Had trouble engaging ABS at the track this week; how come?

[SmoothIsSlow]

Hi all,

I put in ATE Type200 in my '17 BRZ with PP Brembos. My pads were a set of used Performance Friction Carbon Metallic pads; which were slightly used when I bought them. I left the stock rotors on there. I ran Pilot Sport 4Ses on stock PP suspension.

Before the HPDE lapping, we were doing 50mph to standstill hard brakes to try and get us familiar with the feeling of ABS, but I couldn't get them to be engaged, no matter how hard I braked.

We then did three 20 min sessions and I couldn't get ABS to engage either (although I wasn't explicitly trying to.) The brakes did feel very consistent, I think the braking feel at the end of each session felt more or less like they did in the beginning of the sessions.

My instructor thought I just needed to bed the pads in... I have another track day coming up in less than 3 weeks... Should I bother with another set of pads? This was my first time on track but the instructor didn't comment on anything abnormal about my brakes.

To be clear, I may have messed up changing to the new fluid (I let the front half of the reservior run very low). However, I bled the brakes afterward the snafu and the pedal feels just as firm as it did before the fluid change from the stock DOT3 to the ATE Type200. My understanding is that if some air pocket in the master cylinder or in the line is giving me trouble with ABS engagement, it should be very obvious with the pedal feel.

I am not sure if I have air in the ABS line either, since I left traction control on they worked just fine on track.

ThanksQ!

[ZDan]

If the pedal feels firm and you are decelerating hard under braking, you don't have a problem. Goal shouldn't be to engage ABS, IMO...

Aren't PFC Carbon Metallics street pads? You might consider going to a track pad if they begin to lose friction or come apart on you. I've even have some supposedly "high-performance" upgrade street pads give a soft/long brake pedal which felt like the fluid boiling, so if you get that bear in mind that it could be pads.

I've almost always run off-the-shelf name-brand DOT4 brake fluid for hard track usage in my cars, I don't think you should need any "special" brake fluid, particularly with street pads. FWIW I tried ATE Superblue typ200 fluid once in the S2000 years ago, and honestly it did not perform as well at the track as name-brand parts store DOT4... On day 2 with this fluid at Watkins Glen the pedal got softer and I had to bleed the brakes. I get two or three 2-day events out of parts store Castrol or Pennzoil or ? DOT4 fluid without issue.

[ZDan]

Should you bother with another set of pad?
Maybe not yet... IF your instructor didn't notice anything your brakes are probably fine for the way you are using them. But note that at some point you may need to go to more of a track pad.

[Decep]

[austin powers] who buys used brake pads, honestly? [/austin powers]

[MrDinkleman]

Try jumping on the brakes in a (safe!) spot where you know the wheels will lock up, such as a puddle, dirt/sand, etc., before trying new parts. Could be you're just not reaching lockup that would cause the ABS to kick in.

Seems to me my FRS' ABS activates much later than in my other cars (IS300, Yaris) which I think Toyota/Subaru intentionally tuned this way for sportier driving...

[Tokay444]

Grip.

[strat61caster]

Are you able to press the brake pedal to the floor?

If your brake pedal hits the floor and ABS isn't engaging that's a problem, could be both pads not grippy enough and or fluid needing bleeding. I'd try fluid first because it's more likely to be the problem in that scenario, also it's cheaper.

If you're not able to push the pedal to the floor you need to brake harder to engage abs. It's an odd thing to do, autox is a good place to go practice these things.

[churchx]

Also sometimes there might be other reasons for not being able to press brake pedal hard enough, eg. something as trivial, as misadjusted seat with base too high, or too far from pedals, so that near full press thig of almost straight leg rests on seat and thus able to press with less force and/or get tired quicker. Also for experiment sake for harder press you may try to press pedal with mid of feet, without heel resting on floor, it may affect fine pressing precision though vs pressing with toe.

[NoHaveMSG]

How fast are you going when you are trying to trigger ABS? You really need to be abrupt on the pedal as much as you are hard on it.

Go find a large, smooth, empty parking lot. Get up to 40ish and brake hard while making a moderate turn. Should lock up the fronts no problem.

[SmoothIsSlow]

Originally Posted by strat61caster

Are you able to press the brake pedal to the floor?

If your brake pedal hits the floor and ABS isn't engaging that's a problem, could be both pads not grippy enough and or fluid needing bleeding. I'd try fluid first because it's more likely to be the problem in that scenario, also it's cheaper.

If you're not able to push the pedal to the floor you need to brake harder to engage abs. It's an odd thing to do, autox is a good place to go practice these things.

I am not quite sure if the pedal hit the floor. I just know that I pressed as hard as I could while going at roughly 50mph.

With the car off, my brake pedal gets firm after a couple of pumps without sinking to the floor or moving down after the initial travel.

[SmoothIsSlow]

Originally Posted by NoHaveMSG

How fast are you going when you are trying to trigger ABS? You really need to be abrupt on the pedal as much as you are hard on it.

Go find a large, smooth, empty parking lot. Get up to 40ish and brake hard while making a moderate turn. Should lock up the fronts no problem.

Roughly 50mph, was braking in a straight line on track asphalt.

[soundman98]

lol, i can't think of the last time i've triggered ABS in dry conditions...

[strat61caster]

Originally Posted by SmoothIsSlow

I am not quite sure if the pedal hit the floor. I just know that I pressed as hard as I could while going at roughly 50mph.

With the car off, my brake pedal gets firm after a couple of pumps without sinking to the floor or moving down after the initial travel.

The latter is a good sign, the former leads me to believe you can push the pedal harder, I've coached people before to perform a similar exercise, it usually takes three or four attempts before they understand how hard they need to push, like "I'm about to make the seat back break" hard.

Next time if you can ask the instructor to perform the exercise in your car it might be worth it, maybe I'm wrong, maybe there's something off about the pads or the brake system and having someone experienced feel it and confirm is worth it's weight in gold.

[NoHaveMSG]

You must have been running with ProFormance. ATE Type 200 is plenty good if you are new to tracking. That's what I ran for a year. You could try bedding the pads but I don't think that is the issue. In those conditions ABS intervention is really not that severe, usually you will just get a little back and forth chirping out of the front end with a light tug at the wheel. Likely you are not being hard enough on it.