Improving My ABS's IQ

I like having ABS for a track car if for no other reason than it saves me from flat spots. However, whenever I pick up a wheel on trail throttle on the Daewoo the entire system goes into glide mode, which is exciting in the sense that golfing in a lightning storm will stir the senses.

Is there anyway I can stop it from doing this? Maybe disable the ABS for the rear wheels only? Right now I just pulled the ABS fuse, but I'd like a more sophisticated solution.

Could you relocate the rear sensors to the front ABS rings so there would be two sensors at the each of the front wheels?

How about fixing the suspension so you don't lift a wheel?

MrBenjamonkey wrote: I like having ABS for a track car if for no other reason than it saves me from flat spots. However, whenever I pick up a wheel on trail throttle on the Daewoo the entire system goes into glide mode, which is exciting in the sense that golfing in a lightning storm will stir the senses. Is there anyway I can stop it from doing this? Maybe disable the ABS for the rear wheels only? Right now I just pulled the ABS fuse, but I'd like a more sophisticated solution.

drive slower around corners?

srsly, there's no way to fix what you're seeing, other than to not lift the inside rear while braking, or to not brake while the inside rear is off the ground.

how about splitting the signal so that both wheels feed to the ABS at the same time. This way you would have to lock BOTH rears to enable the ABS

Never brake in a corner, particularly with a FWD car. Straightline braking only. Learned that a long time ago. That will cure your problem.

well.. that is very true too.. it's a good way to find yourself going backwards

iceracer wrote: Never brake in a corner, particularly with a FWD car. Straightline braking only. Learned that a long time ago. That will cure your problem.

so trail braking has no place in a FWD car? ever?

it CAN be used to bring the rear around. I used to use it when rallying

I am surprized that there isint an abs equaivelent of megasquirt or ecm projectdotcom. I could understand why aftermarket manufacturers might want to avoid something like that, but managing and tuning an abs system sounds easier that managing a modern efi engine.

HappyAndy wrote: I am surprized that there isint an abs equaivelent of megasquirt or ecm projectdotcom. I could understand why aftermarket manufacturers might want to avoid something like that, but managing and tuning an abs system sounds easier that managing a modern efi engine.

get the A/F wrong and your car runs poorly. under- or over-brake a corner at the wrong time and you crash.

gimpstang wrote:

iceracer wrote: Never brake in a corner, particularly with a FWD car. Straightline braking only. Learned that a long time ago. That will cure your problem.

so trail braking has no place in a FWD car? ever?

It works well on dirt to get wrong-wheeled drive cars to turn. Guys who are trying to keep the boost up left-foot brake them too.

I've not done a lot of on-track antics in a FWD car but I trail-braked a Mini without much trouble. There might have been a better way to get it to turn... but when you are a hammer - everything looks like a nail.

probably what you've got is a two-sensor, single channel rear ABS. the system can see that only one tire is locked up, but only has one channel to do anything with, so it turns loose of both rear brakes to get the one tire to turn again.

this was a huge limitation to my rsx in autocross back when i had it. it would turn in nicely with a little trail braking, but as soon as the inside rear lifted the abs would let go of both rear brakes, and the car would start plowing. so annoying

HappyAndy wrote: I am surprized that there isint an abs equaivelent of megasquirt or ecm projectdotcom. I could understand why aftermarket manufacturers might want to avoid something like that, but managing and tuning an abs system sounds easier that managing a modern efi engine.

The stability control thresholds can be adjusted on my E46 M3 using BMW's NCS Expert software to reflash that partiular computer, and many guys with 2003.5+ cars have programmed the same "track mode" with higher intervention thresholds that the CSL option gives. I haven't gotten that far into programming yet - I still can't get the simple program to enable remote window closing to work - but it can be done.

modernbeat wrote: How about fixing the suspension so you don't lift a wheel?

A tiny amount of lift = maximum weight transfer from rear axle to front axle = minimum amount of understeer for a FWD car.

I don't think I want to "fix" the suspension problem.

Strizzo wrote: probably what you've got is a two-sensor, single channel rear ABS. the system can see that only one tire is locked up, but only has one channel to do anything with, so it turns loose of both rear brakes to get the one tire to turn again. this was a huge limitation to my rsx in autocross back when i had it. it would turn in nicely with a little trail braking, but as soon as the inside rear lifted the abs would let go of both rear brakes, and the car would start plowing. so annoying

There is a sensor at each wheel, but it's actually worse than what you describe. I think the entire system is single channel. When one wheel locks/lifts it sends all for wheels into glide mode. Something like this:

Brake- brake- turn/brake- no brakes holy crap here comes the tire wall.

It's something of an understatement to call this frightening.

I tried pulling the ABS fuse for this last track day and got to deal with both the rear wheels locking up well before the fronts.

I finally put the fuse back in and just stopped trail braking, which kind of sucks because my car turns really well with a touch of trail brake.

Wonkothesane wrote: To elaborate on what Ross said, what if you were to just split the front pickup off so that it got passed to the rear as well. It's not like you're really locking up the rear end of your FWD hyundai anyway :)

You'd be surprised.

pigeon wrote:

HappyAndy wrote: I am surprized that there isint an abs equaivelent of megasquirt or ecm projectdotcom. I could understand why aftermarket manufacturers might want to avoid something like that, but managing and tuning an abs system sounds easier that managing a modern efi engine.

The stability control thresholds can be adjusted on my E46 M3 using BMW's NCS Expert software to reflash that partiular computer, and many guys with 2003.5+ cars have programmed the same "track mode" with higher intervention thresholds that the CSL option gives. I haven't gotten that far into programming yet - I still can't get the simple program to enable remote window closing to work - but it can be done.

Do you know anybody I could talk to about this kind of thing?

MrBenjamonkey wrote:

pigeon wrote:

HappyAndy wrote: I am surprized that there isint an abs equaivelent of megasquirt or ecm projectdotcom. I could understand why aftermarket manufacturers might want to avoid something like that, but managing and tuning an abs system sounds easier that managing a modern efi engine.

The stability control thresholds can be adjusted on my E46 M3 using BMW's NCS Expert software to reflash that partiular computer, and many guys with 2003.5+ cars have programmed the same "track mode" with higher intervention thresholds that the CSL option gives. I haven't gotten that far into programming yet - I still can't get the simple program to enable remote window closing to work - but it can be done.

Do you know anybody I could talk to about this kind of thing?

Sure. Somebody at BMW. Not likely to help your (edit) Daewoo.

A few posts back, you said you're getting maximum weight transfer from inside rear to the front, which is not exactly true. You're not lifting the tire due to braking, you're lifting the tire due to cornering. Take away the braking and you can generate enough lat to lift the inside tire, but take away the cornering and there's no way you can generate enough long to lift the rear.

HappyAndy wrote: I am surprized that there isint an abs equaivelent of megasquirt or ecm projectdotcom. I could understand why aftermarket manufacturers might want to avoid something like that, but managing and tuning an abs system sounds easier that managing a modern efi engine.

I've dreamed of this forever. Would be great for high-end trac control/launch control/different rally modes, etc.

Could one use the GPIO? Or not enough guts?

http://www.msgpio.com/

I think the only way to fix your problem is to fix the suspension so the rear wheel doesn't lift off the ground. In the short term you could try disconnecting the rear sway bar (if you have one) and see if that helps. A bigger front sway bar will help the rear stay planted - perhaps at the expense of more tendency toward understeer, but if you're trail braking you can overcome that. Coilovers would give you all the adjustability you need, if you can get them for a Daewoo.

MrBenjamonkey wrote: I tried pulling the ABS fuse for this last track day and got to deal with both the rear wheels locking up well before the fronts.

I guess the next decision is whether to attack the more difficult but preferable ABS fix, or to take the (relatively) easy way out and install a brake proportioning valve so you can at least make the "unsupervised" system behave in a reasonable fashion.

Sucky, but a lot simpler than re-engineering an ABS system.

I once forgot to pull the fuse on my Neon. After I removed to poo from my driving suit, I went home and removed all the ABS components from the car.

I was a bit surprised to read to "Can't trailbrake in a FWD" comment. I have not found that to be true, as my statement would be, "You gotta trailbrake in a FWD."

White_and_Nerdy wrote: I think the only way to fix your problem is to fix the suspension so the rear wheel doesn't lift off the ground. In the short term you could try disconnecting the rear sway bar (if you have one) and see if that helps. A bigger front sway bar will help the rear stay planted - perhaps at the expense of more tendency toward understeer, but if you're trail braking you can overcome that. Coilovers would give you all the adjustability you need, if you can get them for a Daewoo.

Even if he were to "fix" the "problem" of lifting a rear, that wheel would still lock almost instantly and put the system into glide mode anyways.

The morning, it is early, and my brain, it is... Affected. But...

If you added a proportioning valve to get the bias to where the rears didn't lock so early with the ABS unplugged, would that then raise the threshold at which they try to lock and trigger ABS glide mode?