I want to remove ABS

[Magpie]

My choice would be MCA Gold, however my days of spending large amounts on my car are over. From others Red would be more than enough.

[zero00]

No, never met you as far as I know, just that for all MX5 owners there is an open invitation to attend Automotive Plus/GT Auto Garage Open Day between 10-2 as it would appear you are an enthusiast it may appeal to you

Always a good chance to talk to other owners about your plans etc, see what mods others have done etc

Free food and drinks provided and great displays

[zaibatsu]

Please use google for the love of God.

This thread has a lot of correct information that is in contrast to everything you said, but I'll start by saying that because you read something on google, it does not mean it is correct. In fact, I think because ABS is surrounded by a lot of old wives tales, rather than actual engineering-based descriptions, there is unfortunately a very high percentage of misinformation on the internet about it.

I will try and summarise the key points as to why you are completely incorrect:

1. "Threshold braking" as you read about it (often from drivers and armchair experts, not engineers) relies on the driver braking as hard as they can without completely locking up a wheel (as maximum braking traction is obtained at approximately 30% slip, with 100% being a full lockup). The rarely-acknowledged fact about this method is that you only have the "threshold" of the tyre with LEAST available braking traction.

2. Because F/R biasing isn't directly proportional to brake induced load transfer (let alone L/R load differences due to cornering or road irregularities), this means that a majority of the time (i.e. in most real scenarios), to obtain minimum stopping distance on a vehicle without ABS you will have to have one or more tyres locked up. The reason for this is that while one tyre is at the ~30% slip threshold, other tyres may still be at 0% slip and thus heavily under-utilised. Put very simply, a car without ABS has a very poor ability to distribute the braking force applied by your ONE foot over FOUR tyres that are experiencing different loads, thus different normal forces, thus different friction forces.

3. Enter the world of ABS. Most modern cars have 4-channel ABS, thus each wheel is monitored individually. When you brake hard, if one wheel exceeds a desired slip threshold, the braking force to that wheel is reduced while other wheels can continue to brake, and this process continues until each wheel is at approximately the correct threshold. What this means is that not only can you brake without locking up and potentially flatspotting an expensive soft-compound tyre, but you can actually stop in a SMALLER distance than you could without ABS. Why? Well I already explained that - brake force proportioning based on actual available traction (to individual wheels) in a car without ABS is very poor because it has a) no way to monitor individual wheel speeds, and b) fairly archaic systems to actually distribute force anyway. With ABS, you not only prevent lockups, you gain a system that can MONITOR and RESPOND to dynamically available traction at each tyre.

In regards to the practical scenario, all that's likely happening (assuming a correctly functioning system) is one of your wheels is experiencing a very low normal force, for example braking hard into a sharp corner on a mountain run results in reduced braking traction on the inside front wheel in comparison to the braking force applied to it by a non-ABS system. In most likelihood what you are feeling is the system proportioning that braking force to wheels with traction - whereas without it, you would almost definitely be locking up that wheel, and by simply pulling the fuse, also potentially doing more damage (eg. F/R biasing being negatively affected) because the system is designed around proportioning based on functional ABS. It is VERY unlikely (read: almost impossible) that you would actually be decelerating faster in this scenario without ABS.

Unfortunately like I said, this is (strangely) a subject that is misrepresented by MANY people. I think if you speak to an actual vehicle dynamics engineer however, particularly someone who is aware of the fine details of the workings of a stability control system (for example), you would find they will agree with the information I have given.

My suggestion? Bleed the brakes and make sure the ABS rings aren't damaged. Enjoy your car, maybe throw some stickier tyres on it, you've got one of the best MX5s made in my honest opinion.

[Magpie]

Some light Reading attached to support the previous post.

The braking system of racing cars can be characterized by the relationship between three variables: brake pedal displacement, brake pedal force, and vehicle deceleration. The relationship between pedal force and pedal displacement determines the stiffness of the brake pedal. The relationship between pedal force or displacement and vehicle deceleration is a measure of the sensitivity of the brake pedal. Note that electronic assistance systems such as anti-lock braking systems (ABS) or electronic brake-force distribution (EBD) are generally not permitted in car racing. To brake as effectively as possible, the driver should use the grip offered by the car and tires to its maximum potential. This can be achieved by late braking and adopting a threshold braking technique; in other words, rapidly reaching the maximum possible deceleration (buildup phase) and then modulating the brake pressure to keep the slip ratio of the tires at the optimal value (modulating phase).

The automotive anti-lock braking system (ABS) is an active safety device. It could prevent the wheels from locking when braking and avoid the rear wheel sideslip and wheel spin and loss of front-wheel steering ability, and improve the vehicle utilization of the ground adhesion ability, so as to improve braking stability and maneuverability and reduce braking distance. In this paper, the automobile ABS was established and simulated in the Simulink environment and then simulation curves is obtained. It verified that the ABS has excellent direction maneuverability and braking performance.

[M1474]

Most modern cars have 4-channel ABS, thus each wheel is monitored individually.

Do NBs?

My wife's 2007 Mazda 3 seems to reduce braking pressure to all 4 wheels if one begins to skid, hard to believe ABS would be better in a car 5 years older.

With a modern ABS, if for example the left front tyre has low traction and the system releases brake force to it yet maintains maximum braking to the right wheel, what prevents the car from pulling to the right?

Cheers.

[greenMachine]

Another vote 'for' here.

I have invested much time, energy and money getting the ABS working right in the racecar.

Why? Two parts to that answer. On my OLT, Oran Park turned on the rain, and it was a handful. Especially the test set up at T1. It was most instructive to stand on the pit wall and see the Golf R32(?) braking hard, every single time, without more than a tremor. Rain is supposed to be the great equaliser, right? No, at the end of the day when we had our race it was the one car that had ABS, and the rest of us - we had some great dices, he just disappeared into the distance. The second reason is repeatability, and general level of confidence. I am not a Senna, and my ability to react, my skill level, is somewhat lower. The ability to brake hard, no lockups, maximise the breaking effort at every wheel, makes my racing cheaper, safer and more enjoyable, and yes, even faster!

My one reservation is the onset of the ABS intervention, and the character of the intervention, and whether there is any margin left in the system that could be exploited by reprogramming the ABS computer (or by a more skilled driver braking without ABS). The Bosch literature for their racing ABS units (programmable, adjustable, no doubt prodigiously expensive) contains several hints at this, but I have seen no comparisons, no quantification of the difference. I asked on the big board if anyone had hacked the ABS, seemed like the answer is no, so it is not possible to look at the setup and answer these questions.

Most modern cars have 4-channel ABS, thus each wheel is monitored individually.

Do NBs?

My wife's 2007 Mazda 3 seems to reduce braking pressure to all 4 wheels if one begins to skid, hard to believe ABS would be better in a car 5 years older.

With a modern ABS, if for example the left front tyre has low traction and the system releases brake force to it yet maintains maximum braking to the right wheel, what prevents the car from pulling to the right?

Cheers.

The answer is given in a couple of the posts above.

[Charlie Brown]

Whilst I fully endorse the “yes” for ABS brigade, I do think that you need to check your ABS system.

Why, because I had an instance where the ABS would kick in under very light braking load at around 5kph. The reason was a faulty ABS ring on a new front hub.

The first check I do is to remove and clean all the ABS sensors from the four wheels and refit them. Then drive back to the section of road you experienced the problem and sensibly see if it re-occurs.
If it still does, then head off to your local brake shop and have them connect the car to their diagnostic system to run a test on the full system. If there is a sensor problem this will show up and you can replace the sensor and rid yourself of the pulsation pedal.

Oh and get yourself down to the track with your old shocks as you’ll learn so much more about car control than you will when you have a new set fitted. That way when the new set arrives you’ll be way better.

[taminga16]

Sound advice, thank you CB, you have saved me the pixels.
Greg.

[toadcat]

From some of the posts here you'd think no one could have ever dríven or ridden a motorcycle before the last few decades and lived to tell the tale... These are some of the points I'd like to make:

1: ABS does not always mean you will stop in time for whatever the hazard is on the road. ABS or not, the far more important factor is your driver awareness and hazard perception skills. You should be able to recognise and drive defensively to a point where you very rarely need braking anyway.

Early ABS DOES NOT out-brake non-abs driving - assuming IDEAL conditions.

There are two points here: with practice and training you can comfortably outbrake a relatively early ABS system such as on these cars, especially with good fresh fluid and decent lines. And practise.. I've gone through 3 front tyres on different motorcycles and almost a set of tyres in ~20,000kms from incessantly practising emergency stops in vacant industrial areas.. If you aren't beating an ABS'ed NA you haven't practised enough. No ABS allows you to brake to 99% while ABS reacting and cutting the system back lets you brake to ~95% (numbers made up but that is what I can feel from the tyres). The problem here is if you make a mistake and lock the wheel for any period of time you can flatspot them ($$$) and can potentially really upset the car (esp if trail braking) and lose control. If you aren't on it and immediately reduce brake pressure to allow the wheel to immediately unlock, you will end up stopping further than if you had properly threshold braked which is the only situation you will beat the ABS.

ABS can save your ass big time when you are not expecting the need to slow down. It is useless when you are preparing for turn 1 coming off the back straight - where it shines is when the knob in front chucks the brakes on with no indicator to make the turn off they didn't notice approaching for the last fifteen kilometres.... While its dark, raining, and greasy on a poor road surface... There are also lots of situations where non-abs braked cars can be extremely unstable - go brake hard with the LHS wheels in the wet and the RHS in the dry and watch what happens... In the wet, it is unlikely for most if any drivers to be able to outbrake virtually any ABS system.

ABS provides consistency, but it does not necessarily provide better results.

2: ABS ain't always ABS. There are many different types of ABS systems which are very different in how they operate and give feedback to the driver as well as their fundamental braking capability limited by the amount of channels on the system. For a modern car with 4 channel systems with a system that can electronically adjust the brake bias to each wheel hundreds of times per second, you will simply never outbrake that kind of system with only one pedal for all four wheels and a set brake pressure bias that does not dynamically react to road surface friction changes.

If you go drive an early 90s Falcon with their abhorrent ABS you can feel the brakes coming on and off far slower than you can cadence brake yourself and prevents you from properly threshold braking as well.

3: The brake pedal feel compared to an ABS and non-ABS car is somewhat different. You have far more lines which dull the feel of the pedal. If you feel the point of lock up being reached and the tyres start to sing the pedal then just drops to the floor rather than allowing you to slightly back off and hold it there - i.e threshold braking. On a modern ABS car there the best result (in terms of braking distance) is basically achieved by engaging the system as soon as possible. I don't want a car that interferes with my own inputs when I bought it as a toy to enjoy driving engagement..

Just like long intercooler piping ruins throttle response, having miles of lines connected to valves and ABS-pumps also does it.

[Magpie]

I used to get about 5,000km out of tyres and pads on my motor bike when I was young and dumb. Bike was a KR250 (2 stroke) with a lot of work done to make it go faster.

[Locutus]

Most modern cars have 4-channel ABS, thus each wheel is monitored individually.

Do NBs?

My wife's 2007 Mazda 3 seems to reduce braking pressure to all 4 wheels if one begins to skid, hard to believe ABS would be better in a car 5 years older.

NB8B/C have 3 channel ABS. Both sides of the rear share a single channel.

Here's some information on how modern ABS systems work:
http://www.stoptech.com/technical-suppo ... brake-kits

[M1474]

^,^^ thankyou.

[davekmoore]

So they saved a dollar by not going 4 channel, but at least the much more heavily loaded front brakes are independently monitored and can cycle on and off depending on grip many times a second, thus enabling you to steer as well as to stop.

[toadcat]

So they saved a dollar by not going 4 channel, but at least the much more heavily loaded front brakes are independently monitored and can cycle on and off depending on grip many times a second, thus enabling you to steer as well as to stop.

Yeah that's another point I failed to properly go into... The main benefit of ABS is retaining the ability to brake hard yet still be able to make a swerve without losing control.. A lot of collisions the major factor is not braking distance (as a collision may be impossible to avoid - i.e. vehicle crossing onto wrong side of the road) so retaining the ability to swerve while under hard braking is invaluable. Coupled with the fact electronic stability programs require an ABS system as a base/are essentially a more advanced ABS system they definitely offer a large increase in safety in a lot of situations.

[angusis2fast4u]

I am not a Senna,

not necessarily a response to you but in general, No one will ever become a Senna if we learn to rely on driver aids! most of the worlds best drivers started out in go-karts or driving cars from an early age (i.e. 30 year old driver starting in cars from 20 years or older) - All vehicles which have no aids!

Oh and get yourself down to the track with your old shocks as you’ll learn so much more about car control than you will when you have a new set fitted. That way when the new set arrives you’ll be way better.

Plan on putting them back in this weekend but thanks for the advice, makes a lot of sense and is a very good idea!

From some of the posts here you'd think no one could have ever dríven or ridden a motorcycle before the last few decades and lived to tell the tale... These are some of the points I'd like to make:

Just like long intercooler piping ruins throttle response, having miles of lines connected to valves and ABS-pumps also does it.

FKN LOL! that is so true!

and in regards to the to the comment on longer lines. this was another point which I have been told since starting this thread - pedal feel will be a lot better (i.e giving you a better idea on when the wheels will look up and ABS would be needed) with the fuse pulled - Again I am skeptic on this info as I am yet to read into how much that fuse does..

So they saved a dollar by not going 4 channel, but at least the much more heavily loaded front brakes are independently monitored and can cycle on and off depending on grip many times a second, thus enabling you to steer as well as to stop.

Just learnt the basics ABS hey...


Now I was going through the owners manual and came across this... Does that mean all you people saying the brakes will go to 50/50 are all BS'ing?