I want to remove ABS

[Vat]

Interesting reading here, particularly when you consider that the vast majority of drivers don't hit the brake pedal hard enough to activate ABS, even in accident situations.

I'd go and get the research, but I'm sitting in a hotel room in Honolulu and have better things to do.

This is why manufacturers like Mercedes Benz have introduced driver aids like brake assist, where if the car figures out you've hit the brake pedal in an emergency situation (i.e. cruising along and suddenly you hit the pedal, or you do that and the car picks up that there's an object in front) it'll actually do the rest of the brake pedal application for you.

In the two track days (well, one track and one session) I've certainly been conscious that I need to attack the brake pedal a lot harder.

[MattR]

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..


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?

With regard to shorter versus longer lines, it may seem to have better feel, but that would be other factors coming into play, but in driving an ABS and non-ABS equipped S14 back to back, the pedal feel was basically the same, well as much the same as two different cars can feel.

The length of the lines in the system shouldn't make any difference because the amount of fluid you have to push through the system is dependant on the volume of fluid needed to push the pistons onto the back of the pads and the pads onto the rotors the system is effectively a closed system so the distance the pedal moves is basically the same for equal stopping pressure. If you shorten the lines this won't change the volume of fluid needed to push the pistons and the distance the pedal has to move to displace that volume of fluid. If it did make a difference then the rear brake lines would be equal length, most run down one side of the car if separate from the front, or split on one side of the car if the line is shared to the rear.

There are three ways that I know of to improve the pedal feel of your braking system without changing the overall size of all the pistons used in the system:
1. replace the rubber flexible hoses with braided hoses, this stops the hoses bulging under high brake pressures and therefore less fluid is used and makes the pedal feel firmer. Basically the harder you push the pedal the higher the pressure within the system the more the rubber hose will expand under that higher pressure.

2. brace the firewall/MC to stop the flex so the pedal doesn't move as far by physically stopping the M/C from moving, either a big plate to reinforce the firewall around the M/C or a M/C stopper/brace, and

3. remove or disconnect the vacuum booster, the brake pedal will feel hard as a rock at first, try pushing the brake pedal when the engine isn't running and there is no vacuum in the booster to assist, but will give you a lot more feel of what the system is doing under your foot.

The 3rd option I wouldn't recommend for a road car, especially if dríven by others. With my race cars I don't use boosters as I like the better feel through the pedal I get with a much firmer pedal, and with the S14 I am building I will not be using ABS to save weight and also keeping the system as simple as possible. I am also going up to a 1" master cylinder to better match the calipers I will be using and also future proof if I go to bigger brakes again, if needed as it is easy to "overbrake" a car.

My Charger doesn't use a booster, because it didn't come with one, however I have also upgraded the brakes to BF XR8 calipers and rotors on the front, so if the pedal is too hard I may fit a remote booster in the boot. But with the Charger I will be the only person who drives it so for me it is not an issue if the pedal is very firm.

As your manual pictured above says, and I said back at the start, if the ABS is not functioning, the brake system will function as a normal hydraulic brake system, just no electronics to release braking pressure on the system. The ABS may have an affect on perceived brake bias, in that if a rear wheel locks before a front wheel, it will release pressure to that wheel or both if only a three channel system, but until a brake locks the brake bias will be as designed by the manufacturer.

All pulling the fuse does is disable or switch off the electronics that run the ABS, it has no effect on the hydraulic and mechanical systems in the brakes.

If you do pull the fuse then you are purposely disabling the system and you are making your car unroadworthy. If you have a fuse fail and you ignore it, you are basically making your ABS equipped car unroadworthy.

I use cars in training that we can switch the ABS on and off. One car is unregistered so no problems with what we do with that. The other cars, if they are dríven on the road with the ABS switched off are unroadworthy and if we have a crash with the vehicle in that state we are on our own, so we make sure the ABS is switched on at the end of each exercise.

If you have a crash in an unroadworthy car, and the reason your car was unroadworthy, in this example the ABS was not functioning because you pulled the fuse, or you hadn't replaced the fuse in a reasonable time, you can then be charged with driving an unroadworthy car, plus you may also be charged with things like negligent driving, driving in a manner dangerous, operation of a dangerous vehicle and so on, your insurance company may also wipe you because the car was unroadworthy, and the fault that made the vehicle unroadworthy was a contributing factor to the crash. A good indication in this example is if there is skid marks on the road from your car, and even if you did the best possible threshold brake and were the next Ayarton Senna you would know that one wheel locked up is not a problem and kept your foot at that pressure with the other three wheels turning to stop you in a shorter distance than if you releases some pressure leaving a skid mark on the road from probably the left rear tyre as that is the unweighted wheel due to the road camber, and it is equipped with ABS, then be prepared for a reaming from the insurance company and plod.


So now you aren't putting in the flash suspension you don't have an excuse not to find the $220 for the track day at Morgan Park , I will be able to sneak you in on the car club rate. If you are quick and can get the forms to me over the weekend I should be able to make sure you are in the morning session with everyone else.

Out on the track you can get tuition on your driving, such as braking technique, lines, steering and even basics like how to set yourself up in the car properly so you are balanced and can get the most out of the day.

[Ted]

I see this topic has been bashed around a bit, but I don't get on to this forum much and hope that I can add something constructive. So, don't read anything personal into this.

On a road car, driving on a public road (ie away from a designed race track), ABS is more likely to be felt sooner. There are a lot of factors - undulations, poor state of road, wheel tracks worn into the road surface etc. There is also high road camber to contend with. So when you come into a corner and brake hard, weight bias goes to the front and all of a sudden your 100mm of compression available on the front suspension gets used up and you are sitting about 4mm from the bumpstops. Then the car hits a small bump, and the inside edge of the corner drops away a bit more and suddenly that 4mm is now 8mm on the inside wheel but sitting on the bumpstops on the outside wheel. "Wheel hop" that has been suggested a few times is now on you or just a smidge away. If one wheel gets unweighted enough (in this case the inside one) and there is braking pressure going to it, then its likely it will lock up just momentarily and ABS will kick in. This situation will happen a lot later on a designed race track.

Next, with a booster on a production car with good tyres on a dry bitumen surface, you will find that it requires something like 30-40kg of pressure through the brake pedal to invoke a full lock up or ABS activation. As the surface looses friction, or adds undulations and sharp holes/bumps, the amount of pressure required will reduce. On a slippery surface we could be looking at say 10kg. If you have ever tried a leg press at the gym, you would note that the avg human can push at least double their bodyweight in a leg press action. So to be able to sit at 29kg of pressure is not something simple to regulate. We make mistakes, and its even harder when every other corner has a different level of grip unlike a racetrack. To give an everyday analogy, those who have tried to left foot brake would probably find that they just about put their head through the windscreen. BTW I am not a supporter of left foot braking on the road, but that is a different issue. Most of us are programmed to hit hard with the left leg, and be more gentle with the right. I believe that this is because we operate the accelerator with the right leg and the clutch with the left. So what Vat said above is very true, most of us do not hit the brake pedal hard enough to invoke ABS. But we are not all the same. I have found some drivers who are quite rough with their right leg. These drivers generally sit further back from the wheel and push with their thigh too, and so just struggle to regulate. I have also found a lot of drivers who get pretty close to the threshold point every time. These drivers tend to have a fair bit of driving years behind them, and have been brought up driving poor grip cars on poor grip surfaces, with drum brakes. Or were born in countries with high rainfall or snow and twisty roads (ie NZ, Scandinavia, UK)

Careful when pulling ABS fuses. Not all cars run a dedicated ABS fuse. And the ABS system is used for the stability control system too (not an issue on a NB8B I imagine). So the suggestions of checking suspension and ABS ring condition that angus2fast4u has indicated he will do is good. Check alignment too.

The topic of driver aids will continue to separate. I can only say my view, and that is I do not remove driver aids. I do some work for manufacturers, some of the time on racetracks. There are times that aids get turned off when doing some testing but generally this is with some form of logging turned on. Where the general public get involved, I always run with all driver aids on even on the track or doing quick laps for some clients. I feel that if I invoke any of them, then I have over-driven the vehicle at that point. Yes sometimes its annoying and makes me work harder on less grippy surfaces. But on the road, I also know that poor judgement or application on my part will give me a safety net. Especially the ability to steer around a hazard that I may not be able to stop for.