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Old 10-07-2015, 11:55 AM   #581
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Rear sport rotors or rotors and calipers? Very limited pad availability for rear sport calipers. Better to use 1.8 rear calipers and 949 brackets with sport rear rotors.

Regarding balance, it will depend on weight distribution, pad choice, and driving style. If you predominantly brake in a straight line a square pad setup would be where I start. I'd put some less grippy tires on it and do some testing of the balance, starting neutral and adding prop valve if necessary. If you can't get it right with the valve, stagger the pad compounds and start neutral and add valve adjustments as necessary. I don't think it will be as far out as you have been led to believe.
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Old 10-07-2015, 12:59 PM   #582
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Quote:
Originally Posted by Joker View Post
-- Willwood fronts (Bobcat) / Rear sport brakes (Carb 1521) / SS lines

Unfortunately the Fronts are only 11".. but I got everything for $450, so I impulse bought it like an idiot.

Should I be overly concerned about this? What proportioning would you recommend?
11/10.9 is OK up to about 200whp on hard compound race tires or lower power with Hoosiers. You'll need to run a compound stagger of about .15 Mu.
Crusher ran the same brakes running XP12 front, XP8 rear and a prop valve for fine tuning. We ran NA8 calipers though. Sport rear calipers have larger pistons that make it difficult to balance with compounds. NA8/NB1 rear calipers will fit the sport brackets and rotor.
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Old 10-07-2015, 04:27 PM   #583
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Quote:
Originally Posted by emilio700 View Post
11/10.9 is OK up to about 200whp on hard compound race tires or lower power with Hoosiers. You'll need to run a compound stagger of about .15 Mu.
Crusher ran the same brakes running XP12 front, XP8 rear and a prop valve for fine tuning. We ran NA8 calipers though. Sport rear calipers have larger pistons that make it difficult to balance with compounds. NA8/NB1 rear calipers will fit the sport brackets and rotor.
why would you want to run a compound stagger? and how did you get to the number that's 37.5% less rear Mu? your recommending this set up i'm just wondering why your killing off the rear brakes by 37.5% on a car that is engineered to have a heavy front bias.

On my personal car i run an square compound. that way I don't have strange Mu variances with heat changes.
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Old 10-07-2015, 05:19 PM   #584
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Quote:
Originally Posted by OGRacing View Post
why would you want to run a compound stagger? and how did you get to the number that's 37.5% less rear Mu? your recommending this set up i'm just wondering why your killing off the rear brakes by 37.5% on a car that is engineered to have a heavy front bias.

On my personal car i run an square compound. that way I don't have strange Mu variances with heat changes.
We won more national championships with a set up that way
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Old 10-07-2015, 05:59 PM   #585
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Old 10-07-2015, 06:30 PM   #586
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i was apart of the team that won these championships. 100% brake focused development of professional teams.

2011 PFC Champions

Tony Stewart – NASCAR Sprint Cup Series

Ricky Stenhouse, Jr. – NASCAR Nationwide Series

Austin Dillon – NASCAR Camping World Truck Series

Ron Silk - NASCAR Whelen Modified Tour

Andrew Morrissey - American Speed Association® Kwik Trip Midwest Tour

Dennis (Rambo) Franklin – Carolina Clash Super Late Model Series

Eddie Carrier Jr. - ADRA Dirt Late Model Championship

Chris Madden - Schaeffer Oil Southern Nationals Series Champion

Matt Sheppard - Super DIRTcar Series Big Block

Kevin Cornelius - Late Model Champion, Sunset Speedway

Andrew Gresel - Late Model Champion, Delaware Speedway

Kenny Tremont - Lebanon Valley and Glen Ridge Motorsports Park Dirt Modified

Chad Brachman – Ransomville Speedway

Billy Decker – ROC Modified Tour



Road Racing

Scott Pruett and Memo Rojas - GRAND-AM Rolex Sports Car Series

Patrick Long - Pirelli World Challenge GT

Etienne Borgeat - Castrol Canadian Touring Car

Will Power - IndyCar Series Road Course Drivers Champion

Scott Dixon - IndyCar Series Oval Drivers Champion

Dario Franchitti - IndyCar Series Overall Driver’s Champion

Petri Suvanto - Cooper Tires Presents USF2000 National Championship Powered by Mazda

Tristan Vautier – Star Mazda

Remy Audette – F2000 Championship Series

David Higgins/Subaru USA - Rally America Open Class

Travis Hanson – Rally America Super Production Class

Tony Ave - SCCA Pro Racing Trans-Am

Michael Lewis - GT1 SCCA National Champion

John Black - GT3 SCCA National Champion

Scott Tucker - STO SCCA National Champion

Revere Greist - FC SCCA National Champion

Brian Novak - Formula B SCCA National Champion

Michael Mallinen - Formula Atlantic SCCA National Champion

Tom Bootz - D-Sports SCCA National Champion

Ricardo Vera - IMSA LITES L-1 Driver’s Championship

Eurosport - IMSA LITES L-1 Team Championship

Robert Sabato - IMSA LITES L-2 Driver’s Championship

Lee Davis - Cayman Interseries Driver’s championship

Lee Davis / Ryan Eversley - Cayman Interseries Enduro Championship

Tim Fox - Intercontinental Trophy Cup P1 Drivers Championship

Josef Newgarden - Firestone Indy Lights Driver’s champion

Larbre Competition - Intercontinental Le Mans Cup GTE Am



Japan

Masataka Yanagida and Ronnie Quintarelli – Super GT GT500

Andre Lotterer - Formula Nippon

Yuhi Sekiguchi – Formula 3 B-MAX F308

Yuhi Sekiguchi – Formula 4 B-MAX ENGINEERING

Tomoya Hoshino - Z Expert trophy Gr.A class


That was my first year. talk to me.
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Old 10-07-2015, 06:40 PM   #587
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Quote:
Originally Posted by OGRacing View Post
i was apart of the team that won these championships


That was my first year. talk to me.
You drove the car, were present at every test session, personally collected the data and made the final decision on how the brake system was configured?
Impressive

I pointed out the results as way to illustrate that it was not a inadequately engineered guess. You asked if we deliberately chose a lower .mu pad to reduce brake torque in the rear and balance the system, which you and everyone reading the post already knows the answer to. So I didn't answer that question. I instead validated our setup by stating that it works just fine, by swinging it out.

I have posted this elsewhere, perhaps in this thread, we recommend NA8/NB1 rear rotors calipers when using 11" or Sport fronts. We only suggest Sport rears when paired with 11.75" fronts. We made the 11/10.9 work that year by playing with pad compounds, and it proved a solid workaround.
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Old 10-07-2015, 06:54 PM   #588
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Quote:
Originally Posted by emilio700 View Post
You drove the car, were present at every test session, personally collected the data and made the final decision on how the brake system was configured?
Impressive

I pointed out the results as way to illustrate that it was not a inadequately engineered guess. You asked if we deliberately chose a lower .mu pad to reduce brake torque in the rear and balance the system, which you and everyone reading the post already knows the answer to. So I didn't answer that question. I instead validated our setup by stating that it works just fine, by swinging it out.

I have posted this elsewhere, perhaps in this thread, we recommend NA8/NB1 rear rotors calipers when using 11" or Sport fronts. We only suggest Sport rears when paired with 11.75" fronts. We made the 11/10.9 work that year by playing with pad compounds, and it proved a solid workaround.
10/4
For the record i only keep the rear sport rotors only to keep a parking brake. i was once told "real race cars don't have parking brakes" but watching your car roll down hill is annoying. when teamed up with the 11.75" kit the rear sport brakes are already behind the eight ball. It would be a safe combination and work out well if you have a square compound. aftermarket prop vales are always a must.

it is strange.. with our spec miata teams with PFC pads they can run a square set up PFC11/11 combo. The teams that run a hawk/carbo they go for a dtc60/30 split. Mind you they are jumping the brakes a lot mid-turn to avoid collisions. My only conclusion is that the PFC has a softer bite, so they can jab a brake pedal mid tun without unsettling the car. as with the hawk/carbo maybe the bight is too high. So your left reducing the TQ to try and make up for the aggressive bite. That would in the end hurt performance of the braking system. I don't work with carbos so i'm unsure.
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Old 10-07-2015, 07:06 PM   #589
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SM guys running Carbotech run either 10/8 or 24/10
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Old 10-07-2015, 07:11 PM   #590
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I thought we weren't supposed to do what SM guys do...
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Old 10-07-2015, 10:06 PM   #591
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So what im understanding.. my 11/10.9 set up will not work with my pad application?
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Old 10-07-2015, 10:13 PM   #592
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Quote:
Originally Posted by Joker View Post
So what im understanding.. my 11/10.9 set up will not work with my pad application?
Bobcat is a 10 year old name for the 1521 compound which is designed for street use. Not remotely a race pad. 1521's don't work on track regardless of brake setup unless you're coasting around 15s slower then the car is capable of. Whichever brand pad you choose for track use, I suggest a lower .mu pad in rear by 10-15%, based on our experience with very similar setup.
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Old 10-08-2015, 07:33 AM   #593
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Hello everyone!
First, thank you VERY much for starting this hugely informative/educative thread… I’m learning a lot and try to « get it » ;-)… After 30 pages of reading, I hope I begin to understand what are the very good/best thing to do (11”75 front, 11” rear, PFC pads and so on..)…
Here is my 1st question: What improvement would you do with a US$500 budget? With US$ 1000? I know, it’s not massive, but the answer would be too easy with $1500 or more… Even racing team have to work winthin a budget!

To guide you in your answer, my car is a NB 10AE with stock 1.8l engine (turbo is on the shelf, should be in the engine bay in the coming …18 months or so), weight is 2400lbs ( under 1100kg driver onboard) with a modified chassis:
-lowered (3.9" front pinch weld height, with a positive rake),
-polypro bushes, Bilstein B6 shocks (OEM on the 10th AE),
-frame rail and hard dog Roll bar.
… And Toyo R888 tires
On the brake side, it’s all OEM except for SS brake lines, DS2500 pads front (average mu 0.42) and Motul RBF 600. So I still have the ABS and the not so good OEM “prop” valve which is hugely front bias.

The car is 80% trackday car (no racing), the 20% left is to road test the mods I do and keep the car running once/twice a month…

Regarding my 1st question, I assume removing the ABS fuse, getting a “proper” proportioning valve and fitting same pads 4 corners would be a start… I must state that, for now, I never felt I needed more brake as I’m still tuning my tail-braking, braking point, breaking modulation to increase max speed in corner (or: how to test one’s ball size...) but with much more power in sight, more stopping power will be certainly required.

Also, the miata/mx5 is equipped with floating caliper and I understand the principle… Could you explain what is a floating rotor?


Thank you very much…
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Old 10-08-2015, 10:46 AM   #594
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Quote:
Originally Posted by aidandj View Post
I thought we weren't supposed to do what SM guys do...
it's hard to ignore 500 race cars using the same brakes. :P
but your right they do have very different requirements, and are not trying to set lap times on race day.
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Old 10-08-2015, 10:57 AM   #595
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Quote:
Originally Posted by emilio700 View Post
You drove the car, were present at every test session, personally collected the data and made the final decision on how the brake system was configured?
Impressive
I didn't drive the cars. from all my work i learned to i avoided the drivers as best i could. i wanted to talk to the crew chiefs and the lead engineers. i wasn't present at every test, (some test yes, but not all). Data was sent to us by a team engineer or team owner, and sometimes communication with the driver was the only data we had. I leaned real quick how inaccurate driver data was. i developed a question asking pattern that lead me to the characteristics of how the car was handling. my findings coincided 50% of the time with what the driver was telling me. Most of the drivers think they know what is going on and have absolutely no clue. on some of the cars i personally did have the final recommendation on how the system was configured. PFC had a 5 man team for all of those championships. my field was grand-am, ALMS, PWC, club racing, and inside support for the NASCAR teams.
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Old 10-08-2015, 03:50 PM   #596
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Can someone explain to me why there's such a disparity over brake bias recommendations? On one hand, you've got people recommending to take out the stock prop valve altogether on an otherwise stock setup, and on the other you've got track gurus running more aggressive pads on the front than the rear even with big brake kits.

Is it as simple as that you track guys are running such grippy tires that they can handle and/or need that much front brake during forward weight transfer?

On my street car, on moderate street tires, I definitely feel like the fronts lock prematurely on my square-padded, stock-braked setup. Am I wrong?
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Old 10-08-2015, 07:21 PM   #597
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Quote:
Originally Posted by TalkingPie View Post
Is it as simple as that you track guys are running such grippy tires that they can handle and/or need that much front brake during forward weight transfer?

On my street car, on moderate street tires, I definitely feel like the fronts lock prematurely on my square-padded, stock-braked setup. Am I wrong?
There are lots things that affect it, and yeah, stickier tires mean more grip means more weight transfer means less rear bias desired. Driver preference is also a big part of it, as are track conditions.

Note that in F1, Michael Schumacher used to adjust his prop valve to a different setting for EVERY CORNER. Obviously a Miata isn't an F1 car, but it demonstrates that there are a lot of factors going into it.

--Ian
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Old 10-08-2015, 07:23 PM   #598
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Quote:
Originally Posted by codrus View Post
Note that in F1, Michael Schumacher used to adjust his prop valve to a different setting for EVERY CORNER. Obviously a Miata isn't an F1 car, but it demonstrates that there are a lot of factors going into it.
--Ian
I still can't wrap my head around this. I can barely get in the right gear for each corner.
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Old 10-09-2015, 12:16 AM   #599
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A lot of this is how a driver feels a particular pad combo works for them. Some read a recommendation and run with it as if it's the only possible pad combo that works. I've heard diametrically opposed opinions from 2 different sources regarding particular pads. In the end, if a particular combo works well for you and the car feels balanced then that's fine.

Super large brakes are fine if your budget allows and as the hp increases so does the speed and you need larger brakes to dissapate the heat effectively.

It would be interesting to see some actual test data for stopping distances with stock systems vs the 11.75 kits.
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Old 10-09-2015, 12:21 AM   #600
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Quote:
Originally Posted by wannafbody View Post
It would be interesting to see some actual test data for stopping distances with stock systems vs the 11.75 kits.
How many stops are you going to do? Haha. The best proportioned of the stock setups with stockish grip will probably outperform a lot of the common track setups with stockish grip for a couple stops. Even stepping up to racing grip the best of the stock setups are going to stop better thank a large chunk of what HPDE bros run for a couple stops. But even the worse POS track bro setup you can come up with, like 11.75 from 1.6 rear with stock prop valve is going to outstop stock brakes at the end of a 20 session on the track.
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