How smart is the ABS?

[PhyrraM]

I'm in the process of converting a '93 automatic SS to a 5-speed. In the 2 years I've had the car only once have I ever nailed the brakes hard enough to activate the ABS. They seemed to work fine.

This car will eventually be used for a few things, but it breaks down something like this:

50% weekend spirited driving.
30% daily driver
15% rallycross
5% autocross

It will get Subaru 4-pots and good pads. It will run on 215 section 16 or 17 inch wheels with performance rubber. For rallycross I'm still undecided, but leaning twords 15 inch wheels and proper rally tires.

My question, to those that have done it, should I remove the ABS? Will the 5-speed swap adversely effect it?

Advantages...less chance for breakdown, weight and room for a FMIC.

Disadvantages...No ABS for the "normal" driving, which is most of it.

Opinions appreciated.

[jamal]

I don't think it really matters what you do to the brakes or tires. If it senses wheel lockup it kicks in abs.

I would not want it for rallyx, and with my new wrx brakes I find modulation to be very easy without it, and 4-pots are much better.

[evolutionmovement]

ABS doesn't care what you do with transmission, tires, and brakes as long as you leave the sensor and tone ring (which should be completely out of the way). All it does is compare the spin rate of one wheel versus another by counting teeth on the tone ring and reduces pedal pressure to the wheel that shows a drastic difference in spin rate versus the others. How many others depends on the system. I'm pretty sure these cars would be 4-channel, so all four wheels would be looked at. On dry pavement, it's definitely better than a human, but can be less effective on loose material. I'd keep it as it's probably not worth the bother of removing it all and tricking out the light so it won't always be on (maybe that's easy, I don't know since I don't have ABS).

[PhyrraM]

I believe the system is 3 channel for modulation and 4 channel for sensor input.

Factory 5-speed cars have a "G sensor" that automatics don't have. I do not know exactly what it's function is however.

If I took it out,I would pull the entire system, including removing the wires from the harness. I already have the dash out for other wiring work, so the extra time is negligable. I would source non-ABS brakelines. I would prolly leave the tonerings until an axle/hub needed to be pulled. I would essentially convert it to a Factory non-ABS car.

Anybody Rallycross/Autocross on a factory ABS car? I'd like to hear your input.

[evolutionmovement]

I forget how old these cars are (and I am) with the single channel rear. I can't figure what the g-sensor would be for unless it somehow took decelleration rate into account and adjusted the braking to accordingly. Maybe it would be used as a rough determiner of road condition so it could dial back the ABS use if the car showed a consistent decelleration in spite of lock up (as in snow or gravel, where you'd possibly want some lock up) or in reverse as a check in case of four wheel lock-up on ice where the ABS wouldn't be aware there was a problem normally. Then it would have to have a sensor in the brake system for pressure somewhere. At any rate, I'm sure it would be fine without it if the auto doesn't use it.

[jamal]

On dry pavement, it's definitely better than a human, but can be less effective on loose material.

You mean better than a human who knows nothing other than to mash the brake pedal in a panic?

Which admittedly is most people.

[stipro]

I guess you could have the best of both worlds here. I would leave it in, and wire a switch in the circuit to the ABS relay under the hood. Put the switch on the dash, that way you can control when you have the ABS on/off. You could also just pull the relay out, then replace it when you are done.

[93forestpearl]

A switch on one of the wheel sensors works as well.


I cannot imagine removing the ABS to be loads of fun.

[BAC5.2]

Pull the fuse in the engine bay. I did on my Legacy within the first few weeks of ownership. I never wanted ABS in that car.

In the Forester, it's OK. It's got so much suspension travel, when I floor the brakes, the front end just dives forever. I think I've used ABS once in the Forester, and I would have been better off without it. Not going to remove it though, as I'm sure it'll prove itself off-road at some point.

[evolutionmovement]

Yeah, I've never needed it in the wagon (though with the uneven braking of WRXs on the front and stock rear it would be a help in a panic stop), but the Mazda seems to go off fairly easily with stickier tires. It also has a strong rear bias (the rear wheels are always caked in dust while the fronts stay clean), though it stops well. Maybe it's the rears locking since it also has a much higher front weight distribution. Sometimes you have to make a panic stop and ABS could make all the difference. I changed my mind about it when an idiot slammed on his brakes in the passing lane at 85 mph two cars ahead while I was driving the work E150 for reasons I was never able to figure and were it not for ABS I would've slammed both the guys ahead instead of pulling up a foot or two short. Maybe I could've been a little further back from the Jeep in front, but try that in Boston and you might as well park in the break down lane (in the hours they don't allow people to travel in it) until late at night.

[Adam West]

How much weight could you lose by completely removing (and selling) all the ABS components?

>>ABS sender and lines in engine bay
>>ABS sensors an dwiring
>>ABS ecu box under dash

Guessing 15lbs - anyone know?

My car is on a diet...