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RomKnight
08-01-2016, 11:11
Anyone else tried the Bentley Speed8, BMW V12 LMR and the Audi R8(LMP900) cars?

These cars need brake duct fully open at all times as they seem to take long time to cool down (more than heating up too fast)

Can anyone else confirm?

On tracks like Zhuhai you can have the brakes at over 1000 easily. Even in Dubai GP it is easy to have them at 800+ in a couple of laps but if you keep at it they'll slowly rise the temps.

Adjusting the brake balance a bit rearwards will only mean the rears will lock up sooner.

N0body Of The Goat
08-01-2016, 11:42
The Formula Renault 3.5 is another car that goes against the grain, in that I now increase brake duct size from the default to ~60%, to try and counter how hot the brakes run.

RomKnight
08-01-2016, 11:49
I've not noticed that on the FR3.5

On the LMP900 class though, with the duct at 100% they still keep increasing the temps or better yet, they don't seem to cool enough IMO

Tastakrad
08-01-2016, 13:01
On Zuhai you can get the brakes of the LMP1 easily to over 1000C too. It is propably just the track, not the car itself.

RomKnight
08-01-2016, 13:06
it is not just on zhuhai.

bradleyland
08-01-2016, 13:06
I always assumed this was a limitation of the actual LMP900 cars of their day.

On a side note, does anyone know the maximum operating temperature for carbon ceramic brakes like the ones on the LMP900 cars? I used to go by color, but now I use Crew Chief v3. Jim just warns me when the brakes are getting hot and I back off my braking zones a bit.

hkraft300
08-01-2016, 14:35
Zhuhai is one of the hardest on brakes. Everything I've driven there need a lot of brake duct, usually >65%.
LMP900 have carbon brakes to me they're good at ~450-1050c range, same as other cars so equipped.
I havent noticed a brake overheating issue with them at all. At Road America my LMP900 brake ducts are ~30%, lower at tracks like Spa and Le Mans. Similar to LMP1, though I haven't run a telemetry app yet.

If they're not cooling fast enough, open the duct. If at 1-2 brake zones they hit 1000c+ momentarily I wouldn't see an issue with it, unless telemetry is showing aggressive brake wear because of it.

Edit: I love the LMP900 cars. Try them at Bathurst, Hockenheimring, Nur GP, Rouen short... Everywhere!

RomKnight
08-01-2016, 15:00
can you guys try on hotter days? :)

And try Dubai GP too, please.

And you guys keep say number on the 60% open duct i have to have them at 100% (which is why I find it weird to have such high temps)

Fanapryde
08-01-2016, 15:38
Can I chime in with Formula A too.
After 1 lap, sometimes sooner, Stig is telling me to cool the brakes. Looking at the PCars Dash I see brake temperatures way over 1000C (1272C was the max I saw).
I have opened duct to 100%.
First lap of the FA Championship in Zhuhai: after the first corner he starts shouting at me about brake temp. What does he expect me to do ? Pour water on them ?
Weird thing is that it's only the fronts, rear brakes are rarely over 400C (which is probably too cold), but changing brake bias makes the car too unstable under braking.

ARNAGEist
08-01-2016, 16:03
Newer cars than the LMP900's but this article from racecar engineering gives a good in-site to brake temps http://www.racecar-engineering.com/technology-explained/f1-2014-explained-brake-systems/
Especially this bit

“When we assess brake performance, we do so largely in terms of two parameters: bite and consistency. Bite is the initial friction experienced when the driver first presses the brake pedal and the brakes are not yet at the correct operating temperature. Consistency is a measure of how consistent the friction is for the duration of the braking period” Symonds adds. “Carbon-carbon brakes possess very particular properties. A carbon brake has relatively poor performance below about 400C and has optimum braking performance above 650C. Unfortunately, whereas conventional brakes wear down through the normal mechanism of wear that any frictional material experiences, a carbon brake not only suffers wear through this mechanism but also a process called oxidisation. Oxidisation is in simple terms a burning of the surface of the disc, and at temperatures above 600C it is accelerated and becomes the main mechanism of wear. Bearing in mind that during a braking event the temperatures of the brake discs will reach around 1200C, it can be seen that oxidisation is extremely significant in the brake wear process. On the straights of course, the brake ducts are feeding air to the brakes and so they drop below the oxidisation temperature but as they still maintain these high temperatures for a relatively long time, paradoxically the very air that is being used to cool them contains a high amount of oxygen that accelerates the wear process.”

bradleyland
08-01-2016, 16:10
I wonder though if PCars models the oxidization of CC brakes? AFAIK, there is no brake wear, only temperature.

Fanapryde
08-01-2016, 16:17
I wonder though if PCars models the oxidization of CC brakes? AFAIK, there is no brake wear, only temperature.
I have not paid much attention to it, but there is a brake wear indication in the PCars Dash...

RomKnight
08-01-2016, 17:16
There is wear, brake fade and you might also have to exchange discs IIRC. Unfortunately to test that you'll have to drive for hours... would be easier with driver swap :D

Thanks on the info about the carbon brakes.

Still, with 100% open and temps always 300C above those 650 you won't brake for long. Also, please keep in mind that my report was just in a couple of laps! Imagine 2 hours of this. At a point you won't be able to brake :D and even a clio would lap you while you wait for the discs to cool down :P

In any case this cars are not meant short stints which adds to my point.

hkraft300
08-01-2016, 21:45
can you guys try on hotter days? :)

And try Dubai GP too, please.

And you guys keep say number on the 60% open duct i have to have them at 100% (which is why I find it weird to have such high temps)

I'm usually at "race date", clear weather, 35c+ track temp. Even at Dubai my brakes I'm not having cooling issues. However...


Can I chime in with Formula A too.
After 1 lap, sometimes sooner, Stig is telling me to cool the brakes. Looking at the PCars Dash I see brake temperatures way over 1000C (1272C was the max I saw).
I have opened duct to 100%.
First lap of the FA Championship in Zhuhai: after the first corner he starts shouting at me about brake temp. What does he expect me to do ? Pour water on them ?
Weird thing is that it's only the fronts, rear brakes are rarely over 400C (which is probably too cold), but changing brake bias makes the car too unstable under braking.

What this is telling me: your brake bias is too far at the front. If your front brakes are at 1000c and rears are cold, means rear brakes are sleeping and the fronts doing all the work. Is this also the case with the guys in LMP900?
Push the bias towards rear to share the load, your front brake temps will drop so you can use a smaller brake duct for better top speed :)
My bias is anywhere between 60% to 56% on formula and LMP cars depending on track and setup. You do have to be careful braking to slower corners because if you lock the brakes the rear will swing on you ;)
But you get used to it. Zhuhai is a good place to practice low speed braking: remember to release the brakes a little as your speed drops below ~110mph/180kmh because your aero is starting to become less effective. You may want to dial back on the oversteer/turn-in response because the fronts will respond much better with less braking load on them.

A good way to cool the brakes in aero cars is if you let off the throttle for .5-1 second before every brake zone before you hit the stoppers. The cars decelerates from drag a little and there's less work for the brakes.

Fanapryde
08-01-2016, 22:08
What this is telling me: your brake bias is too far at the front. If your front brakes are at 1000c and rears are cold, means rear brakes are sleeping and the fronts doing all the work.
BB is at 65%, not an abnormal value I think ?

hkraft300
08-01-2016, 22:28
Can't say that's abnormal, but judging by your temps your fronts are stressed and your rears are twiddling their thumbs looking for something to do :)
You could try 60% bias, close your radiator a little and see how your lap time fares.
I feel the fronts are more responsive and experience less wear with more rear bias, also better speeds between corners. But its dependant on driving style.

Fanapryde
08-01-2016, 22:36
Can't say that's abnormal, but judging by your temps your fronts are stressed and your rears are twiddling their thumbs looking for something to do :)
You could try 60% bias, close your radiator a little and see how your lap time fares.
I feel the fronts are more responsive and experience less wear with more rear bias, also better speeds between corners. But its dependant on driving style.
Thanks, going to try tomorrow.

RomKnight
08-01-2016, 22:36
temps for me (especially on the Bentley) are on all brakes (i got those to 800s...) . I used TT for testing... I don't get it. On my side it would be impossible to make a 2h race on this cars.

Guess I'll have to find the time to test it... on next vacations :\

hkraft300
08-01-2016, 23:12
800 shouldn't be a problem.
Unless someone with telemetry can tell us otherwise.
The cars I struggle to work the brakes are group A

RomKnight
08-01-2016, 23:14
I wasn't clear... by those I mentioned the rears. The front brakes are much higher :)

hkraft300
08-01-2016, 23:19
Over 1100c I find them really hard to control, like they get sticky.
Some cars like the Aston DBR1-2 I'll push the brake bias to 60 to balance tyre temps, but with brake duct open enough to keep the front brakes below 1100 peak.
LMP900 I'm not having this issue.
Are you using ABS? Could that be why your brake temps rocket? Though I'd imagine you'd cook your tyres before you kill brakes. What is your brake pressure? Mine is usually ~85-87% on these cars. I'm not using ABS.

RomKnight
08-01-2016, 23:29
I drive with no assists but I can have that real so I tend to press my mapped keys to disable them. But I can't confirm if they got on by mistake... damn me if that's it :D

The brake pressure is whatever is the default and I did mess with the dial I have mapped (otherwise whatever is default when I get out of the pits).

I rarely lock the brakes (even braking very late - one of my strong points, seriously). The CSPv2 and now v3 pedals are really good for brake modulation and why I really recommend load cell ;) ABS is nigh useless for me.

hkraft300
08-01-2016, 23:37
I've used load cells years ago at a sim race centre running rfactor. They're excellent.
Anyway these cars have so much grip you don't need it.
At 100% brake duct and <60% bias if you're overheating them: that's not normal.
At least not from my experience with the cars in game.
Give me a few minutes to load up I'll post some numbers.

RomKnight
08-01-2016, 23:39
thanks. I won't be able to test until sunday again though. i'll verify the cache on steam too... just in case (been awhile)

hkraft300
09-01-2016, 00:48
So I thought I'd run some laps to check (any excuse will do ;) ). Race date, time 1400, clear weather with 10 laps of fuel at each track. Brake temps peaking ~1000c front momentarily once each lap. Rear brakes are within ~200c.

Audi R8
Zhuhai Pressure 83, balance 59, duct 80
Bathurst 82 58 35 (temp peak at turn 1)
Road America 84 59 30
Dubai GP 85 58 30

Speed 8
Zhuhai 85 59 65
Bathurst 90 56 10
Dubai GP 85 56 25
Road America 85 58 20

I also tried the Speed 8 with full fuel and same settings at Zhuhai and my temps did start to creep beyond 1100c, but that's at 65% duct. So I'm sure I can open up the duct and push the bias back a touch not be worried.

RomKnight
09-01-2016, 14:01
1st August 2015? If I recall correctly it was 37 on the track (don't remember ambient temp, but at least mid twenties for sure)

Anyway, you can do that with 65 brake duct... I have mine at 100% :(

Imagine me trying to cope with this if we can reach 30+C ambient and 40+C on track (here we race with real weather)

I'm screwed :)

Since I can't test ATM again, I'll just assume it is on my side. Maybe the setup didn't save but if the default is 60% open +5% wouldn't do much difference i think (never tested).

Thanks for testing mate. Appreciated.

hkraft300
09-01-2016, 14:17
^ I'm starting to think otherwise. Maybe its normal and not a bug.
Push the bias slightly forward from mine on a hot summer day and I can see it causing strife at Dubai and Zhuhai, but never really needing 100% duct.
Like I mentioned, maybe you need to push the bias back a touch (to closer match f/r brake temps) and use cooling techniques at some stage in the worst case scenario, during the hottest part of the day. Because if your temps are optimum peaking at 1000c once or twice during a hot afternoon and you can push, your brakes may get too cold at night.
I'll give it another go on some hot summer days and see how they fair.

N0body Of The Goat
09-01-2016, 14:48
I think part of the issue revolves around us not being able to set independent front and rear brake duct sizes.

Take the BMW M3 GT, which does not have ABS in real life. The default brake bias is 56% front, but especially at the moment, I'm feeling the need to push in forward at least 2% with an otherwise default setup, to reduce the risk of the back end stepping out uncontrollably.
Even at tracks with long straights like Spa, I find it quite risky to set the brake duct lower than ~42, otherwise the front brakes tend to exceed 600C and I start to notice brake fade.
With 56% brake bias, the front brakes are often ~100C or so hotter than the rear brakes, but with 58/59% bias and ~42 ducts the rears are rarely reaching 400+ Celsius and the fronts are still risking 600+.

What I'd like to be able to do is set ~45 brake duct for the front and ~38 for the rears i.e. a setting that keeps fronts and rears in their optimum temp window, while giving me stability if I trail brake into corners a little.

Fanapryde
09-01-2016, 16:34
Can't say that's abnormal, but judging by your temps your fronts are stressed and your rears are twiddling their thumbs looking for something to do :)
You could try 60% bias, close your radiator a little and see how your lap time fares.
I feel the fronts are more responsive and experience less wear with more rear bias, also better speeds between corners. But its dependant on driving style.
Did some testing, ending with brake bias lowered to 55% and radiator 100%. Stig kept shouting...

Something weird though: since a Windows update on thursday, my brake pedal did not feel like it should. I tried recalibrating in game and even fully pressed there was no visible input. Tried to recalibrate in the Fanatec software, but could not do it manual, had to go automatic. Deleted the Fanatec software and installed it again. Issues were gone.
But hete it comes: next FA race in Brno: my brakes barely reached 950C front and 600C rear, though I really tried to stress them. Stig never complained ... :confused:

Fanapryde
09-01-2016, 19:44
But !!!
Another FA race on Silverstone in rainy conditions, same settings as Brno (less downforce now).
Stig shouting again: fronts 1250, rear nearly 1000C... WTF !?
I think there is not much use trying to find a reason, there is clearly something wrong here...

hkraft300
09-01-2016, 20:46
Don't be offended, but are you opening the brake duct or engine cooling radiator?
Are you dragging the brakes at all?

Fanapryde
09-01-2016, 21:34
Don't be offended, but are you opening the brake duct or engine cooling radiator?
Are you dragging the brakes at all?
Brake duct 100% open,
Radiator is 85% (could close some more, since I barely get 73C water temp.
Not dragging the brakes. I tried all braking techniques I know of.
I just finished some more races and always brakes overheating (FA championship in career).
In Monza, first lap (warm up) in qualy: after the second chicane, Stig was allready there with his comment...
I mean...:mad:

hkraft300
10-01-2016, 02:26
Maybe inadvertently? See if the brakes are coming on in-game telemetry just in case, even if your foot is off it.
Monza is tough on brakes. I'll give it a go see how I fair.
Otherwise maybe its spot on: the FA struggles for brake cooling at some tracks in summer?
Though something is definitely amiss if brakes are roasting at a wet Silverstone...

Fanapryde
10-01-2016, 08:15
Maybe inadvertently? See if the brakes are coming on in-game telemetry just in case, even if your foot is off it.
Monza is tough on brakes. I'll give it a go see how I fair.
Otherwise maybe its spot on: the FA struggles for brake cooling at some tracks in summer?
Though something is definitely amiss if brakes are roasting at a wet Silverstone...
Correct thinking, but no. I can see that clearly on the PCars Dash, where it shows pedal input.
And to be 100% sure I even tried deliberately lifting my foot a bit away from the pedal.

While Brno also needs a fair part af braking, the temps were a lot lower.
Still a mystery to me...

hkraft300
10-01-2016, 10:17
Don't know mate. You're no noob to be making noob mistakes, so there's little I can offer.
What were the ambient temps? I haven't driven the FA for a long while, nor tested them. Brno isn't a track I often visit. I've yet to grab me a telemetry app to get my data jollies off lol



What I'd like to be able to do is set ~45 brake duct for the front and ~38 for the rears i.e. a setting that keeps fronts and rears in their optimum temp window, while giving me stability if I trail brake into corners a little.

I've noticed here this has been requested in the past. Do you think it'll make it to #2? I hope so.
LMP1 Aston can run the rear tyres hot purely from cornering and acceleration. At Le Mans in the Aston I'm getting >110c rears at the end of the lap but front brake temps are 250c+ hotter than the back. Got the bias forward to ease the workload of the rears. Lots of grunt y'see.
R8 at Road America doesn't get wayward with more rear brake bias but at 59% the temps are even, sometimes a little hotter at the back with a bit of lock here and there.
You may be right to have the forward bias in the M3, it'll stop in a shorter distance even if the rears are going cold. Though you must take in to factors like brake disc size (stopping power), cooling efficiency, tyre sizes, aero pressure front vs rear...
Data I'd like to see included in the car selection/garage menus in the sequel :)