Has anyone discovered a relatively easy way to disconnect the ABS system for an autocross or track day?

 

Pull the (30amp?) fuse. I did it recently at an AutoX and your speedo won't read, but RPM's work fine and you'll get some dummy lights. The car runs fine and you don't have to worry about DSC.
Made quite a bit of difference too, the car rotates very well with the ABS off, as it should.

Just take a look at your fuse box and remove the small 30 amp fuse and you are all set.

 

Hi....

The fuse trick is ok....but there's an easier way.

Pull the connector of the brake fluid bottle....Voila, no ABS.

peter

Team M7
www.m7tuning.com

 

Nice. Does that affect the speedo as well?

 

Thanks Peter and Tom -

Damn, I'd send you a SASE for that one!

I'll try it at the next AX. Running the Victoracer/V700 combo and getting into the ABS way too much.

 

It does not affect the speedo at all.

And a bonus is " No DSC" either :smile:

peter

Team M7

www.m7tuning.com

 

Silly question, but why do you want to disable ABS? I understand disabling DSC and ASC+T for AutoX but why ABS?

 

Probably thinks it is cool or something. ABS is the best thing to have ever come down the pike for braking systems. All you will accomplish by disconnecting it is to flat spot your tires and add a second or two to your times on the track or on the parking lot.

 

No PocketPool, I don't think it is cool or something.

While I agree that ABS is one of the finest safety devices ever created for the automobile it does have its limitations. Skilled braking can outperform it in snow, gravel, in trailbraking or in my case where two different sizes and compounds of tires casue the ABS system to come on much to soon therefore decreasing the maximum braking at the front wheels.

If you think I'll be so slow bring that POS of yours out to an event here and we'll see.

 

Proof's in the puddin'

 

if you think your better than the ABS, by all means just do the sensor disconnect. don't do the fuse. if you pull the fuse you will loose ebd, and I don't care how good you think you are, you will not out perform ebd. Oh, and make sure you're ahead of me so you don't go sliding into my car.

 

For wat its worth, I disabled my ABS on my WRX. (made on/off toggle sw).
99.99% of the time, ABS is off. 0.01% "ON" at the dealer.

And I think im cool.

The ABS on that car is too sensitive for me. The MCS's program has
been pretty good for me on the streets.

 

I don't know that the EBD has a role in my problem but experiencing the car's braking capability without it may allow me to come to an intelligent conclusion.

Lately there seems to be a rash of persons, both here and on other boards, who, without any empirical knowledge, strongly object to the removal of stock systems, even if the purpose is to assess the beneficial aspects of the system. Hey, I'm talking about a specific problem in an offstreet environment here.

The design criteria for all of these systems is clearly for safety and parts life in a street environment. If they have a positive role in a race environment it is probably more by chance than design. I leave the DSC on for tire warming laps and sometimes in the rain. As BMW has made it virtually impossible for us to implement new software for these systems we may be better off with them disconnected.

It is highly unlikely that I will purchase a vehicle with such a closed system again. Takes all of the fun out of it.

Oh, don't worry 'bout me sludding into ya Coon. T's doubtful that ya will be in a position to get hit by my front bumper 'less y'all getting lapped.

 

>Lately there seems to be a rash of persons, both here and on other boards, who, without any empirical knowledge, strongly object to the removal of stock systems, even if the purpose is to assess the beneficial aspects of the system.


I think the problem is that a lot of people who don't really know how to drive
their cars all that well are trying to imitate a good driver and finding out
they need computer assist.... BOY IF I NEED COMPUTER ASSIST SO DOES
EVERYONE ELSE!!! slight exaggeration, but this could be the issue.


Now watch me crash my WRX into a pole.


I think if one's driving the car to the limit where it is asking for
performance over what the car was programmed to do on the streets,
it would be better without such assist. but that's just me.

 

That may be true, however, I design ABS systems so I sort of know what I'm talking about. EBD replaced the proportioning valve used in older vehicles. Without you will have no proportioning to the rear brakes and be more likely to oversteer. If you disable that, you might want to plumb a second brake pedal so you can reduce the braking to the rear when you need it. I agree that DSC and ASC+T are not desirable features for the track, but ABS is questionable as to why. If you got into ABS on the track you will probably want it to still be able to steer. unless I guess you are on gravel or packable snow tracks ABS will stop you faster and will always stop you with the ability to control steering.

 

Amazing.

 

Isn't the ABS program based on a given (or fixed) environment?
Isn't that why the ABS do not work well in gravel or on snow? If you alter
your suspension or use different type of tires outside the ABS parameter
tolerances, or drive on loose terrain... wouldn't it perform less than par?

Just wondering... because after I altered my suspension on my other
cars most ABS systems did not perform as well as when it was bone stock.
It feels okay to some because usually we put on grippier tires and the car
stops better anyway... but at the limit ABS has not been as effective on
modded cars that ive played around with in the past.

 

ABS does not work as well as 'locking' the brakes in snow, on gravel, and in sand, and similar environments because of the 'wedge' that forms in front of your tires when your brakes lock on these surfaces.
changing the rolling radius of your tires affects the ABS as well.
also, remember that intentionally disabling any safety device renders all claims against the manufacturer null and void

BTW if you believe that you can really stop a car faster than the ABS, I think you are mistaken(IMHO) I can pump my feet pretty fast, but 1000+ times per minute...NOPE.

 

To answer your other question. No the algorithm is not a "fixed" algorithm. It determines the available mu of the road and many other factors and adjusts the algorithm based on wheel slippage. The system are, however, tuned using stock chassis, wheels, tires, brakes. This means if you drastically alter these you can change the effectiveness of the ABS. Example, if you put larger brakes with better friction pads, they will be able to produce more braking torque. The ABS will try to compensate for this but it is expecting that the brakes are still stock brakes so estimation of mu may not be as accurate and therfore degrade performance or cause the system to become more/less sensitive. but still isn't as bad a human trying to do the same thing.
Even in gravel and snow ABS allows you to steer clear of the obstacle rather than plow into it and many ABS systems have detection for such surfaces to improve handling and stopping.

 

Yes! That's where I am trying to go.....oversteer on command. My guess is that it would be beneficial to keep the EBD system intact.


It's not always the absolute shortest braking distance but also being able to control the attitude of the car and how the suspension is loaded. The ABS takes away all feel and control and is too slow to turn off. Aside from wishing for more effective trail braking I don't have much problem with the ABS on the track. AX is a different story as things happen much faster and being able to induce considerable oversteer in short bursts can be very helpful especially when 60+% of your weight is on the front wheels.

 

Thanks, mattcoon. Im getting smarter every day. :smile:


polmear- keep an eye open for a possible recall on 02 WRX's ABS system.
I can stop MUCH faster without its ABS than with it. It's just too sensitive
and algorithms not quite right. The MCS on the other hand with my light
mods, no prob. :smile:

 

Could be you have very sensitive feet, and can push the car right to the edge of lock-up. I rarely experience lock-up, unless in a panic stop (I also rarely push the car to the point of needing that much brake); I'd be willing to bet I could stop a car within a few(6-8) feet of the exact same car with ABS. It's just that, that 6-8 feet could be the difference between life and death on the street; on the track...well that's a different story.

 

My perception: The brake system on the MINI sucks The ABS is either too sensitive, or too slow reacting to be any good....but that's not what annoys me most. It's the CBC! It's EVIL! The car insists on activating ABS/CBC when I brake pulling into a driveway or parking spot or anything low speed, causing the pedal to fall away from my foot (and subsequent humanoid-braking mapping algorithm) and dramatically screw up my braking trajectory (and lengthen the stopping distance).

CBC sucks!

I agree, the EBD is the strong point of the MINI's brakes; it does a great job for the most part. It does put too much emphasis on front braking when on-track or evasive braking.

Is there a way to deactivate ABS and CBC, but leave the EBD on?

 

Peter -

Tried this last weekend on a sandy course where two of us were getting into the ABS too early due to rear lockup.

Unfortunatly, the ABS was still there, maybe a little "duller" but definitely still there.

 

this trick only disables ABS and puts the unit in EBD only mode. what you felt would have been EBD trying to keep the rear wheels from locking (proportioning the braking)