The problem on the e30 is twofold. Flexy calipers and tiny rotors. Improving anything costs. Sure, I could have told you to get a BBK with 11.75"x1.25" discs and stiff calipers. But before you get there, perhaps you could improve what you have.
BTW If you drive hard, you will NEVER keep your brake pedal stiff more than half a session. Unless you bleed your brakes every session. ;-)
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So I see an argument for better brake cooling there, but not more track oriented brakes. Unless you are telling me that a set of race pads will keep my rotors significantly cooler and thus prevent my brake fluid from ever getting hot enough to boil water? That seems unlikely?
But let's say I add better pads and more cooling. Will this really keep the fluid below 212? Because if you're right that my brake system is pulling/letting in more moisture than most it seems like those two things wouldn't help?
My car is lighter than most E30s, and I never shoot for top speed on the straights. I'm not even half way through the HawkHP+ after 4 track days on them. I'm inclined to think I'm not cooking the pads, especially when braking power never returns.
I'm sorry, I don't mean to be dismissive. I'm just trying to understand completely, partly because I enjoy understanding, and partly because I'd like to be able to diagnose similar issues in the future using a better upstanding of the system :)Leave a comment:
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Brake fluid has gotten hot. Whatever moisture in the fluid has produced vapors. Some of it has condensated back to water when cooling down, some of it is still air.
The cheapest fix is to get much better track pads. Hawk HT10 would be a good start... and ducting.
When you realize the limitations of the stock e30 brakes, then look at improving the brakes themselve.
Some racers can do with stock brakes just because they use way more momentum than most HPDE drivers. But stock e30 brakes still suck... ;-)Leave a comment:
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Since you seem so sure, could you explain to me why you think the hawks would produce a mushy brake pedal even after the car is cool? My understanding is that would only happen if they were cooked, but that they would recover as soon as brake temps dropped within their operating range.Leave a comment:
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Soft pedal after almost every track day
I've done 4 track days so far this year, and after almost every one I end up with a much softer pedal by the end of the day, regardless of the brake temps. This is the sort of problem I can feel driving home. The one time I didn't change the fluid immediately before an event, was after my first HPDE of the year (it was raining hard, rarely used brakes), but by the end of my second HPDE I don't think I could lock my tires up. Since then I've changed fluid before every event and have survived.
Completely flushing the brake fluid (using superblue) makes the pedal feel a lot better. Not to anything you'd call the firmest pedal in the world, but safe feeling. The fluid seems to me the issue, but what is causing the issue?
What concerns me is that I can do a flush, and during the course of a track day I can feel the brakes getting worse. While I know regular changes are advised, certainly the guys doing enduros aren't changing brake fluid every hour or two? I'm not even a heavy brake user. I'm still focusing on other areas of my technique and using slow-in-fast-out. I rarely brake past 80% of the car's ability. I'm moderately concerned that the day I start doing the local tracks at 90+% that my brakes won't last the day.
So what might be killing my fluid? Or perhaps exaggerating the feel of bad fluid? Remember, the issue continues after the brakes have cooled off, and doesn't ever improve. Thanks for any sage wisdom you guys can provide! :)
In case it matters:- Hawk+ pads front and back
- Blank rotors
- Calipers rebuilt 6 track days ago.
- Z2 tires (When I say I can't lock the wheels, these are them)
- SuperBlue or Type 200 (alternating)
- SS lines installed 6 track days ago
- Hard brake lines are original.
- No brake cooling.
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