ABS Delete Any one runs without ABS

[yeaseth]

The e30 ABS system has a low IQ

[MatRacer]

Massive Lee, I totally agreed with you regarding the fact that ABS doesn't affect "initial" brake byas.


However, here is what I found on post #86 of another ABS intersting threads on ABS delete: http://www.r3vlimited.com/board/show...ght=abs&page=6

There is a ton of misguided information in here.

Even an early ABS system like the E30 is going to help you in nearly all situations brake better and perform evasive maneuvers better, and allow safe driving in rain/snow/oil situations vs without it.

The idea that you can simply remove it and have better braking ignores MANY engineering principles.

First off ABS systems are almost always coded and internally programmed around a specific mechanical bias for that application. Certainly in modern cars, and to a lesser extent older cars, the bias is VERY likely to be shifted from that bias which is optimized for use without ABS. Plus or minus a static bias valve is just the tip of the iceberg. This is done with bias valves, brake compounds, rotor diameter, piston diameter etc.

Even early ABS systems have a degree of Electronic Bias adjustment so that if the rear is locking up, pressure is relieved in the rear line(s) to allow it to catch up. This ABS function is not even the pulsations we all come to associate with ABS working... its something most people don't even know goes on.... and yet it allows for better braking and traction. (EBD is the modern term)

Remove the ABS system and a car with slightly higher rear bias for use with ABS suddenly becomes a car that locks up in the rear too quickly. Mess with the master cylinder and change from a staggered to unstaggered, or the reverse, and you're CERTAINLY at risk for making a system that is now outside the compensation parameters of the ABS brain, and quite possibly lengthening braking distances.

Put on aggressive pads at just one end? Might as well put in a staggered master! You've just radically changed the Cf of that end, and spoiled the bias that the ABS computers is programmed for.

There are so many ways you can screw up an ABS system that its not even funny.

You see, every move the ABS computer makes is based on an EXPECTED result! If you mess around with bias through pads, BBK, bias valves or masters, the result of a timed valve change in the pump MAY NOT be as expected, and the ABS computer will believe its due to road conditions and wheel slippage that is changing... it will be faked out because you've messed with the mechanical bias... so you get into loops of poor compensation and BAD ABS results.

There was an excellent point made that you can still threshold brake with ABS, and its therefore unlikely to lengthen your stopping distances in the dry... It can really only help by possibly identifiying the rear as near lock up, and releasing pressure to help STAY in the threshold braking in the rear.

At any rate, removing the ABS to enhance braking is just plain mis-guided on a street car. There is a remote possibility that if you restrict your racing or DE to dry days, and delete ABS, delete bias valves, and install a dual master with bias bar that you can fine tune your brake system to outperform the factory system in a small set of limited circumstances... but you're likely a very, very skilled driver at that point with a ton of experience in track driving without ABS....

Just my 02 cents worth.

(been doing a lot of research on these issues, and hope to have some pretty slick product available to you guys to enhance braking and transplant options soon)

Base on that post, which seems to be logical, messing with the brake Byas when having a functional ABS system would not be good idea. You may limit the need for the ABS to kick in, but once it has kicked in, Its intervention may be wrong...

I'm still analysing this... Not sure if it is actually that that will happen, but it make senses...

[gobuffs]

I'd be curious how much of a task it would be to implement the e46 ABS in an e30. I know bimmerworld makes a standalone harness for it. Pretty decent amount of $$$, but as long as BMW stuck with the same tooth count, you could probably get away with reusing your factory wheel speed sensors.

http://store.bimmerworld.com/epic-mo...tem-p1691.aspx

Easy. It's great. I'll take the E46 ABS over my old non ABS any day. I don't usually engage it, but it is there if I do.

[JMPAuto]

My e30 s52 time attack car with abs delete has been running well for the past year. Front lock ups are very common but everytime because of a driver mistake. Its easier to lock the front when running 225/45/15 (tried NT01, RA1, C51) compared to 235/40/17 (NT01 - current setup). I definitely need a little bit more brakes in the rear with my setup. Thinking of putting IE big brake kit in the rear with small rotors to fit 15" wheels.

How much more braking can we get from the rear when using aftermarket brake proportioning valve?

Current brake setup:

Front - mazda rx7 conversion with Hawk DT60
Rear - stock calipers with PFC01
Stock master cylinder and rear proportioning valve
Car weight: 2350 lbs
Weight Distribution: F55%-R45%

What is the stock brake balance of our car anyways?

[Lodsin]

Only if the driver doesn't know what he does. The fine art of braking must be learned. It is not about mashing the brakes as hard as you can and counting on the ABS to save your arse...

I'm definitely no pro racer, just autocross/dailyfor7years/spirited and my car never had working abs. Never once flat spotted a tire, and only got into a skid for about 2-4 ft under heavy braking. Not sure I would want a track car or any sports car with ABS, but that would be dependent on the car.

[Massive Lee]

As you found, disabling the ABS means locking up and flat spotting tires...

Only if the driver doesn't know what he does. The fine art of braking must be learned. It is not about mashing the brakes as hard as you can and counting on the ABS to save your arse...

[aventari]

What is the production year of your car? Maybe bumps can "lift" the entire car, front and rear...

I have a feeling bumps and track-level hard braking overrough pavement confuses the ABS into thinking wheels are locked and it just pulls the brakes but doesn't seem to repply for whatever reason. It's really scary and you have to release and reapply and it really undermines your confidence to so hard into corners.

Mine is an 87 325is 4-14-1987 production date.

ABS is not related at all with braking balance. The braking balance is a problem that most likely was always there, but was masked by the ABS.

There's a fixed pressure limiting valve right under the fusebox by the fender. remove it and fit a 10mmx1 union. Then plumb and adjustable one from Wilwood or Tilton. They are cheap at around $50 each. Tilton's is available with metric 10mmx1

Many people who have so-called "upgraded" the MC to a larger one will have a balance problem as they swapped a 22/17 MC to an equal bore 23,8/23,8 ot 25,4/25,4 - bigger rear piston (compared to the front) means less pressure)...

Thank you! this is great info!

[jlevie]

I have an E30 track car and experienced ABS "lock up" or "ice mode" or whatever you want to call it when the system freaks out over bumps into a corner and you lose all braking power. This happened twice in one day with 2 different drivers and we almost crashed/went off track.

So I pulled the ABS fuse. However now the bias is way too much front brake and I've lost braking power and it's easy to lock them up now.

I put some more aggressive pads on the rear to get some more braking out of them, but I'd like to add an adjustable bias valve and remove/gut the stock bias valve. What's a good valve to use? Is there a write-up on how to do this? I'm not too familiar with modifying braking systems.

As best I can determine, "ice mode" occurs when more than one wheel (usually the rears) is locking up. It does not reduce braking pressure on an E30, though it will result in a hard pedal. The cause is simply going too deep into the braking zone for the track/tires. The fix is obvious, brake earlier.

As you found, disabling the ABS means locking up and flat spotting tires...

[Jalves619]

I'd be curious how much of a task it would be to implement the e46 ABS in an e30. I know bimmerworld makes a standalone harness for it. Pretty decent amount of $$$, but as long as BMW stuck with the same tooth count, you could probably get away with reusing your factory wheel speed sensors.

http://store.bimmerworld.com/epic-motorsports-mk60-standalone-abs-system-p1691.aspx

[Massive Lee]

ABS is not related at all with braking balance. The braking balance is a problem that most likely was always there, but was masked by the ABS.

There's a fixed pressure limiting valve right under the fusebox by the fender. remove it and fit a 10mmx1 union. Then plumb and adjustable one from Wilwood or Tilton. They are cheap at around $50 each. Tilton's is available with metric 10mmx1

Many people who have so-called "upgraded" the MC to a larger one will have a balance problem as they swapped a 22/17 MC to an equal bore 23,8/23,8 ot 25,4/25,4 - bigger rear piston (compared to the front) means less pressure)...

[MatRacer]

What is the production year of your car? Maybe bumps can "lift" the entire car, front and rear...


Is There really a system upgrade at a certain production date?

[aventari]

I have an E30 track car and experienced ABS "lock up" or "ice mode" or whatever you want to call it when the system freaks out over bumps into a corner and you lose all braking power. This happened twice in one day with 2 different drivers and we almost crashed/went off track.

So I pulled the ABS fuse. However now the bias is way too much front brake and I've lost braking power and it's easy to lock them up now.

I put some more aggressive pads on the rear to get some more braking out of them, but I'd like to add an adjustable bias valve and remove/gut the stock bias valve. What's a good valve to use? Is there a write-up on how to do this? I'm not too familiar with modifying braking systems.

We almost went

[MatRacer]

Thanks!

Did some more reading. Seems like the ABS module is designed to work with the stock brake byas, including the rear brake pressure regulator, which make sense. So from there, I will keep the rear brake pressure regulator.

If I come to the points of adding a BBK, I guest I will delete ABS and add a brake byas valve.

[RangerGress]

Bringing this thread back to life!

Presently "building" a 325i 1989 with a S50. The goal is to get a fun car that car be daily driven, but also tracked. It had functionnal ABS before swap. Big brakes is on the list, but wont come this year.

My plan for this year was deleting ABS + addition of Stainless Steel Braided Brake Hoses (to replace old dryed out rubber hose) since my last tracked car was a jetta MK2 without ABS. I wasn't having any problem with the absence of ABS.

However, after reading all this thread and the E30thech link, I'm leaning toward: keeping ABS + addition of Stainless Steel Braided Brake Hoses + brake bias valve (as this one http://www.iemotorsport.com/bmw/E30-brakes/wwvalve.html).

I will be able to try ABS and decide if I want to keep it or not...

What you guy think?

One question for Massive Lee: From your last post(#65) "Honestly, I very rarely hit the ABS", I can read that you still have ABS on your car. Is this on your E30? If yes, I guest that it is not as dangerous as stated in post 40... Not trying to pick on you, just trying to make my car as good an safe as possible for its purpose... within my budget...

Keep the ABS. It will make it harder to flat spot tires.

Don't spend a bunch of money on a big brake kit until you're working your brakes so hard that track pads and cooling ducts on the OEM brakes can't keep them cool enough. It is entirely possible that scenario may never occur.

[Massive Lee]

Hi Matt. My e30 M3 running 17" wheels, R compounds and front/rear uprated brakes has perhaps triggered ABS once or twice in maybe 40 track days. And I understood very well why it happened when it did. My mistake.

If you are a novice tracker, I suggest you keep it. If you are a very experienced tracker and have good brakes, then you don't really need it. Let's not forget that while ABS can be faster on the track, we're talking Motorsport ABS here, not first generation e30 ABS.

Currently redoing my M3 as a full race car and ABS is removed. The boosted system is replaced by a three MC set-up. Now running Massive/AP Racing brakes.