This a non-trivial project. You'd save time and money trading your car in for one that has ABS. As a DIY project, you've basically got to find a donor car with ABS (same year preferably) - pull all the wheel speed sensors (assuming they are still in good shape), sensor rotors, ABS actuator, ABS master cylinder, proportioning valve, all electrical runs to sensors, ABS ECM, etc.
Instead of making a new thread, I have some questions about abs.
Abs make kicks in when your tires lock up, unlocks them, locks them again, and the unlocks them. Many times during a extremly hard braking stop.
From what I understand, this is good because you can turn during an extreme stop, but doesnt it increase your stopping distance? I would think that a locked up tire would be better than a tire that is still rolling.
I do know that from autocross, if you lock your tires in a car without abs, your not gonna turn at all. You need to find that part of the pedal where its jsut about to lock up, which gives yuo the most stopping power, while allowing you to turn.
Am I right in this or lost?
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SCCA First Place 10/25/09. NST
Last edited by Crowbar911; 11-20-2009 at 04:33 PM.
Crowbar911, you are correct. You gain maximum stopping power (in most cases) when the tire is skidding on the surface (wheel is locked). On some exceptionally slippery or mixed traction, ABS "may" be able to slow you down faster.
But the real benefit of ABS is keeping control of the vehicle in emergency stopping or stopping on low traction surfaces. Since the tires continue to turn, you gain that small amount of control - basically you're input via the steering wheel will still have an appreciable affect the direction of the vehicle.
But lots of times, ABS is peddled as a means for shorter stops - which is almost always false. If anything, ABS can be an impediment to short braking - as few people will know to apply as much pedal pressure needed to engage ABS and hold it during the duration of the braking event. Pumping brakes on an ABS car negates the ability of ABS. ABS generally will have a low speed cutoff - where it will not come on at speeds below XX MPH.
I can't the number of times that myself or others get rear ended and have the other driver say, "I don't know why I couldn't stop in time, I had ABS." In effect, ABS lulls the operator in a false sense of security. A little different now, since some systems are tied into a vehicle stability/traction control system. More and more of your premium makes are implementing automatic braking. Too me personally, even though I'm a tech-head at heart, it is a shame that they're trying to take the driver out of the picture and have the car almost drive itself.
The only time ABS increases stopping distance compared to non-ABS braking systems is on warm, dry, smooth pavement, and the amount increased is a few feet or less when stopping from 60 mph. Under essentially all other conditions, no human can brake a car as effectively as a functional ABS. Don't blame the system for you and your supposedly uncountable number of acquaintances who have been rear ended. The root cause is not paying attention and following too closely. If those people did not have ABS, they still would have hit you and your friends anyway, maybe at 0.2 mph slower under ideal conditions.
The only time ABS increases stopping distance compared to non-ABS braking systems is on warm, dry, smooth pavement, and the amount increased is a few feet or less when stopping from 60 mph. Under essentially all other conditions, no human can brake a car as effectively as a functional ABS. Don't blame the system for you and your supposedly uncountable number of acquaintances who have been rear ended. The root cause is not paying attention and following too closely. If those people did not have ABS, they still would have hit you and your friends anyway, maybe at 0.2 mph slower under ideal conditions.
I see you have never driven a vehicle with ABS on ice, snow or gravel, because your stopping distance will most definitely "increase" most times by at least a car length to 3 or 4. You are unable to achieve the same friction between the tire & the road, compared to a vehicle with no ABS. A large percentage of drivers are not even educated about the pros & cons of ABS. Who reads their owners manual? This one simple feature should be at least explained by the manufacturer that sold you the vehicle, or who ever teaches you to drive, but I've never heard of it. All ABS does, is give the uneducated driver a false sense of security. What good is the ability to be able steer around something, while a computer is pulsing your brakes for you, when there is almost always something on either side of you, being another vehicle, a street curb full of pedestrians etc. Where you gonna go?
I prefer to have the option of full wheel lockup to stop me quicker. ABS would be the first thing disabled from any vehicle I own.
As far as someone wanting ABS, I would suggest test driving a vehicle with ABS under all conditions & then evaluate whether you prefer it or not.
Also there is no point adding ABS to a non ABS vehicle, unless money is no object. Just buy one with.
I see you have never driven a vehicle with ABS on ice, snow or gravel, because your stopping distance will most definitely "increase" most times by at least a car length to 3 or 4. You are unable to achieve the same friction between the tire & the road, compared to a vehicle with no ABS. A large percentage of drivers are not even educated about the pros & cons of ABS. Who reads their owners manual? This one simple feature should be at least explained by the manufacturer that sold you the vehicle, or who ever teaches you to drive, but I've never heard of it. All ABS does, is give the uneducated driver a false sense of security. What good is the ability to be able steer around something, while a computer is pulsing your brakes for you, when there is almost always something on either side of you, being another vehicle, a street curb full of pedestrians etc. Where you gonna go?
I prefer to have the option of full wheel lockup to stop me quicker. ABS would be the first thing disabled from any vehicle I own.
As far as someone wanting ABS, I would suggest test driving a vehicle with ABS under all conditions & then evaluate whether you prefer it or not.
Also there is no point adding ABS to a non ABS vehicle, unless money is no object. Just buy one with.
i disagree with this point, i've driven both ABS and non ABS cars on snow/ice. i felt that the cars with ABS stopped shorter AND stopped in a straight line much more so than the non ABS cars. having driven on sheet ice with ABS i cannot fathom doing it without ABS with any modicum of safety.
I could go on & on, but I have personally test driven over 500 cars & trucks with ABS & none of them stopped shorter on ice, snow, slush, gravel etc, & no noticable decrease on dry pavement. Its just plain physics, more friction(lockup, skidding)=sooner stop.
Also depends on the generation of ABS units - some are "smarter" about unique traction surfaces than before. Also depends on the driver's experience with one system or another. Cannot pump the brakes on ABS equipped cars, as that usual results in a confused ABS system. Blindingly pounding the brake pedal on a non-ABS equipped car is also a recipe for trouble.
In loose materials - sand, gravel, snow - generally a non-ABS car will out stop (distance wise) an ABS equipped car, because of the tendancy for the locked wheels to dig into the surface, plowing material out and around the tire. ABS trying to maintain will prevent the tire from locking, so the amount of material that could be plowed out is significantly less, if any at all. The "smarter" ABS sensors will use additional information to determine what surface is present (some cars have a user adjustable knob or setting) - and cycle the ABS on a different strategy. Actually allowing the car to lock its wheels up, and release in a similar manner that one would pump the brakes in
Ice is a tricky material. If all the wheels lock up simultaneously on an ABS equipped car, then the ABS system usually fails - as it relies on each wheel sensor for relative calculations. Some of the smarter systems will vary cycle time to compensate, but again, results will vary. Some cases, ABS will stop shorter on ice, other cases, it will be longer. My corolla does not have ABS, but the Matrix does (ABS + EBD) - just the way the cars are setup, ABS is a good fit for the Matrix, but personally doesn't make much sense in my 8th gen Corolla, atleast for my driving conditions.
Of course, having ABS is not a substitute for no common sense or a golden safety net for trying to push the car too far. Cannot bend physics with ABS - no magic here. Used correctly, ABS is just another tool available to the driver. Used incorrectly - well, YMMV.
Never seen a user adjustable ABS setup on any vehicle. Maybe an adjustable rear brake proportioning valve, but not on production vehicles. Trailer brake modulator, yes, factory equipped on Ford trucks. Curious to see on what manufacturers models this comes on. Might be an insurance nightmare, giving people control of that. The only thing I've seen, is on some older model Audi, BMW & some off road vehicles, the manufacturer gave you an on/off switch, to disable it all together. But of course there's a crazy law not allowing them to do this anymore. There's a newer innovation called brake assist which applies more brake pressure for you in a panic stop situation. Also a front assist system that keeps you a safe distance from the vehicle ahead of you, be it by engine management & if necessary braking. And last, stability control, which decides whats best & does it for you. Too much of technology thinking for you.
In fact there have been study's that show you are more likely to be in a fatal collision with a vehicle equipped with abs. Major cause of alot of rear end collisions. On anything but pavement you need an extra tractor trailer length to stop in most cases. At any time you are surrounded by others that don't have a clue how to stop properly. Its amazing how some passed a driving exam. As you can probably tell I'm not a fan of ABS. In my opinion it decreases your ability to stop sooner when you absolutely need to. Never purchased a vehicle with ABS & so far have never had a collision, unintentionally.
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