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Mazdaspeed Archive => Suspension => Topic started by: emmi on September 14, 2015, 09:04:53 AM



Title: Will Disabling ABS put ECU in panic mode?
Post by: emmi on September 14, 2015, 09:04:53 AM
On track, part of the my thrills involve having the confidence and ability to be at maximum threshold braking capacity where the tires are at that limit of maximum traction and locking the tires.  I've never been a fan of abs for track and it almost killed me at Laguna Seca inside my FR-S.  Was at full braking mode entering Andretti Hairpin when 1 tire went over a tiny gap on the track causing it to lock momentarily.  Though it was only for a split second, it was enough for the ABS to start cycling the brakes... causing the car to almost feel like it was speeding up. 


enough of that.  Im swapping an 05 MSM into my 01 NB LS Sport (non-ABS) and I do not want ABS what so ever.  But my question to you all is, Will that cause the ECU to go into panic mode and possibly cut power? 


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: SilverMiataRacer on September 14, 2015, 09:50:08 AM
ABS is a standalone system and has nothing to do with the ECU.

I'm always amazed at guys that think ABS on the track is bad.  If it was so bad why would any of the race teams have it on their cars?


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: Okibi on September 14, 2015, 11:13:34 AM
I'd much rather have it than not. it seems to work really well and cuts in to save me flat spotting my tyres or sliding into solid objects.


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: eviltwinz on September 14, 2015, 01:14:29 PM
^^^ What he said...


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: emmi on September 14, 2015, 04:29:53 PM
Thanks for the info. 

I believe it's a matter of preference and I'm not going to debate or advocate one side versus the other.  It's amazing technology for sure, it's just not for me.


I'm pretty sure the programming of ABS and Traction Control used by race teams are completely different from the super safe systems that roll out on factory cars. 


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: mr_hyde on September 15, 2015, 04:44:49 AM
I'm pretty sure the programming of ABS and Traction Control used by race teams are completely different from the super safe systems that roll out on factory cars. 

This is very true.  To clarify, you are putting a '05MSM drivetrain and ECU into your '01 but want to keep the '01 non-ABS brakes?  If that is true, the brakes will be fine and the ECU won't care.  Unless you are doing that to be emissions complaint or another specific reason, you would be MUCH better to go with a standalone ECU.

For anyone wanting to simply pull the plug on their ABS system, a good deal of the rear proportioning is done electronically in the unit.  I tried to run mine with the ABS unit off (toggle switch in '90MSM) exactly once and the extreme rear bias from triple digits made skid marks in more than one connotation.   :shockeyes: :shockeyes: :shockeyes:


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: emmi on September 15, 2015, 08:56:15 AM
I'm pretty sure the programming of ABS and Traction Control used by race teams are completely different from the super safe systems that roll out on factory cars. 

This is very true.  To clarify, you are putting a '05MSM drivetrain and ECU into your '01 but want to keep the '01 non-ABS brakes?  If that is true, the brakes will be fine and the ECU won't care.  Unless you are doing that to be emissions complaint or another specific reason, you would be MUCH better to go with a standalone ECU.

For anyone wanting to simply pull the plug on their ABS system, a good deal of the rear proportioning is done electronically in the unit.  I tried to run mine with the ABS unit off (toggle switch in '90MSM) exactly once and the extreme rear bias from triple digits made skid marks in more than one connotation.   :shockeyes: :shockeyes: :shockeyes:

Thanks for clarifying. I'm swapping most of the entire MSM into my 01 LS with Sport S package which iirc uses the exact same brake set-up (minus abs) as an MSM.  Because I'm a Cali resident, I'm going to swap everything first and BAR the car.  Then start the mod party.


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: mr_hyde on September 16, 2015, 05:04:28 AM
That will be a nice project.  In CA, I completely agree to do it 'correctly' and get the state to sign off on the entire swap.  Once that is done, you can go back and do it correctly...


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: '95MSM on September 20, 2015, 05:52:31 AM
I'm pretty sure the programming of ABS and Traction Control used by race teams are completely different from the super safe systems that roll out on factory cars.  
Very true of the top level series, but back in the day, the MSM was raced in a Touring class with limited mods, like adjustable brake proportioning. The driver/owner I swapped info with only found one track where the car was faster without box-stock MSM ABS (but I assume with a proportioning valve). That track was Sears Point, which I'm guessing you are familiar with since you have experience at Laguna. My guess is that he used the brakes to rotate the car more quickly in the hairpins.


Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: gtred on November 09, 2015, 10:17:54 PM
The car won't brake right if you merely unplug the abs.  The MSM does not use a rear proportioning valve, while it uses similar sized master clyds and larger rear brake cylds than other NB's... which, without the ABS, will lock the rear brakes prematurely.  It seems to use the abs system to balance the brake bias/ control rear lock up.

Yes, as previously stated, ABS is great for a racecar... if you have a racing ABS system.  The MSM ABS is not one of these.  For me, the MSM ABS really gets in the way of my thresh-hold braking confidence.  When I stand on the brakes, I just can't "feel" when I'm getting close to lock up.  The car doesn't get "light and funny", you don't hear a little bit of tire squeel,  the pedal doesn't pulse... the pedal just gets hard; "stand on it with 2 feet" kinda hard but "you're not stopping any faster".



Title: Re: Will Disabling ABS put ECU in panic mode?
Post by: ECEng on February 03, 2016, 10:17:40 PM
I don't mean to dig up this "old" thread, but I just want to clarify something with ABS. 

With our older cars, where ABS was very premature, the system lets you brake at the very limit of useful braking, it only interferes once you start locking up a wheel.  In this case, that locked up wheel is not providing any grip at all, ABS bringing that wheel up to speed again will only shorten your stopping distance (compared to locked up) and help maintain vehicle control.

Fast forward to today's ESC/ABS systems such as that found in a FR-S.  These are much more advanced where even a "bad" calibration will not "cause you to almost crash".  And if the ESC system is the same as the BR-Z (99% chance it would be the same...), the ESC is better at controlling the car than 99% of the people out there - it is a very well tuned system.  With the one wheel hitting the gap and locking the wheel, ABS of course will pull fluid out of that corner's caliper, thus reducing the wheel speeds.  But with today's CAN bus monitoring rate and pump speeds, the wheel is brought back under control and to maximum braking ability usually within 50 milliseconds.  The great thing with modern ABS, all the wheels are controlled completely independently.  ABS working on that 1 wheel will not effect the other 3.  IF ABS ended up controlling all 4 wheels in this system, it is due to the driver (driver pressing harder on the brakes, whether from surprise or from the bump or anything else).  If you had a data logger in the car, monitoring longitudinal forces, I'm sure you would not see a perceivable drop in deceleration longer than 50-100ms (from the tire locking up and spinning back up to reference vehicle speed).  But to say that ABS made you "almost accelerate" and crash, I would have to say that is just "driver feeling" and not in any way quantifiable with data.  You may not like the feeling of ABS (especially as the pedal kicks back at you from pulling fluid out of the system), but it definitely does not make a car unsafe.  If the FR-S had ABS deactivated during a maneuver such as the one stated, I'm sure either the locked wheel would never recover, or the stopping distance of the vehicle would have been significantly longer than if ABS was activated (either from wheels staying locked or from the driver manually pumping brakes to regain control).


I'm not saying it isn't your right to disable ABS or to say you like to drive without ABS, I just want to make sure there is no false information floating around - especially for those that are not as experienced in driving.

Source - ABS/ESC is what I do for a living