brake strength testing with results

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nomis3613

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Hi Folks,
I've done some testing on the effects of brake strength, thought I'd share the results in case someone was interested. All testing done offline with DS3 controller. Sure, some of it is repeating previous testing by others on here, but I thought it best to start by checking whether the basics still work the same. EDIT: Test methods are below.

First up is straight line braking. The cars are Opel Speedster Turbo, Volvo C30R and Ruf Yellow Bird, all running Sports Hard tyres.

braking_straight_line.png



Next question, is what happens in corners? So it's time for some circuit testing at Tsukuba (unfortunately the Yellow Bird needed some crazy toe and ballast settings to stop flying off the track backwards). Here are my comments on the handling while under brakes

Ruf 3400S on Sports Hard
0 / 0 slight understeer, car "flops" into understeer mid-corner if releasing brakes while turning (a chassis setup problem)
5 / 0 more understeer, but smoother transition into mid-corner grip
10 / 5 most understeer, shortest braking distance, fastest lap
0 / 5 less understeer, more "flop" after releasing brakes while turning

Volvo on Sports Hard
0 / 0 mild understeer
5 / 0 dulled turn-in under brakes
0 / 5 gentle slide of rear under brakes

Ruf Yellow Bird on Sports Soft
0 / 0 oversteer everywhere (not just under brakes)
5 / 0 less scary
0 / 5 rear slides very easily under brakes

Ruf 3400S on Racing Soft
0 / 0 stable, outside front scrubs and overheats if turning while braking
5 / 0 more understeer, requires greater steering angle to turn while braking
0 / 5 rear slides under brakes, but car "flops" into understeer after releasing brakes.

Hope this is food for thought, I'm keen to hear what you folks make of these results.

Straight Line Test procedure
1) in offline practice, go to High Speed Ring backwards
2) MT, ABS 1, tyre/fuel off, grip reduction real, damage off
3) tuning: 0 ballast, LSD initial <15, LSD braking 5, default suspension except camber 1.8 / 1.3, sports soft tyres
4) coast to whatever speed you like just before the start/finish line (I used 230km/h except for the Yellow Bird which used 250km/h)
5) brake as you cross the line (helps to have a ghost to check you're braking in the same spot each time), do not downshift while braking
6) write down the grid position where you come to a complete stop

Cornering Balance Test Procedure
1) in offline practice, choose a track you are very familiar with (I chose Tsukuba)
2) MT, ABS 1, all other aids off, tyre/fuel off, grip reduction real, damage off
3) tuning: 0 ballast (use as last resort if car very unbalanced), LSD initial <15, LSD accel <15, LSD braking 5, default suspension except tune camber ( <2 for sports tyres and <3 for race tyres), rear toe (-0.4 to 0.3) and springs to achieve neutral balance for baseline
4) run laps, paying careful attention to manouvrability/stability while braking, how the car responds to gentle dabs and the chassis response as you release the brakes.
 
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nomis - I have produced similar results in my straight line braking tests. There is defenately a difference between 8/10 and 4/6. Both provide a little bit of trail braking, but the higher set of numbers does seem to provide more stopping power.

That said, I haven't spent hours and hours fine tuning. Right now my brake settings are a little more gut feel. On 450PP tunes I'm finding that 7+ numbers are working. For 600PP tunes I'm closer to the middle. I should really test more around this, but I had a few 600+ PP cars lock up too easily with the super high number. Rarely am I below 4. I can think of only one tune, 400PP for Nurburgring that I went with lower settings. On the ring, I find that people tend to over-brake for the corners and lower settings made it easier to roll onto the brakes without slowing this low horsepower car too much.

I'm not sure about your corner testing posted above? I would be a bit concerned with any LSD tuning entering into your tests. Maybe no LSD customized or test with the 10/40/20 stock settings to get before and after results?
 
Why perform the first test if you're going to exclude the best result from the second test?

Seconded.:boggled:

I'm further confused because you did test 10/5 on the first car, and not only found worse handling, but still a better lap time, then seem to have thrown that aside and continued with other settings?
Is this because you determind maximum braking power would give the fastest laps regardless? Or....?
 
I have been testing, tuning and tweaking a GT500 GT-R for High Speed Ring all week long. Through one session today, I decided to toss the Brake Balance up to 10/10. Even on a track that only has 3 braking points, it still produced my best lap time to date. (56.295 Tire Wear off @ 625pp) Unfortunately, it made the car far too unpredictable under braking for me to confidently use it in any race with tire wear or extended laps. So, even though it gave me the best single lap time, I went back to my old setup for the 50 lapper we ran tonight. It is something to keep in mind for those who run with tire wear off though.
 
Why perform the first test if you're going to exclude the best result from the second test?
(I assume you mean "why didn't you test 10/10 when that produced the shortest stopping distance?", please correct me if I've misunderstood)
To start with, I should clarify that the point of this is to identify general trends with the brake settings, not to find the fastest brake strength for 3 random cars in 3 random states of tune.

So 0/0 was a baseline, then 5/0 and 0/5 to test the effect of bias, then 10/5 to compare against 5/0 to see what happens when the strength is increased (although I should have tested more to see whether it works on proportion or difference). Then I skipped 10/5 for the other cars because the change from 5/0 wasn't that exciting (ie similar handling and braking distances decreased as expected)



Motor City Hami, thanks heaps for sharing your thoughts.
There is defenately a difference between 8/10 and 4/6. Both provide a little bit of trail braking, but the higher set of numbers does seem to provide more stopping power.

...people tend to over-brake for the corners and lower settings made it easier to roll onto the brakes without slowing this low horsepower car too much.
Yeah, to me it feels like the higher numbers will pull you up slightly quicker, but you do lose some modulation, so gentle dabs to wash off a little speed end up with too much braking.

I'm not sure about your corner testing posted above? I would be a bit concerned with any LSD tuning entering into your tests. Maybe no LSD customized or test with the 10/40/20 stock settings to get before and after results?
Stock LSD still gives you very high values, I believe. I had decel minimised, accel to heat the inside slightly faster, and initial below 20. Personally, I don't think these LSD settings would skew any of the trends.


Is this because you determind maximum braking power would give the fastest laps regardless? Or....?
Nup, and I don't believe it necessarily would be fastest. If a high setting made the car unbalanced at corner entry it could be slower than a lower brake setting. See my first response for what I was hoping to achieve.

I have been testing, tuning and tweaking a GT500 GT-R for High Speed Ring all week long. Through one session today, I decided to toss the Brake Balance up to 10/10. Even on a track that only has 3 braking points, it still produced my best lap time to date. (56.295 Tire Wear off @ 625pp) Unfortunately, it made the car far too unpredictable under braking for me to confidently use it in any race with tire wear or extended laps. So, even though it gave me the best single lap time, I went back to my old setup for the 50 lapper we ran tonight. It is something to keep in mind for those who run with tire wear off though.
Thanks heaps for sharing. Just wondering, did you notice any more tyre wear with the brake strength maxed out? (for the record, I was keeping an eye on tyre heat during testing and didn't notice any changes between settings)
 
1: To start with, I should clarify that the point of this is to identify general trends with the brake settings, not to find the fastest brake strength for 3 random cars in 3 random states of tune.

So 0/0 was a baseline, then 5/0 and 0/5 to test the effect of bias, then 10/5 to compare against 5/0 to see what happens when the strength is increased (although I should have tested more to see whether it works on proportion or difference). Then I skipped 10/5 for the other cars because the change from 5/0 wasn't that exciting (ie similar handling and braking distances decreased as expected)

2: Thanks heaps for sharing. Just wondering, did you notice any more tyre wear with the brake strength maxed out? (for the record, I was keeping an eye on tyre heat during testing and didn't notice any changes between settings)

1: Personally, I felt the exclusion of a 10/10 test was a poor decision and I simply questioning why. If it produced the best stopping distances, you had to know that people would be interested in seeing how it translated into braking ability into a turn, or moreso around an entire circuit. Furthermore, even on your point, comparing 0/0 to 5/5, the next step is to also consider 10/10.

2: Actually, no. At least not directly. I ran 10 laps on each set of Race Softs at HSR. The very last set, I upped my Brake Bal to 10/10 because I had a comfortable lead. After 10 laps, my tires seemed to have just as much life as any of the other 10 lap cycles. So... While I don't think it increases tire wear directly, I believe the higher Brake Balance, causes the car to slide, jerk or twitch much more than with lower numbers, which would indirectly stress the tires more. It also leads to later braking points, less margins of error and increases the risk of driver mistakes. But to be fair, lots of settings come down to risk vs reward when we're talking about single lap times. I'd have to test on a track, that required more braking to try and magnify any potential issues.
 
1: Personally, I felt the exclusion of a 10/10 test was a poor decision and I simply questioning why. If it produced the best stopping distances, you had to know that people would be interested in seeing how it translated into braking ability into a turn, or moreso around an entire circuit. Furthermore, even on your point, comparing 0/0 to 5/5, the next step is to also consider 10/10.

2: Actually, no. At least not directly. I ran 10 laps on each set of Race Softs at HSR. The very last set, I upped my Brake Bal to 10/10 because I had a comfortable lead. After 10 laps, my tires seemed to have just as much life as any of the other 10 lap cycles. So... While I don't think it increases tire wear directly, I believe the higher Brake Balance, causes the car to slide, jerk or twitch much more than with lower numbers, which would indirectly stress the tires more. It also leads to later braking points, less margins of error and increases the risk of driver mistakes. But to be fair, lots of settings come down to risk vs reward when we're talking about single lap times. I'd have to test on a track, that required more braking to try and magnify any potential issues.
1: Fair enough. I guess everyone has different theories, so they are looking for different things in the results.
(this isn't meant to be defensive...just clarifying) I just did some tests that I thought would be interesting, then thought I'd share the results in case others found it useful

2: Yeah, I've had similar experiences with brakes only causing wear indirectly. I've never seen tyres overheat in straight line braking, but if the brake settings let you go harder on the steering, then you burn through tyres quicker.
 
nomis - I applaud your efforts. You are one of the few people in the tuning forum who will actually do a test and post your findings. There are so many around here with firm beliefs and no evidence to back things up.

Did you buy the new testing course? My brake testing in the past was on the Top Gear track. Too bad there isn't an actual brake test in the test course.

Are you planning more testing around this subject? What more is the community looking to learn? My questions about braking are these:

1.) What settings produce shorter straight line stopping distances?
2.) Are there any negative affects of shorter distance settings?
3.) Can brake balance affect handling balance during turn-in? If so, what settings produce a more stable condition and which produce more trail braking turn-in?

I think I am effectively finding a propper balance in my tunes for corner entry, but I still question whether my settings should be really high (8/10) or somewhere in the middle (4/6) on differing types of vehicles. Maybe post a suggestion for a standard way to test and the format (most of what you have in your OP) and other interested tuners can post their results as well. I'm interested and can post some testing on different cars.
 
Hami, thanks for the kind words. Not sure where I'll go next, but one day I'd like to get around to looking into whether balance is determined by the ratio (ie front 50% stronger) or difference (front 2 clicks higher). And looking at the effects of camber on braking.

Test Course?? What Test Course?? *googles it* Wow, yes, gotta get that, thanks for pointing it out. My dodgy hack with a custom track to measure acceleration did the trick, but this will be much easier. Yes, a brake test would be the icing on the cake.

For choosing how high to go with the settings, I find it helpful to turn off ABS and see what brake strength will lock the wheels.

Good idea about posting the method so hopefully others can add their own results. I'll add it to the OP.

Cheers,
Simon
 
I have mine set to 4/4 on all my cars, but then again I have ABS set at 4 aswell. I tend to brake very late and very hard. It's a very good setup I think for my aggressive driving style.
 
so are we saying some cars putting higher values (e.g >5) is better? or only for some cars? I was debating putting my cars 8 8 but then i saw all the tuners seem to have lower values and i thought what do i know:sly::indiff:
 
so are we saying some cars putting higher values (e.g >5) is better? or only for some cars? I was debating putting my cars 8 8 but then i saw all the tuners seem to have lower values and i thought what do i know:sly::indiff:

I don't think we have solved it. More testing like Nomis is doing is needed. In the past I have used brake balance just to balance the car during turn-in and for good trail braking. My settings have stayed around the middle simply because I haven't done much testing beyond building a split front/rear. The few cars that I have tested have been lower PP cars on sport tires. On these, really high settings produced shorter stopping distances. Now that I am playing with this on other cars, I am finding that high settings on really fast cars can indeed create brake lock up, even with ABS 1.
 
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