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07-10-2012, 10:03 PM | #1 |
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Developing brake failure paranoia... what's the deal?
Hoping to pick the brains of those more mechanical and with more track experience than me.
Started watching the Continental series race @ Road America this evening, and before race coverage they replayed a horrific practice crash at turn 12. Guy's brakes apparently failed. Made me recall another brake failure during the Road America Rolex race last year where a Camaro ended up over the fence at turn 1. So the obvious answer is that brake failure is the result of overwhelming brake components in race conditions, and under the absolute most extreme conditions. This in spite of having world class mechanics, and the best possible equipment. But I've also heard of brake failure at your run-of-the-mill track day. Anyone here experience brake failure? Any warning signs? Cause(s)? I drive within my limits on track, and I'm at only novice/intermediate level. Since I've upgraded to a Stoptech front kit and Pagid pads, I have more confidence than ever in my setup, but the idea still haunts me. Thanks. |
07-10-2012, 11:01 PM | #2 |
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I have only seen one brake failure at an HPDE in 4.5 years. It was on brand new pads that were "dual street/track" pads <gag>. The driver stated that he had no warning that the pads were going away. The driver was in Novice group.
The car approach the end of a long straight and failed to brake - cutting to the inside the of the turn as a car ahead turned in (phenomenally dangerous) - instead of staying to the safer outside. It made contact with a few inches of front fender of the car ahead and rocketed by it - very narrowly missing T-boning the car ahead. It blew past the corner and ran off into a gravel trap and did not roll. The failure to brake was attributed to crappy pads that just gave up. One can only speculate whether the driver should have felt the pads going away - but he was a novice. The car was NOT a BMW. ----------- Take-away lesson is to use track pads when your speed or the nature of the track's design call for it. Use good brake fluid and change it appropriate to your use. Inspect your brakes back in the paddock throughout the day - know their state. Don't assume. Be aware of potential brake fade and take it seriously. Look at runoff areas at hard braking turns and understand where you would go if you had an issue. Some organizations (very few - I think) have "No Brake" exercises. While these are primarily intended to teach vision, offline driving, thinking ahead etc - the speed scrubbing component is very valuable as well. Brakes are the first place to look if you want to start changing an HPDE car. |
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07-11-2012, 09:06 AM | #3 | |
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In terms of brake inspection between sessions, anything in particular I should be looking for/at? |
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07-11-2012, 09:21 AM | #4 |
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I too have only had one brake failure, when I first tracked my E92 (2009). I ran at CMP, a short track in SC and after three laps with stock pads, brake fade suddenly reared its ugly head, and it made for an interesting turn at the end of the back straight. I changed pads, and no issues with failure since. Given your driving level now, and with the brake upgrade, your PRE TRACK TECH INSPECTION should be completely sufficient to determine if your pads/brakes are satisfactory for the event you are about to participate in.
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07-11-2012, 09:31 AM | #5 |
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This is good info for those who haven't read it.
http://www.caranddriver.com/features...-lightning-lap If brakes fail...you should be still turning into the turn really early (assuming you're not going to hit someone) and add more steering than required to scrub speed or get into a 4 wheel slide. It helps to look at all big braking zones and plan what ifs. Sometimes turning the opposite way provides more runoff room. Again...look at all corners and play what if. The driver in the Kia in the CTC race got the car turned and scrubbed some speed. He had to give up using more race track to avoid hitting other cars on track This is a double edge sword because you should try to hit things straight on as that's how the car (and you) are designed to take the biggest impact.
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07-11-2012, 10:57 AM | #6 | |
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07-11-2012, 12:21 PM | #7 | ||
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Yep, that's the one. And this was in a practice session where presumably everything was checked out just prior to. Don't get it.. What explains a complete failure like this?? Is it likely that the driver disregarded warning signs? |
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07-11-2012, 12:32 PM | #8 | |
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No matter how unlikely ny part on a car can fail, a motor can blow up, tranny can implode, suspension parts can break, and something in the braking system can fail. All of which can cause their own kind of catastrophe and unfortunately for Mark he experienced a brake failure at one of the worst possible spots. |
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07-11-2012, 12:40 PM | #9 | |
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07-11-2012, 01:47 PM | #10 |
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I've seen more lug-bolt failures, or oil pump nut backing out, or water pumps fail, or radiator failures, or blown engines, than catastrophic brake failures at HPDEs in my 10+ years of doing this.
There are far more things on a car to fail than the brakes, and the brakes being a vital safety feature, is one of the few things that MUST be over-engineered. Race environment is an entirely different matter.
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07-12-2012, 04:03 PM | #11 |
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Catastrophic brake fade and brake failure are two different things. As someone pointed out, brake fade is driver error in most cases. Given enough effort, you can overheat practically any brakes, and it's up to the driver to recognize early signs and take corrective actions. The good thing there is that it usually happens at the end of a braking zone (simple physics - the brakes are hottest there), and you'd lost most of your speed by then (it also usually happens in slower turns because there is more braking done before them). Also usually there is one of two hottest points on the track that are the same for most cars, and thus track designers make good run offs there. So it's really not that scary. Just listen to your brakes, and do not feel pressured to push on every lap - nothing wrong with taking a cooldown lap in the middle, even if you have to let everyone by. Also, avoid pads with rapid drop-off in friction or those that disintegrate when overheated (some combo street-track pads have this tendency).
I had two strong brake fade incidents, and both times I just scrubbed the speed by steering and ended up with two wheels off in both cases. In both cases run offs in front of me were rather big - I guess by design. Both incidents were avoidable if I was more experienced, and both could have been much worse if I lost my cool. Now complete brake failure is a different thing. I guess it more of a lottery, but it's very unlikely on a well-maintained car. I just hope to never have to deal with it. |
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07-14-2012, 06:43 AM | #12 | ||
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07-14-2012, 11:08 PM | #13 |
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I've said it before and I'll say it again...there is no such thing as a dual purpose track pad. On the track, good fluid and track pads, stainless lines also help. I rather use OEM than a dual purp pad. My preference and what I always use on the track PFC-01s
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07-15-2012, 06:23 AM | #14 | |
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Although, surprisingly the pagid rs29's that I'm using now are turning out to be just fine for the street. |
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07-15-2012, 09:55 AM | #15 |
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I too run PFC 01s at the track, and do not change them until they wear out. They do fine on the street despite the squeal.
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07-15-2012, 09:59 AM | #16 |
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I also confirm that dual use pads suck ass and that PFC 01 work great. I ran them on the street for months but eventually decided to use OEM on the street and PFC at the track, because of the PFC squeal. No issues stopping cold.
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07-15-2012, 12:15 PM | #17 |
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Going back to the original point, it is possible to install a few components and get brakes that are pretty much bullet-proof. That said, driving technique can overcome any thermal management regime and compromise performance and safety.
You need to have good equipment that suitable for the job at hand and you need to know how to use it within its limits to avoid failure. Fortunately for brakes, good braking technique is also good corner set-up technique, so if you are good at one, it helps with both. I use PFC-01's on the front brakes, PFC-06's on the rear, Castrol SRF fluid and Goodridge stainless lines. I will run the PFC-01's on the street - they work just fine, and even quiet down after a week or so - but if it's a longer gap between events I put on Stoptech Streetsport pads on the front for daily driver use. I leave the PFC-06's on the rear for the season, and it looks like they'll last forever at this point. |
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07-15-2012, 12:49 PM | #18 |
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^ if you can get your brakes "bullet-proof" the pro's would have done it already and then some.
I think you just do the best you can in two points - one prep your setup as much as you can - good calipers, fresh high temp fluid, race pads, and pre-flight check. Secondly, once you have confidence that your setup is as best as it can be, it's mental. Mentally you put that fear aside - fear of what may (or may not happen) and instead focus on being attention to how your car is behaving. Most brake failures don't happen suddenly - usually a turn or two before it'll give you some "indicators" that will warn you. Then another mental factor is this - I've learned to not watch crash videos before I do a DE otherwise thinking about what MIGHT happen sometime is crippling on track - not just to your performance but your overall enjoyment/experience at the track. Stay focus and work up to speed/braking while being attentive to how your car is doing. I can relate to OP's concern - for many of my early DE's I'd think of a million things that COULD happen and miss out on enjoying the car at the track... my two cents. -D |
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07-15-2012, 09:11 PM | #19 | |
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I'm just back from an HPDE, and as Car54 suggested above, I made it a point to identify run off areas and contemplate worst case scenarios in my warm up session. Helped to set my mind at ease.. (The fact that my local track is in the middle of a field also probably helps the cause.) I suppose there will always be a chance for disaster. I'll continue to take prudent measures pre-event, heed warning signs while on track, and hope for the best. |
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07-15-2012, 09:17 PM | #20 |
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^ actually for me this crops up alot (in my head), then I try to cool analyze all the pre track prep and checks I've done and then try to put it out of my head. A lot of it is in the head
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07-15-2012, 09:21 PM | #21 |
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07-16-2012, 10:21 AM | #22 | |
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