Disabled the driving aids. Here are my impressions.

[diss7]

Originally Posted by bestwheelbase

What's the story about the damaged car in post 181?

I was trying to troll. Wanted all the pansies to think I'd written the car off because I didnt have the aids on.

But the owner of the car chimed in and ruined my efforts.

[Seattle944t]

Originally Posted by diss7

This may come as a surprse to you, guy; but I'm not here to prove anything to you. Just because I can't provide the information YOU need to believe something, does not make it untrue.

I started this thread to provide my feedback/impressions of what removing the aids achieve.

If you need more data to satisfy your own doubts, I've stated numerous times how you can do it.

If you can't, thats fine. But it doesn't then become my responsibility to provide this for you.

When you start making up stuff about how you think ABS works and present it as fact, it is in fact your responsibility to provide the proof.

ABS doesn't use a G force sensor. It's not in any of the tech docs. Think about it, why on earth would a manufacturer add an unnecessary complication to the system? What possible purpose would there be for adding a G sensor to the ABS? Oh nos, this person is stopping too fast! They might, uh... stop. Why add extra sensors, design work, debugging, and testing at a significant cost to prevent something that isn't a problem and is actually a better result?

It doesn't even work how you think the speed sensors work. If there was a max deceleration rate from the wheel sensor it would be impossible to lock up all the wheels as a user has posted in this thread. The Max decel rate on the speed sensor would kick in, yet somehow you blame his better track rubber being at fault because it's being used on the street and not up to temp so the traction is lower. Which still violates your wheel speed sensor max rate theory.

The sensors are based on wheel speeds relative to each other, and there is a max rate percentage that any wheel can decelerate *relative* to the other sensors. So if you can get all the tires to lose traction at the same rate you can fool the ABS to think you are stopped, but in reality you have just locked up all four wheels. This is exceedingly easy to do with R-Compound tires in snow for example.

EDIT: After posting this, I realize that that since the VSC uses the ABS system, and the VSC is using yaw and G sensors the ABS system is technically using the G sensor. But it is not using the G sensor to detect lockup - it's using it to detect (and correct/prevent) spins as part of the VSC.

I even found a nice Subaru article about their ABS system that explains exactly what I stated above (to fulfill my burden of proof):
http://drive2.subaru.com/Fall04_WhatsInside.htm And it is a Subaru ABS system on the FR-S.

At the heart of ABS is an electronic control unit (ECU) – a small computer. It determines when the brake of one or more of the four wheels is about to lock up based on input from wheel-speed sensors and other sensors.

Wheel-speed sensors measure the rotational speeds of the wheels, and the ECU calculates potential lock-up under braking by comparing those speeds.

[Byebye]

Originally Posted by diss7

Interesting results. I would rate the V710 over the tyre I am using (123s) so would've expected similar findings to what I have experienced.

Edit - It would be interested to hear your feedback from first removing the abs fuse, and finding your new braking points / lockup points, and then reinstalling the fuse and seeing if these points are the same. I don't blieve they will be.

I think you are right. If the ecu is determine g-force through deceleration what is happening when you have wider stockier tires? You are in fact decelerating faster which in turn the ecu is not applying abs because of slip. It's doing it because of rapid deceleration.

[Rayme]

Originally Posted by Byebye

If that's the case than you could test that by leaving the vsc on and over steering the car. If what you are saying is true you should be able to drift all day.

But again does turning of vsc disabled ebd?

If you pulled the ABS fuse you can't test anything, the ABS modulator has no power to activate the brakes by computer command, so no EBD or VSC.

Originally Posted by Byebye

The ecu uses deceleration to calculate g-force.

The car has a G sensor, no need to read the wheel speed.

[bestwheelbase]

Originally Posted by diss7

This may come as a surprse to you, guy; but I'm not here to prove anything to you. Just because I can't provide the information YOU need to believe something, does not make it untrue.

If you need more data to satisfy your own doubts, I've stated numerous times how you can do it.

If you can't, thats fine. But it doesn't then become my responsibility to provide this for you.

Let's get this out of the way. The above quote is textbook argumentum ad ignorantiam. Argument from ignorance. People use it in an attempt to shift the burden of proof. It's a logical fallacy.

"The claim that whatever has not been proved false must be true, and vice versa (e.g., There is no compelling evidence that UFOs are not visiting the Earth; therefore UFOs exist — and there is intelligent life elsewhere in the Universe. Or: There may be seventy kazillion other worlds, but not one is known to have the moral advancement of the Earth, so we’re still central to the Universe.) This impatience with ambiguity can be criticized in the phrase: absence of evidence is not evidence of absence."

-from The Demon-Haunted World by Carl Sagan.

Alright, moving on...

diss, mate, your two points (one, that the brakes do not function properly if EBFD is unplugged, and two, that ABS is triggered by G-forces) contradict everything we know about these systems. The conversation you had with a racer may not even apply to the road-going 86. It is common for race cars to use different ABS systems, with adjustable parameters, or not use ABS at all.

When we question you, it is not a personal attack.

[diss7]

The TR86 is a race car, that Toyota Racing NZ build up from an RC spec, which is a road going version.

The rest of your post, I agree with.

[bestwheelbase]

Originally Posted by diss7

The TR86 is a race car, that Toyota Racing NZ build up from an RC spec, which is a road going version.

The rest of your post, I agree with.

Built from road car does not necessarily mean it retains standard ABS.

[Byebye]

Originally Posted by Rayme

If you pulled the ABS fuse you can't test anything, the ABS modulator has no power to activate the brakes by computer command, so no EBD or VSC.



The car has a G sensor, no need to read the wheel speed.

Yeah the "g" sensor is the yaw sensor but the car still can calculate g force through deceleration. The car needs to know wheel speed for ebd to work. Like I said above steering angle, yaw, wheel speed for ebd to work properly. Pulling the abs fuse can't disable all those sensors.

And the claim is pulling the abs fuse disables abs which in turns disables vsc and ebd. I don't believe this but I still haven't fully understood how they all integrate with each other.

[Byebye]

Originally Posted by diss7

Yes, I pulled the ABS fuse. Why?

I'm no longer in fear of the car deciding to do somethig on my behalf that I don't want it to do.

I've never owned a car with so many driving aids, and this would be one of the least powerful cars with with the most mechanical grip I've owned.

I used to always feel my car do weird things. After reading up on all the querks it has; namely ebd, auto lsd, ice mode. It's assumed pedal dance turns most of these off but no one seems to know for sure. It's all bullshit in the most part. I have traction control, the accelerator. I have ABS/EBD/stability, the brakes and the steering wheel.

My car brakes much harder now. I have bigger brakes and good street tyres or semi slicks. Where as before it would engage abs, now I can break much harder. Obvioulsy it will get to a point now where it will lock up, but let me tell you it's well beyond the point where abs used to jump in.

When I have skidders on, and go drifting, the car is better. Where as before with the aids off/pedal dance, it would still get involved if you reached big angle or did a quick switch, it doesn't now.

On canyon/hills, it's also much better. Coming out of corners, where one wheel might unload, it used to apply the brake to the inside rear tyre. I believe this is its auto LSD. I don't need this, I have a 2way. Car seems to fire out of corners in these situations now.

Commuting to and from work, this is where I'd like to have the aids on. This is when I'm probably paying the least attention, on the phone, kid might run out etc. what id like to do is get a switch made up that just activates or deactivates this abs fuse.

In short I feel much safer driving the car aggressively without any aids. It now reacts how you would expect it to.

If you've owned a turbo silvia or another lightweight rwd car that didn't have aids, you'll enjoy your 86 much more with this fuse pulled.

If you're reading this thinking I'm a mad ****; and you feel you need the aids to enjoy the car, that's fine. I feel a little bad for you though.

I'm actually all for these types of aids if its what they need to put in a good car to make it safe for some. As long as they're easily disabled, which in this case I am only certain of when pulling the fuse.

Just to go back to the op - by pulling the abs fuse you have essentially disabled abs and ebd. I don't know about auto Las but sounds to me like you were experiencing ebd.

The driving school I went to had an abs toggle switch mount on the dash. I don't see how difficult it would be to put something like that in.

When I auto crossed I ran with all aids on then with vsc sport then all off and my times got much faster.

Do you think ebd is still active when vsc is disabled?

[dodj]

Originally Posted by Rayme

The car has a G sensor, no need to read the wheel speed.

How would it determine which wheel is loosing traction/locking up etc without wheel sensors?

If for example you hit an ice patch and pressed the brakes, your wheels would lock up WAY before any G limit was approached.

Wheels sensors could work without a G sensor but not the other way around.

[Rayme]

Originally Posted by dodj

How would it determine which wheel is loosing traction/locking up etc without wheel sensors?

If for example you hit an ice patch and pressed the brakes, your wheels would lock up WAY before any G limit was approached.

Wheels sensors could work without a G sensor but not the other way around.

The abs use the wheel sensors to work obviously. I was talking about the VSC, it has its own g sensor - no need to use the wheel speed to "calculate G's". Completely inaccurate way to calulate the G's since when they lock their rotation is basicly zero.

[Rayme]

Originally Posted by Byebye

Yeah the "g" sensor is the yaw sensor but the car still can calculate g force through deceleration. The car needs to know wheel speed for ebd to work. Like I said above steering angle, yaw, wheel speed for ebd to work properly. Pulling the abs fuse can't disable all those sensors.

And the claim is pulling the abs fuse disables abs which in turns disables vsc and ebd. I don't believe this but I still haven't fully understood how they all integrate with each other.

You need to better understand how the system works.

VSC is vehicle stability control, it's pretty much the sum of EBD, ABS and TC working together. Various computers calculating input and working together. It's a bit more complex(I'm not saying I know everythign) but this isn't really the point I'm trying to make.

The system has inputs:
- Throttle/pedal position
- Yaw/G-sensors
- Vehicle speed
- Individual wheels speed
- Steering angle
- Current gear
- Brake application
- Etc.

It has very few outputs though:

- Throttle control, which is just the computer overriding the pedal position sensor
- Braking via the ABS pump

Needless to say, if you disable the ABS pump, you have no more computer operated braking (only manual), so yes, removing the ABS fuses pretty much cancel EBD and ABS and VSC.

[bestwheelbase]

I asked Toyota. Here is what they said.

About ABS:

"The anti-lock brake system uses wheel speed sensors."

And about EBD:

"EBD is the precursor to ABS, where brake pressure is reduced at wheels that are carrying the least amount of weight (i.e., the rear wheels during hard braking, when weight shifts forward) to prevent a skid. EBD uses the same actuator and wheel-speed sensors as ABS, but EBD only needs to detect subtle differences in wheel speed before it reduces brake pressure on a lightly loaded wheel (or wheels)."

And about VSC:

"VSC interprets data from a steering wheel position sensor and the ABS wheel-speed sensors to determine if the vehicle is following the driver’s intended path. If the vehicle is deviating from the direction in which the driver is steering, VSC is designed to reduce engine power and pulse the left- or rightside brakes to help correct the situation."

And about BA:

"In an emergency stop, Brake Assist acts as your copilot. If it recognizes that you’ve suddenly hit the brake pedal very hard, but not quite hard enough for full stopping power, it increases the fluid pressure into the braking system, helping to provide maximum stopping power."

[Bonburner]

call me evil minded but i dont like all these aids .. i got this car for its purity .. not all this annoying hassle .. and im disapointed how long the "disable" buttons take to "turn on" not to mention how it doesnt really turn them off ..

for what its worth this worlds needs natural selection to come back anyways ... :x