No ABS?

[RangerGress]

I followed the ABS thread at Bimmerforums but stayed clear of it so as not to get crushed. My perception is that ABS was designed to help the driver retain control, not to stop the car quickly. I'm not convinced that ABS will stop you faster then genuine threshold braking.

The ABS in my car didn't work for months. I tried hard to perceive lock up because flat- spotting tires was a problem. What I found is that it was not always easy to detect that one of the 4 wheels had gone beyond threshold and was now locked up. The changing variables of weight on that tire, car speed, and the nature of the road's surface made detection of a wheel locked up occasionally challenging. The experienced racers at BimmerForums all made it sound like it was easy to detect lockup. Ok, I'm a relative newby, but there were times when it wasn't easy. There were times when I could not feel it thru the wheel, pedal nor butt, especially when the road was smooth. What I had to detect was a sudden unexpected and slight change in braking g's, that couldn't be accounted for by all the other things that were happening. I was blowing thru a tire each weekend.

A SpecE30 is not that tightly sprung. Maybe that is another reason that it was harder for me to detect a locked up wheel, then some of the anti-ABS racers at BF.

Finally I got my ABS working. All it took was reconnecting the light in the dash and replacing a relay. ABS makes it obvious that you are on the brakes too hard. So it's the perfect signal that you need to back off a little. I don't know that I would use ABS to stop me, but I'll certainly use it as an indicator to back off the brakes a little.

[Jean]

ABS is the anti-blocking system. It keeps the wheels for locking up. A locked wheel will have much less stopping power than a wheel at the threshold. Older cars such as e30s had a rather primitive ABS programming (still much better than its US counter part of the days). If one wheel locks, it kicks back on the rake pedal releasing all four wheels.

Personally, I think it is still great for most everyone driving on the street or with only average rack experience. But people who track their car may prefer to regain full control on their brakes. It is possible to remove the relay to disable ABS, or install a switch.

I was kidding :) My 318i does not have ABS, I've only been in 1 close call when I locked my brakes up in rain and quickly got off the brakes and applied the brakes gently to stop sliding into a truck in-front of me that slammed on his brakes....

No issues in auto-x either ....

[nando]

Interesting - for some reason that never dawned on me.

For new cars, it brakes tires individually, doesn't it? So, this wouldn't be an issue?

I'm pretty sure it brakes them individually (except the rear) on our cars too - we have a 3 channel ABS system. ABS is to help braking while turning on a slippery surface, not just to prevent lockups in a straight line.

[gobuffs]

E30 ABS is a very primitive system.

I removed it from my track car as it was easier to remove than to get it working right (or so my thinking was at the time). Kinda wish I would have kept it (at least be able to turn it off and on to see the difference).

I have AP race calipers up front with PFC01s, Tilton pedal box with AP MCs, M coupe rear brakes. Still trying to get the balance adjusted right...

[kommissar]

I regard of Sean's comment, I'd say he is right. ABS will keep you from flatspotting one wheel, by releasing all four wheels... Which means you are loosing any possibility to brake. Basically, your braking power under ABS is the braking power of the wheel with the least grip.

I always thought ABS would release only the wheel that is locked. It makes absolutely no sense to release all 4 wheels if only one wheel is locked. That would seemingly be dangerous in track conditions and street panic stops.

Sorry Massive Lee, but I'm quote sure that Hallen is right. Are you absolutely sure that it will unlock all four wheels? The rear wheels may not brake independent of one another, but the front wheels have separate brake lines and are controlled independently of one another. Look at the ABS unit under the hood, and note the amount of brake lines coming out of it.

The fact that the vibrations from the servos in the ABS unit travel back up through the pedal does not mean that it is affecting all of the wheels.

[Massive Lee]

ABS is the anti-blocking system. It keeps the wheels for locking up. A locked wheel will have much less stopping power than a wheel at the threshold. Older cars such as e30s had a rather primitive ABS programming (still much better than its US counter part of the days). If one wheel locks, it kicks back on the rake pedal releasing all four wheels.

Personally, I think it is still great for most everyone driving on the street or with only average rack experience. But people who track their car may prefer to regain full control on their brakes. It is possible to remove the relay to disable ABS, or install a switch.

[Jean]

What's ABS ? :D

[PiercedE30]

I would suggest learning to brake without it. That way if you ever find yourself with a bunk ABS system, you will be able to react to it properly.
That said, the makes of MegaSquirt are coming out with a General Purpose Input Output controller in the next 3/4 months. They have definitely talked about using it to control a 4 channel ABS. Once it comes out and they get a few of the software kinks worked out I am definitely putting a 4 channel system in. Plus, it is only going to be about 300-500 dollars.

[Scott///M]

I say you go for it.

Just don't throw any of your ABS stuff away. Because once you flat spot a couple of sets of tires and give up a position or 2 because you're getting out braked... you'll want to put it all back.

But the only way to know for sure is to do it.

[Hallen]

I regard of Sean's comment, I'd say he is right. ABS will keep you from flatspotting one wheel, by releasing all four wheels... hich means you are loosing any possibility to brake. Basically, your braking power under ABS is the braking power of the wheel with the least grip.

Lee

I always thought ABS would release only the wheel that is locked. It makes absolutely no sense to release all 4 wheels if only one wheel is locked. That would seemingly be dangerous in track conditions and street panic stops.

Picture one completely bald tire on a car with the rest of the tires in good shape and you are driving in heavy rain. You do a panic stop but because the one tire is hydroplaning, your car does not really slow down at all because the ABS is release all the brakes because one wheel is locked. Why would engineers design something like that?

[Sean]

If i wanted to give it a shot, could I just unplug the ABS computer? Or, is true ABS without having the ABS unit at all (where all the brake lines go in) going to feel noticeably different?

[joshh]

Some people like to have more control over the brakes. This is something you'll have to try if you really want to know.
I prefer ABS but I feel ABS kicks in a bit too early sometimes.

[Sean]

There's currently a heated discussion on Bimmerforums (track section) on ABS or no ABS.

I regard of Sean's comment, I'd say he is right. ABS will keep you from flatspotting one wheel, by releasing all four wheels... hich means you are loosing any possibility to brake. Basically, your braking power under ABS is the braking power of the wheel with the least grip.

My suggestion is to keep ABS for street driving where panic stops can occure. For a racecar driven by an experienced piot, you'll go faster without ABS. Other opinions might differ.

In regard of Erik's brake set-up. You will have way too much front bias. You're not the only one with a front-only kit with bias problems. I suggest you ditch the pressure limiting valve to the rear to help gain some of the balance. Ask PaintPro21 on S14.net.

Lee

Interesting - for some reason that never dawned on me.

For new cars, it brakes tires individually, doesn't it? So, this wouldn't be an issue?

[Massive Lee]

ABS is good to have to eliminate risk of locking up just one tire. You can still threshold brake with ABS as well.

There's currently a heated discussion on Bimmerforums (track section) on ABS or no ABS.

I regard of Sean's comment, I'd say he is right. ABS will keep you from flatspotting one wheel, by releasing all four wheels... Which means you are loosing any possibility to brake. Basically, your braking power under ABS is the braking power of the wheel with the least grip.

My suggestion is to keep ABS for street driving where panic stops can occure. For a racecar driven by an experienced piot, you'll go faster without ABS. Other opinions might differ.

In regard of Erik's brake set-up. You will have way too much front bias. You're not the only one with a front-only kit with bias problems. I suggest you ditch the pressure limiting valve to the rear to help gain some of the balance. Ask PaintPro21 on S14.net.

Lee

[Sean]

Why.....

It's been proven a bunch of times that an ABS computer will outbrake a human. Even a really good driver.

Not to mention you can threshold brake all day long, but you can still have one rear tire lock up and flat spot for a split second, while the others keep turning.

ABS is good to have to eliminate risk of locking up just one tire. You can still threshold brake with ABS as well.

That's my take on it, know that's not the answer you were lookin for....