Brake booster question

[Christopher W.]

Originally Posted by RETed

Read the Grassroots Motorsports magazine brake primer - Pulp Friction - here:
http://www.scirocco.org/faq/brakes/p...n/pfpage1.html

Pay attention to page 2, as it goes into brake master cylinder bore sizing...

Personally, I don't usually trust propaganda spewed from vendors, as they are trying to sell you something.


-Ted

I agree with you about propaganda from vendors. I will say that Stoptech's whole point that I read was with a properly designed front brake system you don't need big rear brakes. I am a bit of an exception because I want rear brakes for other reasons besides just performance.

Here is a quote from their paper on rear brakes. The first quote was from a customer of Stoptech.

"The folks at STOPTECH should consider developing a rear kit to match their front setup. They'll be very happy with the performance improvement if done properly." Well, since our FRONT systems are designed properly, we save you the need to spend your money on the back axle. Let's reword that quote to reflect the STOPTECH philosophy: "Our competitors should consider developing a FRONT kit to match their stock bias condition. They'll be very happy with the performance improvement if done properly, AND will save their customers the cost of a rear brake upgrade in the process."

All of that being said I am not going with Stoptech. I have today talked to the guys at Revolution Brake and got the answers that I was looking for. They are not part fitters. They are brake engineers. They actually take in account all of the stock systems specifications and try to replicate that as close as possible with the larger Wilwood rotors and calipers. They use computer software to do this. They said that they can usually get the brake bias damn near spot on to the original specs. They said if it is a little off it usually tends to add a slight bit more towards the rear than stock.

They see no problem so far with the stock MC. They haven't crunched the numbers yet so we will see....I should have my kits by the third week in July.

[Phoenix7]

sounds cool and expensive. How much $$ you dropping for this mod? Please do a brake test so we can compare the benefits with other 3 rotor guys on stock systems.

How big are you going, btw?

[Christopher W.]

I hadn't planned on doing a before and after test but that is a really good idea. I kind of wanted to get this all hooked up while I have all of the susp. and changing the rear out. But I will think about a before and after test.

I will get back with exact specs on brakes but I think he said 12.8 or 325mm by maybe 22mm on the two piece rotors. I don't know if the backs are going to be different size than the front. We discussed the Dynalite calipers but still looking at different options once they do more research.

They also said a conservative estimate would be around 10-12lbs less per corner. Time will only tell on that... He was telling me in an extreme case their kit for a Z06 shaved 31lbs per corner, awesome!!

The numbers in general are $1400.00 for the front and quite a bit more on the back. With the additional parking brake set up probably around $2800 for the rear. I am not quite sure why the price is so much higher on the rear. I will get into specifics more when they get back with me.

[My5ABaby]

You could put Evo IX brakes on your FC. Apparently they fit fairly easily.

[Christopher W.]

Fitting and working as a well designed system are two totally different things. You got to take into account front to rear bias, peddle feel, heat dissipation and sure other things I am not familiar with.

The Evo's are not designed for this car. You might get lucky by getting some other car's brake system to fit and work properly on the RX but I kind of doubt it. Or taking a lot of effort to make something work. It was already stated in this thread or somewhere else that the guy on the other forum who has tried using evo brakes is having issue getting it dialed in.

I think worst case scenario for me will be having to add a brake bias adjuster. That's what track days are for....dialing it in.

[My5ABaby]

Originally Posted by Christopher W.

Fitting and working as a well designed system are two totally different things. You got to take into account front to rear bias, peddle feel, heat dissipation and sure other things I am not familiar with.

The Evo's are not designed for this car. You might get lucky by getting some other car's brake system to fit and work properly on the RX but I kind of doubt it. Or taking a lot of effort to make something work. It was already stated in this thread or somewhere else that the guy on the other forum who has tried using evo brakes is having issue getting it dialed in.

I think worst case scenario for me will be having to add a brake bias adjuster. That's what track days are for....dialing it in.

I was under the assumption that the guy on the other forum got them working.

[Christopher W.]

Yea, the last I had read the fabrication had gone ok but I think Ted said something about problems relating to the operation. I haven't check in to that thread for a couple of months now. I had definitely thought about those though..

[hIGGI]

AFAIK there is difference between S5 NA and S5 TII brake booster in USDM cars...i never had problems with my S4 brake booster, but after upgrading front calipers to brembo 4 piston calipers, my pedal feel went bad....upgrading to S5 TII brake booster and bolt-on 929 MC fixed it....bigger brakes sometimes comes with bigger pistons and upgrading MC is good idea to get back desired brake pedal feel...

[WE3RX7]

I'm a fan of custom brake systems and am currently figuring out how I want to setup my FC as well. I too will be going with a larger rotor, BB and MC.

If not to make bigger, but simply to improve upon 20+ year old technology! Aside from improved braking for 500+whp, I also want quick exchange calipers, etc for track days that will make pad replacement quicker!

Just keep us posted on your setup - I know even though you're doing it for mostly cosmetic reasons, what you discover in your system may provide useful insight...

[classicauto]

FWIW, the stoptech brake setup on an FD will fucking hang you off the seatbelts. It uses stock rear rotor's and caliper's and (according to Stoptech) maintains the proper ratio between master cyl. bore and caliper piston bore.

But man oh man does it ever stop.


The only thing I see being omitted from this discussion is the fact that power has very little to do with braking capacity required.....sure, more power means you'll be (presumably) heading into a corner with more speed, and therefore need to shave that off. BUT - the larger factor working your brakes over while stopping is WEIGHT.

If you're running a stockish FC TII at the track, you can run into fade issues because you're trying to stop a nearly 3,000lb car. Trim the fat off and the brakes are required to do less work.

[Christopher W.]

Originally Posted by WE3RX7

I'm a fan of custom brake systems and am currently figuring out how I want to setup my FC as well. I too will be going with a larger rotor, BB and MC.

If not to make bigger, but simply to improve upon 20+ year old technology! Aside from improved braking for 500+whp, I also want quick exchange calipers, etc for track days that will make pad replacement quicker!

Just keep us posted on your setup - I know even though you're doing it for mostly cosmetic reasons, what you discover in your system may provide useful insight...

Well, I wouldn't say mostly cosmetic reasons but that is a big factor. I love the looks of big brakes....but they gotta freakin work. And when I say work that means better than the stock brakes in every way. We will see...

[WE3RX7]

Dont take this as me attacking you, however, big brakes actually DONT work on street cars as well as you'd think. They are intended for a car that gets heavy abuse on the track... if you're going to looks, cool.. but if you do it with intentions of having better street performance, they are not what you want.

[RETed]

Originally Posted by WE3RX7

Dont take this as me attacking you, however, big brakes actually DONT work on street cars as well as you'd think. They are intended for a car that gets heavy abuse on the track... if you're going to looks, cool.. but if you do it with intentions of having better street performance, they are not what you want.

For someone who makes odd comments, I don't think you're qualified to make such statements.
True, "street performance" does not usually stress out the stock brakes, and most people who complain about the stock brakes are actually looking for better "brake feel".
A aftermarket (big) brake kit can mimic the stock brakes and give you better feel...if designed correctly.

Just to go over those odd things you've said...

I too will be going with a larger rotor, BB and MC.

You're another one that needs to GO READ THE BRAKE PRIMER LINK I POSTED.

If not to make bigger, but simply to improve upon 20+ year old technology!

What improvement?
Other than different brake pad materials, the brake design hasn't changed much over the past "20+" years.
You can argue about full-floating calipers versus multi-piston fixed calipers, but this technology has been around for decades.
About the only thing I noticed that changed recently is CCM rotors...on Porsches; since we're not messing with these, this point is moot.

Aside from improved braking for 500+whp,

The OP was talking about a non-turbo 20B.
Getting to 300hp should be alright, but pumping out 500+ out of such a set-up is very expensive.
Thus, this is not really applicable to this thread, and if you wanna talk about your set-up, why not start your own thread?


-Ted

[Christopher W.]

Originally Posted by WE3RX7

Dont take this as me attacking you, however, big brakes actually DONT work on street cars as well as you'd think. They are intended for a car that gets heavy abuse on the track... if you're going to looks, cool.. but if you do it with intentions of having better street performance, they are not what you want.

You might in the end be right....

I still think a well thought out and designed system with higher quality parts than stock and good street pads will be better than stock on street.

I myself don't know how to design that system so I hope the people I am dealing with are not full of fluff.

Hopefully sometime in the fall I will have some sort of empirical evidence.

By the way Ted that's a great article in GRM.

[WE3RX7]

Not qualified? You don't even know me....

My comment on the larger rotor was probably not put the best. I mean I'm using a larger rotor... not larger BB and MC.. the BB and MC are just new aftermarket units spec'd out for my needs. Also, I'm referring to the parts being 20+ years old and believe it or not, braking systems have come a long way in 20 years besides just "pad material".. and dont quote the term "20+", last I knew FCs started in '86 thus 2006 would make them 20+...

Please remove yourself from the pedestal you put yourself on - I am not attacking your knowledge as I definitely feel you know your way around the 7s, but your just as "qualified" as myself when it comes to forum discussions.

I'll build my brake setup the way I want it, just as Chris W will build his the way he wants it. You're so eager to attack somebody and on all the forums I've seen you on, you manage to bring a bit of negativity and arrogance...

Sorry to hi-jack your thread Chris...

Lets keep the topic going as I am interested to see what you come up with along the way...