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Thread: ABS on a track car

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    Senior Member bellwilliam's Avatar
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    Default ABS on a track car

    Is ABS a good thing ?
    When is it a bad thing ?
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    Senior Member vantagesc's Avatar
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    At least one bad example is when ABS is overly obtrusive and steps in when it needn't. The dreaded "ice mode" comes to mind, where the system is tricked and reduces braking force too much, causing the driver to miss the turn all together. The cause of "ice mode" is debated, but sometimes it is attributable to an overly cautious ABS program. The driver can sometimes fix it by getting of the brakes momentarily and then back on.

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    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by bellwilliam View Post
    Is ABS a good thing ?
    When is it a bad thing ?
    IMO it's a good thing in a street car when it's not too intrusive, and when the pulse amplitudes & frequencies are 'proper' (not a huge amplitude pulse).

    In most street cars it's usually a good thing IMO. Depends on how aggressive it is though, I've driven some cars where it was way too intrusive and I definitely could've done a better job without it.

    Some ABS systems let the tire get to threshold, and then once there, they seem to bring the tire back a bit (to what feels like 80-90% of it's ability). Those suck.

    The 335i had a great ABS system. S2000s seem to have good ABS.

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    Senior Member bellwilliam's Avatar
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    R there any high level racing series that allows ABS ?
    Does any formula car allow it ? How about say enduro cars like LeMan 24 hours car ?
    Last edited by bellwilliam; 02-04-2011 at 01:35 PM.
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    Faster than Oli jimt's Avatar
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    +1 on the S2000 ABS. I engage it pretty much at every corner. I'd probably spin right off the track in a car without ABS at this point.
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    Senior Member bellwilliam's Avatar
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    How about when u go into a spin or slide. Does ABS cause the vehicle to act unpredictable ? As abs pulsates.
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    Sir flink
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    I found the Bosch ABS in the GTO to be very good on the track. It just worked. Slam the pedal and let the software take care of everything.

    I have a full race braking system in the e36 race car: dual masters, balance bar, no ABS, no booster. The lack of ABS rather sucks. If you lock a wheel the braking distance is greatly extended which is quite dangerous, especially with inside passing.

    I rarely flat-spot tires nowadays. Mainly because I routinely throw away a little bit of time on each turn.

    Bumps and crests in braking zones become a problem. That bump on the left as you enter the BW buttonhook: have to ease off the brakes over there, else the fronts will lock as the suspension unloads, and they stay locked after the car lands. Similar braking for the corkscrew at LS and the carousel at Infineon.

    Once you get used to it, the main remaining problem is braking-while-turning. The inside tires are unloaded but the braking force is the same on each side. So locking the inside wheels is basically unavoidable. I have to do weird brake modulation things running up into the cyclone at thill to prevent inside-tire lockups.

    In the wet I prefer to madly pulse the brake pressure so that when they lock up, they'll come unlocked a fraction of a second later. Manual ABS. It extends the braking zones but is more predictable.

    It's pretty miserable, but I do like the simplicity of the brakes. There's a pedal, the master cylinders and a T-piece. Nothing else! There's so little to go wrong.

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    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by bellwilliam View Post
    How about when u go into a spin or slide. Does ABS cause the vehicle to act unpredictable ?
    No. ABS pulses are very high-frequency so it's not like the system is slamming on & off the brake pedal....

    I've notice that a lot of newer vehicles actually have too much (for dry track driving) mechanical rear bias built into them. The result is that when you are slightly sideways or doing aggressive trail-braking, the rears sometimes reach threshold before the fronts. So even in those cases, it's still good to have ABS.

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    Senior Member DocNrock's Avatar
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    The GT-R ABS is pretty good. If anything, however, there is a bit too much front bias. I've been running Carbotech XP10's, but just got a set of CL RC6E's for the front and RC6's for the rear. The RC6's have a slightly higher mu than the 6E's, so hopefully that will slightly decrease some of the front bias.

    I ride the ABS in every hard threshold braking zone. I don't use it when trail braking.
    Last edited by DocNrock; 02-04-2011 at 03:12 PM.
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    Senior Member bellwilliam's Avatar
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    Quote Originally Posted by J. Tyler View Post
    No. ABS pulses are very high-frequency so it's not like the system is slamming on & off the brake pedal....
    but does this mean "both feet in" thingie don't apply ?
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    Senior Member bellwilliam's Avatar
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    my questions boils down to:

    do you track ABS and non-ABS any differently ? driving line ? while sideway ? trailbraking ? driving 2 wheels in dirt, 2 wheels on pavement (as in passing) ? braking over curbs ?

    basically, is there a circumstance that you drive one way on car with ABS, another on car w/o ABS ?

    how about setup ? brake pads material ? how about brake pads as in brake bias ? does ABS brakes run hotter than non-ABS one at threshold braking ?
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    Pro Lurker GreyFocus's Avatar
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    when i went from ABS to no ABS in my focus it was actually by accident, i was supplied the wrong wheel bearings unknowling (none ABS wheel bearings) and installed them before a event, and ran the whole weekend, all weekend didnt run into lock up issues, and didnt find out i had the wrong bearings till that monday LOL. So i guess the focus ABS wasnt very intrusive in the beginning, and/or im not to hard on the brakes, but i havent had abs since, and that was 3 years ago. my miata didnt have ABS either, never had issues on track. Despite what some have said, my Z's abs doesntseem very intrusive either, yet others have said other wise, maybe braking style is a big part of it

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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by bellwilliam View Post
    my questions boils down to:

    do you track ABS and non-ABS any differently ? driving line ? while sideway ? trailbraking ? driving 2 wheels in dirt, 2 wheels on pavement (as in passing) ? braking over curbs ?

    basically, is there a circumstance that you drive one way on car with ABS, another on car w/o ABS ?

    how about setup ? brake pads material ? how about brake pads as in brake bias ? does ABS brakes run hotter than non-ABS one at threshold braking ?
    Been a while since I really tried to go fast with ABS, but here we go.

    ABS different?
    driving line: no
    slideways: no
    trailbraking: yes. trailbraking is a little easier
    2 in dirt: yes, it's a little helpful when the dirt tires don't lock. Locked tires rarely help things. a 3 channel abs system might perform worse here though.
    braking over curbs, squirrels, dips, gophers, oil: yes. braking on these surfaces without ABS sometimes doesn't go well.

    brake bias: set the bias correctly so that the car behaves well (trailbraking) before abs engages. After abs engages, it isn't as critical.

    I go deeper into uncertain braking zones with ABS if there is a penalty for failure. For example, curb into buttonhook with traffic ahead or turn 11 in the wet at infineon). The biggest advantage is the ABS generally gets the job done consistantly. Without, if you make a mistake and lock up, the braking distance can increase dramatically and requires quick reflexes (and is counter-intuitive and very stressful). Also, if the conditions are screwy, the ABS will choose the correct pressure and make the most of what's there. The driver would have to guess both pressure and distance without ABS.

    In a spin I still go both feet in. I figure if the car does decide to hook, I'll hope it won't hook as hard if a lot of the tire is already being used for braking.

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    Senior Member robburgoon's Avatar
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    Quote Originally Posted by GreyFocus View Post
    when i went from ABS to no ABS in my focus it was actually by accident, i was supplied the wrong wheel bearings unknowling (none ABS wheel bearings) and installed them before a event, and ran the whole weekend, all weekend didnt run into lock up issues, and didnt find out i had the wrong bearings till that monday LOL. So i guess the focus ABS wasnt very intrusive in the beginning, and/or im not to hard on the brakes, but i havent had abs since, and that was 3 years ago. my miata didnt have ABS either, never had issues on track. Despite what some have said, my Z's abs doesntseem very intrusive either, yet others have said other wise, maybe braking style is a big part of it
    So.... you lost ABS and never noticed?

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    i dont care
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    we had to remove the abs on the robispec mod class evo after first event.. it was dangerous, would completely disrupt braking.

    im sure it depends on what kind of car & abs system if it will work or not on track....
    driving cars n stuff....

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    Sir flink
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    Quote Originally Posted by bellwilliam View Post
    my questions boils down to:

    do you track ABS and non-ABS any differently ? driving line ? while sideway ? trailbraking ? driving 2 wheels in dirt, 2 wheels on pavement (as in passing) ? braking over curbs ?
    I'd say the largest difference is in braking while turning. I have a sad video.

    YouTube - 2011 01 07: Thunderhill, full final session
    Observe the skid marks on the hill up to T5. Also observe the cloud of smoke from the locked up inside-front.

    One lap later: YouTube - 2011 01 07: Thunderhill, full final session. See that long skidmark? THAT'S MY HOOSIER

    how about setup ? brake pads material ? how about brake pads as in brake bias ? does ABS brakes run hotter than non-ABS one at threshold braking ?
    OE brakes are too rearward biased, because the designers didn't anticipate the amount of rear->front weight transfer which r-comp tires produce. But if the ABS is working properly it really doesn't matter much - the ABS regulates the tire slip ratios and can compensate for bias differences, weight transfer, traction differences, pad torque differences, etc. IF it's working properly.

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    T1 Corvette roller fs SIK02SS's Avatar
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    Quote Originally Posted by vantagesc View Post
    At least one bad example is when ABS is overly obtrusive and steps in when it needn't. The dreaded "ice mode" comes to mind, where the system is tricked and reduces braking force too much, causing the driver to miss the turn all together. The cause of "ice mode" is debated, but sometimes it is attributable to an overly cautious ABS program. The driver can sometimes fix it by getting of the brakes momentarily and then back on.
    Very much so this and I will use myself as an example in Rob's video from PIR a few weeks ago. Started in 3rd place and went sailing off track braking for turn 2...2 laps in a row. I also did this numerous times at MMP last year. Apparently my ABS was only partially working though as the controller was unplugged testing in a cold parking lot on cold tires and cold brakes i can still lock the tires, but at least now when they lock I can get them to release by easing off where as before, once they locked...they locked until they let off on their own..which left me like a couple times.

    Quote Originally Posted by bellwilliam View Post
    R there any high level racing series that allows ABS ?
    Does any formula car allow it ? How about say enduro cars like LeMan 24 hours car ?
    Not to my knowledge...legally. A lot of pro teams use Motec and Bosch engine management which can give you traction control though.

    Quote Originally Posted by bellwilliam View Post
    my questions boils down to:

    do you track ABS and non-ABS any differently ? driving line ? while sideway ? trailbraking ? driving 2 wheels in dirt, 2 wheels on pavement (as in passing) ? braking over curbs ?

    basically, is there a circumstance that you drive one way on car with ABS, another on car w/o ABS ?

    how about setup ? brake pads material ? how about brake pads as in brake bias ? does ABS brakes run hotter than non-ABS one at threshold braking ?
    Yes
    No
    No
    Yes- IMO manual brakes are easier to trail brake as you don't have to worry about the ABS intruding on you
    Yes- ABS makes life easier if you're trying to brake..w/2 in the dirt , but can also cause some very very bad things like Ice mode.
    No
    Yes- ABS controls the wheels slightly better over curbs/bumps (again..sometimes)

    Yes. With ABS you have the same pedal every corner (advantage you) over the car that is running manual brakes and the pedal goes further to the floor the hotter the brakes get. No ABS teaches you to really mind your brakes.

    Setup is different as manual brakes you (hopefully) have a bias adjuster. This adjuster could feasibly change depending on track temperatures, weather, AND different tracks (you want control of this in arms reach in the cockpit)

    pad material selection is the same, find a front/rear pad that makes you/the car/life happy, go with it

    I do not know, never tested. My guess is it's a toss-up

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    Pro Lurker GreyFocus's Avatar
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    Quote Originally Posted by robburgoon View Post
    So.... you lost ABS and never noticed?
    yeah i thought it was pretty funny too

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    Member heelntoe's Avatar
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    2008 Civic Si

    Have tested in autox and HPDE, with stock pads, hp+ and ht10. The ABS is touchy, but it definitely shows its economy car roots. I have repeatedly tested this and threshold braking achieves much shorter braking distances. In fact, If I engaged the abs from the beginning it would increase braking distances by a full braking marker at my local track. I repeated this over the next ten laps, and confirmed this with a codriver and traqmate. My codriver could not understand why his braking performance was so poor until I told him to stay off abs.

    However this ties into my next point. My car is not a sports car. The caliber of ABS programming is quiet important. On something like an s2000 or Porsche ABS system, I am quiet positive the ABS would be only beneficial. If an ABS system is programmed aggressively it can compensate for so much more than your foot can (small undulations, small patches of track surface with different levels of frictions, fluid drops...etc) because of the sampling rate. It will check for slip a hundred times or more per second for slip detection. Things such as aerodynamic drag and suspension load all change as you get on the brakes, especially for a high speed straight into a second gear corner. You have aero helping you brake initially and quickly dropping off, but depending on the car and how long it takes for it to set the weight transition all affect how much braking you can extract from the tires. This is why you cant simply sit on a set braking level down a big braking zone. You have to taper off.

    Personally, because of my car's conservative ABS system I have learned to drive the car as if it has no ABS. As such transitioning to a non-ABS car has little effect on me as I dont count on ABS to save my ass, ever. Trail braking, sideways or not...always the same.
    Last edited by heelntoe; 02-04-2011 at 07:18 PM.

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    Post-College Racing Sloth hikickracing's Avatar
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    I learned from watching countless hours of best motoring that ABS definitely has its place but can be very difficult to tune. Sorry, bad input.
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