I hate cars

I bled my Rotora BBK finally today. Everything about these brakes is great. However I still have the same problem with ABS being waaaay too intrusive.

This is completely rediculous, almost funny how terrible the ABS is on this car. I took it out and did some tests today with measured stopping distances. I also did it with the ABS off to see just how front biased the car is.

I hope you guys realize how big of a deal this is..... I took off 32 feet of stopping distance by disabling the ABS and modulating it myself! I do have to explain this however....

The car had an all time best of 201' from 80mph without the ABS which feels extremely good. Of course this is without measuring equipment which is why I tried to get a good number of stops for an average.

If I just slammed the pedal down it felt like there were no brakes and it took 233' to stop. If I applied pressure aggressively and held it right where it would pulse the ABS a few times I stopped somewhere in the middle of the two numbers.

Something has to be done about this. 32' might as well be a mile when you're on a track or trying to avoid something.

I've heard the the manual transmission control module and/or sensors might be set up a little more aggressively... Is there any truth to this? I may go and put it on the scanner soon and look into the ABS system but I highly doubt there's a way to alter any parameters.

It just seems like the super conservative ABS in this car will not allow it to take advantage of the sticky tires. It's rare to get a screech out of the tires. It's happened exactly twice ever with my foot planted through the floorboard.

I've tried it with VSA off and it seems to be a little more aggressive but that could be my imagination.

And a big question for those of you that hit ABS regularly (Inaccurate lol). How exactly does yours pulse? Unlike other cars I've driven that usually have a very pronounced quick pulse, the TL seems to have a very slow large pulse but it's humming the whole time almost like it's not working right.

TRIOD3SIGNS

By and large the ABS is there to give you steering control to avoid a collision. GRINDING YOUR FOOT INTO THE FLOORBOARD to avoid a collision is a reflex for most drivers. NOW if it were straight for track use or all lanes on the road had 3 foot barriers holding us in, then yes, NO ABS would be OK on dry days. Maybe a disabling button like we have for our VSA. Have you disabled the ABS & try to manouver the car around after locking... you can't. I know you are leaps & bounds better at driving than most, which is why you might feel limited, but think of the little guys..."ME" LOL

Now NO ABS & WET ROADS.....I'm not even gunna go there

NAiL05

Dunno I hit ABS last night in some slick rainy weather on the 6mt. It felt interesting the car stopped. I dunno I guess the pulses were pretty fast. I see where you are coming from though owning older cars with no abs. But its nice to have when one of these days your not paying attention and you need it in the wet. IMO its useless in the dry.

junktionfet

For what it's worth, when I was on the track my ABS never engaged, even when the brakes were in good shape. I used full braking force, but of course they aren't panic stops--they are quick but progressive applications of the brake pedal. The grippy tires and track surface worked together and the tires never locked.

I did get a few split seconds of ABS pulsing when I started trailbraking heavily. As one side of the car got unloaded and the pedal was still pretty heavily applied, I could hear/fear a little something. It went away though--undoubtedly because I was releasing the pedal at that point, and also perhaps due to the Electronic Brake Distribution sorting things out.

One of the things I don't like about our cars is the Emergency Brake Assist. I know why they include it in the car, but I wish it wasn't so sensitive OR that it could be disabled somehow (even if I have to deal with an idiot light on the dash).

At any rate, I've never measured stopping distances, but it does seem like the ABS system doesn't push the tires to the razor's edge of traction. The best ABS system I've felt was the old ATE/Teves Mk II. Some GM cars had it, as well as Peugeot 505s. It was a hydraulic assist unit (didn't have a vacuum booster) and had its issues of course, but the deceleration always seemed so brutal on the Peugeot 505 Turbos I recall. And those cars didn't have inordinately sized brakes or insanely wide tires either.

It was designed to interfere when a tire's speed dropped to 15% or less of the vehicle's speed, and it had a maximum modulation speed of 15 Hz. This brought the tire to near-lockup condition, and the feel in the pedal was quite pronounced, but who cares?

The Honda/Nissin system seems to kick in well before the tire has lost that much traction, and stays engaged too long--pulsing and therefore interrupting valuable deceleration time. A simple reprogramming may be all that's required to make it kick ass, but I doubt it's an easy task to do so.

Inaccurate

Wow, sometimes I wonder if I own a different TL than the rest of you all. Or, perhaps it's me and my perceptions

I will maybe need to break-out the video camera again so that we can compare our versions of reality. Everyone hates VSA traction control, I love it. Now, my ABS seems to perform differently than other TL's.

My 2006 TL is completely the opposite of what you described. My ABS is very high modulation frequency and barely felt thru the pedal. Plus, I hear nothing unusual.

My previous cars were a 1991 Acura Legend coupe (mine) and a 1993 Acura Legend sedan (wife's). With both of those old cars, the ABS was crude. The ABS modulated very slow and jerked the car as the ABS locked/unlocked the wheels. And, the pedal felt *very* harsh and scary under my foot. The brake pedal would be jumping up and down under my foot. It was a very unpleasant experience.

With my 2006 TL, I barely feel the pedal vibrate under my foot with ABS engaged. And, please note that I always drive barefooted. I never feel the ABS jerking as the ABS locks/unlocks the wheels. And most importantly, the ABS is sampling/modulating super quickly. If I had to take a WAG, I would say maybe 20 times per second.

IHC, I am a bit confused by your wording. You say that the ABS is too conservative. That is, the ABS is to quick to engage preventing good braking. However, the ABS will not engage until it sees the wheel(s) locked-up, which is the max braking force for that respective wheel(s). So, the ABS can not be engaging prematurely.

However, I can see how the braking distance would be longer with the ABS engaged. The ABS must lock/unlock the brakes (aka, modulation) to test the available traction. Thus, there is a significant period of time (dwell) where the ABS has the brakes well below the threshold of traction.

When the ABS engages, the ABS will limit the braking that you requested. A person mashes the brake pedal, and the car *refuses* to apply the brakes . This *is* scary and aggravating. I experienced this with my previous tires when they were worn-out.

I jumped to the conclusion that the damn ABS nearly got me into an accident because the ABS refuse to cooperate with my demands. This is just human nature. A person will often hate/blame someone that presents bad news. This applies to the ABS too. Later that evening, I realized that the true blame was me driving too fast with those worn-out tires that could not support that rate of deceleration. And I realized that evening that the ABS was my friend, not foe, and prevented me from making the situation worse if I locked-up the front wheels and lost my steering.

In closing, I would like to repeat. I do agree that the braking distance is longer with the ABS. There is a significant period of time (dwell) where the ABS has the brakes well below the threshold of traction as it samples the traction available. I can see how this would hurt the braking performance.

Bender

With my jeep I just pulled the ABS relay. Brakes worked much better than they had ever in the past, especially with the large tires.

With my MT, I feel that it stops on a dime. Now if it was only a Jewish car and would pick it up too.

junktionfet

Inaccurate, I understand what you're saying, but there are some clever features of ABS systems at play.

While some lockup may initially occur, consider that wheel speed is not digital--a wheel isn't "stopped" or "turning"... there are many subtle levels. The ABS system will of course do its job if a wheel actually stops turning (lockup), that's simple, right?

But the ABS ECU also monitors wheel speed and will start modulating brake pressure when lockup is perceived to be imminent. In other words, if a wheel is spinning x% slower than the ECU thinks it should, brake pressure is modulated in order to keep the wheel speed above that threshold. What's being said here is that it seems like that threshold is set too low... the ECU should allow the wheel to come even closer to "lockup" before it starts intervening.

The problem with early intervention is that those short moments in time where the pressure on the caliper is reduced or zero adds up, and the net result is that the brakes aren't working as hard as they theoretically could. Therefore braking distances are artificially lengthened.

If the the system allowed more wheel slip, you'd sacrifice very little in terms of lateral traction/steering and have more overall "on" time for the brakes. I have a ATE/Teves handbook from the 80s that shows lateral traction plots in dry and wet conditions, and in the dry, a tire actually has marginally more lateral traction while slipping than it does otherwise... up to a point of course. My guess is that the engineers in our case chose a very conservative slip coefficient.

I hate cars

That is exactly right, I could not have said it better. To sort of prove it I could beat ABS by about 4-5' with the stock tires but 32' with sticky tires.

While there is a HUGE cornering increase with the good tires there's much less of a change in braking.

If I pretend the car does not have ABS and try and modulate myself it stops much faster but once the first pulse starts it's all over.

Inaccurate, you described the operation of mine perfectly so I guess there's no defect.

To those who are comfortable doing so, try the braking with the fuse pulled especially if you've upgraded tires and you will see what I mean.

Inaccurate

junktionfet,

I agree about the wheel speed delta triggering the ABS, and not an absolute lock-up. I guess I was thinking in too simple of terms.

Thank you for pointing out how the oem system is too conservative. I now understand.

I agree that the oem system is hyperactive to react. The traction control is the same way. I was shocked last week to see how the VSA kicked-in so early with hydroplaning. I had hit a large patch of standing water on the freeway. I had my cruise control set at 55 mph. I was aware of the standing water as I traveled thru it. I then saw the VSA triangle blinking. I immediately concluded that I was hydroplaning. However, it was very mild and I could not sense the hydroplaning. So out of curiosity, I took no corrective action. I was surprised to see that the car *disengaged* the cruise control on it's own in reaction to the prolonged hydroplaning.

Jackass

My '05 6-speed I would describe the same as Inaccurate described. I feel nothing, but hear a light growl when the ABS hits. There is no pedal change when the ABS hits. Now in previous cars this was not the case.

1995 Probe GT -- Pedal came back up when ABS hit and the growl was fast and loud. Scared the crap out of me the first time the ABS hit and the pedal started coming back up. This was my first car with ABS.
1999 Z-24 -- Pedal sank and pulse was much slower and car jerked all over when ABS engaged. It was more of a grinding/clicking noise than a growl.
2002 Grand Am -- Pedal gets soft, very light growl, and overall smooth.
2006 tC -- Pedal came back up a bit, light growl, very fast modulation, and overall smooth.
2005 TL -- Pedal remains the same, very light growl, very fast modulation, car remains very smooth and usually would never know ABS was on other than the flashing light on the dash.

I do not drive like a mad man these days so it is usually only in the snow/ice that my ABS hits. All of my previous cars were all tested to their limits multiple times.

Silva-type-s

iTrader: (3)

i can see why you hate cars

AtlM5

I too think that the ABS sets in way too soon. Right before this stop sign there is a spot where the road dips down a little because the road was repaved and every time I'm going over 10mph and try to stop my abs sets in. My ABS modulates pretty fast but it definitely vibrates a lot; it feels like I'm dragging the front of my car on the ground and I hear a grinding sound.

I hate cars

I had a crazy idea to remove every other tooth from the reluctor rings on the wheel speed sensors. But with my luck the computer compares the vehicle speed with the wheel speed sensors and would not work right. However if it worked the computer should see half the deceleration rate and half the wheel speed. If I could easily remove these things and buy new ones cheap I would try it but probably not yet because there are many potential negatives.

NAiL05

Well the sensor does detect the current pretty much a hall effect as I recall. You might be able to get away with making a spacer decreasing the strength of the magnet slightly. It can't be too much or it will trigger the ABS light. I am not sure what the spec requires but that would probably cut in a less aggressive ABS interruption when your braking. Dunno how well that would work just a random idea that just popped up. Not sure if that sensor has a minimum/max voltage it needs to see or its just there to count teeth to sense. Need to look more into it.

BG74

I think the 6MT must have a different logic because both my '05 and '07 with Brembos stop so aggressively that not only do the tires chirp (almost squeal), the sunroof shade slams closed on its own.

Also, don't forget about the brake assist system - hopefully it's not still active with the ABS disabled.

phee

iTrader: (5)

2nd gen abs sounds completely different. mine is so fast it almost feels like my pedal is shaking.

CSWBiggs

if you're really threshold braking...you shouldn't be creeping in on the abs :P

trail braking shallow into a turn is a true test of you ability to sense lock up

-Jason

I hate cars

I think the whole problem is that the trigger for ABS is not just one wheel comparative to the other wheels, it's absolute deceleration of a wheel even if all 4 are decelerating at the same rate. In other words it's calibrated for stockish deceleration levels regardless of whether all 4 are decelerating at the same rate. I wish it were only based on comparing all 4 to one another or at least a much higher deceleration rate to trigger it. This has to be the only reason I can beat ABS by such a large margin.

I do like it a little and I tend to use it more with the larger front swaybar. It locks the inside front tire much easier when trail braking so it's nice to have the system back off that one tire. But straight out braking in perfect conditions is seriously hindered. I have a rental car right now with mine in the shop and I do have to say the TL does stop very well. I had to do several ABS stops in the rental on the way home and they were nowhere close to the TL.

Inaccurate

You must had known that I was going to comment on this one.

No way is the oem system limited to a fixed level of deceleration.

You seen my 0-60. Now, apply that same level of performance to the braking.

The only time in my life that I have felt this level of braking was with my GS1100 motorcycle with a full-race slick (no treads) on the front tire. Granted, my diet can't match that motorcycle, but it does spark my memories.

As you recall, I have my weight (what little is remaining) sitting over those front wheels. Brakes are to grip the rotors to the point of lock-up. Beyond that, It comes down to traction. You know I have the traction (0-60) with that weight over those front wheels. It is far beyond oem levels of deceleration.

No way is the oem system limited to a fixed level of deceleration. As I have progressed with the diet, I too had concerns/fears of how the onboard computer systems would react to such off-of-the-chart parameters. I knew that the diet would be pushing the computer’s programming windows. With nearly a 1000 pounds removed --- How is the ABS going to react? Will the PCM be able to shift gears quick enough? Will VSA be able to provide safe corrective action? Are there some unforeseen programming that could be triggered with all that weight gone?

However, I am happy to say that my fears have been unfounded. The computer systems (vsa, abs, pcm, ecu, srs) have done an excellent (flawless) job of handling the extreme set of operating conditions that the diet has thrown at them.

Inaccurate

BTW - Stop beating on that rental car

Just joking. Do few 100-0 ABS stops for me too before you return that "monster".

I hate cars

I hear what you're saying. But we need to explain the 32' stopping distance between abs and no abs.

Can you do me a favor? Try your car with no abs and post the results?

Also, what is the overall diameter of your tires? I was actually thinking of using 18" a-specs with 265/35 tires for a slightly larger overall diameter to see what changes may happen.

Don't get me wrong, after driving the rental car (Pontiac G6) I realize that the TL is in another class and I tend to complain but I still think there's a lot more left in the braking distances.

Inaccurate

Sure. Can you please refresh my memory on what fuse to pull?


I am using the Michelin PS2 in size 235/40-17. These are 24.4 inches and 21.0 lbs.

n3o

iTrader: (2)

Pull the ABS fuse. Problem solved.

Bender

Pull the fuse/relay, you may have a light on the dash come on but you can put a piece of tape on that if it bugs you. I personally hate abs.

NAiL05

Or yo ucan just pull the bulb.