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Keith Tanner
Keith Tanner MegaDork
10/28/22 12:40 p.m.

Thin pads have less heat capacity than full depth pads, so they do run hotter and wear faster.

BA5
BA5 Reader
10/28/22 1:08 p.m.
sergio said:

I've been happy with Hawk HP plus. Had R4s before, I like the Hawks more.

Me too, I like the HP+'s as well.  I'm not sure that's a common sentiment around here, though.

For anything that's dual street/track use, I feel like it's almost more important to make sure your fluid, calipers and rotors are in top condition.  The pads probably won't be your limiting factor.

GameboyRMH
GameboyRMH MegaDork
10/28/22 1:17 p.m.
Tom1200 said:

In reply to GameboyRMH :

I don't know 86s well but was the stability control partially on? If you are aggressively rotating the car this will cause the rears to overheat.

Also if the pads were thin that will also do it. I milked the rear pads on my formula car and I would actually get a soft pedal. Put fresh pads in and the problem was gone.

I ran with the stability control+TC in full-off mode (similar to "pedal dance" mode except it will switch back to full-on if you got into a big high-speed slide - this never happened). There was plenty of pad thickness (I would guess at least 75%?) left when I started the session, by the time it was over there was about 2mm at most. There are puddles of melted pad material all around the rear rim.

Keith Tanner
Keith Tanner MegaDork
10/28/22 1:22 p.m.

In reply to BA5 :

I'm not in agreement there. Specifically, I've seen a car go off in just a couple of laps due to overheated HP+ pads :)

Fluid is definitely going to be stressed on track. But you can use the same fluid for street and track if your maintenance is good because fluid only has a maximum operating temp, not a minimum. Rotors are just dumb chunks of iron without a temperature range, so that's just a matter of making sure they're not actually undersize. They're actually more likely to take damage if the pads are outside their happy temp. Calipers, that's just plain maintenance.

There is no magic all-around pad as they're tuned for certain temperature ranges. That's why the pads are most likely to give you trouble unless you've been lazy about your fluid changes.

For those who haven't experienced it, a long pedal is overheated fluid. A hard pedal that doesn't do anything and stinky brakes are pads. Anytime someone reports overheated brakes, I always make sure to ask what the pedal feels like so i can be sure to address the right parts.

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) UltimaDork
10/28/22 1:34 p.m.

I was at the Firm for that track day also. Keith's description of a "long pedal" is what I experienced after the first cool down. 
I sanded the glazing off of the front pads (probably unnecessary) and did a thorough flush and they're good. 

Toot
Toot New Reader
10/28/22 2:22 p.m.

Before we had dedicated track cars we had separate pads and rotors as a set.  It is not anymore expensive than trying to get 1 set to do both.  They both just last longer.

 

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) UltimaDork
10/28/22 8:09 p.m.
Toot said:

Before we had dedicated track cars we had separate pads and rotors as a set.  It is not anymore expensive than trying to get 1 set to do both.  They both just last longer.

 

I bought an extra set of front rotors this week. I'll have to decide what pads to buy. 

GameboyRMH
GameboyRMH MegaDork
11/3/22 1:00 p.m.

I started replacing rear brake parts last night, got one corner done. The outer pad had 1mm of material left and the inner pad was down to bare metal, the inner side of the disc had lost at least 1mm of metal as well. Sliders had plenty of fresh-looking grease and moved easily so I left them as-is. I'd guess the slightly unequal wear was more due to temperature differences than slider friction.

The front might need new discs as well, they're not badly grooved but they're not totally smooth or flat. There are raised ridges at the inner and outer edge of the braking surface and the middle of the braking surface feels a bit bulgy. I'm going to put a street setup on the rear and probably leave the front as-is until spring, at that point I'll change fluid, front discs, and I'll have to decide what new pads to try. I'm thinking I'll add GT3 brake cooling scoops to the rear as well, with the drum-in-disc setup there's only a tiny sliver of a gap for air to enter the inside of the disc vanes, I may have to just point airflow at the gap where the caliper sits.

Edit: Leading candidates for replacement pads right now are Powerstop PSA and EBC Bluestuff NDX...

LanEvo
LanEvo Dork
11/4/22 11:38 p.m.

Two points

  1. can you get Raybestos ST43 compounds for your car? If so, your problem is solved. They're full race pads that have enough cold bite, modulation, and noiselessness to work well enough on the street. Fill the fluid with Castrol SRF or Prospeed RS683 and be done. 
     
  2. Corner 4 at Mosport can be taken flat out in a car with downforce and/or very high levels of mechanical grip. You can definitely take it "no brakes; slight lift; steady throttle." But full throttle? Proceed with caution! I can do it in my 2600lbs racecar on radial slicks and full race suspension. Even then, it's scary. I don't know that I could pull it off in an 86 on trackday tires.
GameboyRMH
GameboyRMH MegaDork
11/5/22 12:18 a.m.

ST43s are available for Toyobarus, although the price is over 2x the other pads I'm considering! Would these be able to break in with a brake vent system that can't be blocked off though? The Pentosin DOT4LV fluid I've been running seems to be doing the trick, no fluid issues even when the rear brakes melted down.

Tonight I changed the other side of the rear brakes and oddly this side had about 6mm of total pad material left vs. approximately zero on the other side. Wear was even between the two pads (unlike the nearly material-free side that had at least 1mm unequal wear) and the sliders also moved easily and are full of fresh grease. What gives? I've never noticed any pull when braking so I don't think the two sides are getting unequal brake force somehow. One side catching more wind than the other for cooling maybe?

MrJoshua
MrJoshua UltimaDork
11/5/22 7:57 a.m.

In reply to GameboyRMH :

Is it possible you were repeatedly triggering ABS traction control on that one corner? If not on the track-maybe at one particular spot on your daily drive-Ex: just a little slip turning right from a stop into fast traffic?

LanEvo
LanEvo Dork
11/5/22 8:15 a.m.
GameboyRMH said:

I started replacing rear brake parts last night, got one corner done. The outer pad had 1mm of material left and the inner pad was down to bare metal, the inner side of the disc had lost at least 1mm of metal as well. Sliders had plenty of fresh-looking grease and moved easily so I left them as-is. I'd guess the slightly unequal wear was more due to temperature differences than slider friction.

The way I look at it, automotive brakes are a relatively primitive hydraulic system with quite a few flex points. It's not some sort of precision machine with microscopic tolerances. There are going to be small differences in piston pressure, fluid quality/temp, rotor runout, hub runout, how well the caliper is centered etc etc. that will add up to minor differences in pad wear from corner to corner or between the two sides of the same caliper. These differences are amplified when pads get thin as the heat capacitance of the system goes down.

Bottom line is I wouldn't sweat a few mm difference in thickness when you get to the end of the pads' lives. To me, that's just a sign that you should be swapping out pads a little sooner.

adam525i
adam525i Dork
11/5/22 10:12 a.m.

Do you know what your pad wear looked like before heading to Florida and the Firm? I know this was your first track day on them but I presume you daily drove on them all summer too so that would be interesting to know and give you a better idea of how much pad you should have left before heading to the track. I think going up a step in pads though at this point is a no brainer for on the track, the question will be if you want to swap back and forth. That can be an easier thing to do if you are keeping an extra set of wheels around just for the track and have to swap anyways. 

LanEvo comments about corner 4 are very true and it is very car, weather, tire dependant and not something you don't work up to over the day. I found this past August when I was last there that I was flat in the E28 from 3 over the top of 4 and then just the slightest lift around the apex at the bottom just to get things lined up for 5 but it gets your heart going every time. A bit more power (which I should have next year) will mean I'll need to lift a bit before committing to the turn (and that is the most important part with 4, when you get to the turn in you need to be committed to whatever speed you have and keep that car balanced as it gets light over the top, I can show you a video of what happens when you don't and it is not pretty). I would highly recommend doing a school with the Trillium club there next year with one of their awesome instructors over the OTA or another club less focused on developing skills.

z31maniac
z31maniac MegaDork
11/5/22 11:09 a.m.
Floating Doc (Forum Supporter) said:
Toot said:

Before we had dedicated track cars we had separate pads and rotors as a set.  It is not anymore expensive than trying to get 1 set to do both.  They both just last longer.

 

I bought an extra set of front rotors this week. I'll have to decide what pads to buy. 

If you use something like Carbotech or Gloc, you don't even need to switch rotors. 

Run something like their AX6 on the street and the proper XP range for the temps on track. The compounds are compatible so you don't need separate rotors. Also, the brake dust isn't corrosive, so if you end up doing a day in the wet or drying, the brake dust doesn't start attacking the wheels. 

That and I'm a big fan of how they feel on track. 

I have read on this forum about people having trouble getting them to bed properly, but I never had an issue. 

 

GameboyRMH
GameboyRMH MegaDork
11/5/22 3:25 p.m.
MrJoshua said:

In reply to GameboyRMH :

Is it possible you were repeatedly triggering ABS traction control on that one corner? If not on the track-maybe at one particular spot on your daily drive-Ex: just a little slip turning right from a stop into fast traffic?

Don't think so, the car doesn't get driven on the street much other than to and from events and when I'm on course the TC is always in full-off mode. On the street I usually use the reduced-TC Track mode. The street pads that were on the car until this spring (and back on the rear now) had even wear. One factor may be that the FIRM is mostly right turns so maybe the left-side wheels traveling a longer distance put more heat into the brakes on that side? The 2 heaviest braking zones are both after slight left turns leading into sharp right turns. When I put the winter wheels on the front I'll see if there's more wear on the front-left pads as well.

adam525i said:

Do you know what your pad wear looked like before heading to Florida and the Firm? I know this was your first track day on them but I presume you daily drove on them all summer too so that would be interesting to know and give you a better idea of how much pad you should have left before heading to the track. I think going up a step in pads though at this point is a no brainer for on the track, the question will be if you want to swap back and forth. That can be an easier thing to do if you are keeping an extra set of wheels around just for the track and have to swap anyways.

Before I left Ontario there was at least 75% left (no real DDing, mostly autocrosses and driving to/from) I hadn't checked between then and the track day, but I could've eaten up some more of the pads on a mountain road detour between south TN and north GA. It should be a safe bet that the pads had at least 50% left before the track day began. I definitely want to avoid swapping pads back and forth and have no plans for a dedicated track wheel set, I only have my spring-to-fall performance wheels and then the winter (storage) set.

z31maniac
z31maniac MegaDork
11/5/22 4:07 p.m.

In reply to GameboyRMH :

Just run track pads if thats the case. When I had my NA I just ran Carbotech XP10/8 all the time. It was 95% HPDE car, but I would occasionally drive it to work, or to brunch, and it was always driven to the track. 

adam525i
adam525i Dork
11/5/22 8:45 p.m.
z31maniac said:

In reply to GameboyRMH :

Just run track pads if thats the case. When I had my NA I just ran Carbotech XP10/8 all the time. It was 95% HPDE car, but I would occasionally drive it to work, or to brunch, and it was always driven to the track. 

I've got to agree with this and that is what I do with my E28 for similar usage.

GameboyRMH
GameboyRMH MegaDork
11/5/22 10:42 p.m.

Yeah this is what I did with my AE92 as well, but I didn't like the way the braking forced ramped up rapidly with temperature in autocross or how the car ate rotors, so I've been trying to approach the issue from the other side. The Toyobaru also needs to work in near-freezing temperatures which could be more of an issue if I choose an overly-aggressive pad. Right now I'm thinking EBC Bluestuff NDX could be a good match, they can work at both colder and hotter temperatures than Yellowstuffs and are easier on rotors, they just wear out faster.

RacerBoy75
RacerBoy75 New Reader
11/5/22 11:19 p.m.

I have never driven one of the Toyobarus, but here are some general guidelines on what i have learned from years of racing and track days. If the pads have only half or less of their thickness left, don't use them on the track. The thickness of the pads insulate the calipers from the heat, which is pretty important. And when they are thinner, the entire pad gets hotter and they wear even faster. 

If you are moderately quick on the track, cheap pads like the Hawk HPs won't last and will fade. It's been my experience that any of colors the EBC pads are also junk (I have no experience with Bluestuff NDX, maybe they finally came out with a product that actually works on track). I tried green, yellow, and orange EBCs, and they all faded and left big deposits on the rotor which caused terrible juddering. I know how to bed pads, the only brand I've used that did that were the EBCs. This was on a Boxster, which was moderately quick and had big enough brakes to work very well on track once I found a good pad compound. 

Many people are tempted to run less expensive pads (understandably so), but don't cheap out on the most important safety item on your car at the track. I run PFC 08 pads on my Cayman and they are insanely expensive, but they last a long time, and work really great. They are also surprisingly good on the street, but they dust like crazy, and sometimes squeal very loudly. Any good track pad will do that. Also use good fluid, something like Motul 600 or any of the other high-temp fluids. 

The bottom line is that you can't make street pads work well on the track, but you can make track pads work well on the street. The track pads won't be ideal, but at least they will work. If you are going to do track days, it just isn't worth cheaping out! Or resign yourself to changing pads out before and after track events. Yeah, I know that is a pain, but if you want to be quick, you can't be lazy.

Don't use street level TC at the track, use track level if you have the option. On track the TC may be intervening and you won't even notice. Many systems apply the inner pads of the rear brakes and that will wear the pads out very quickly. You will glance at the outer pads and see that they have lots of pad left, but the inner pad may be nearly worn out.

wspohn
wspohn SuperDork
11/6/22 10:40 a.m.
Keith Tanner said:

Thin pads have less heat capacity than full depth pads, so they do run hotter and wear faster.

Interesting comment.  One of the vintage race cars I ran had pads that were all pad material and no backing plate (except a thin sheet metal disc bonded to them to keep them from rattling in the caliper), so they were considerably thicker than any pad bonded to a backing plate. I wonder if that made them last pretty well in racing?

GameboyRMH
GameboyRMH MegaDork
11/6/22 12:12 p.m.

EBC Yellows worked as advertised on my AE92 and I know plenty of people who have had good results with their pads, so I wouldn't shy away from that manufacturer as a whole. I didn't even have problems running them down to 25% material or less on the track. If this car weren't used in the cold or for autocross I wouldn't have hesitated to slap Yellowstuffs on it. Orangestuffs seem to be a popular choice for dedicated track pads on Toyobarus.

I haven't used any TC on course at all yet, I would only consider using Track mode on a wet track day.

z31maniac
z31maniac MegaDork
11/6/22 1:27 p.m.

In reply to GameboyRMH :

I legitimately wonder how some of you are driving on the street that the heat of the brake pads comes in to play. I drove my track rat NA to the track in sub freezing temperatures on R comps with track brakes and didn't die, multiple times. Never had a problem with anything. 

When I still rode sport bikes quickly on the street, we subscribed to the thought that, if you're having to use your brakes, you're riding to fast.

z31maniac
z31maniac MegaDork
11/6/22 1:28 p.m.

In reply to GameboyRMH :

I'm not even getting into how EBC's are E36 M3 pads. 

Tom1200
Tom1200 UberDork
11/6/22 1:44 p.m.

I will reiterate my solutions for this:

A. Bigger brakes; it's what's on the Datsun and I simply use quality Street pads.

B. Cooling, this is what has been done on the F500. I autocross and road race it so I need pads that work cold.

I also ran street friendly pads in my daily driven Showroom Stock Miata.  

Personally I'd try to see if I could keep the pads cool as installing bigger brakes won't be cheap.

GameboyRMH
GameboyRMH MegaDork
11/7/22 10:45 a.m.

I'm trying to avoid bigger brakes since they're expensive up front and tend to increase consumable costs by swapping out mass-produced production rotors and pads for pricey racing parts. I don't think the stock Toyobaru brakes are really undersized for stockish power levels either.

For cooling I've already added GT3 scoops to the front (which is why I think the front brakes fared so much better) and will add some to the rear as well.

I've been researching pad options further and I've been thinking that ST43s could make sense if they can last at least 2x as long as the PSAs or Bluestuffs, which is plausible as those are very fast-wearing pads while the ST43 is known for its longevity. It would still be a huge purchase, a set of those pads would cost about as much as I paid for my current summer and winter tires combined.

Edit: I also finished swapping winter wheels on over the weekend, I forgot to compare pad wear between the two sides as I was distracted by a new fender rub issue I found, but the front-left had about 25% material left.

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