damian

iTrader: (2)

I recieved some PMs asking about the brake setup on my race car, so I decided to make this summary post.

First of all let me start by saying the brake system has gone through many iterations and probably will go through a few more over the next few race seasons. The changes I have gone through and things I have learned along the way is for another mind-numbing thread. This thread is meant to be a summary of my current setup rather that the long and painful history to get it to this point. ;-)

Basic Info:

Hydraulic System:
ABS totally removed (no abs)
Power Assist (brake booster) totally removed
Dual Master Cylinder Manual setup with Balance Bar
Remote Balance Bar adjustment

Brake Bias Gauge Setup:
SPA Digital Brake Bias Gauge with electronic inline sensors
(shows both front and rear line pressure or bias %)

Front Brakes:
Calipers = StopTech ST-40 (with custom piston sizes)
Rotors = StopTech 332x32mm
Pads = Hawk HT-14 Race HB141V.650
http://www.stoptech.com/

Rear Brakes:
Calipers = RacingBrake rear upgrade
Rotors = 322x20mm
Pads = Hawk HT-10 HB158.515
http://www.racingbrake.com/RX7_REAR_...2107-311-0.htm

Brake Ducting:
Custom made aluminum rotor seal plates and ducting. These were based off the ones I made out of carbon-fiber for the 'Big Red' setup I used to have up front (now on GooRoo's car).

Pics:

Manual System & Brake Bias Gauge Setup










Front Brakes



Front Brake Ducting

I needed to make a new duct set for the front since the StopTechs have a larger inner diameter hole.












Rear Brakes

I really like the RacingBrake rear kit, the rotors are very impressive and their design keeps the temps very manageable with no ducting needed to the rear.




I do not have it working 100% the way I would like it yet, but I got it about 80% there...now its just tweaking to get the bias right.

I have a lot of people to thank that got me this far, thanks to:

- Andy (GooRoo) for being the brain behind the numbers of the setup and helping me with the redonkulous spreadsheets that calculated all the stuff I needed to know to get the brakes to where they should be with what we had to work with.

- Brand Barber, for a few fun phone conversations that helped me understand the system better (that is the dual MC system from his old track car, that was sold to fritz)

- Fritz, for sellin me the dual master setup :-)

- Howard Coleman, for his countless informative posts on many topics, including brakes.

- StopTech, for some very helpful phone calls and tech info on brakes setup.

- RaceingBrake, for making a very nice rear kit that balances a front upgrade.

- ProParts, for being my sales conduit to StopTech and dealing with crazy timeline requests.

- and... whoever else was there when i was tryin to get the brakes to work right and helped me bleed gallons of fuild through there ;-)

...any questions? :-)

KaiFD3S

iTrader: (37)

Nice Damian, you gonna do a write up on this install

turBRO240

iTrader: (1)

Id actually like to hear the whole "painfull history".

Itl give me a better idea and understanding on what to do with my brake setup.

Smitter

so you are running a stop tech kit on the front and stock calipers with rear slotted rotors on the back?
i have a set of the stop techs aswell and have often wondered why i cant find em for the back? i guess they are not need cause 80% braking comes from the front??

so the slotted rear rotor are the same diameter a the stock ones?

TRISPEEDFD3S

iTrader: (26)

The rears are stock calipers with a bracket made to use a super big rear rotor. Set up from Racing Brake.

speedturn

iTrader: (1)

That looks very nice

Rx7_Nut13B

iTrader: (1)

The painful part...... How Much?

damian

iTrader: (2)

Side note on the bias gauge setup:

I decided to pay a bit more and get an electronic setup that is based on inline sensors, rather than mechanical gagues. The reason is I did not want to run brakes lines into the cabin of the car to the mechanical gauges.

OC94Rx7

Thanks Damian for posting this thread so quickly!

Regards
Oliver

Eggie

Damian, would you be willing to post piston sizes for everything? Also, how much additional leverage does Valskis' dual-MC mount provide over the stock pedal?

TIA.

damian

iTrader: (2)

I'll see if I can find the spread sheet that has all the data in it.

gracer7-rx7

iTrader: (16)

Damian's Piston sizes are listed in the thread below:

https://www.rx7club.com/showpost.php...postcount=1254

GooRoo - "3) Damian's Stoptech setup has custom 36/42 piston sizes and 13"x1.25" rotors"

damian

iTrader: (2)

Some more info for ya:

stoptech caliper piston sizes:
42mm and 36mm

stock rear caliper piston size:
35mm single piston calipers

predal ratio:
supposedly 7 from the documentation I have on the manual cage that connects to the stock pedal, however I am not 100% sure that is correct.

front
cp2623-92
(0.75") 3/4"

Master Cylinders:
front - AP Racing cp2623-92 (0.75") 3/4"
rear - AP Racing cp2623-92 (0.75") 3/4"
(I actualy changed the rear one at nasa nationals in between sessions, the origonal was a CP2623-90 (0.625") 5/8")

I am pretty sure there is another thread somewhere on brake setup that has GooRoo's spreadsheet and good info on what all the numbers mean and how they work together.

diyman25

Find a similar set up like your design. This set up use a lot of stock parts, And is Bolt on too

piston size
F:3/4、R:13/16

PDViper77

iTrader: (9)

Wow...........

damian

iTrader: (2)

Very cool find... looks like a nice setup too.

rx7will

iTrader: (6)

Does your car have the brake pad knock back problem. Or do you run the anti knock back springs.

damian

iTrader: (2)

Thanks for reminding me about that!!!

Yes, as my car got faster and was pulling more lateral Gs, I did get a bad pad knockback issue, so I did install the knockback springs and it basically removed the knockback problem.

jantore

Where did u find this? Is there more info about this setup?

I need to uppgrade my break master cylinder. And im looking for ideas how to do it.

JT

damian

iTrader: (2)

>>Where did u find this? Is there more info about this setup?

You can see the site its sold on here:
http://www.revo-tune.jp/catalogue/li...3S%29&s_md=and

>>I need to uppgrade my break master cylinder. And im looking for ideas how to do it.

Keep in mind this is not just a master cylinder upgrade, it is totaly different setup than stock, removing the power assist.

Specter328

iTrader: (2)

What is the difference between manual and power assist brake setups in terms of feel? What are the pros and cons of the manual setup?

damian

iTrader: (2)

Well, that is a very loaded question and could take a very lengthy in-depth explaination....but I will try to summ it up in a simple answer:

Simple Answer = better brake feel and balance ability

A manual system, with no Power assist, will typically give you much better pedal feel, since there it is only your foot making the pressure, and not a brake booster between you and the master cylinder, assiting you.

Also, a dual MC manual system allows you to use a balance bar and be able to set the bias of the front/rear braking...allowing you to maximize the braking for the cars setup and/or track and/or weather conditions, et, et.

Pros:
Great pedal feel
bias adjustable
if one line or MC fails, you still have one line with pressure
highly customizable with different MC sizes

Cons:
Not easy to get setup properly and you must match the entire system to have it work corretly, the MC sizes must match the caliper pistons sizes and the front/rear caliper piston sizes must be balanced right, et, et.


Keep in mind this is really meant to apply to race cars or cars that are tracked very often.... with my experience with it all, I would never do this to a street car or even a street car that sees some track time.... I would only do it to a full on race car or a car dedicated to a lot of track use.

DigDug

So you don't have to tap up at all after corners with the springs?

damian

iTrader: (2)

yes and no :-)

let me clarify, I no longer have to 'pump' the pedal to get the pressure back, but I do still 'tap' for a brake check...they are 2 different things.

Before the knowback springs, I did have have to 'mini' pump once or twice to get the pedal back to the top with pressure, between very hard braking zones. That I no longer had to do after the knockback springs.

The brake 'tap' I still do as a brake check, to make sure i have pressure before i have to threshhold brake.

The thing is, as u upgrade your brake system with better components your knockback will increase, more rigid calipers and larger rotors will cause more 'deflection' that produces pad knockback.

Here is a great article on knockback:
http://www.stoptech.com/tech_info/wp_knockback.shtml

I love one of the listed solutions in that article, and the appropriate answer:

*****
5. Slow down and reduce cornering forces

Naturally, this solution is no fun and is not recommended.
*****

MAZDASPEED08

can you adjust the brake duct airflow so your pads can get to operation temps?
looks like they would stay to cold