Need some education on brakes please

TURBO2GO

TURBO2GO

Illustrious Member
Joined
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So I have some questions regarding braking, bias, and bias adjusters.

I seem to catch a lot of cars in braking zones. I close a lot of gaps. I am pretty much at the limit because I keep pushing until I activate the ABS then I back off a hair. Now I am using aftermarket brakes, pads, and tire. That seems like it would change a lot of what you need for the best bias and the shortest distance. So why don't more people use these? A separate valve for front and rear and a SPA dual gauge with exact percentage shows seems like it would make adjustment and fine tuning easy. And it would shorten your distances. I remember having an older maxima that on several tests had braking distances second only to a Corvette and the second shortest distance Road and Track had tested. The tires weren't that special but I remember them mentioning that front and rear balance was spot on.

Do the ABS systems naturally redistribute the force? Are the adjusters more for a system without ABS?

And on an unrelated note, is there a way to permanently turn off TCS? It is nothing but a PITA, a lot of times I forget then I am going around a corner and see that I have no power and there is that yellow light flashing again. I am always taking my hands off the wheel to turn the thing off on the next straight.

Thanks in advance

DG205z.jpg
 
TURBO2GO said:
So I have some questions regarding braking, bias, and bias adjusters.

I seem to catch a lot of cars in braking zones. I close a lot of gaps. I am pretty much at the limit because I keep pushing until I activate the ABS then I back off a hair. Now I am using aftermarket brakes, pads, and tire. That seems like it would change a lot of what you need for the best bias and the shortest distance. So why don't more people use these? A separate valve for front and rear and a SPA dual gauge with exact percentage shows seems like it would make adjustment and fine tuning easy. And it would shorten your distances. I remember having an older maxima that on several tests had braking distances second only to a Corvette and the second shortest distance Road and Track had tested. The tires weren't that special but I remember them mentioning that front and rear balance was spot on.

Do the ABS systems naturally redistribute the force? Are the adjusters more for a system without ABS?

And on an unrelated note, is there a way to permanently turn off TCS? It is nothing but a PITA, a lot of times I forget then I am going around a corner and see that I have no power and there is that yellow light flashing again. I am always taking my hands off the wheel to turn the thing off on the next straight.

Thanks in advance
Click to expand...

Dave theory vs reality. You would spend an awful lot of time and money to make minimal improvements.

If you REALLY want to run faster times in your NSX go out and buy a beater and run that at 10/10ths for a year. You will learn more driving a car that is "disposable" as hard as you can than turning 8/10th, 8.2/10th, 8.3/10ths, etc in the NSX.
 
Really? you think it would be that minimal?

What if the bias is off by 10-15% from ideal? Cost is pretty low Jim.
 
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The problem with the NSX is the left front and right rear are on one line and the other two are on the other which means you need two bias valves. So not only do you have to adjust front and rear but sync the two valves so left and right are even. My understanding is it's a whole lot of trouble for minimal gain. You are better off playing with different brake pads front and rear to get a bias you like.
 
How on earth does the ABS work when the lines are in an X pattern?
 
I always thought MOST cars use diagonally linked brake systems. It is definately NOT unique to the NSX.

That said, the ABS works because it reduces the brake line pressure at the wheels, not in the brake lines.
 
So in a way ABS redistributes the force to each wheel? This process is what I am confused about.
 
I think ABS just reduces brake pressure for the wheel it senses is locking (rotating at a certain speed less than the other wheels)
 
TURBO2GO said:
So I have some questions regarding braking, bias, and bias adjusters.

So why don't more people use these?
Click to expand...

I would have to guess that the average hobbyist isn't really precise enough to be worth the investment, and more importantly the distraction of fiddling with the bias. Street cars don't have telemetry showing real-time brake rotor temperatures), relying on split and lap times to see if changes are effective. So, really dialing it in (as might be possible with something very high-tech like an F1 car) would prove difficult if not impossible for most people, given the constantly changing dynamics of road temperature, surface condition, fuel level, coefficient of grip of the tires as they age (even within one session or race), etc. Getting it "close", leveraging designed-in bias, tire pressures, and pad compounds is probably "good enough" for the vast majority of hobbyists. Now, for competition, those near the front of fields, maybe their cars and their feet are indeed good enough.

I also agree with the Captain that, comparing to other items like maximizing apex speeds, line, and acceleration exiting corners, those items provide a much greater benefit to lap times than being able to brake a few feet deeper. Not to say that precious 10ths can't be gained with braking, but for most of us, we already leave enough "out there" such that maximizing braking is lower on our priority list.

Here's another thing to consider: it's another variable, another thing to screw up if an adjustment is made in the wrong direction or at the wrong time.
 
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As dquarasr2 said conditions are going to change more often than your ability to adjust for them, the bias on an F1 car is changed by the driver corner to corner on the track. A street car will never be svelt or taut enough to utilize that granular of adjustments.
Id imagine the biggest real world benefit you could see would be to have a 'wet track' and a 'dry track' option; Wet track having about 15-20% more rear bias than dry.

by the looks of that dali kit its more of a 'set it and forget it' solution to upgraded caliper volumes and less of a adjust on the fly set up. Sure you could probably make it work but thats a lot of stopping pitting changing bias, stopping pitting changing bias just to dial it in for a moving target of temps and conditions. If you have aero it gets exponentially more complicated. I even removed ABS to even farther simplify the equation.

Personally, when it comes to brakes I like to know what they are going to do, and do ONLY that specific thing 100% of the time. Even if it were not ideal i would rather learn to go fast in spite of something over being stuck with information paralysis.
I say learn the system, change pad compounds F/R and get quicker.

fucking with anything at the track takes away from the fun and the seat time. You cant try new things with your driving if your always changing the common denominator in the pits.

Do you data log every session you run currently?
 
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dquarasr2 said:
I also agree with the Captain that, comparing to other items like maximizing apex speeds, line, and acceleration exiting corners, those items provide a much greater benefit to lap times than being able to brake a few feet deeper. Not to say that precious 10ths can't be gained with braking, but for most of us, we already leave enough "out there" such that maximizing braking is lower on our priority list.
Click to expand...

illwillem said:
Do you data log every session you run currently?
Click to expand...

I agree with what everyone has already stated here. Quit messing with your car and work on all the free improvements to your skill before adding another variable. Data logging will definitely help. Shoot, Harry's Laptimer & a GoPro camera will even be a great start.

As for the TCS.. get yourself a set of Post-It notes and write on it. "REMEMBER TO TURN OFF TCS BEFORE YOU LEAVE THE PIT!", and put it on the steering wheel.

- - - Updated - - -

Here's a nice little article in the NSX Wiki if the Post It method doesn't work:
http://www.nsxprime.com/wiki/Disable_TCS_ALB
 
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I have a smart TCS that automagically, through ROM, remembers the last state of the TCS computer. When I fire the car up it flashes the TCS light to remind me that its off. If I left it ON before I shut off the car it will be on when i get back in to drive. Ever since I installed it ive never had the TCS back ON and was actually thinking about gutting the system all together.

you can unplug the TCS ecu just behind the drivers seat or splice an in-line breaker switch to the power wire of the unit. It wont be as fancy but will effectively eliminate you having to do it everytime
 
Can the ABS reduce force per wheel on impending lockup? And if that is so, isn't it then sort of adjusting brake pressure on the fly? If the fronts or rears or front right and left rear or any combination are near lockup and the ABS computer reduces pressure to those wheels only and keeps the others at full pressure, isn't it then basically adjusting the bias per wheel on the fly?
 
I think your car has the 2nd generation modern 4-channel ABS system while the Pre (2000?) cars have an archaic, terrible 2-channel system. Your ABS system is very good and modulates/pulsates the line pressure to each individual wheel as needed to prevent lockup.

Ideally you want your bias to be correct and have the ABS modulate as needed rather than being overworked by constantly adjusting for an improper brake setup. I forget, do you have a 4 or 2 wheel ST BBK? Either way, I wouldn't mess with it. From where you're at now, the only way to really improve your braking performance is to ditch the entire setup, go to a non-boosted twin master cylinder setup with a proper bias adjuster, remove ABS (and be perfect with your applications) or going with a $10-15K programmable race abs system.
 
I agree with the others..at some point you spend too much time chasing small theoretical hardware issues when all you need is more attention to the fleshy software that drives the car.My suggestion for next season is no more messing with car and just hire a good coach.
 
docjohn said:
I agree with the others..at some point you spend too much time chasing small theoretical hardware issues when all you need is more attention to the fleshy software that drives the car.My suggestion for next season is no more messing with car and just hire a good coach.
Click to expand...

Amen!
Start recording and posting your sessions. You'll get plenty of free coaching from us.
 
docjohn said:
I agree with the others..at some point you spend too much time chasing small theoretical hardware issues when all you need is more attention to the fleshy software that drives the car.My suggestion for next season is no more messing with car and just hire a good coach.
Click to expand...

Dave is only telling half the story. He went and bought more "hardware". He asked me not to tell, and I won't, but I think it's ridiculous for him to lead people off on these theoretical tangents and then on top off it to only tell half the story.
 
I would have thought that shiny new orange racing suit would have helped with the brake bias. ;)
 
CL65 Captain said:
If you REALLY want to run faster times in your NSX go out and buy a beater and run that at 10/10ths for a year. You will learn more driving a car that is "disposable" as hard as you can than turning 8/10th, 8.2/10th, 8.3/10ths, etc in the NSX.
Click to expand...

I think this is the best advise here. I wish more people tracked the NSX did but for strictly a time improvement to dollar ratio; its the cheapest and most sure fire way to get your NSX to go faster.
 
My post is more to learn than to get advice on going faster. I like knowing how things work. I wanted to understand bias and abs systems better.

It sounds like with a 4 channel ABS you are in fact adjusting bias on the fly in a rather crude manner. But certainly it is better than a system with poor bias without abs. Essentially, the fine tuning of bias matters more on a 2 channel system on the older NSX and on cars without ABS. This is the info I was looking for. I suppose even adjusting the bias on a car with any sort of ABS is problematic. You can't quiet lock up to see where you need to back off and which wheel.

Billy you mentioned dual master cylinder. Why do race cars use that? Is it a pressure thing or is it for more control? What is each master cylinder doing is what I am asking.
 
Billy it's not prop valves. I didn't want to say anything yet but I am considering a ceramic brake system. Ive somewhat commited to one. Nonetheless that isn't why I asked this question as I said I want to learn about how brake biasing and ABS systems work.
 
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Dave, my apologies. You are trying to learn how the NSX's ABS system works and I can't fault you for that.

However, what many on here (including Billy) have alluded to is that the "perfect brake balance" is a fight that isn't worth fighting. In the theory vs reality equation - the reality is there is very little to gain for an awful lot of wasted brain power and money.
 

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