12 inch Wilwood brake- hats and caliper mounts now ready

[Guest z1 performance]

.25 inch steel will be perfectly adequate for a brake setup of this size on a car with this kind of weight...most of the AP kits simply use aluminum brackets.....

[Bob_H]

You know, looking at your stock mock-up with the prototype bracket, I couldn't help but notice that with the thin bracket, the caliper is centered on the rotor. Now, when you up that bracket thickness to the .25 inch, the caliper will move.......but unfortunatly you have already made the spacers for the rotor... I'm not liking what I'm seeing. Let me know what I am missing.

Your initial cc.com response is not good btw.

-Bob

[Bob_H]

Alright, no more nice guy here.

stop making absolute statements w/o math or engineering to back it up.

A general statement such as:

.25 inch steel will be perfectly adequate for a brake setup of this size on a car with this kind of weight...most of the AP kits simply use aluminum brackets.....

First, what weight was used. A 240z with no driver can be 2200 lbs. A 280z with two passengers and a v8 can be over 3000 lbs. So what did you use for your calculations or comparisions?

And to say another kit uses aluminum and since this one is using steel that it is "ok" is a farce at best. What thickness aluminum vs the .25 inch steel? Do you have the relative strenghts of the two materials? And there is a difference in types of aluminum, so which type did they use?

I may be coming down hard on you and Juan, but you are taking peoples lives in your hands when you sell them a brake kit and I believe you should be held to a higher standard than, "this high performance shop said it was ok" and "it is perfectly adequate for this size of car and weight". Those are very general arguments that hold zero water when the foot hits the pedal,(pun intended).

The more I hear Juan and you responsd with the why and how of the kit, the more scared I am for those purchasing it. You are liable if one of the "kits" fails due to poor engineering so you should be even more worried about it than me. It is better to be way overengineered than under engineered.

I will continue to push this till satisfactory answers are put out, by you or someone else. I would rather be considered the ass and save someones butt than be polite and have someones brakes fail someday.

-Bob

[Guest Looking for apt in Alb Ny]

So what are you not liking? the fact that the POS bracket which I have mentioned many times will be made professionally by me and my CNC operators. yes the hats have been made. that should answer your question right there. I have the hub nut screwed loose . It made my life a bit easier dealing with a thinner bracket for measuring.. that's why its centered hubnut loose because of the thinner prototype bracket.. I have never gotten anykind of negative feedback for my work. I don't plan on being a millionaire What I create for myself I provide for others are at my expense. you may not like what you see which is fine. You are not only putting me down but others who have joined to help build the setup. why don't you give us a hand I reward anyone who helps and asks for a deal. Maybe we could use someone like you to give input instead of giving negative opinions .

[Guest Looking for apt in Alb Ny]

I called the guys up at PrecisionBrakesCompany.com. I asked them about a few things such as lines and the .25 inch bracket. They all agreed it will be suit. That is what they use. Grade A .25 steel for their caliper mounts. I work with engineers and am very well educated. The money given for my parts only gets funded towards making innovative designs and paying the expensive hourly rate.I hardly benefit. I really don't know what else to say.

[Drax240z]

I called the guys up at PrecisionBrakesCompany.com

 

Do you know who you are talking to there? Is it an 18 year old kid on a summer job, or a professional engineer with years of experience? I'm not saying their assessment is incorrect, only saying that finding someone else to agree with you doesn't make it right.

 

Grade A .25 steel

 

Well I've heard of "Grade A" beef... but never "grade A" steel. But what do I know?

 

Listen Juan, I don't want you to think that I am trying to shut you down, or detract from your business (or anyone else doing a similar thing) I am just strongly suggesting that in order to ensure you are doing things safely, you should have your designs verified by someone that knows how to verify it, in a way that would stand up in court. Its not like you are designing a wood shed here, you are working with brakes, and a mistake most likely means someone is seriously injured. Furthermore, a mistake may not come out in the form of a catastrophic failure for a few years, after fatigue. By then, you might have 100 cars with your system equipped, and each and every one might be in jeopardy if the safe life is too short. What do you do then?

 

I'm by no means saying stop what you are doing, I am simply saying that you should know what you are getting in to if your parts are not strong enough to give a fatigue life long enough to cover the length of time the part is used.

[Guest Thurem]

Allright partypoopers (you know who you are), I found a site that lists the yield strength and the ultimate tensile strength of mild steel. http:// http://www.kastenmarine.com/alumVSsteel.htm The yield (strenth until deflection) is 36000 PSI and ultimate tensile strength is 60,000 PSI. So, if you have a solid rod that is one inch by one inch you can hang a 60,000 pound weight from it before it will break.

Lets consider a 3000# Z decelerating at 1G (the tires traction limit with no aerodynamic downforce), we are gonna hang all that force on the front tires. That's 1500# of force per tire. We are running a large 26" tire, so this force is multiplied by the ratio of the tirediameter/rotordiameter. 26/12=2.17 force=2.17 times 1500# = 3250#. Now we have a rough estimation of the maximum amount of force being applied to the caliber in the direction of wheeltravel.

Let's say for example (worst case scenario, really bad bracket design) the caliper is only being held by a sliver of the 1/4" bracket, the sliver is 3/8" the thickness of the bolt holding it, nevermind the rest of the bracket and the 2 bolts holding it on. This would yield 3/8" times 1/4"= 0.09375 squareinch holding your caliper. The yield strength of MILD steel is 36,000 PSI, so 0.09375 times 36000= 3375# , in other words we cant even make this bracket deflect (ie. bend or stretch), in a worst case scenario.

This is OBVIOUSLY only an estimation of the forces, but I think it clearly demonstrates that this bracket is way strong enough.

Anybody with a better understanding of this, with more accurate numbers, and better math, bring it on and prove me wrong. Otherwise, you have been schooled. Naysayers and partypoopers go away.

By the way, I was the one that suggested this design to Juan in the first place. And I outlined the general design for him, including the .25" bracket.

Thanks Thure

[Drax240z]

Your bracket will deflect. Yield strength isn't simply the strength until deflection, look it up.

 

- At what temperature is your 36ksi yield strength? What happens at 40C? At -40C?

- Are you sure you have 36ksi yield mild steel?

- What if its a 3800lbs Z, fully loaded, big guy, etc?

- What if the car is pulling over 1G in braking?

- What if you hit a pothole while you are at max braking?

- What is the safe fatigue life of this braket?

- Are you sure your 36ksi mild steel is 36ksi throughout?

- Are there any stress concentrations on the part?

- Is the area you are doing analysis on the most stressed part of the bracket?

 

I'm not saying your bracket isn't strong enough. I'm saying you can't prove it. Yes, at least you've gone this far and done some basic stress calculations, and with fairly conservative estimates on the loads, you have a static factor of safety of 10 at the point that you are calculating.

 

Obviously I have been schooled by you, and I know nothing of what I speak. Hmm, I guess I wasted 5 years of my life on an engineering degree, when I could have just read this post. Anyway, I'm out of this discussion, do what you wish with your parts and good luck with them. I hope for your customers you don't have any problems and none of this is ever an issue.

[Guest Thurem]

Obviously I have been schooled by you, and I know nothing of what I speak. Hmm, I guess I wasted 5 years of my life on an engineering degree, when I could have just read this post. Anyway, I'm out of this discussion, do what you wish with your parts and good luck with them. I hope for your customers you don't have any problems and none of this is ever an issue.

Well I'm not an engineer, and this is not a Spaceshuttle. So you don't have to patronize me (was I guilty of that?). With a safety factor of 10 we should be in the ballpark though, what is your opinion on that?

Let's for a moment consider catastrofic failure of the bracket. Where is the caliper gonna go? It propaply won't fall of the rotor, unless you're running Dubs, most likely it will get wedged between the wheel, the rotor and the strut. So the wheel will most likely just lock up and make some real nasty noise, now the reason it broke was because you applied the brakes really hard (ie. you wanted to stop), so you will now come to a stop with a locked up front wheel. Even though I don't think this bracket will ever fail, failure will most likely only have consequenses similar to getting a flat or a blowout.

 

 

 

At what temperature is your 36ksi yield strength? What happens at 40C? At -40C? Please tell me about it, in use the bracket should be heated by the heat from the brakes.

- Are you sure you have 36ksi yield mild steel? Let's see if Juan does not up me one on the mild steel.

- What if its a 3800lbs Z, fully loaded, big guy, etc? You would then be over the loadrating of a Z (I think)

- What if the car is pulling over 1G in braking? 1.1 or 1.2?

- What if you hit a pothole while you are at max braking? Wheel lockup, less load on brakes.

- What is the safe fatigue life of this braket? What's the fatigue life of a 30 year old car designed for a 170 hp motor, now equipped with a 400 hp motor.

- Are you sure your 36ksi mild steel is 36ksi throughout? No. I hope it's better than that.

- Are there any stress concentrations on the part? Most of the stresses are going to be in compression, not tension. SO....

- Is the area you are doing analysis on the most stressed part of the bracket? No, I figured all the available stress on a very small part of the bracket would prove my point.

 

 

I can't prove jack sit. With my backyard enginering hotrod degree, though, I can tell you it won't break. If it does break, read the disclaimer.

Who can prove running 400 hp thru the stock wheelflanges with some 275/35 - 17 is not gonna break something?

The nature of this sport/hobby dictates risk management. If you don't like this bracket buy the other guys product, which was designed in the same fashion as this.

And for a final point, I've read that steel is approximately 3 times stronger than aluminum of the same dimension, so a .25" steel bracket has the same strength as a .75" aluminum bracket. The mounting ears on the wilwood caliper are less than 1/2" thick, so the bracket is stronger than the caliper-----> Blame scoot over.

Enough ranting, allready. 8) 8)

Thure

[Tim240z]

Just the facts guys.....things are heading down the wrong path here. You both have valid arguments....at the end of the day, it's the buyer's responsibilty to ensure that he's putting a solid piece of engineering on his car (no pun intended). As always in life.....Caveat emptor!!

 

Caveat emptor!

let the buyer beware

 

Smart consumers know their rights and act on them. Information is the best defense against purchasing defective products or falling vicitim to fraudulent practices. Learn the facts. Ask questions.

 

Tim

[Bob_H]

With my backyard enginering hotrod degree, though, I can tell you it won't break. If it does break, read the disclaimer.

Not to pick on you in particular, but I take strong offense to that general statement when it is applied to brakes that are sold to the public. You are not trying to increase the horsepower of your engine, or put a better seat in your car. You are changing the one thing that has the largest impact on your safety in the car. Therefore anyone designing a brake kit should be held to a higher standard than a backyard engineering degree or second hand information. Not only that but Juan will be legally liable for his work.

Juan, you are taking this the wrong way and this is taking a bad turn. It is not about you or what you have sold in the past. It is all about the sound engineering of this brake kit you have chosen to sell. I think it should be clear I am not basing my opinions on the design of the prototype bracket but on your final thickness. Here is a response from Jack Hidley of Maximum Motorsports. Maximum Motorsport is a aftermarket Mustang company,(among other things), who primarily deals in upgraded suspension for the Mustangs, esp. heavy duty ones for racing.

Bob,

1/4" plate is too thin for this application. When the brakes are applied, the caliper trys to keep moving with the rotor. This causes a torque to be formed which causes the caliper bracket to be twisted. The end result is that the brakes may chatter and you will have very tapered pad wear.

 

The best way around this is to use material stock that is thicker than the offset from the caliper to the mounting flange on the spindle, and then offset mill one or both faces to give you the correct offset.

 

Using 1/4" material on a Mustang gives you about 2.5mm of pad taper once the pads are worn out. For comparison the Ford brackets are about 0.4" thick and have a brace behind them.

_________________

Jack Hidley

Maximum Motorsports Tech Support

 

Are you seeing what he is saying? He is saying make a thicker bracket, say .5 inch, and mill the mounting areas down to fit the thickness you are limited to with the spacer. This gives the bracket more resistance to twisting moments and makes it stronger. It will make the part more expensive to make...

you may not like what you see which is fine. You are not only putting me down but others who have joined to help build the setup.

Please don't think this is an issue of it being fine if I like it or not. It is all about safety. I am not putting you down, so please don't take it that way. I am trying to point out the deficiences in your design and avoid future problems so you are still around as a Z car aftermarket company. That is in everyones interest. Whether you chose to believe it or not, your responses to me affect those who are looking to buy your product. Again, it is not my goal to smear your reputation or show that your company is junk, but to ensure the kit you offer is safe to a higher standard than other aftermarket items such as intakes/hoods/etc..

You should also be concerned about the flex Jack Hidley mentioned because this is a high performance brake system that you are offering as a good track alternative. With the flex Jack mentioned,(which he has measured), you are reducing the performance of your kit. Not something you want.

And let me bring up one important point in this discussion that I forgot until now,(those engineering classes are coming back). The bracket will never be in pure tension. Because the caliper is offset from the bracket, it will always, again always, be creating a moment about the two bolts that attaches it to the spindle. It is a force,(the braking), at a distance,(the center of the rotor to the center of the bracket, say 1.5 inches). Therefore this bracket will see not only tension, but bending and twisting. As such, it will deform the contact the caliper makes with the rotor. Now repeat that many, many times over, and the calculations are not so simple anymore. Thure, not to take away from your calculations, but they are just too simple for the complex brake system. Again, you are assuming only tension, which if it were true, and your figures were correct, might be a good assumption. However, there is bending, twisting, and tension,(as well as some areas of compression). It is not a simple math excercise, but a involved CAD analysis. Accurately modeling the forces involved is what makes this so hard. Therefore, the minimum thickness I would personally accept is the thickness of the stock spindle brake mounting point, which for our cars is 3/8 of an inch or thereabouts.

Again, this is not a personal attack on you Juan, or an attack on the integrity of your company. You have just stepped up to the plate to offer an aftermarket brake kit, and I, as well as others, feel you should be held to the higher standard since it is the brakes, not a bling bling carbon fiber hood.

-Bob

[Guest Looking for apt in Alb Ny]

I am not going to post to anymore regarding this bracket. I will redesign it to be offset and .5 inch thick which I was thinking of doing in the first place. Im very aware now of the of what more is involved.The .25 would have allowed ease of machining. Thure much thanks to you for the help and involvement. Bob, keep cool and take a break hehe break that wasn't funny. Talk again later when I get some new designed

[Mikelly]

You guys amaze me... OK, I have several materials books here for RACE CAR manufactures parts... These are parts that fabricators (Like Mike Gibson, Juan, Ross and I use for supplies) use to build these kits when ever we can substitute something that is already in use. EVERY SINGLE caliper mount brackets that I see in these catalogs is 1/4 inch thick. If the stock car and road race boys don't have failures on 1/4inch mounting ears, I'm quite certain a road Z won't.

 

Bob_H, Making a comparison between a Mustang that Maximum Motorsports makes suspension and brake parts for (At 3500#+!) and a 2400# Zcar is not even in the same hemisphere. 1/4inch thickness of these parts will be fine. When Pete P brings his car to my gettogether I'll be checking to see what Arizona Zcar offered in their package, but I'd bet serious dollars that their mounts were 1/4inch thick as well... But hey, What do I know. I guess all these cars running on AZC brakes should immediately stop using them because they are SOOO Dangerous and SOOO prone to failure. GEEZ!

 

This thread and the intentions of some of the posters makes me wonder why anyone would want to make anything for the Zcar community. It seems pretty obvious to me that Juan and JSK are not appreciated for their efforts. But hey after all there are soooo many other options out there for the Zcar community, right?

 

And as an FYI, My caliper brackets on the package I bought from Mike Gibson... They are 1/4 inch.

 

Mike Kelly

[Guest z1 performance]

My point as well Mike. Not to take anything away from those with the engineering degrees, but sometimes you guys tend to get caught up in the design side of things, without any regard to cost or actual need. Even if its not redone as Juan says it now will be, the current bracket is the proper size for the application

 

As I said in the previous post (and no, I don't work for Juan nor sell his parts), most of the aftermarket big break kits from AP, Alcon, Brembo, etc use T6061 aluminum, 1/4 inch thick (these are for cars like the WRX, S4, Viper, Supra, all of which weigh more than any Z or ZX (again in stock and "usually modified form"; there is no way to engineer a system around what everyone's car weighs, so the only intelligent way to do it is around a stock car, or a car with common mods). Some of the trruly high end kits (over $3000-$3500) use the next grade up (T70xx..I forget the actual designation). Considering most Z and ZX owners out there still use the stock front brakes, or if a Z guy, maybe the Toyota 4 piston caliper upgrade, this system will no doubt transform the car completely, and be all the braking you ever would realistically need. I have no doubt that a Grade A (yes metal is graded!) steel bracket would be overkill for this application as long as good solid hardware is used (again, Grade A) and the mounting points are carefully planned so as to minimze uneeded twist/flex under load transitions.

 

Bob - with weight, I was assuming a normally weighted Z or ZX, which even with a V8, is still less than a Mustang IIRC.

[Guest Thurem]

THANK YOU, MIKELLY AND Z1PERFORMANCE. I would like to reiterate the three points I have previously made. The bracket in steel is stronger than the mounting ears on the caliper. The amateur stress analysys that I presented was assuming the caliper was being held by a 3/8" sliver of the bracket, not the whole bracket, still proved adequate though. Other manufacturers have made similar setups, without any known failures (known, as in they would have been sued out of existence, and they are still around).

Thure

[Z-Dreamer]

Way to go guys Great job on slamming someone who spends the time and effort producing custom quality parts for our Z's.

 

If you self proclaimed experts don't approve of the parts, don't buy them!

 

In other words, "PUT A SOCK IN IT!"

 

Mark

[jaime240z]

All this talk about Big Brakes and vented rotors and Big calipers............. makes me want a set! Juan, I noticed your kit on ebay and I see the quantity running low. When wiil you make another run? I don't have the cash to order right now but I will in a few weeks. Thanks! 8)

[Bob_H]

on second edit, realize all the you's are general in nature and are not refering to any one person in particular. I put a name if I am refering to a post in particular. Sorry, that is sometimes not clear....

 

(sentence removed because it was inapproprate) I invite all of you to go back and read this tread from the beginning and see just how "attacking" and "slamming" we are to Juan and the kit. It is healthy concern and was worded as such.

First, I do not, and will not ever follow the "they do it, so it must be ok" philosophy. Drax240z put it well when he said many of these companies don't have an engineer to back up their designs. I may call Stoptech and pick their brain as they are one of the few companies I know that employs an engineer. And to claim that I do not appreciate Juan or anyone else in the Z car communitys efforts is a direct insult and not even close to the truth. If you read carefully that should be clear. Just because I or someone questions a design does not automatically mean we don't appreciate what they do or what if offers.

However, to make an upgraded brake setup, which will clearly see more brake torque and force than the stock setup, and yet utilize a thinner peice of material than the stock mounting ears does not point to good logic, no matter who uses it. That is why I said 3/8 is really the min. thickness it should be. This setup will likely see nearly twice the force of the stock setup. The actual end design of the bracket will make a large difference in exactly how much it will deflect or if it will at all. This is a near and dear issue to my heart as I am very, very hard on brakes with my track time. As such, I tend to find the weak spots very quickly. And I don't want to find that weak spot going into turn 1 at VIR at nearly 150 mph.

It is sad how everyone automatically assumes I or others are out to slam the Z car vendors, or show how poor their product is. Come on guys. Anyone consider for even just one moment that I want him to suceed more than any of you? Anyone consider that I might be trying to save someones beautiful car from hitting somthing when the brakes fail? To sit here and make blanket "It will be adequate" statements is just plain irresponsible esp. considering you have absolutely NO idea what the final design will be with respect to the location of the holes,(which has one of the larger impacts on if the bracket will bend or not). ALL you know is the thickness of the material. I don't think he even said what type of steel he was using,(again, that makes a difference). And there is no such animal as Grade A steel. You ever notice that most of the aftermarket brake kits that do utilize the 1/4 inch steel all have the holes in line with the stock holes, so as to minimize any extra forces introduced into the bracket? Juan's initial prototype clearly did not follow that trend. And Arizona Z cars brackets are Aluminum to the best of my knowledge and may not be a direct or good comparison.

And let me address a few other points. We cannont say the bracket he is designing will be stronger than the mounting ears on the caliper unless we know the specification of the caliper material and the type of steel he is using. Again, I feel it is irresponsible for us, any of us, to say it is ok or not w/o actual figures to back it up. That is why I have asked this as a question all along. Yet many of you come to the defense of the product saying it is ok and it will do fine without many of the critical dimensions and locations that will clearly impact the overall performance of this bracket. What type of steel, where are the holes, where are they in relation to the stock mounting points, etc... All that has been provided is it will be 1/4 inch steel CNC or Laser cut. Thats it.

And since it wasn't clear in my first post where I quoted Jack from Maximum motorsports here is the link to that thread:

http://www.corner-carvers.com/forums/showthread.php?s=&threadid=10621

You will notice I provided the approx. weight of the car, approx. tire size and what I felt was the important info. I did not take his quote out of context, but Mike you may have misunderstood my take on the weight issue. Jack knew I was talking about a mid 2000 lb car. And not may 240Z's are at 2400 with a driver in it. Mine was 2300 with no gas and no driver. With me and a full tank of gas, mine was closer to 2500. There are not many 2400 lb Z's with a driver onboard. I would say most 70-78z's sit about 2500-2900 with a driver and gas. Nor are there many 3500 lb mustangs with no driver on board. Yes, the Mustangs are about 3000-3500 loaded for the applications he was testing Vs. about 2500-3000 for the Z's. He merely showed that as a comparison and a reference.

Everyone, please look at the global view here. I very much want Juan to succeed in his venture. If I had known Mikes,(Gibson, fonebooth) brackets were that thin, I would have brought forth the same questions. And I for one really don't like the Outlaw calipers as many of them only have bolts going from one side to the other to provide the rigidity in the caliper. That is why I have stayed away from Mike's brakes. I have explored just about every aftermarket brake option for our Z's and am very worried about the design. If I can find the weakness in the BMW M Coupes brakes, I'm sure I will find the weakness in any aftermarket Z setup unfortunately. If I can avoid that, I will.

These are very real concerns, and I can't for the life of me understand why some of you insist the product is ok w/o more knowlege and insist we are attacking Juan's intent and goal. Read three times, then respond. I am guilty of this at times as well. As such I tend to re-read a lot more than before to better understand what someone is asking.

-Bob

[Mikelly]

Think before I read? You want to re-word that? I have read and monitored this whole thread from the beginning. I don't appreciate your comments or the direction you have taken this thread FROM the beginning Bob. If you want to debate Juan's designs with Juan offline, then do so. But spare the rest of us your lesson in engineering. I go by WHAT WORKS, PERIOD. As another poster commented, If you don't like his design, then don't buy it.

 

Since you are such a smart guy, Why don't YOU make something that works, then come back to the table. Until then, I'd applaud everyone who does, and be glad they took the initiative and risk involved in actually DOING something and then providing it to the public.

 

Mike Kelly

[Drax240z]

Well so much for staying out of this.

 

But Bob pretty much echo'd my views on the whole situation. My concern is genuine, and if I haven't put that across in a very tactful manner I apologize. (however, I think if you re-read my posts you'll see they aren't trying to slam people) My goal was to educate, question, and prove or disprove that there was enough knowledge/research to carry on with a design like this.

 

I think we all need to take a step back and look at the big picture for a second. We're all wanting the same thing in the end, big, beautiful, safe brakes that suck your eyeballs out of your head. By questioning said design and forcing someone to back it up, are we going to end up farther from that goal? No. We're going to all come away with more knowledge, so I can't put my finger on why this is a bad thing to anyone.

 

To reiterate: I'm not out to get anyone, and from Bob's last post it's pretty clear that he isn't either. Its hard to play the adversary sometimes without ruffling some feathers, but please guys lets keep it civil and constructive, and end up with our eyeballs stuck to the windshield.