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ABS in a S30


Guest Hatchet9mm

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Major work and expensive. You have to have an ABS controller, pump and wheel speed sensors on all 4 wheels. Possible? Yes, but not cost effective. The other reason is WHY? It works as a safety device of the drivers with lack of experience, but typically is not really a performance upgrade. Threshold braking is the maximinum you can achieve and is far beyond what ABS will do, as it kicks in way before that. Even when running road courses in my 540i BMW with a highly developed & engineered ABS system, I can brake into corners harder than the system will allow and once the ABS kicks in, you can actually feel yourself accelerate, as it takes away braking power.

 

If you get yourself in trouble, it's nice to be able to just stand on the brakes w/o any wheel lockup, but I'd prefer a good non-ABS system. Also, you want to go with some real calipers and rotors with either setup, which is already as much as most want to spend on brakes for their Z car. Just my 42 cents. :)

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Guest Hatchet9mm

Thanks guys, I realized that is was not cost effective when i got into indepth research. Thanks again, I'll probably go with some 300zx rotors and calipers all around

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Threshold braking is the maximinum you can achieve and is far beyond what ABS will do, as it kicks in way before that. Even when running road courses in my 540i BMW with a highly developed & engineered ABS system, I can brake into corners harder than the system will allow and once the ABS kicks in, you can actually feel yourself accelerate, as it takes away braking power.

 

 

1. Not all ABS systems are configured equally. However I still find your comments hard to believe. Every ABS system I've ever seen works to maximise the negative slip ratio on the tyres (individually I might add whilst maintaining car yaw as requested by steering input), and does so by pulsing the brake pressure to just before lock (Ie when the individual wheel speed sensor indicates its slowed beyond the others). I would have to assume, though I will check with a mate who works on the ESP systems for Bosch, that this cycles through each wheel/brake/tyre (so the other tyres provide a reference for the `correct' wheel speed), hundreds of times a second.

 

2. If you can outbrake a modern (<5 years) ABS system, you must be a better driver than 99.9999% of the population.

 

Dave

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The main purpose behind ABS is not to decrease braking distance. It is to improve steering control while under hard braking.

 

It is actually quite common for braking distance to decrease without ABS, but it takes skill and concentration. I like being able to slam on the brakes in the wet and I know the ABS should kick in and make my life easier. I dont always want to drive like a race-car driver.

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BobbyZ,

 

Thats a very good point. If I'd stopped to think about it I'd've realised that in order to turn the car, you probably don't want to be at peak slip ratio, as IIRC the lateral force possible decreases as slip ratio increases. Ie, you're `using' the tyres force to slow down so it has none left to turn.

 

Thanks for the correction. :)

 

Dave

 

PS. Of course a race car with ABS has a very different requirement I'd assume.

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The main purpose behind ABS is not to decrease braking distance. It is to improve steering control while under hard braking.

 

It is actually quite common for braking distance to decrease without ABS, but it takes skill and concentration. I like being able to slam on the brakes in the wet and I know the ABS should kick in and make my life easier. I dont always want to drive like a race-car driver.

 

Say hello to the reason of ABS. Youre opening sentence was nearly dead on- Though theres a little more to it that should be pointed out. 99% of the drivers out there do just that, they slam the brake pedal in an emergency situation. Abs is intended as a safety device vs a performance device because joe schmo doesnt naturaly know to squeeze the brakes, and would prefer to stomp on them.

 

However it should also be noted that while older abs systems still had a hard time matching a well-trained foot (short of a very sports oriented vehicle), modern systems are starting to give well trained feet a good run for their money in a wide variety of cars. Its natural to assume as technology goes on so will this.

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I'm going to have to back on my last comment. I believe that the main purpose of modern ABS/ESP is to assist the driver in avoiding an accident. In the event of a brake lock situation with the steering wheel straight this probably means the driver wants to stop as quickly as possible. Given these systems include a steering position sensor, I think you'd be hard pushed to manually brake as well as the system.

 

That being said, each system is configured/tuned individually to the manufacturers requests/satisfaction, and some manufacturers are stupid. :) So perhaps some cars won't stop as well as you or I could, but if it was configured appropriately, I don't think many people would be able to out-do the system.

 

Dave

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Just to throw in my $0.02 in here, I don't think there are many drivers that can reach that "better than ABS" level when under a real panic situation. On an open country road in good weather last year I missed a kid on a minibike by maybe a foot, and only then because I managed, by a huge force of will, to let off the brakes for just a moment and dive for the ditch. There I was looking at this kid - just a little guy - knowing there's going to be a bad SPLAT if I don't go behind him (he was moving from my right to my left), the brakes locked up tight, and I just couldn't for the life of me get my foot to come off the pedal. Later inspection showed I bent the bracket holding the pedal arm, maybe 20°. Heck, I'm one of those guys that goes out and practices his threshold braking in everything I drive, and I can about stand my Z on its' nose, but there was just nothing I could do to convince that foot to let off until it was darned near too late. If I had had, say, 50 milliseconds less time to think I would have hit him. Under those conditions, ABS would have given me a chance to not think and point the car at the dirt sooner. Heck, it might also have kept it under control once it left the pavement.

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