Anyone have any Brake Questions?

[OG_Racing]

No thoughts on my little Cougar project? LOL

Andrew

Andrew,
Sorry, it's been a busy day. Not knowing exactly what the dimensions are of your cougars front suspension, I'm not ready to suggest that kit.. If it's going to be driven on the street, your braking demands will be very small. You would be well off using the rotor option that came on the Mustang originally. Combine that with the proper proportioning valve, and a good set of pads. should give you adequate braking power.



If you want to go something more high-performance. I can recommend a ZR34 four piston caliper with the two piece rotor.

[CTSV]

OG is there any formula for choosing the caliper piston sizing to maximize total braking in a booster or manual system? I was always under the assumption the front piston area must be 50% greater than the rear for proper bias etc.

[OG_Racing]

OG is there any formula for choosing the caliper piston sizing to maximize total braking in a booster or manual system? I was always under the assumption the front piston area must be 50% greater than the rear for proper bias etc.

yes, there is a formula but it's not a %. you'll need to factor vehicle weight, center of gravity, rotor size, piston size, master cylinder size, pedal ratios, booster advantage, tire size, tire compound, tire stagger, brake pad Mu, and a few other variables.

[Titan1021]

I have Wilwood 6 piston front brakes. And for now will have stock drums in rear, I will replace soon. My question in can I run 3/16 brake line for the whole car. 1968 camaro, power brakes 9 inch dual dia booster, 1 inch bore master. Thanks.

[dontlifttoshift]

Why doesn't every pad manufacturer publish CoF/temperature range charts like Wilwood does?

[OG_Racing]

Why doesn't every pad manufacturer publish CoF/temperature range charts like Wilwood does?

Good question! dontlift..,
When i worked at PFC that question was asked allot. PFC didn't want to release the graphs for proprietary reasons, also it would be useless. All the temperature ranges that you see from wilwood or hawk are an illustration, A cartoon. They give you round about what "Mu" or coefficient of friction you have at what temperature. it also illustrates max and min temperature ranges. although it's nice to see where your compound stacks up, I find this information very confusing for racers. No team that I have ever worked with (exception of compass 360, Hondas running CTC) knew their rotor temps. Rotor temps means very little to compound choice. Every compound will create a different temperature range, and that information cannot be illustrated. Example: lets say you have a GT car, this GT car is a 1970 camaro with a Bear brake kit, and it's running track days. Run a low Tq compound like a PFC14 and you'll see 1600*, run a higher tq compound like a PFC13 and you might only get to 1000*. Rotor temps are a consideration when picking out rotor sizes, but it's not something used to determine what pad is best. Club racers would call in all the time and say "i have compound XYZ and i see 400-1600* rotor tems, what pads do i need?" to that i would reply "calm down , what kind of car do you have, and what events are you running?". You need to match the pad to the application, after that we can worry about what temperature range you need to be in.

I'll give a quick run down of Compounds and applications for the pads that OG Racing Offers.
FYI PFC is discontinuing and replacing out some compounds. If you see a 01/11 (for example) that means the 01 is going away, and the 11 will be replacing it.


Autocross, street, drifting
PFC 10/20
pagid- None
Hawk HP+

Low Traction racing events, Dirt racing/rallycross
PFC 97/14
Pagid RS42
Hawk- Black

GT car, low downforce, high grip race compound tire (if you have 275+ BFG rivals this is for you)
PFC 01/11
Pagid RS19
Hawk-Dtc 60

GT car, High Downforce, Slicks
PFC13
pagid Rs14
Hawk - None

Formula car (indycar), High Downforce, Big slicks, high hp
PFC 07
Pagid rs15
Hawk - none

[71RS/SS396]

If you see a 01/11 (for example) that means the 01 is going away, and the 11 will be replacing it.

Nooooooo! LoL! What's the difference in the 11? I use the 01 primarily in my car so I'm interested in what to expect with the change.

[OG_Racing]

about 4% more TQ and better modulation. The quote i got from the pad engineer was "slightly better in every way". Fear not Tim!

[NOT A TA]

Thanks for answering questions Johnny! Here's my situation. 70 Firebird (TA clone) Hotchkis suspension with Bilsteins from around the turn of the century. Never knew the spring rates. 3500 lbs with frame connectors, Del-A-Lum UCA/LCA bushings, 275/315 Yokohama AO32 tires. I ran it at drags, land speed races, open track days, and HPDE's on various road courses as well as normal street driving. As I got better as a driver on road courses it got harder and harder on the stock power assisted disc/drum brakes, particularly on big tracks. I was running dedicated pads/rotors and shoes/drums for street or track. Got to the point I was running porterfield R-4's and their custom made rear shoes on parts store rotors and trying to bed in pads etc. on the street so they'd be ready for a track weekend. Then I'd get them so hot on track I'd crystalize the rotors in about a day of HPDE. They got hot enough that the plastic centercap emblems in my wheels would melt.

Then I won a contest and part of the prize was a set of Baer brakes. I talked over my use of the car with Todd @Baer (RIP) and he sent me a set of their 6P front and 6P rear calipers with 2 piece 14" rotors all around along with their spindles and a rear bias valve. Now I'm putting the car back together with upgrades and need to figure out a master cylinder setup. I'd prefer if possible to use a manual master to eliminate possible problems with any type of power assist. Just one less thing that could sideline me at an event and I look at every electrical connection, plumbing connection, and unnecessary convenience as a liability. Currently running an automatic so not much engine braking (although I do shift it manually on track) and will be switching to a 5 speed manual eventually after the current upgrades are tested.

Along with the brake upgrade I'm doing some aero mods and additional chassis stiffening. I'm extending the front air dam and making a splitter, adding a taller rear spoiler, belly pans, front brake ducts, diffuser, and side skirts. Some of the aero items will be swapped for land speed racing where less drag is more desireable than more downforce. Adjustable G braces, new solid body mounts, welded frame connectors , and LCA mount braces will stiffen up the chassis a bit more. With the added downforce and brakes I expect to have to raise the spring rates once I test the car on track. New tires are Yokohama AO48's 285/295 18's. I like big tracks like Sebring and Road Atlanta but will still go to smaller venues like PBIR and Lime Rock (East coast guy).

So suggestions for a manual master (or dual if recommended) would be great as well as any other suggestions you might have.

Threads like this are kinda dry without pics so here's my car at Sebring before I tore it down to the shell for this rebuild.

[OG_Racing]

John,
congratulations on winning a brake kit, that's awesome! The melting of center caps is a fairly normal thing, the crystallization of rotor is not. There seems to be a combination of things working against you on that set up. First of all the the drum brakes, I'm surprised you were able to find a race shoe. The low torque nature of the drum brake can certainly put an overload on the front rotor. that could be the main reason why you're burning up rotors. The Porterfield r4 are a low torque compound. From my experience, I've seen lower torque compounds put more heat into a braking system when compared to medium or high torque pad. The higher torque compounds are used for shorter amount of time and less heat leeches in the system. all of this can be fixed.

Something else we might consider is your rear axle. I've had a lot of club racers trying to race on the non floating hubs with not floating axle. those who have tried have met challenges. Even cars that use the press in bearing of the Ford 9 inch have had issues keeping a rotor centered in the non-floating caliper. I recommend calling Schwartz performance. See what axle you need to run with a non floating calipers like the bare six piston. They have a allot of experience with bear and should be able to point you in the right direction.

Good call on trying to remove problems before they are problems. Not many people understand how frustrating and expensive that can be. If we are going to do manual brakes, I want to see a dual master cylinder unit. If there is going to be a leak you won't lose both channels of brakes. Also it would be a good way to adjust for brake bias on-the-fly. Also you won't be able to get the same feel out of a boosted system, as you will with a manual. If we got the MC sizes correct you shouldn't notice an increase in pedal effort.

In order to get you correct master cylinder sizing i need the car scaled out, and the center of gravity. I need to know how much it weighs, the cross weight, and center of gravity. I can get all the other information I need off of baers website. Let me know where you're located in FL. i have dealers across the south that i can recommend to scale the car when it's ready.

[NOT A TA]

The crystalization history was just for background and so others reading don't think they NEED big brakes to get started on track. However they may limit the driver once the driver gets as good as the car.

rear axle: Knew I'd forget to include some kind of info. GM 8.5" 10 bolt that's been modified with Moser 3.5" bearing Ford style ends and Moser tapered axles.

I'm at a loss to figure out what to do about scaling. If I have to build the entire car before figuring out what bore masters would be best I'll still need something to assemble so I can mock up mounts for the masters, fab lines etc. If it was a race car with lift off hood I wouldn't worry about it but PT cars with pretty painted firewalls, inner fenders, frames etc. are more of a challenge to do things like this once assembled. Any ideas on how I can mock up everything without having the masters so once a decision on bore size is made I could just bench bleed the masters, install them, and bleed the system on a freshly painted fully assembled car?

[OG_Racing]

The crystalization history was just for background and so others reading don't think they NEED big brakes to get started on track. However they may limit the driver once the driver gets as good as the car.

rear axle: Knew I'd forget to include some kind of info. GM 8.5" 10 bolt that's been modified with Moser 3.5" bearing Ford style ends and Moser tapered axles.

I'm at a loss to figure out what to do about scaling. If I have to build the entire car before figuring out what bore masters would be best I'll still need something to assemble so I can mock up mounts for the masters, fab lines etc. If it was a race car with lift off hood I wouldn't worry about it but PT cars with pretty painted firewalls, inner fenders, frames etc. are more of a challenge to do things like this once assembled. Any ideas on how I can mock up everything without having the masters so once a decision on bore size is made I could just bench bleed the masters, install them, and bleed the system on a freshly painted fully assembled car?

as far as big brake kits. I like to call stock calipers donkeys. they are tough, heavy, and cheap. Dont try to turn a donkey into a race horse. You can grab used master cylinders off Roush yates nascar picking yard. NASCAR sheds used parts all the time. Call up roush yates and see if they have any mock up master cylinders IE ones that are blown out. they will probably let those go for 10-20 bucks.

[71RS/SS396]

The crystalization history was just for background and so others reading don't think they NEED big brakes to get started on track. However they may limit the driver once the driver gets as good as the car.

rear axle: Knew I'd forget to include some kind of info. GM 8.5" 10 bolt that's been modified with Moser 3.5" bearing Ford style ends and Moser tapered axles.

I'm at a loss to figure out what to do about scaling. If I have to build the entire car before figuring out what bore masters would be best I'll still need something to assemble so I can mock up mounts for the masters, fab lines etc. If it was a race car with lift off hood I wouldn't worry about it but PT cars with pretty painted firewalls, inner fenders, frames etc. are more of a challenge to do things like this once assembled. Any ideas on how I can mock up everything without having the masters so once a decision on bore size is made I could just bench bleed the masters, install them, and bleed the system on a freshly painted fully assembled car?

I know you probably don't want hear this but...... that Ford bearing set-up is going to be problematic for track use, you're going to fight leaks, you will also likely have pad knockback issues with fixed calipers.

[OG_Racing]

I know you probably don't want hear this but...... that Ford bearing set-up is going to be problematic for track use, you're going to fight leaks, you will also likely have pad knockback issues with fixed calipers.

tim's right. we've had plenty of American iron gys have tried the ford press in bearing. we haven't had one work yet. They either go back to a floating caliper, or upgrade to a floating axle.

[NOT A TA]

The possibility of leaks is disheartening to hear, however I put the rear together years ago and ran the rear on track before without leaks. I replaced the O rings with new ones from Moser and also used blue silicone when I installed the disc upgrade so I guess I'll see what happens.

Are the knockback issues caused by the axle walking in the bearing?

[71RS/SS396]

The possibility of leaks is disheartening to hear, however I put the rear together years ago and ran the rear on track before without leaks. I replaced the O rings with new ones from Moser and also used blue silicone when I installed the disc upgrade so I guess I'll see what happens.

Are the knockback issues caused by the axle walking in the bearing?

The knockback comes from the bearing itself having end play, I've see new, out of the box ones have .015"-.020" simply by pulling and pushing on the axle by hand.
Imho that Moser ball bearing is not designed for the lateral loads a good handling car can produce. The A20 tapered Ford bearing is better but would require a different axle and it's not perfect either. A floater is the only real long term solution imo.

[TheJDMan]

Johnny C,
You touched on something above that I have been struggling to find an answer for, namely scaling my car. Do you know who or where I can find a race oriented shop that has a set of four corner scales and can help me with suspension setup? Ideally I would like to find a shop in the Fredericksburg area if possible but I can also drive the car up to Sterling if necessary.

[OG_Racing]

Pipper motorsports, or angry sheep motorsports. Both service the va area and are highly recommended.

Pipper is more of a high end fabrication. Angry sheep is new to the area but they are the shop the sets up Irish mikes continental tire cars.

[F23]

Don't know if the thread is done or anything, but I've got a few questions.

1. Just got a 1969 Mercury Cougar, discs in the front, drums in the back. I'm going to get new rims, so size constraints aren't going to be a problem for the rotor size. I'm going to do a pro-touring set up, and plan to do track days and road courses. Stock weight, and I'm trying to do it on a pretty strict budget. If I don't have to do a complete redo of the master cylinder and everything, that'd be great, but I'm looking for some serious braking power.

2. 4 piston brakes or 6 up front? Disadvantages and advantages of both

3. Recommended rotor size

4. Power assist brakes. Good or bad? How expensive would it be to do to my cougar?


Thanks
F23

[Nicks67GTO]

Here's a real general one that I can't seem to get my mind around....

Why does a front set of Brembo brakes for a newer ZO6 Vette command $4-8K?

http://www.carid.com/2006-chevy-corv...2FgaAn3T8P8HAQ

Is it a materials and machining thing? It just seems absolutely ridiculous considering a stock ZO6 brake setup is pretty darn good in its own right. Is it just a status thing or are they actually that much better?