Here's my take on my ABS failure. Got a rock caught in between the ABS teeth on the axle and the sensor, and the tip of the sensor snapped off and also cracked the inside of the sensor. Suck.

Fortunately this occured while on a small track. The car spun incredibly fast, and I wasn't even braking very hard. It's the only time that I've ever spun more than 90 degrees in this car.

On the plus side, my axle isn't screwed up. I thought it was, but it turns out that the ABS sensor falling part is what was causing the axle to stick and click when turned.

Picture in the followup.

Warren

 

What you're looking at is the end of the ABS sensor. The black round piece is the part that popped off, and you can see that it's missing the tip.

If you look inside the sensor housing, you can see that it damaged some stuff in there too.

Warren





[Modified by Warren, 4:39 PM 5/18/2002]

 

Oh, one more thing, regarding melting ABS wires. Mine were somewhat deformed, but not melted enough to cause a short or expose any wires. It's the part that's closest to the rotor.

I recommend shielding that short section ( an inch or two ) with some insulating tape or something.

Warren

 

I can't see the pic . Anyway, i know alot of people don't like using abs on their race cars for whatever reasons and some who do like it. What are the pros and cons of having and not having ABS?

 

Pros: Less flatspotted tires, better control on wet track
Cons: Less predictable sometimes, worse braking distances when you go lawnmowing, adds minimal weight

Good ABS systems do no increase or decrease your braking distance. It just helps when you overbrake, or if the rears are locking (on a fwd car).

Warren

 

Warren, was your failure condition immediate - as in did the ABS light never go out after you started the car?

 

Well my 93 si doesn't have abs so i wont have to worry about it.

 

Your ABS light should certainly be on, and if you jump your maintenance jumper it should flash:
(main code/sub code)
4/1 for FR speed sensor or
4/2 for FL speed sensor
(if it's the same as my car).

 

Yeah, sudden and immediate failure, and then the ABS light stayed on.

That sensor popped out of the housing and was basically just sitting on the teeth of the axle, which is why I had such a hard time rotating it backwards, even though it was out of gear.

Warren

 

I donno about that. I have seen several back to back tests where cars were tested with ABS and then with ABS disabled and the stoping distance with ABS was always better. There was one where they used a pro race driver, and the ABS still produced shorted stoping distances.

Another con for ABS is when you go a for a loop, the ABS keeps the wheels turning making much harder to predict when and where the car will stop.


[Modified by SPiFF, 11:39 PM 5/18/2002]

 

Due to my "butt dyno" experiences, I would wonder how that result would change with different traction.. In snow and ice conditions, it has seemed that ABS increases my stopping distances noticeably, at least in low speed conditions. Of course, you know how trustworthy a butt dyno is, but it's a strong enough impression, that I'd like to see some tests done on that.

 

One more point, those tests I was referring to were all done on street tires and street conditions where wheel lockup is a bigger factor. On R compmound tires, it is a little different since they grip so much better then your avg street tire.

When I drove a Civic with no ABS and Type-R brakes at CMP, I was worried at first about lockup. But with Kumhos they just gripped so well that it was only an issue a couple of times. One thing is for sure, when you are used to having ABS to back you up, it is hard to back off the brake to "pump" going 100+ MPH into a 50MPH corner when your front tires lock up a bit. (Turn 1 at CMP).

 

I guess we've taken poor Warren's thread a bit off topic, but it's still good stuff

I find the ABS most useful under hard braking where the track has significant camber and/or elevation change. Turns 14 and 11 at VIR (long course), turns 1 and 5 at Summit are two in particular. I can always feel the rear wheel ABS cycling in these places. These are also places where if one were to fall off the track, some fairly unpleasant things could happen.


All this having been said, Carlisle made it clear to me that I lean on it as a crutch more than I should. Being able to simply wail on the brakes is a nice luxury to have - but this strategy doesn't work so well without ABS.
--Karl, who saw God that time his bleed screw backed out...at 125mph...in the braking zone heading for T14 at VIR...

 

ABS on late model Porsche, BMW, Ferrari are extremely effective. WAY better stopping distance than if you turn it off. Especially true if the car is in turns, or wet/snow.

The one in my 95 del Sol VTEC for example is so so, it's only 3 channel (2 solenoid for front, 1 for rear), and it cycles pretty slow. I still keep it on though, since it isn't that bad.

Also, one common mistaken on car with ABS is people tend to back up on the pedal pressure when they feel it cycle. You're suppose to keep the pedal down and let ABS do the work for the best results.

 

So what's the verdict? Do you thing ABS is better on a race car or more suited for the streets. I've never really liked abs because the brake peddal always seems to feel different, to me anyway. But i'm used to driving my car that isn't ABS equiped.

 

For sure, braking quality is hugely related to tire quality/grip, so of course a grippier tire is going to stop a car faster, and I've found that ABS engagement/feel/effectiveness increases dramatically when upgrading to a tire with only a small increase in grip.
I went from a good tire (AVS Intermediate) to a great tire (S03), both in a 225/50-15 size, and while the S03s have only a marginal increase in strait line stopping power over the AVS Is, the ABS just feels way so much better on the S03s.

 

ABS on on the race track:

Pros -
No brainer, stab it and hold it.
With FWD, if the rears start to lock, you can still maintain or increase line pressure to the fronts (w/o ABS you'd modulate the pedal to unlock the rears thus decreasing line pressure to the front).

Cons -
Those who've mastered threshold braking no loger have a braking advantage over novices w/ ABS!
When you've gotten yourself in to a loss of control situation, "both feet in" will not produce the same predictable spin that four locked wheels will. (I learned this the VERY hard way 7 years ago.)

All things considered, I like it. The ITR's system is a very good one; keeps the contact patches right at the limit.

 

Will
-who will make shields for his ABS wires... and keep an eye on sensors