kbiz

So far I think it's more than feasible for the 4pot BBK... the only questionable parts so far are the cost of the brackets and the SS brake lines. You can make your own SS lines but I'll have to look into what tools are required. You can also have them made to length and there's a speed shop not too far from me that is old school... like muscle car and racing not rice rockets I was talking with them on Friday and it sounds like there is huge mark ups in application specific SS brake lines. They carry the best brands and by buying sections of the brake lines off of a spool and maybe having them add the fittings could make it much cheaper. As far as the brackets go, they are really simple... they're not CNC machined or anything, though if we went with a much thicker bracket the mounting locations would need to be milled down for offset.
The 6pot calipers might be tough to get into the $700 range... but we'll see. All my figures are at retail right now so maybe we can get a break from someone for multiple orders.

nissansource

iTrader: (10)

SS lines are cheap to get made. estimated 60 bucks

atlsupdawg#2

kbiz,
You'll need a swaging tool, either hand or bench mount type, and a go/no-go gauge. A good set together may run about $150-$200 bucks.

BlackSpec02

iTrader: (17)

I think unless there is going to be a rear kit w the 6pot fronts we should shoot for 4 pot fronts... wouldnt 6 pot front and stock rear mess up the bias a lot?

kbiz

Cool... thanks. I'll check out what those suckers look like.

kbiz

Either way would probably be fine. Most of the Superlites have the same mounting dimensions whether 4 or 6 pot. So we can pick out either one. I don't think that going with 6 pot fronts and stock rears would "Necessarily" create worse biasing than 4pot fronts and stock rears. It's possible that the 6pot might provide less clamping force per equal pedal pressure than 4pots would, depending on the specs of the two. As far as my understanding, the increase of piston number on a caliper is not specifically for clamping force but more for the way the clamping force is distributed across the backing of the pad. In race cars or heavy track vehicles, often times the pads can wear VERY unevenly, among other pad issues. If anyone has any other technical input on this, feel free to chime in. I've pretty much decided I'll be going with a 4pot caliper for the fronts so I haven't done much research on the history of 6-8-10-12 piston brake calipers One thing can't be ignored, just because you don't need something, doesn't mean you don't WANT something. Having that SL6 in your signature list and seeing that number 6 on your calipers every time you wash your wheels can be a perfectly valid reason for spending a little more cash. To each their own. I watch movies on an 8' screen... I don't need that! Maybe we should all drive Toyota Echos...

My opinion is that a Wilwood SL6 should be pretty close to an SL4 or an FSL caliper in clamping force. And as infantsam pointed out, it’s the brake torque of the fronts vs. brake torque of the rears that equates to the bias percentage. Clamping force, rotor radius, and coefficient of friction between pads and rotor after bedding are what create the braking force or torque. If you have too much piston area with the same stock master cylinder, you can actually produce less clamping force… Also deflection or flexing of various components can reduce clamping force… so those are what we’re all trying to avoid.

Think about this for a minute… If you upgrade your brake pads with a compound that has a higher coefficient of friction and you add SS brake lines (thus less expanding of the flexible lines and more pressure making it to the caliper pistons linearly) wouldn’t this alone increase your braking force for the fronts vs. the rears? Wouldn’t that change your brake bias? I think the important think to keep in mind is that even the stock brembos are not the absolute perfect bias. Regardless of heat and brake fade, etc… one could design a brake combination that yielded a superior stopping distance against the Brembos. And there is a margin of acceptability that will not throw your car into the danger zone. I also believe that the majority of BBKs out there, even if front and rear kit combos, have worse stopping distances than even the non-brembo stock brakes… of course there are other vast improvements…

Several kit builders make Wilwood front kits with both 6 and 4 pot calipers. But as I’ve been informed from inside the industry, there may be very little testing on these configurations, regardless of what the sales reps may claim.

If anyone wants to go with 6 pot front calipers then trying to match piston area to the stock brakes, as closely as possible, may be the right idea. That is if you are wanting to keep the stock rear brakes… I’d then be inclined to go with a more aggressive pad for the rears because you’re going to have a larger rotor up front which is going to be the biggest factor in brake torque. But I haven’t seen a ton of people hurtling to their deaths because they have a monster kit up front and stock rears… People have been doing just that for quite a few years now. If anyone has had problems with their front only kit I’d love to hear their experiences. But we should definitely try to maintain stock bias as close as possible. Originally I wanted to copy other brake kits on the market, but I’ve been realizing that most of these kits are not tested to the degree that I would have thought they should. The factors the kit builders use to chose components are the same ones we are discussing. I do think that we should stick with the 13” and 14” rotor choices as well as 4pot and 6pot options. The main reason is simplicity and that I think that will appeal to more people who will recognize those combinations from the Wilwood kit builders. If we’re contemplating a group buy, we have to keep in mind the mass appeal. The more people, the cheaper the price. I’m probably most interested in the 13” rotor and 4pot caliper combo myself… but I’m wanting to keep 17” wheels.

kbiz

Oh, and thanks again for loaning me those brackets!! Big props to glogan for contributing to the cause and filling me in on where he got his kit from. I ended up getting a ton of info from Precision Brakes including the instruction manuals for the fronts and the rears. Plus being able to actually look at the brackets and see how they were constructed made a difference. The funny thing is that the brackets could actual be a simple rectangle of T6 Aluminum with two drilled holes and two threaded holes. There's really no good reason for the special shape of the brackets and probably less than a couple ounces difference in weight... that would be such a simple bracket design that people could probably make them themselves. Even if you used a shop to drill the holes and tap two of them, if you bought two cut lengths of T6 or T7, I can't imagine it costing much. I just picked up about 20 lbs of T6 and T7 scrap bar stock aluminum at $2 per pound (that's a lot of metal!). Just about every city has some metal distributors and if they cut metal they'll have good scrap pieces... the big band saws can't grab the ends of the pieces and it's not worth their time to try and distribute it other than scrap. I think the going scrap price on aluminum is under two bucks per pound so if you pay them more than that they'll usually be fine with it... especially if you pay cash

But if you don't want to go looking for metal... check out onlinemetals.com. They're one of my favorite metal distributors and I'm lucky because they happen to be located in Seattle! But even ordering online, T6 Aluminum that's 3/8" x 3" x 5" would cost you $3.80 each, cut and ready to go. That's the size of the brackets for the 14" rotors.

spf4000

Agreed. I have the stock Brembos, and they are definitely front biased. That's why some BBK setups yeild shorter stopping distances on same tires as they make the brakes a bit closer to neutral so that the rear tires are doing their share of the braking as well.

kbiz

One of the things I noticed last time I changed pads was going with a little more aggressive rear pad made a noticeable difference on my stock non-brembos. I went through two brake jobs on the front and still had 20% left on the original rear pads... what's that?? Now I'm actually getting a little brake dust in the rear and I can feel the bite and a tiny bit less front dip on medium to heavy braking. Definitely better feel and on wet roads the abs is less likely to kick... I'm pretty sure the stockers aren't ideal bias either...

BlackSpec02

iTrader: (17)

which kits have been proven to stop shorter that factory brembos? we should look into which equipment (size rotors, #pot calipers, caliper brand, pads, width of rotors... all that stuff) they are using.

Also, in bracket design or shape... wouldn't strength be an issue?

kbiz

Most of the kit builders provide Zero proof of testing, let alone any statistics or figures on things like stopping distance. If anyone has a lineup of kits and their actual performance stats I'd love to see it. That info would help out a ton... but as I said before, I'm thinking that most of the kits are not really TESTED other than how they feel and are they locking up the rear.

As for the bracket, yeah strength is paramount. I mean it's a bracket... it's only job in life is to keep it's shape and not break... The rectangular design would be stronger than the cut out design that some of the kits are using. One thing is that a rectangular simple bracket might not look that fancy when you just dropped over $2k for this kit. But if you hit it with the grinder and make it look a little more specialized... oh, and every kit I've seen so far uses T6 Aluminum for their brackets.

Fast brakes uses a little more rectangular bracket for their kit:

Havok_RLS2

iTrader: (9)

This has got to be one of the BEST damn threads ever created on this forum. I'm loving it! Give me more!!!

gringott

iTrader: (17)

Stop tech did a brake comparision online, don't have the address handy, but if my memory serves me, stock brakes stopped in a shorter distance than any kit combo, until heat and brake fade became an issue. I think you will find that to be the case with most kits. BTW, I am up for the 4 pots.

KNS Brakes

iTrader: (2)

Some more opinions for the discussion

Unless the car is very poorly designed then you won't shorten stopping distances by adding a BBK. What you get is heat capacity and pedal response. And as stated - a BBK may worsen stopping distance if bias gets too out of whack. Generally cars are designed with less than optimal rear bias for safety/handling reasons.

Also - I wouldn't think brake torque is tremendously affected by SS lines - it's not like regular lines blow up like balloons. It would appear that all the compliance in a stock type system does absorb some strain energy which would reduce torque - but maybe not enough to drastically affect torque. It does affect pedal feel a lot though. Fixed calipers are MUCH better feeling than floating. I've been told that a floating caliper absorbs about 100 lbs of force -not a huge percentage of the total piston force at high pedal pressures.

atlsupdawg#2

I've heard this as well..

Not to jump off the beaten trail of what this thread is about, but would you think modeling a brake system, in terms of bias and piston area, after other high end vehicles be beneficial in shortening the stopping distance?? For instance Porsche. Most people now-a-days are unware that they were dominant on the track not because of their engines, high HP or overall balance, but because of their brakes which were also used on their production street cars. In a perfect world considering the Z's f/r weight ratio were close to the Porsche, given the piston area and rotor size would we be able to effectively model a brake system from that which would outperform the current system?

kbiz,
Glad you posted pics of the brackets. Man those look simple to fab!!! All you'll probably need is a band saw, a steady hand, drill press, maybe a grinder to radius a few corners, and a little elbow grease to clean 'em up when your done. I think we can do without all the fancy shapes since no one will pay attention to what they'll look like anyway. As long as it safely performs what it's designed to do, that's good enough.

Havok_RLS2

iTrader: (9)

We done yet??? I'd really like for someone to make this happen so we can all see the results. If you think about it, anyone who is able to fab these brackets will be sitting on a real goldmine. Think about it. All those $1700 - $3000 big brake kits will be a thing of the past and give us guys who can't drop thousands upon thousands into our Z's cuz our wives wont let us now have options.
You guys wanna start a bulk parts buy? Count me in.

BlackSpec02

iTrader: (17)

Well I dont know about you guys, I want a BBK for the best possible performance (yeah the looks are great too)... it seems like it wouldnt be smart to throw a BBK on your daily driver and increase stopping distance... for a track car, great, because of the heat and fade.

What would be the best option for stock-like stopping and less heat/fade... larger rotors? just buy the OEM brembos? Do pads, lines and fluid and call it a day?

J Ritt

iTrader: (4)

You guys are honestly scaring the Sh#t out of me with comments like this...



What you guys aren't accepting about those fancy brackets, calipers, brake lines, etc., is that they were designed by the top manufacturers using FEA by an engineering team that does this as their life's work. The components were built, tested, redesigned, retested for strength, durability, resistance to corrosion, heat cycling...the list goes on. Some companies are throwing together kits using the parts bin approach, and the result is those simple rectangular brackets that have been shown. For the companies designing complete systems like we do, an enormous amount of time, thought, money, and testing has gone into these kits.
Do you realize the environment that these parts are operating in? In harsh conditions you're looking at potential repeated exposure to 1000+ degrees Faranheit, massive amounts of torque consistently being applied to the parts, corrosive environmental effects such as road salt, brake fluid, etc. Don't you think it would be a good idea to analyze the stresses that these parts need to withstand?!?

A comment like this is terrifying to me...Now don't you think if you "hit it with a grinder" that it could damage the structural integrity of the part?!?!?

The more people that chime in on this thread, the more misinformation and wayward thinking I see popping up...regarding brake torque, the simplicity to manufacture these components, the lack of understanding of the basic physics involved. Let me clear this up right now with what's being proposed... you will NOT decrease stopping distances significantly from stock (and most likely not at all). You will also most likely produce a brake kit that is inferior in terms of durability and performance to the stock components, including the stock base brakes. The amount of work that goes into an OEM brake system is huge. Yes, these will look snazzier.

So you would rather save yourself the $1000 and have your wife driving around on a brake system that hasn't been designed and tested properly? Do you think what is being done here is a novel idea? What do you think Brakeman, UUC, ECS, etc. have been doing for years? Don't you think that if there was a potential goldmine to be made that everyone and their brother would be putting out OEM-level brake kits?

Outside of the fact that you are going to have little to no support on these products after they are purchased, you guys have NO idea what is involved with the manufacture of quality parts. What chromium content will your rotors have? How resistant will they be to heat checking/cracking? What thickness of anodizing will be used on the hats? What will be your max acceptable runout spec on the rotor and hat assembly? Will the bolts on your caliper brackets have Dacromet coating? How will you decide on the proper torque specification to mount the bracket? The list of these types of details is endless...and my engineers would blow your mind with the level of thought that has gone into these issues...which is why every mom and pop shop isn't selling world class brake system. It is not easy to do, and it's only possible by people far more technically knowledgeable than anyone I've ever seen on these message forums, definitely including myself!

KBiz,
I understand what you are trying to do, and I salute you for your efforts. That said, you have some seriously fundamental misunderstandings on a lot of fronts. For example, ss lines are not going to increase your brake torque. They will decrease the amount of time it takes to do work. You talk in one of your posts about sizing the pistons based on caliper deflection...how exactly do you plan to measure deflection on the caliper you will spec for the kit, and how will you translate that info into your piston sizing decision? You also mention uprated coefficient of friction on the pads to be used. Do you realize that this number is dynamic depending on temperature, and that each pad compound has a torque curve related to temp? How do you plan to deal with ABS, and control driver pedal effort to prevent premature ABS activation (all related to piston sizing and torque output at the wheel end)? Are all of your SS lines going to be bench-tested prior to shipping? At what pressure, and through what pressure cycle will you test them? How do you plan to attach your fittings on your lines? What are you going to tell these guys when they call you for tech service in three years...after you've sold your Z and moved on to something else? How much is it going to cost them at that time?

Cheap is not always good, and there is some serious cost involved with answering these and many other questions. That's why the brake kits from the top manufacturers are $1700+. Also, I'm amazed that people do this stuff on a $30k car. I've seen people do some crazy stuff on $500 track ***** beaters, but on this car?!?!?!?

Again, choose to listen, or choose to ignore me...that's up to you. I just don't want people to think that you can go read the tech pages on our website and start churning out a technically competitive brake kit...it's just not possible. If we were talking plenum spacers, I wouldn't give a rat's you know what...but we're talking about a safety item here though, and this is coming from experience watching people go down this path repeatedly only to get burned. All of them start out with good intent and are trying to save a buck. I suggest thinking this situation through, and ask yourself whether it's worth saving some money in the short term. You will pay...yes, WILL pay in the long run...most likely more than it would have cost you to do it right in the first place. For those of you that do choose to ignore me, copy this thread into a Word document and put it somewhere safe. Pull it out in three years and see if I'm right...then don't get mad at me when you call for help and I tell you, "I told you so!" (which I would never actually do, but I'd be thinking it. )

Ugh...this is giving me a headache. Just please be careful guys...

BTW, here is the testing article referred to in this thread: http://www.zeckhausen.com/Testing_Brakes.htm

kbiz

Dude, you need to read a little more closesly before jumping to conclusions. I appreciate the feedback but make sure you're clear on the comments you're quoting and don't take them out of context...

I was commenting on the lack of quality and workmanship in some of the brackets that kit builders are making. Take another look...
I was commenting on the possible mindset of SOME kit builders with regard to bracket design.

Attached are some pictures of Wilwood Caliper brackets from Precision Brakes Co kit. You can faintly make out the lovely precision and, of course, the ever so popluar grinder marks...This kit utilizes the FSL caliper.

(Edit) This might have sounded a little harsh... I don't want to slam a company’s products, especially since I haven't laid out any of my own money for their goods. Precision Brakes Co is very professional and has very good instructions and very helpful and knowledgeable folks… very cool to talk with. So we'll just leave it at that.

KNS Brakes

iTrader: (2)

kbiz - he shoulda read my post and the ensueing response(s) first -

I learned my lesson - NEVER insult potential customers knowledge.

I'm watching - I'll jump in and help if I think I can add some actual value without screwing you guys up!

side note - I'm not sure I'd look at that bracket and think "Precision" but I've spoken with Darryl on numerous ocassions and I'd suspect it's an accurate part.

cheers buddy!