Anyone have any Brake Questions?

[OG_Racing]

I have Bear's Performance Pro Street Axles.

Does that mean I should replace the entire rear brake kit with a floating caliper kit or I just need to get a floating caliper only?

I am tired of these aftermarket parts. I have the wilwood kit and have no way of telling what the offset is. I could not find the part number for it

72Z/28,
Believe me, I know how frustrating can be. When building racecars for your first time it's "here is all the parts you can buy, good luck figuring that out". I am unaware of any floating calipers that will bolt to a dialight bolt pattern. Try giving Wilwood a call, they might have something on the shelf that would work.

When PFC was designing the Ford Mustang big brake kit they had to keep the stock caliper in the rear. This Is because the axles would move in and out. A floating caliper was needed to deal with all the changing tolerances. On the front kit was a giant 4 piston mono block caliper, the rears had to have a stock caliper with an upgraded rotor.

that caliper itself that you are using has a .92" offsett. http://www.wilwood.com/Images/Calipe...lite-cm-lg.jpg

[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.

[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.

[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?

[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.

[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.

[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?

[OG_Racing]

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

1. Serious Braking power starts with a Serious Tire. we could put the largest brakes in the world with a GT-r Sized 409mm rotor, if you have a 255mm all season tire then you wont be able to use it.

2. 4 piston. all day every day. The more pistons a fixed caliper has the harder it is to get an even amount of pressure to each piston. The only time we do a 6 piston is for NASCAR. fitting a 323mm rotor and a caliper under a 15" wheel is a real choir. At that point we need to go to a 6 piston to keep the caliper OD smaller.


3. for a 3000lbs car with 300hp we could get away with a 12-13" Floating rotor with hats. It will be able to fit under a 17x9 wheel with a 275 tire.

4. for a street car. keep them. Race cars I like to go full manual. you'll get allot better feel with a manual but it will take extra effort to make the car stop on street pads.

[OG_Racing]

Calipers.
FYI
Piston count means nothing. how many pistons you have means 0.00000 to performance. Going form a 1 piston to a 6 piston will not increase your performance AT ALL!! there is a knee in the graph, but generally speaking the more pistons you have the worse a caliper gets. a caliper needs not to be judged by piston count but instead by rigidity, and piston size.

Pistons,
Everyone remembers the digital Camera war of Megapixels. Nobody knew what the flip a megapixel even was. The marking men said this camera has 4 pixels and that's better then 3 pixel. when in fact the amount of pixels it had meant nothing to the quality of photographs. it was a trick to get people to buy the next model. Brake manufactures have done the same with piston counts. They say "OH look a 8 piston!! buy now!!". The fact of the matter is this - the more pistons you have the worse your fluid will travel to all the pistons consistently. We found that the ideal number of pistons to have in a fixed caliper is 4. 4 pistons push evenly on all edges of a pad, and it can still keep consistent fluid pressure. we have also found that more pistons you have above 4 the less consistent a caliper becomes with fluid delivery to each piston. The only time we've seen 6 pistons be better performers then 4 pistons was is the size of a caliper was an issue. in NASCAR, we use 6 piston caliper to clear that tiny 15" wheels. for 90% of the applications out there we don't need to worry about that. so that 8 piston caliper you've been eyeing... run away from it.





Rigidity
a caliper is only as good as how stiff it is. a solid caliper can be felt in the peddle. time after time the peddle can be relied on to be in the exact same spot. If your reading this and not agreeing then your system is in desperate need of improvement. flex of the caliper is the same as the flex in the lines. people go crazy with stainless brake lines. they do this because it improves peddle feel. Unknowingly, they swap the stainless lines onto a caliper that flexes. the stiffer a caliper is the less it will flex. A flexing caliper requires the pistons to travel further to apply the same amount of pressure. the extra travel in the pistons means the pistons are moving further out of the bore. they will need to travel further back into the caliper to be able to remove pad pressure off the rotor surface. A caliper, let me restate that. a Good caliper has square O rings. these square O rings retract the pistons only so much. for example lets say 1mm. if a caliper flexes and the pistons need to travel 1.1mm that means the O rings cannot retract the piston, and you will still have residual brake pressure on the rotor. that residual pressure is creates drag. The Drag is acting like the brakes are still on. imagine you heading down the back straight. how much more MPH do you think we can get if your brakes where off.



Piston Size.
we have gone over this before, so i wont go too in depth about master cylinder ratios. i will focus on the pistons themselves. Everyone overlooks the piston size. so your calipers are a 12 piston.. your pistons must be the size of dimes. that's not a good situation. When looking at a fixed caliper we want to see 4 large pistons. this gives us the best hydraulic advantage.

[OG_Racing]

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?

allow me to answer this in order... Yes, Yes and Yep.

First off are you asking about comparison to the C6z brakes, or to the c5z? when you see a brake kit start for 8k you can begin to think "this might be a quality system". after that start to do some fact checking. where does the iron come from. you can machine the rotor in the usa, slap a "made in the usa" sticker on there, but that doesn't mean the iron is from america. allot of places will lie about where the Iron will come from so watch out for that. when compared to a oem piece the aftermarkets are much better. the OEM piece is engineered to look like a racing caliper but be cheap to make. stop tech has a good side by side video. the video demonstrates caliper flex in a OEM fixed caliper. Yep your going to pay for the "brembo" name. Brembo knows they got a good name, and your going to pay for it. let me explain it this way. PFC makes a corvette kit. it's exactly the same as the brembo one (except the rotors are slotted, not drilled) and that kit costs $7,500 for front and rear.

As a Professional brake guy a 8k brake kit a good starting point. Our GT "race" brake packages they start at $10k, most of our NASCAR Short track packages Go for $25K, and our Carbon Carbon kits start at $250K. If you walk in with your street car, am i going to try and sell you a nascar Braking system? ..i'll anser my own question by saying "Hell no". These kits wont stand up to road salt, or general day to day abuse they will slow you form 200mph rapidly. Moving a 25k nascar package would be a good sale for a sales man, but not the right fit for one of my customers. it's all about matching up the brake system to what you need. I'll make sure the calipers, rotors will be what you want.

Calipers.
Lets go and tell a story about this shady tree corvette shop that i now refuse to do business with. They had a customer with a c5z corvette used for track days only, no street time. it was taken to the track and put away until the next track day. Before i came around they had sold this guy a $15K brembo Racing system. I think they pulled the wool over this guys eyes to get the sale, because he was pissed about it. They must have done the old "he wants a BBK, put the most expensive one we can find on there. We'll tell him about the price when he see's the bill". I kept hearing the owner of the shop tell the customer "i'm sorry about the brake system... i didn't know it was that much...ect" . Little to everyone's surprise that was the exact kit that car needed. it was a nickel finish, 360mm, monoblock 4 piston Brembo Racing Brake kit. it's perfect for track day only car (aka a race car). that kit was 15k but it will never give him a headache, drag, nothing. the owner of the shop and the customer had no idea what they where doing, and completely got it right. if they pit that kit on a road car or a double duty (street/race) the nickle finish would deteriorate and the whole kit would fall apart. so they accidentally did the right thing. they did the right thing with the right parts not right thing buy trying to screw the guy. if we have a road car it needs to have a coating that will protect it from the elements. it needs to be set up for the long haul. thankfully those calipers are less expensive then the Race versions.

Rotors
That brembo kit you listed i wouldn't recommend that for any car. it has drilled rotors. Drilled.. shoot me. i've been talking to people about how awful drilled rotors are. All i get in response is "are you sure?". Yes, I'm flipping sure that drilled rotors are crap. Fact of the matter is it cost 3x less to drill a hole then it does to cut a slot (that's why the oem's do it) . Someone decided that "I'll cut my rotors to look like racing rotors.. but all i have is a drill press" and then the drilled rotor was born, just to make my life harder. Sorry i'm normally a more positive person... The holes are said to release gasses. i have no clue what gasses they are talking about, if your pads are putting off gasses you got the wrong pads, and an marketing major came up with that quote. the holes themselves actually remove a lot of material from the rotor. This material is desperately needed for the rotor to cool itself. think of it this way it's easier to start a log on fire if you put the flame on the thinnest part of a log. because the rotor has less thermal capacity and is easier to heat up it will be easier to fail. yes i'm sure...