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Anyone have any brake questions?

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Old 07-20-2015, 07:09 PM
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So brake sliders and lube. How do you guys make the stock calipers not stick? It seems every couple events my brakes start sticking and I have to pull them apart and clean the lube out of the sliders and put new stuff in. I'm using the purple synthetic ceramic stuff. Most times it gets so stuck in the rubber slider that I feel like I'm going to tear the thing trying to get it out and I have to work at it for 5-10 minutes.
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Old 07-21-2015, 11:21 AM
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I use high temp disc brake bearing grease off the shelf, myself. Never had an issue with it cooking.

"They say" higher grip pads put less heat into the calipers, fwiw.
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Old 07-21-2015, 03:13 PM
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I love this thread.

How do you reccomend measuring brake temps while out on track? Thermocouple tapped into brake caliper?

Is it worthwhile having this data displayed on a gauge to the driver?

Ta.
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Old 07-21-2015, 06:03 PM
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There are some (fairly inexpensive) stickers that are single use and will "display" the highest temp reached (they are non-reversible), just like these:

Amazon.com: ALC-THS0080X285 Alcon Caliper Temp Indicator Strip Kit: Automotive Amazon.com: ALC-THS0080X285 Alcon Caliper Temp Indicator Strip Kit: Automotive

No added value in having them displayed. Have used them to check if everything is OK in the first couple runs or if additional brake ducting is required.
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Old 07-21-2015, 06:49 PM
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Originally Posted by sixshooter
I use high temp disc brake bearing grease off the shelf, myself. Never had an issue with it cooking.

"They say" higher grip pads put less heat into the calipers, fwiw.
We probably use the same permatex stuff. I switched to HP+ mu is the highest I've seen on a pad that works from stone cold. Not like I really need that feature since I can get the wheel centers hot enough to instantly steam water.
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Old 07-21-2015, 06:58 PM
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Originally Posted by Leafy
We probably use the same permatex stuff. I switched to HP+ mu is the highest I've seen on a pad that works from stone cold. Not like I really need that feature since I can get the wheel centers hot enough to instantly steam water.
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Originally Posted by Mobius
Hopefully so, but let's hope it's never necessary. Experiencing your safety gear in action is ... not optimal.
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Old 07-21-2015, 07:00 PM
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Originally Posted by sparkybean
I love this thread.

How do you reccomend measuring brake temps while out on track? Thermocouple tapped into brake caliper?

Is it worthwhile having this data displayed on a gauge to the driver?

Ta.
three ways. a IR measuring device that reads into a data logger. just point it at the rotor. rotor paint, and caliper temp sticker. the caliper temp sticker is the only one that i use. it just lets me know if a caliper is worn and needs to be replaced. if your not melting stuff you really don't need to know how hot a rotor is getting.
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Originally Posted by Mobius
Hopefully so, but let's hope it's never necessary. Experiencing your safety gear in action is ... not optimal.
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Old 07-21-2015, 07:02 PM
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Originally Posted by OGRacing
#ConeLife
No kidding, on a car with power that also stops amazingly well, you can get a lot of heat into the brakes and then its got no where to go because you just stop driving almost immediately after wringing it out. I have some issues with brake fade at pros depending on the course.
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Old 07-21-2015, 07:46 PM
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You can use thermo paint, a K type thermocouple that rubs on the rotor, temp stickers on the calipers, thermocouple embeded into the pad, non contact sensor pointed at the rotor. There are many options, it is a matter of cost/convenience.

Paint/stickers are will tell you peak temps. This will allow you to make informed decisions and are probably the cheapest.

Sensors will give you data as to where you are generating the heat and help improve technique or identify issues with the brakes like pad drag causing heating.

If you have time to look at the brake temps whilst on the track then you have too much free time However a warning light when you have exceeded the pads temp range maybe worthwhile.

This product could be adapted to live monitor/log brake temps Opti-Grip however the sensor range is only 0-500 F. For a rotor you would need 0-1100 F.
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Old 07-21-2015, 07:47 PM
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Double post
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Old 07-23-2015, 08:49 AM
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I installed my TSE Gen2 11.75" BBK and M-Tuned rear BBK (sport rotors with non-sport 1.8 calipers spaced out) a few nights ago. I'm running Carbotech XP10 front and XP8 rear. It's 2400 lb (with driver), 225/45/15 Version 2 RS3 on 15x9's. I absolutely love the pedal feel. There's still the first 1/2" or so that is dead, just like every other passenger car I've driven, but after that it hits a brick wall and the pedal is much easier to modulate than the stock brakes. Is this first bit of dead pedal because of the booster? Or just compliance in the system?

My issue is that the input force for lock up is way way way too low. When the brakes are warm, I'd estimate a lock up force of around 25-30 lbs. I'm trying to weigh the differences between swapping a 1" master cylinder, or deleting the booster and swapping to a 3/4" master and increasing the pedal ratio. I really like the linear feel of a non-boosted system (I've driven FSAE cars for years) and I've never understood why there's only a few people on this forum that have deleted it. I also generally like high force inputs, so I'm not sure the ~25% increase in input force will be adequate from the 1" master.

Does anyone have experience with a similar setup, and deleting the booster?
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Old 07-23-2015, 12:01 PM
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Originally Posted by acedeuce802
Does anyone have experience with a similar setup, and deleting the booster?
An FSAE car weighs a quarter of what a Miata does. IMHO, non-boosted brakes don't belong on cars weighing over a ton and using disc brakes.

A 1" master swap from a 929 is easy and very effective.

--Ian
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Old 07-23-2015, 12:57 PM
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Originally Posted by codrus
An FSAE car weighs a quarter of what a Miata does. IMHO, non-boosted brakes don't belong on cars weighing over a ton and using disc brakes.

A 1" master swap from a 929 is easy and very effective.

--Ian
But they also have 7" rotors, and 1" caliper pistons (2 per caliper). Just trying to play devils advocate that the components are tuned for the size of the vehicle, and lockup force is the true back-to-back comparison, which can be matched with the Miata. I calculated my current setup at 23 lbs lockup force. I believe we design lockup on the FSAE car to be around 75 lbs, and some teams design to 100 or 125 lbs. 75 lb lockup can be acquired on my setup by deleting the booster, and increasing the pedal ratio to 5.5. If this is too stiff, than 55 lbs can be achieved by lowering the master bore to 3/4".
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Old 07-23-2015, 01:36 PM
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Default Anyone have any brake questions?

IMO, you have chosen a more aggressive compound than necessary for the street tire you are using, hence the easy lockup. You have much more leverage with the giant rotors now and may not need the high torque pads as much. Try something with less initial bite. Or switch to Hoosiers, lol.
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Old 07-23-2015, 06:44 PM
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Originally Posted by codrus
An FSAE car weighs a quarter of what a Miata does. IMHO, non-boosted brakes don't belong on cars weighing over a ton and using disc brakes.

A 1" master swap from a 929 is easy and very effective.

--Ian
Not really true, as long as everything is sized properly and you have your lever ratio correct you'll have no problems. However there's a reason most pro racecars now have assisted brakes, driver performance, its hard to brake consistently when your leg is tired an hour into the race.
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Old 07-30-2015, 12:04 PM
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Default Anyone have any brake questions?

2300lbs endurance car, 11" dynalite front, sport rear brakes, prop valve and abs delete, 205 r888 tires. What pad combo is gonna last us for 24 hours on a track that is heavy on the brakes, ie stop and go. Xp10/8 wouldn't have gotten to the end last year. Pagid yellows, pfc of any variety? Shoot
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Old 07-30-2015, 12:36 PM
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Originally Posted by Oscar
2300lbs endurance car, 11" dynalite front, sport rear brakes, prop valve and abs delete, 205 r888 tires. What pad combo is gonna last us for 24 hours on a track that is heavy on the brakes, ie stop and go. Xp10/8 wouldn't have gotten to the end last year. Pagid yellows, pfc of any variety? Shoot
Nothing. Best guess would be Raybestos ST43 but they suck to drive on a light car and chew rotors. We had our best luck with Carbotech RP2 followed closely by XP24. I think there is a PFC compound designed for stock cars that might be hard enough.

Cooling is key. Big (2.5"+), functional brake ducts aimed at the caliper. Also teaching your drivers to save brakes. That means a long lift before a slow initial line pressure rise, less than threshold deceleration and rolling off early into the turn. A skilled endurance driver can run less than 1.5s off qual pace and make the brakes last 2x as long. In the 25hrs, we always had tires to spare but wanted to save fuel and brakes. So, gentle corner entry, very fast through the turn, short shifting on the long straights.
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Old 07-30-2015, 04:07 PM
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Originally Posted by Oscar
2300lbs endurance car, 11" dynalite front, sport rear brakes, prop valve and abs delete, 205 r888 tires. What pad combo is gonna last us for 24 hours on a track that is heavy on the brakes, ie stop and go. Xp10/8 wouldn't have gotten to the end last year. Pagid yellows, pfc of any variety? Shoot
We've been using PFC 08s all around on our crapcan e30, didn't weight it but probably 2400lbs+, no ducting, 225 RS3s. Very impressed with the pad, I believe we got 3-4 lemons races out of them before we had to swap them, never had them fade.
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Old 07-31-2015, 08:30 AM
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<p>
Originally Posted by emilio700
Nothing. Best guess would be Raybestos ST43 but they suck to drive on a light car and chew rotors. We had our best luck with Carbotech RP2 followed closely by XP24. I think there is a PFC compound designed for stock cars that might be hard enough. Cooling is key. Big (2.5&quot;+), functional brake ducts aimed at the caliper. Also teaching your drivers to save brakes. That means a long lift before a slow initial line pressure rise, less than threshold deceleration and rolling off early into the turn. A skilled endurance driver can run less than 1.5s off qual pace and make the brakes last 2x as long. In the 25hrs, we always had tires to spare but wanted to save fuel and brakes. So, gentle corner entry, very fast through the turn, short shifting on the long straights.
</p><p>Thanks, sucks but thanks Car's always been good on tire life, 8+ hours on a single set of R-comps. Rain did help us last year but brakes were munched away. Car has TSE brakeducts installed and current test (gamble) is DTC60 up front with HT-10 in the rear.</p>
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Old 08-03-2015, 09:00 AM
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Originally Posted by Oscar
2300lbs endurance car, 11" dynalite front, sport rear brakes, prop valve and abs delete, 205 r888 tires. What pad combo is gonna last us for 24 hours on a track that is heavy on the brakes, ie stop and go. Xp10/8 wouldn't have gotten to the end last year. Pagid yellows, pfc of any variety? Shoot
the non endurance PFC 01 compound should give you twice the life of a set of carbotechs. The PFC 08's would last you two events, but those have been on Back order for a while now.


I really cant express how fast carbotechs burn up. The reason we don't see them in any pro race is the compounds won't last the 2 hour race. I've worked with track support shops that refused to sell PFC, simply because the carbotechs burn up quickly. that way they can make 2 sales instead of 1. that and carbotech gives a really deep discount to any track day shop.
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Originally Posted by Mobius
Hopefully so, but let's hope it's never necessary. Experiencing your safety gear in action is ... not optimal.
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