
2. Fade resistance
3. Stopping distance

For me at least, stopping distance is less important than how much of the braking potential I can use consistently, but I'm sure I'm probably in the minority here. If the kit includes brakelines, is it too much to ask that the lines be designed like the AutoEXE lines which ape the stock setup of two separate lines with a fixed connecting fixture in the middle?

I disagree with the assertion that people looking for a BBK don't care about stock wheel clearance; I certainly do. My aftermarket wheels are the same 18x8 size, though caliper clearance is significantly larger than the stockers. Still, I switch periodically between my two sets, so any kit must work with the stock wheels. Also, I would prefer a kit that has solid rotors; no slots or cross-drills if possible. I know such a configuration probably severely limits your market so I'd accept slotted before cross-drilled. What I'm looking for is a kit that is as subtle looking as possible, in marked contrast to Chamberlin.

I must say if you have matched front and rear calipers, red or black is fine. The Racing Brake kit is front calipers only in red or black and since the factory calipers are silver, having mismatched colors on the calipers is something that bugs me a little. It's not a deal killer, but since you're designing a kit from the ground up, I figured I'd just throw it out there.

 

So here's what people have requested so far:
Calipers:
4, 6, or 8 piston

Rotors:
Stock size, two-piece, or 13" two piece, or 14" two piece, slotted or non

Colors:
Silver, Red, Black

Appearance:
As wild as possible, as subtle as possible

Performance:
As good as stock, better than stock, or much better than stock

Holy crap people! I'm not Brembo, for cryin' out loud!

Reasons:
1. A 6-piston caliper might be slightly narrower, allowing it to fit behind more types of wheels. Not everyone has the same wheels you know...
1A. 6-piston caliper allows more pad surface area.
2. Must fit behind stock wheels because people back east drive on snow tires in the winter.
3. The more weight saved, the more expensive the kit gets.
4. The more expensive the kit gets, the fewer people will buy it.
5. The more expensive it gets, the less likely the retailler will want to sell it.

 

here is what i think... the stock size is fine with a 2 piece lighter rotor... 4 piston caliper... this will add weight in regards to overall weight.. but the unsprung weight is reduced therefore compensating for the weight of the caliper... i would like to see a high quality rotor and caliper... the only question i have is the pedal going to be spongey with the additional pistons? i would assume brake lines would be included and the option for rear brake lines at an additional cost... this seems reasonable but hell i have had a few beers tonight

 

Yup. This is what happens in an open survey as different people have different tastes and needs. In the end, it's what niche you choose to service.

 

OK here is my opinion. I have been looking for a while for a Brake upgrade and my biggest concern is, what happens when rotors or pads run out, is the manufacturer going to still be around?

So I can see why people want calipers that fit over OEM rotors and will take OEM pads. Another take on this would be to ignore making rotors, just make sure your calipers fit over OEM rotors and take pads from the likes of AP, Brembo, Endless, etc.

Also, with F/I in mind I still see 4 pot as being more than enough up front. I think you can balance 2 pistons over the size of an RX8 pad just fine. I would also like to see a small piston 4 pot in the rear while maintaining the hand brake.

Cheers

Andrew

 

if i am correct... which i am not sure i am....there is no point of having the stock brake pad because of the additional pistons... you want to increase pad surface to increase braking... if he uses the right company with a 2 piece rotor the rotor would be really cheap to replace... and pads are pads... they are a minimal cost when you have a big brake kit

 

The company whose parts I'd be using will definitely still be around years from now. They're both an aftermarket company and an OEM supplier so they're pretty big.

The problem going from single piston calipers to quad-piston calipers is piston surface area. Fact: the RX-8 does NOT have a lot of piston surface area. The brake system operates at a fairly high PSI, probably somewhere around 3000 PSI at full clamping force. That's just a guess, but a fairly edumacated one. LOL This is so Mazda can use a smaller, lightweight caliper for weight reduction, and still get away with using a cheaper iron one. Domestic cars typically use larger iron or aluminum single piston sliding calipers, or in the case of PBR's aluminum Mustang and Corvette pieces, "two pistons on the same side" sliding calipers. They also use lower system pressures, around 1000 PSI or so, and more piston area. There's some serious juggling going on with pad compounds in order to get something soft enough to work in these conditions. In other words, US brake systems are not meant for high speeds or high temperatures, at all. Mazda's system will operate comfortably at higher temps due to the pad compound, and the higher system pressure will afford better pedal control and less fade from possibly boiling the fluid (high PSI raises the fluid boiling point, or it should). Think you can feel the heat coming from your RX-8 brakes after a spirited drive? That's because you can!

Now, we can't have too many pistons in the overall system without lowering the system PSI too much (i.e. lots of pedal travel for little piston movement). That's a bad thing. Some calipers are far too large, some are too small. Currently, there is no caliper which is "just right". If I can sweet talk this company into changing just two bores out of 6 on their 6-piston caliper, I'll have a very affordable (relatively) strong 6-piston brake to use on the RX-8 and MX-5. The pad surface area available would allow me to use 13" front rotors which weigh around 12.5 lbs each and would fit behind nearly every wheel ever made for the RX-8. This would be an increase in performance, size, and heat resistance. Better in every category.

But... as great as that sounds, I must CONVINCE said corporate giant that making one small CNC machining change will be worth it to them overall. Since most JDM brake systems operate in the same manner as the Mazda, and since the caliper would likely work for the 6 and the 3 too, there would be a wide range of applications open to this "new" 6-piston caliper. Do I have a chance in Hell of doing this before Sevenstock? Probably not. I believe I can complete the engineering by then, but I've got to find the "tail that wags the dog" to get the calipers made.

On the other hand, they do make a 4-piston caliper in approximately the same range of piston surface area as the Racing Brake combination, but they're more expensive calipers, by alot! While I'm not anxious to repeat what RB has done, if the pricing could be a reasonable $1300-1400 while still offering some profit for all involved, this still might be a good plan as it will force brake kit pricing down overall if people want to compete with me. The problem is, who foots the bill for the development kit. If I can't get the 6-piston design changed to work for us, then I'll have to use the 4-piston caliper, and the retailer has bluntly said he's not interested in paying for, or selling that one.

If I had the arrangement of a small $3000-4000 loan, I'd simply do this all on my own, because I can see the potential of not only the RX-8 kit, but also the MX-5, 3, and 6 kits to generate much needed income for me, in addition to the stories I could get published on this process. As it sits right now, I can perhaps bring about $700 of my own money to the table, which isn't even enough for all of the parts at cost for just the front brakes.

Also, you can't simply put a new caliper over the Mazda rotors because they're a very narrow size. Again, Mazda was doing their best to reduce weight and still offer good brake leverage with a fairly large diameter rotor, so they narrowed the rotors considerably. No aftermarket stuff will work on it.

Also2, you cannot just stick a "Brembo" pad on someone else's caliper. Things don't work that way. However, with the company I want to use, there are MANY different pad MFGs who make different compounds for these calipers. Far more than for Racing Brake or Stoptech I think. I don't believe that pad compound will be a problem at all.

If I size things very carefully (i.e. use industry standard hubs and rotors) it will be possible to later bolt on a pair of Titanium rotors, if someone feels the need for an ultra-lightweight brake system (and damn the cost!). TI rotors weigh somewhere around 4-5 lbs for the same size! I'm just saying this IS possible, not that I'll ever be able to do it.

I'm just spelling all this out for the club members so you can understand the challenges I'm facing. The engineer I'm using has done brake systems for 200-mph NASCAR vehicles and 5000-lb offroad racing trucks. It's been quite educational working with him so far. We have access to a CAD-CAM program with infinite stress analysis capability and water-jet cutting for the brackets. Tolerances within .001", or so I'm told. Aluminum ain't cheap, but he thinks it's possible to cut 100 brackets (50 complete sets) for around $600 for material and labor. Obviously, that's too many to start out, but if gives you an idea about how he thinks big!

I don't believe that 14" rotors will be the way to go, BUT the caliper I'd like to use will work with both. 14" (355mm) rotors weight too much and cost too much. It might be possible to do dual-design brackets to work with both, and that's an option we're considering.

It all hinges upon money, and having the 6-piston caliper available to us. Wish me luck, I'm making phone calls on Tuesday!

 

If anyone wants to chat with me about this feel free to call me at 760-799-0368 this weekend. I'm getting on the road to Palm Springs today.
Eric

 

I am also not 100% about my logic but I assume that while larger pads would definately help, the same size pad with extra pistons, ie a wider pressure application, you would see added clamping force. Not as much as wider piston area.

Yes but if the calipers only fit over these rotors and that company goes OOB, you are left with very expensive, albeit cool looking, book ends.

Calipers have to be cast to take a specific pad backing plate shape, again, imagine if it used a proprietary shape and again that business goes under.

I dont mean to herp on the business going under thing but as an unknown quantity you have to give people confidence that when you buy their product that they have choice of pads and rotors incase they dont like yours (for whatever reason) or you aren't around to produce them. PhotoMunkey, in this respect I know that you cant talk details now, but are you going to be able to ride on this companies name?

 

You are 100% wrong. Same size pad with extra pistons would probably mean a reduction in PSI as far as the fluid is concerned. You would have to put the same size pad on a significantly larger rotors to see an increase in brake leverage.

Yes, definitely!

 

The obvious missing brake manufacturer in RX-8 land is Wilwood. At least, I can't readily (four minutes of Googling, Wilwood site, Good-Win Racing) find any evidence there is currently a Wilwood-based kit available. Their products and business fit everything described here so far. Am I missing something? If that's the case, it would help a lot of people here settle in their minds either with reassurance that they believe the stuff will be good enough, or confirm that they would prefer greater content in an upgrade, depending on what their personal expectations and requirements are.

I'm assuming that the piston size you want changed to is represented in another caliper in the company's lineup? And that the pistons are configured the same (same length and basic design)? Same high-pressure seal type?

Just a little review of basics:

T = P x A x 2 x mu x Re

Brake torque = Hydraulic pressure x Total piston area on one side of the caliper x two sides of the rotor x coefficient of friction of the pads x Effective radius of the pad working against the rotor

Notice that number of pistons and pad area are not present in the formula.

Not every company would propose using the same caliper piston size set on the RX-8 and MX-5. If you just look at hydraulics, it might should work, but the effective radius of an RX-8 rotor (either one) is much larger, giving increased torque to decelerate the much heavier vehicle with larger-diameter tires. So even though the same brake kit would bolt onto each car, and the "clamping force", or P x A would be the same for a given pedal force, the response of the vehicle would be significantly different. There is at least one brake company that would have an appropriately smaller caliper piston size set available for the smaller, lighter vehicle with equal rotor diameter to avoid having a kit that was grabby or difficult to modulate.

Pad volume is a real benefit, as it allows more brake work to be done before the pads wear out. This is not the same as pad area.

Note that thick pads require longer pistons to avoid getting cocked in the bore at high extensions. So you add the thickness of the pad and the length of the pistons. You want some beam section to the caliper to help make it stiff. You just may end up with calipers that may not clear every wheel, including stock 8-in. wide, et+50 wheels.

 

Ahh yes I hadnt thought of reduction in PSI ... ohh well I knew there was something not quite right about my logic.

So to get back to the original question. I would be interested in a 6 or 4 pot system. Price is a factor. Racing Brake kit is my #1 choice at this point in time because of both reputation and price. Obviously something that fit under OEM rims is a bonus. And lastly Pad and rotor choice as I hate being stuck on one option.

Cheers

Andrew

 

Yup, give that man a cigar...

Yup, give that man another cigar! My stock on free cigars is running perilously low... At this point, what is unknown is whether W will be interested in playing along. I must whisper nice things in the right ears this coming week. I believe that they DO have another piston in their extensive lineup which will work, and that they COULD quite easily make a 6-piston caliper which would meet our requirements. Likewise, I also wouldn't mind if they'd make a 4-piston caliper which would more closely match our needs. And I sure wish they'd list caliper weights on their website too!

Granted, but if the BRACKETS work for both vehicle AND are designed to use a common, familiar mount, THEN I may use whatever caliper I choose, with the pistons I chose. They may then share a common rotor between the RX-8 and MX-5, but might ultimately use a 6-piston caliper on the RX-8 and a 4-piston caliper on the MX-5 in order to reduce pad surface area and change the dynamics of the MX-5 kit.

And it might be the one casualty of compromise in this equation.

Or I might use thinner pads, with thinner pistons, and a forged aluminum caliper for a stiff cross-section, and I could still end up with a 6-piston caliper which WILL fit behind a bunch of different wheels.

There will be some trade-offs with this kit. Weight vs. price. Longevity vs. fitment. I WILL use top-flight components, it WILL be a bolt-on package, and it WILL have to sell at a certain price point. Brakes are not an item where skimping just for the sake of saving $100 is a good idea. This kit will be rugged, durable, and offer better stopping performance than stock or I won't do it. Period. There will be no half-assing this. If I find that I'm more like Enzo Ferrari in my draconic control of the parameters, well then that's not a bad thing, is it?

Eric

 

I personally can't do cigars, but we could probably work out something with Macallan