F@#%@#g abs almost killed me

I have to disagree with you there. I don't care HOW good of a driver you are (And I have extensive experience driving all different kinds of vehicles, including long before ABS was even thought of in the US), but if you lose wheel traction due to a wheel locking up, no human being can pulsate the brakes as fast as an electronic ABS system can to maintain some semblance of control. Go ahead and try to pump your brakes 32 times or more in 1 second. Not going to happen. Try to manually control the precise amount of pressure on the brakes to maximize stopping, while keeping the wheels from locking up. Not going to happen. You are fooling yourself if you think you can do better.

ABS was not mandated "because of all the idiots who don't know what the hell they are doing". It was mandated for safety reasons because no human being can come even close to the preciseness and control that an ABS vehicle is capable of.

All of this being said, I DO agree that Toyota could use with some software enhancement to improve the response of their ABS system in the Tacoma. Obviously they can only do so much, especially with how light the rear end is. Light rear end=ABS activation is higher due to low traction. I am not saying that people don't know how to drive, or that people are not skilled drivers. Far from it. I AM saying that driving an ABS equipped truck, ESPECIALLY one that has been modified from stock in ANY way, is different than the same truck at 100% stock. Also as has been mentioned, traction is the key, so TIRES are very important.

 

What do you mean ABS is mandated ?

It is not a legally required system in North American passenger vehicles

 

In the United States, the NHTSA has frequently considered mandating anti-lock brakes on light vehicles, but has refrained as a result regarding concerns testing procedures and real-world crash data that failed to meet expectations.[23]


http://en.m.wikipedia.org/wiki/Anti-lock_braking_system#section_7


Light Vehicle Antilock Brake Systems (ABS) Performance Test Development
NHTSA's most recent notice on ABS, ANPRM; Deferral of Rulemaking (61 FR page 36698), announced that the Agency was deferring a decision to mandate antilock brake systems (ABS) for vehicles with a gross vehicle weight rating (GVWR) of 10,000 pounds or less. This was done because the real world crash avoidance performance of these systems appears to be below expectations. However, even though the Agency does not require ABS on light vehicles, light vehicle manufacturers are currently voluntarily equipping a large percentage (approximately 55 percent) of new light vehicles with ABS.



http://www.nhtsa.gov/Research/Light+Vehicle+Brake+Systems

 

I challenge you to find any professional driver in any sport, motorcycle to NASCAR, that will agree with you.

 

Correction: ABS is a program. It needs wheel sensors. This is THE component that feeds information to ABS, ESC, hill control, you name it.

So, you can have ESC without ABS.

 

I don't rub elbows with any pro racing drivers, so not gonna say one way or the other how they feel about it. but lets keep it to passenger vehicles shall we.

Obviously no human can pulse the brakes as fast as a computer, nobody is arguing that. But if I am in a panic stop and I decide that it's even an option to try and swerve, then let off the brakes! Sometimes there just isn't a damn thing you can do regardless of what systems you have equipped. I prefer to at least have full control and not let a computer decide i can't skid when i feel it's the appropriate action. My statements apply mostly to snowy and wet conditions. dry smooth pavement ABS can be ok.

I will agree the fact that its a truck with a light rear end is most likely the biggest reason it kicks in too early.

 

F1 banned ABS because it was too sucessfull. A very well calibrated ABS system will always be better than a pilot. It's simple to understand: it can control on a wheel basis and it pulses at much faster rate, it's like having 4 brakes pedals.

ABS helped them to make corners at faster speed than normal braking system.

Renault found a way to overcome ABS ban: they put a light in a dash to indicate how and when to brake. I don't know if it's still the case today.

 

None of this alters the fact that ABS increases stopping distances on loose traction surfaces

So , essentially, yes , I can stop in a shorter distance on snow without ABS than with it

Also F1 doesn't drive in snow and Renault no longer fields a factory team

 

I hate ABS, but only because all I ever had from age 16-39 was cars & trucks without it. I'm used to controlling the skid. When I'm approaching a stop sign in snowy / icy conditions, and the ABS won't let me skid .. or stop .. it freaks me out. But as other pointed out, the genius of ABS is it does allow you to STEER in such conditions. That's the big advantage. But not one I'm used to. I still prefer the skid .. it's what I know. Now that the truck's paid off, I'm going to do the ABS kill for local road winter driving.

 

Lets put it in another way: do you need to brake in order to "activate" ESC ?

ABS is indeed a system comprised of software and hardware but the only hardware needed to ABS to function properly is wheel sensors. The rest is software managed and it's not hard to build one. It's a algorithm that goes like this:

If beak pedal is pressed, then

If one or more wheels are locked up, then

Pulse brakes.

Of course, this is the most basic program, it has much more conditions than that ( vehicle speed, tolerance, time, wheel rotation, calibtation, etc ) but you get the idea.

So, for ESC to function, it needs at least three components: wheel sensors, steering position sensor and yaw-rate sensor ( Gyroscopic ). It doesn't use information from ABS system (I mean, the software itself), especially when you aren't braking. However, it get indeed same information as ABS system because of wheel sensors, that we often say "ABS sensors".

Did you see ABS applying brakes? It's the opposite... They need to co-exist in order to funtion properly.

Finally, take note that you can disable ABS without disabling ESP ( Jeep, they call it "ABS offroad" ).

Think about it: other than wheel sensors, what other information from ABS does ESC needs to function ?

Disclaimer: I'm a programmer.

 

I think you may be misunderstanding some of what it being meant by "mandated". At least with what I am trying to say. Though it is not directly mandated, if a vehicle IS equipped with ABS, federal law does state that you cannot modify it, remove it, or alter it from factory. So there is some mandate on ABS.

Yeah, I did forget to mention the independence of wheels.

You will not find a vehicle with ECS that does not have ABS. The ECS system needs the input from the ABS sensors, as well as the solenoids that the ABS system uses to properly modulate the control for ESC.

Some of your information is incorrect. An ABS system requires a LOT more than just wheel sensors and programming to work. It requires individual solenoids for each wheel, and a pump, as well as an accumulator. A lot more to it than just sensors and software.

It also does not operate at you are describing. It does not simply "pulsate" the brakes if a wheel is locked up. Depending on the wheel that is locked up, or approaching lockup, the system will reduce the allowable pressure to that individual wheel. I did mention pulsation earlier, but that is actually the older systems. Systems built around 1999 are modulated by pressure rather than pulsated. The pressure reduction applied to the individual wheel is lowered once that wheel is no longer in a "lockup" even, and nominal pressure is then maintained. If that wheel (or any other wheel) again reaches lockup or near lockup, the system again controls pressure to prevent or remove lockup at that/those wheel(s). The noise/vibration that you feel is the pump activating to allow more precise control of pressure since the ABS system has no actual control of the brake pedal itself. The pedal itself will move or fade down as the base pressure that you have applied on the brake pedal is spent. The pump allows the ABS system to continue to apply brake pressure as needed.

I am not 100% privy to the Toyota systems, but with GM, which is still the same basic design, even if your pedal goes all the way to the floor, the ABS system pump is quite capable of continuing to apply brake pressure to the wheels. The problem occurs when people push the pedal to the floor and panic, thinking that there is no more brake apply, and they let up off the brakes. Try it some time. Get yourself in a SAFE area like a parking lot, that is icy and slick. Floor the brake and just hold it. The pump will continue to maintain brake pressure, even if your brake pedal touches the floor.

Quick research shows this per Toyota:
"ABS operation: Based on signals received from the 4 wheel speed sensors, the skid control ECU calculates the speed and deceleration of each wheel, and checks for wheel slip conditions. The ECU controls the pressure holding valve and pressure reduction valve in order to adjust fluid pressure of each wheel cylinder according to the slipping conditions."

So while a human may be able to try their best at controlling all 4 wheels locking up/skidding/etc., They can NOT individually control a single wheel. What does this do? It helps you maintain control of your truck. So if just one wheel locks up, the system will still allow proper brake force to be applied to the other 3 wheels, so that you have maximum brake force, with maximum control.

How does this help? Lets say you are driving in the snow and ice and one of the wheels loses traction for whatever reason. Let's say the left rear wheel. The system will control the pressure to that wheel, as well as it's companion wheel, the right rear wheel. Why would it control the pressure to the right rear wheel? Because in order to maintain control, even lateral pressure needs to be applied for each axle. If the right rear wheel were to brake normally, and the left rear did not, the vehicle would tend to enter a slide towards the side with the greater braking force, and the rear of the truck would try to come around. This "balanced" control allows the vehicle to continue to travel in a controlled line, while still maximizing the brake force. No human can accomplish this with a single brake pedal. We would need 4 pedals, one for each wheel, and then 4 legs!

 

X2

 

On paper this sounds great and is exactly how a good ABS system is supposed to perform, however, the real world is that these trucks do not seem to perform in this manor. As evidenced by myself and many others here. What seems to happen is it senses a wheel begin to lockup and then seemingly takes away brake pressure from all wheels, even the fronts which are probably a ways off from locking up. And then you end up helpless just coasting forward hoping it will decide to stop you eventually.

This system could probably be good if it was tweaked enough, but there are obviously issues with it. Why some people can't recognize that and think it's dangerous to drive without ABS makes no sense to me. At least that's the way some have come across.

 

While I agree, and have agreed that there is an issue that needs to be resolved, the system does NOT remove all pressure from all wheels. If it did, it would have been subject to recall years ago.

 

these 'some people' are the very well educated scientists, physicists, and engineers who
build entire careers working in the automotive industry designing safety systems and regulations.

if you or anyone on these forums think they know how to do ABS better
then drop what you are doing and head over to Toyota they will pay
you big bucks to learn something new that the current engineering team
seems to be missing...something so totally obvious that a flea-bag internet
forum already has the answers which seem to elude Toyota product management team. lol

don't forget you must design a 'one size fits all' ABS system, you can't do one-offs based on
driver preference.

 

Can we all just agree that stopping distances on snow are reduced WITHOUT ABS

thanks

 

Lol. calm down big boy, I never said I wanted to re-engineer an ABS system. I'm talking specifically about people on this forum that freak out when someone asks how to disable ABS on the tacoma. I have been driving up to this point in my life with no accidents, all without ABS! its a miracle i know. the point is that on some cars ABS is done very well, this isn't one of them. So write all of the scientists, physicists and engineers a letter, cuz the Tacoma needs some tweaking.

 

yes

with no ABS at all [or no ABS activation] stopping distance is shorter in snow

 

ABS still sucks on these trucks.

 

Most driving is not done in snow/ice or sand it is on hard paved surface it that case ABS on any thing is superior. It does effect breaking in more unusual conditions however it gives your ability to steer sliding wheel do not. Is the ABS more sensitive on the Tacoma? Have you driven other 4X4 trucks and made scientific comparisons stopping distance etc. saying the Tacoma is too sensitive etc. is far to general. It is the best breaking truck in its class there is something to that. ABS pulsing the breaks is not what it is all about the pulsing is valuing not the application it is a very complex 4 channel breaking system that reads wheel speed, all 4 wheels and does it’s best to keep them all turning at the same speed, a tire that is sliding has no traction and no rotation so it is released until it matches the others speed while they take over it is not just simple algorithms and something that pumps the breaks and it does this very fast. Is it the best breaking system made? Doubtful but it is a damn good one.