Breaking Brakes

[TurnLeft]

Hi to you all, I recently came to the conclusion that I needed to understand more aspects of tuning that I more or less took for granted. I’ve been using the tuning guides of @Motor City Hami,
@praiano63, @DolHaus, and @Ridox2JZGTE, and all the info I could get my eyes on, but there were holes in using all these guides, at least for me. To fully understand all the components PD includes for tuning I would have to test them. So I decided to stop all tuning and start from the ground up. My current ongoing tests include, Steering Control Sensitivity, Tire grip comparison, Track grip comparison, Track top speeds ( used to adjust the transmission), wheels (inch up 1, inch up 2, standard), spring vs weight vs tires, and the subject of this thread - BRAKES.


My idea for tuning brakes was to find the maximum brake power before the wheels lock up and use that, so I tried putting the brake balance at 10/10, Comfort Hard tires and go full speed on a straight line and hit the brakes full, the results, no wheel lockup. Went to check on the data logger using wheel speed, vehicle speed, and brake, no sign of the wheels locking up.


I then had a conversation with Ridox, : ”Another thing is brake balance, in GT6, each car has predetermined brake bias hidden inside the car parameter. So, if you run 0/0 brake balance on standard brakes, the front tire usually will lock up first ( no ABS ). I often run higher rear to give the car best possible rotation under braking without causing oversteer. The best method to set your own brake balance is to not use ABS, find a short track to drive on, like Tsukuba, and start from 0/0 or 1/1, brake on 1st turn.Make a note of how the ca handle under braking, stable ? twitchy ? understeers ? Make adjustments to your liking.

Once you find a good value on no ABS, use ABS 1, and brake again with the same value. You will notice differences on some cars, with ABS 1 you often find you will want to increase the BB value a bit, and can run a bit more higher rear before the car over rotates under braking.”


So I went and tried the ABS:0.For the tests shown below I was using the NSX Type R’92, I’ve only done the tests with Standard brakes on Comfort Hard/Medium tires so far. I’m also doing the same tests with the RX500, Skyline GTR ’02, Civic Type R’08 and the Challenger R/T ’70, with the 6 different street tires available, but I haven’t finished those yet.


The method I used to determine when the wheels lockup is as follows:

1-Track: Indianapolis Motor Speedway, Brake balance 0/0

2-Manual Transmission set to 1st gear, after the start line and after the first curve , as soon as the road gets straight and that I’m at the max speed on 1st gear I hit the brakes using the square button on the PS3 controller and hold until my speed is at zero.

3-1st gear again, after the next curve, same procedure.

4-Still on the same straight, going to 2nd gear.

5-Still on the same straight, again on 2nd gear.

6-after the 3rd curve now up to 3rd gear.

7- after the 4th curve again at 3rd gear.

8-Cross the finish line and save.

9-Restart procedure using BB= 1/1, and so on.


Data logger

1- I check to see at what speed the vehicle is going when my front wheel gets to zero, (wheel lockup) , record the values

2-Same thing as above but with the rear wheel.


So far my opinion on brakes is it would seem to be better to do the tuning with the ABS0, to me it’s like tuning with Sports Soft or Race Soft tires, some of the characteristics of the car may be covered by the high grip of the tires, so I use less grip tires to tune. Likewise the ABS1 may be covering up the cars faults and you will not be able to see it. This is just my opinion, I’m far from the best tuners, and if I’m wrong I would be very grateful if one of you can enlighten me with your knowledge.

These are the results of the tests, on the CH - 4/4 and CM - 5/5 there was a slight irregularity which I can't explain. The wheels lockup was longer at the slowest speed, ???

These are the results from the CH tests in graph form.

These are the results from the CM tests in graph form.

These are the results from the CS tests in graph form.

These are the results from the SH tests in graph form.

These are the results from the SM tests in graph form.

These are the results from the SS tests in graph form.

Good day to you all, @TurnLeft

 

[Le_Manuz]

don't forget about suspensions, they have a big impact
when you brake, the weight shift to the front and reach the max pressure depending of their setup
would be good to correlate your data with the height
maybe it only starts locking at the front when you reach min height value on front
and start locking the rear when it's at the highest height

 

[TurnLeft]

don't forget about suspensions, they have a big impact
when you brake, the weight shift to the front and reach the max pressure depending of their setup
would be good to correlate your data with the height
maybe it only starts locking at the front when you reach min height value on front
and start locking the rear when it's at the highest height

Thats a good idea, I'll run the new tests and try to see if that is what's happening, I just wish they would give you the numbers like for the wheel speed, I checked on one of my saved laps and the car was at it's lowest height (around -20) at 102 kmh vehicle speed & 42 kmh wheel speed, the wheel lockup occurred at 91 kmh, the ride height was then, -17 or 18, hard to tell.

The tests I did were all on stock settings, when I'll have enough data I'll try changing the spring rate and dampers to see if the lockup can be reduced. Will probably have to test the camber and toe settings since the have an effect on the contact patch.

Thanks for the input.👍

 

[TurnLeft]

I’ve just updated the original post, finished the tests on all the street tires ( CH,CM,CS,SH,SM,SS ), also did a small test with the camber effect on brakes. There are a few irregularities in the test results, as I tune other cars I will update and compile the data. I’ve also done a small test with the abs at 1, and between abs0 vs abs1. I was going to test the effect of the spring rates, toe angle and dampers on the the brakes, but I’ve ran out of time, I’m going on vacation and I won’t be able to do any tests for a while.


These are the results between the different tire types and different braking balance adjustments, all done with abs0. The line indicates at what speed the Front/Rear wheels lockup and skid.

Here's a little test with the camber's effect on braking, I was going to do different Front and Rear settings but I ran out of time (and patience), Just look at the original and F/R =7 (front and rear set to 7) The difference is small, but there is one.

This is a test I did with abs1, the yellow line is with a brake balance of 10/10, and blue line is with a balance of 1/1, I was pretty close at braking at the same time, notice how much faster you stop with the 10/10 setting.

This test is with abs1 (yellow) and abs0 (blue), what I did was find the maximum values I could put on the abs0 before the wheels would lockup (values were 4/5) and use those with abs1 after. I was pretty close for the braking point, the abs1 has a slight advantage, but you can't give any more braking power to the abs0, while there is more room to increase the abs1 thus giving it more braking power and a shorter braking distance.

Personal opinion on brakes:

1) From now on I will always tune with the abs at 0, it’s easier to see if something is not working right, every change you make to the suspension is less attenuated then when you use abs1. (my opinion is always open to change if I see that this is not the best way)

2) Abs1 in theory will let you do faster laps, it is very hard to lockup the wheels with it, you can put much more braking pressure to the wheels and get shorter braking distances without having the tires heat up, thus giving you more grip on acceleration.

3) With abs0, if you tune your brakes to say SH, and you are one notch away from the wheel lockup threshold, putting any tire with lower grip will result with the wheels locking up, thus your window for different tires is much smaller than with abs1, the best thing when tuning the brakes for abs0 and getting the best braking power is to do it for one type of tire, it will work for the higher grip tires but you will not have the best results with those.

4) I am not a pro/con abs0 or abs1, both have got their qualities and defaults, abs0 demands more attention to the braking zones, mistakes are less forgiven but the satisfaction of controlling something a little more wild is more gratifying. Abs1 will let you get away with murder, you’ll make faster laps and enjoy a beautiful sunday drive on race track. (you’ll have time to read the side boards in the curves on the tracks)

5) On certain tracks where you don’t have to really brake hard, you can set the abs0 one notch over the lockup threshold to get a little more braking bite, the tracks that come to my mind are Suzuka East, Deep Forest, High Speed Ring, Cape Ring Inside.

6) The reason I chose to find where the wheels lockup is it gives me the maximum braking power I can load to the Front/Rear wheels, once you have this you adjust the balance to suit your driving needs. Because of weight distribution, weight transfer and suspension settings you will never get the front and rear wheels to lockup at the same value, at 5/5 the front is working more than the rear.

7) Lastly, remember that I’m not the best tuner, driver and by no means a brake expert, I don’t even know how to change them on my car, but I know how to open my door and put gas in it. These are just tests to see how brakes seem to work in GT6, thats all.

I haven’t done any test with racing tires or racing brakes, maybe when I’m able to drive my Toyota 7 with consistent lap times I’ll will make an update with those figures.


Just would like to say a little thank you to @Ridox2JZGTE 👍, thanks for sharing with me your precious time and knowledge on the matter, BTW, I’m now ready to continue my project with your NSX Type R’92, will give you some news soon, it’s your fault that it’s taking so much time, you should have never mentioned about abs0/abs1 settings on your post.
Have a great day every one, I'm leaving tomorrow for my much deserved vacation, but I will try to keep up using my i-pad when my wife is not looking. .
PS. when I come back I will try to analyze the MLSD with some testing.

 

[Ridox2JZGTE]

Wow, nicely done research and those graphs , @DolHaus, you may be interested to link this thread on your tuning guide ? This might also give more insight on ABS 0 tuning vs ABS 1 discussion on the FITT thread - mainly braking aspect of tuning.

 

[DolHaus]

Wow, nicely done research and those graphs , @DolHaus, you may be interested to link this thread on your tuning guide ? This might also give more insight on ABS 0 tuning vs ABS 1 discussion on the FITT thread - mainly braking aspect of tuning.

Agreed, very well done indeed.

@TurnLeft
I always liked the graphs and numbers approach but found it a bit bewildering, that section you've added about your opinions is absolute gold for making sense of it all 👍

I might work the personal opinions section into the OP and would be most grateful if you could repost this in the General Tuning Guide thread

Great work as always mate

 

[TurnLeft]

Agreed, very well done indeed.

@TurnLeft
I always liked the graphs and numbers approach but found it a bit bewildering, that section you've added about your opinions is absolute gold for making sense of it all 👍

I might work the personal opinions section into the OP and would be most grateful if you could repost this in the General Tuning Guide thread

Great work as always mate

Thanks for the comments, i would be happy to put it in the General Tuning Guide, just tell me what you want and what you want me to leave out. (I've got to go finish cutting the lawn and trim the hedge so I'll do this when I come back in according to your answer.)

 

[DolHaus]

Thanks for the comments, i would be happy to put it in the General Tuning Guide, just tell me what you want and what you want me to leave out. (I've got to go finish cutting the lawn and trim the hedge so I'll do this when I come back in according to your answer.)

Maybe the second post with the introduction from the first perhaps?

I might update the main guide soon so I'll copy and paste (with your permission of course) the parts of your findings that are most relevant to the guide.