Big Brakes on 05 Mustang Help

[Nitemare]

Hello everyone. I purchased the Roush mustang 4 piston front brakes (like the ones on the 427) and a set of Wilwood rear brakes 4 piston. My question is, do I need to upgrade my master cylinder 0r would the stock )5 Mustang GT on work?

http://www.wilwood.com/Images/BrakeKits/Kit Photos-Small-Parts Laid Out/140-9228-D_kit-sm.jpg

Thank you. Please tell me what you think.

Its Wilwood 140-9228-D

 

[DRock]

Your probably gonna through off te brake bias with those kits together.

But your stock master cylinder will be fine

 

[Nitemare]

what do u mean by brake bias?

 

[stang389]

front and rear braking correlation
generally mustang are heavy front brake cars (ie. the gt500, fr500 race cars). IF your brake bias is off (to much rear brake) This can cause the car to not react in the way you would want under heavy braking on the track causing the car to be off balance on turn entry.. ^ just a rough brake down.

 

[Nitemare]

Thank you very much guys. Anyone running a similiar setup that van comment on my setup?

 

[stang389]

well the supersnakes run 6piston front an rear, i just think 4 piston front and rear might be to much for the car. just run aggressive rear pads and good rear rotors and the car should be balanced

 

[retfr8flyr]

I run 6 piston Wilwood front and 4 piston Wilwood on the rear with the stock master cylinder. The brake bias seems to be fine and I haven't had any problems either on the street or at the track with my setup.


Earl

 

[Nitemare]

Yea I have the wilwood brake pads and wilwood rotors and for the front, ill be running the Roush 2 piece.rotors and Roush brake pads.

 

[Thekid760]

griggs runs a 4-on-4 setup with stock cobra master.

 

[hammerdown]

Some stupid questions here. I don't know a whole lot about how our brakes are setup, but I do know that the ABS has independent control over all 4 wheels so wouldn't the ABS naturally keep everything in balance as far as break balance and one or more tires giving up traction before the others? Again, it's just one area I've not really looked much into, is there not a proportioning valve somewhere were you could can in and adjust the bias front to rear yourself?

Thanks,
-HD

 

[51ngh]

4.6 3v cars do not have abs control on all 4 wheels. also do not run proportioning valve. There are better ways to bias a brake system. Running less aggressive pads in the rear will bias the system towards the front. Also running smaller rotor size will bias the system too. If you run the same rotor size front and rear you have just moved the bias towards the rear. It is recommend to run the same pad compound but different rotor size for street cars. In race cars the bias is usually set 90/10, 90% front and 10% rear for dry conditions. For wet they move the bias towards the rear to prevent lock up and they can do that with a bias bar since they usually have two different master cylinders, one for front and one for rear. With different piston bore size to biasing. 6 or 4 piston calipers help with initial bite and heat capacity of the brake system. Also keep in mind if you upgrade to bigger brakes you also increase your unsprung mass and rotating mass of the wheels(less WHP).

 

[hammerdown]

4.6 3v cars do not have abs control on all 4 wheels. also do not run proportioning valve.

Ok, this is gonna feel like a call-out, please know that's not my intent, but your post confuses me.

This is the information as it reads in the shop manual:

206-00-1 Brake System — General Information 206-00-1
DESCRIPTION AND OPERATION
Brake System:
The brake system consists of the following system components:
• a vacuum-assisted power brake booster
• a front-to-rear split hydraulic system
• front disc brakes using a dual piston brake caliper and disc system
• rear disc brakes with an integral parking brake, using a single piston brake caliper and disc
• a 4-wheel anti-lock brake system (ABS). Refer to Section 206-09.

Also pinouts for the anti-lock brake controller indicate inputs from all four wheels. Here some pictures (sourced from ALLDATA).

Again,.. Not trying to insult your intelligence here, and I'm not saying you're wrong. I'm saying I'm confused by this and am just trying to resolve what you're telling me with what I'm interpreting from the shop manuals... (right here right now is the first time I've really done any digging on the subject)

Thanks!
-HD

 

[51ngh]

Its speed sensor, Anti locking system, it is there to prevent wheel lock up and has nothing to do with brake balance bias.

 

[Nitemare]

This is some interesting info.

 

[DiMora]

4.6 3v cars do not have abs control on all 4 wheels. also do not run proportioning valve. There are better ways to bias a brake system. Running less aggressive pads in the rear will bias the system towards the front. Also running smaller rotor size will bias the system too. If you run the same rotor size front and rear you have just moved the bias towards the rear. It is recommend to run the same pad compound but different rotor size for street cars. In race cars the bias is usually set 90/10, 90% front and 10% rear for dry conditions. For wet they move the bias towards the rear to prevent lock up and they can do that with a bias bar since they usually have two different master cylinders, one for front and one for rear. With different piston bore size to biasing. 6 or 4 piston calipers help with initial bite and heat capacity of the brake system. Also keep in mind if you upgrade to bigger brakes you also increase your unsprung mass and rotating mass of the wheels(less WHP).

Yes, 4.6 3V's DO have ABS control on all four wheels. ABS = Anti-lock Braking System. If you lock up a rear wheel, ABS will kick in and get it rolling again.

There is a wheel speed transducer and pickup with associated wiring on each wheel of the S197's.

 

[ZmanM3]

 

[DiMora]

I researched brake bias to death.

Multiple parties told me not to screw with the rear brakes...that includes the head test driver at Roush Performance and the Stop-Tech engineers. Brake pad upgrades, stainless steel lines, slotted or dimpled rear rotors, and of course high-performance fluid are fine, but swapping the rear to different calipers or changing rear rotor diameter can definitely screw up bias.

Products like the Stop-tech 4 and 6 piston calipers (ST-40 and ST-60) along with the associated 14" front rotors, Brembo GT500 brakes, BAER front brake upgrades, etc. are all designed to NOT screw up bias in these cars.

Think of it this way: A stock GT comes with X amount of bias. The stock GT brakes, in an emergency stop on a car with cool brakes, will stop in X distance, with anti-skid modulating. The main limit in my scenario is tire contact patch, tire compound, inflation, and surface...IE we are limited by tire traction and anti-skid modulation when they do lock up.

Adding high-performance brakes (bigger rotors, upgraded pads, SS lines, fluid, slotted floating rotors) is done mostly to dissipate heat better, provide better brake application feel (decrease pedal mush), and prevent fluid boil / brake fade / brake loss when things do get hot.

Stop-Tech and Brembo did their homework so as to not upset the bias, but still make a product that looks sexy and can dissipate a ton of heat.

Changing the rear rotor diameter or hydraulic balance of the rear calipers via a branding change, if using a brand that was not specifically designed to NOT change bias, can cause instability in turns when braking.

So...most guys will be fine with some fancy paint on the rear calipers to sex them up a bit, a change to a good pad, some SS lines, and, if desired, some same-diameter slotted rotors so as to not screw up bias. If you want more than that, do your homework very, very carefully.

Again, Stop-Tech and Roush advised me AGAINST changing rear calipers or rotor diameter. I'll see if my Roush contact can tell me how bias is controlled on the S197.

 

[51ngh]

Let me guess the Roush contact's name starts with S and drive a track Pak car.

 

[DiMora]

Let me guess the Roush contact's name starts with S and drive a track Pak car.

Yes.
Do you know him?

 

[DiMora]

Our brake bias is controlled by our ABS module- " Electronic Dynamic Proportioning system". To change it requires a computer flash.

The FR500 and GT500 have a different proportioning setup than our GT's have.

So, as 51NGH states, we don't have a proportioning valve per se, but we do indeed have " bias" and we do have 4 wheel ABS.