fjm9898

iTrader: (2)

Many of you might have seen the 6pot Brembo brake upgrade thread kicking around for a guy who doesnt seem to be active anymore. I saw this thread and it got me thinking and working on something.

Now the old thread used the 17z caliper which is cheaper and easier to find. It utilizes a 330mm rotor which is similar to our OEM rotor and which is why he was able to bolt them right up (with his drilling the holes out on the caliper)

I have been looking at the 18z caliper. Harder to find and more expensive, sure, but it uses a 350mm rotor, similar to the EvoX front rotor. This is where we can actually call this a BBK as it actually increases the size of the rotor over stock.

I also found that the 18z caliper was used on a 34mm thick disc and ours is only 32mm. However, audi guys have been using custom and Mercedes 32mm discs with these calipers without issue.

Now the trick here is i need more information. I cant tell if the 18z caliper is larger (from the mounting point) to fit that 350 disc or if the mounting point changed on the Porsche to space the caliper further out to fit under the 350mm disc.

In that old thread some one posted an image of the 18z caliper showing the increased mounting hole size. This help sums up a mounting bracket will be required but how will that bracket need to be designed is the question. If the caper needs to get spaced further from the hub then its a pretty standard mounting bracket that will make everything fit right. If its not that means the bracket will need to be offset, rotating the caliper around the disc.

So here are my questions i cant seem to find proof to.

Can we go and buy an EvoX 350mm disc and mount it directly to an Evo8? From what i found this is a yes if you change out everything to EvoX. Reason being is that calipers are pushed out to fit the disk. But my question is does the offset of the disc change as well or does it land in the same plane as the evo8/9 setup. This is important to know so we know how this bracket needs to be made, I.e. 3 dimensional to move the caliper further or closer to the car, or if we can put a plate plate in there and the caliper offset lands it directly over the disc.

Then what do we do about the rear. I have herd rumors that the SRT8 caliper bolt right up, but i havent seen it. so the SRT8 calipers run on the same diameter and thickness disc an evo does? If it is all good then you get a better caliper, but not a larger disc. If we want a larger disc that is where things will get tricky. Custom Disc is easy if i get 5 people to do it, group buy.

All of these can be solved though with little to no work form us short of a standard plate bracket which i can produce. I contacted GiroDisc and Mike said he can make use custom setups to do this all for us, but he would require a group buy of 5 people. I think this is where i am going to lose you guys as it would require 5 people to chip in a decent amount for new discs, and even more so if we tried to do the rear as well. Some of you are saying this isent a cheap BBK anymore, but really there is no way to know until it gets built. just have to remember these would be brembo monobloc calipers. A brembo GT kits is $3500 even if you purchased GiroDisc this should still be no more then $2000, even less if you used OEM EvoX or other cheap aftermarket rotors. I am just thinking GiroDisc to keep quality standards up to matching levels of the GT kit.

I am having a hard time finding a cheap evo x rotor for testing. If anyone knows some one with some parts, or parting out, i would snag a rotor and look into mocking this up.

LetsGetThisDone

iTrader: (1)

Or, just buy a willwood radial mount 6 piston caliper, build a bracket, and bolt it up..

fjm9898

iTrader: (2)

How does that increase the Disc diameter.....?
And nor is that a monobloc caliper.

LetsGetThisDone

iTrader: (1)

You're building a bracket, you can make it fit whatever diameter disc you want as long as the caliper has the proper opening for it. I would not be concerned about monobloc vs 2 piece.

fjm9898

iTrader: (2)

You cant get larger rear discs for the evo unless you just go and buy an off the shelf BBK which then defeats the purpose of making a custom one. You can go and buy discs from the BBK people but those were designed for their caliper and they are going to charge alot to just sell you discs instead of a complete kit. I looked into it.

We can use the EvoX (which i confirmed with GiroDisc) for the front and then a custom one having to be made for the rear as there is no off the shelf combination possible for our rear hub (confirmed by both Giro and DBA) unless you go buy the parts from a BBK manufacture, defeating the purpose of this thread and raising cost.

I want to use a high quality name brand caliper that has been proven time and again which is why its in a OE application. We are not talking about some Chinese off the shelf 2 piece caliper (not saying Wilwood is). Yes 2 piece can be strong, but at a price. OE Brembos for half that cost. That is half the point of this kit i am working on. You cant seriously tell me the Brembo monoblocs are not good and why the same caliper design is used by so making top OEs straight from Brembo and many using the same exactly caliper from them. I find hard to believe the off the shelf Wilwood is where its at and that these Brakes designed for very heavy and fast cars arent as good. I guess Audi, Porsche, Ferrari ect. all have it wrong then? Hell, Formula One cars must be using the wrong calipers then huh?

At any rate the point remains. Low cost BBK with the high quality Brembo calipers with proper piston/disc sizing for a correct Bias, that is what i am working on. I am not just tossing junk yard parts together ***** nilly. (Bias shot the fronts to the rear idea out the window real fast)

I guess i really am in the wrong part of this forum and probably should take this to the motorsport section to get people caring about brake performance instead of looks.

LetsGetThisDone

iTrader: (1)

Lol, nice rant. I am far more concerned with performance over looks. Hence why I have not bought a BBK, I have not needed it yet, despite tracking my car.

my friends 97 gsx has wilwood superlite 6 pistons up front, and wilwood dynapro 4 pistons out back, and it ****ing stops. Its the full TCE kit that fits 17" wheels. So many guys of you guys have such a hard on for brembo, its funny..

Yes, go to the motorsports section. Where you will be told that some VERY fast TA evo's run the stock brembos, Like the last guy that wanted to be an *** about brakes, grimmgrak. His thread is still there, but it's locked..

fjm9898

iTrader: (2)

I know you CAN be fast on stock brakes. I was in that thread saying how my stockers with PF pads and Centric rotors are awesome. this is purely to upgrade even further, and it is an upgrade. Albeit not from crap to amazing but its still a step forward. I am running 600hp at the wheels and barrel into turn 1 at over 150mph. i could always use more brakes, we all could, granted we already have decent ones, but we could always have better.

but obviously its a moot point since no one else has chimed in over the past 24 hours but you to bad mouth the idea. so lost cause it seems.

Grimgrak

iTrader: (3)

I could chime in with my shiney new alcons hehe.

fjm9898

iTrader: (2)

doesnt help me with what i want to do and if i work this out i can have a 6/4 setup at still half the cost you paid for just your front Alcons.

More math i do though it seems that the rear rotors actually should stay OEM size to keep bias happy. need to confirm this. If that is the case then i guess we dont need a Group Buy after all and i can be happy with my fancy new 6/4 setup

LetsGetThisDone

iTrader: (1)

I'm not bad mouthing it, I'm just saying there is an easier way. You have to build a bracket for either caliper. And since I've built brackets for both, I can say that building a radial mount bracket is far easier than a lug mount bracket. Mostly because you adjust the height of the caliper on the bracket with spacers. And you can buy a good set of new wilwoods for less than $1k, and the replacement pads are much less expensive than brembo pads, as well as replacement parts for the calipers such as seals.

these have 2 options for piston volume, and both options are less than or around $500 each, and they offer them with their thermlock pistons for a considerable amount more. They're also smaller than the brembo's you want to run, which will help with wheel fitment..

http://www.wilwood.com/Calipers/Cali...?subname=Aero6

fjm9898

iTrader: (2)

That is on the front. What about the rear? You have to keep the bias correct which is the big sticking point i am working with. It really isent as easy as going and buying bigger calipers and bolting them on. if the bias is not correct the car is going to have a tough time going around a corner if your driving style is correct. If your an On/Off type of braker, or just doing straight line, yeah its not a big deal. I dont want my back end coming around as i trail brake into a corner because of to much front bias.

That being said, those calipers are still twice the cost of 18zs and even more so then the new caliper setup i am looking at.
How is radial easier? Its pretty easy to machine a flat plate with some holes in it to make a bracket for lug mount.

you say there is an easier way but having to do 3 dimension machine work, pay more and have less pad options doesnt sound easier to me. 18z was one 6 piston option but i have moved away from that as there are many other offerings from brembo for dirt cheap with the same piston combo. I can get two calipers for $200 less then the one Wilwood you linked.

LetsGetThisDone

iTrader: (1)

Sigh, I tried...

fjm9898

iTrader: (2)

sigh you dont understand.

Got the bias calcs back and with a only 1.6% shift in bias to the rear, the brake system is a go and calipers are on order. $850 for all 4 calipers. I guess in your world i should of paid $1100 for 2 Wilwood calipers instead huh? You work for them or something? I mean obviously Brembo couldnt of made as nice of a caliper for GM performance cars, Porsche or any of those cars as Wilwood. So I must be way off base.

Mods can lock/deleted this thread because it went no where fast.

LetsGetThisDone

iTrader: (1)

Your first post barely had a blurb about the rear brakes. I don't think the car needs more rear brake, but that's just me. My front brakes are typically a decent bit hotter than the rears. I've driven several vehicles with only a BBK in the front and the bias is typically fine.

If you want custom discs, order them from Coleman brakes, they build custom stuff, and its less expensive than most company's shelf parts..

fjm9898

iTrader: (2)

If you increase the front brakes then the rear becomes insufficient. Its how brake bias works. When you add to much front its a bad thing and the rears cant keep up. You cant increase the front Pistons from 46/40 to 41/28.5/28.5 (the small piston version of the wilwood you linked me) making the front much larger and keep the balance of the car. You might not notice your bias as badly in AutoX were everything is nearly an on off switch but i promise you it wont work trying to trail brake into a sweeper from high speed. You are going to swap ends rear quick as the rear will be to light.

This is why people buying just front BBKs are actually adding to on track danger. And when i say track i mean road course. If you drag racing or street use or highway pulls where your braking in a straight line and its not a big deal.

This is why formula one and all top end race categories have brake bias adjustment. You have to keep things balanced in a bad way when trail braking at high speed. The Evo was setup with a 71.5% forward brake bias because that is what Mitsubishi determined it needed to brake properly. You go buy a BBK for the front with more pistons (larger pad surface area) and a larger disc and that balance is going to shift further forward to the front.

Brakes need to be upgraded together front and rear and done properly to keep bias balanced. Call any brake company and they will tell you the same. I had a very reputable company help me on the calcs and we had multiple phone conversations. I know i can trust them because the owner once had an evo, so they have all the needed information on making those calculations. I called other brake manufactures to check on their biasing as well.

This is why in the end i need to keep the OEM rear disc size. Moving from a 2 piston to 4 with more area required the disc to stay the same diameter to help not shift the balance to far back. 1.6% is negligible. Yeah it wont look "cool" with tiny OEM rear discs and larger front but in the end i am happy as i will not require any custom discs and the car will remained biased the same. Just need to make some brackets and she is ready to go.