So I was showing off my car to a buddy of mine the other day and we cranked it pretty good for maybe ~10 minutes total with a few sprints. I had to use the brakes a decent amount a couple times to slow down from 90mph to 45 mph, but nothing too extreme or crazy...

Problem is that after doing this about 2 or 3 times, I noticed there was some pretty massive brake fade, and when approaching a semi-sharp turn after, attempting to use the brakes to slow down from ~35mph... the car barely responded and I almost had to grab the e-brake (I managed to take the turn at high speeds).

Now I understand what brake fade is, but I figured with disk brakes on both the fronts and rears and them being Brembos, we shouldn't have this problem. Has anyone else encountered this problem? Or did I simply push the car too hard?

 

 

You have to remember even though they are brembo brakes, they need time to cool down. You said 3 stops from 90-45 within 10 minutes plus normal braking. This is pushing more the limits of the factory brake fluid (what you felt) but more-so pushing the longevity of the brake rotor/pad since it's much easier to warp when so hot. It good to hear that you were able to brake in time for the turn, but next time exercise some caution, we don't need another nationwide story about a high speed crash.

 

If you really only did a few hard stops from the speeds you say over 10 minutes, the brakes should not have faded. I did worse than that with my little 5at brakes.

If they just would not stop its pad fade. If the pedal went soft its boiling fluid which it sounds like did not happen.

The first thing that comes to mind is have the pads ever been replaced and with what kind.

Brakes need time to recover but a minute between hard stops is enough. People track their cars on stock brakes and the Brembos hold up ok. Keep in mind they are only 12.2" and the TL does weigh 3500lbs.

 

Well the turn I was panicked about wasn't too crazy. I was trying to slow down from 35mph to ~15 or so. Hardly anything crazy enough to make the news I hope.

I just bought the car from a private party recently, I took the car into a dealership to have inspected before purchasing and the dealer told me the pads were Brembos with 8mm left. I was warned to basically never use any aftermarket pads as they would not hold up.

I didn't notice any problems during the three sprints, but it was the turn that made me (really) notice. Its possible that I was just taking that turn too soon after doing one of those hard(ish) stops so maybe they didn't have time to cool fully as you guys mentioned.

 

I do a lot of hard braking and cornering, I have never felt that my brakes were failing me...

Inspect brake fluid pressure, fluid itself, rotors and pads. While in neutral, pump the brakes 3 times, it should be super stiff that you can't pump no more.

 

The weak link is the fluid. It's hydroscopic, it attracts water. Water boils at 212 degrees, fresh clean brake fluid boils at over 500 degrees. When contaminated fluid gets hot it boils, air bubbles form and, since air compresses, the pedal goes soft and becomes ineffective.

That's why then first thing you do before you go to an actual track event is to change your brake fluid to high temperature racing fluid.

In my days as a sports car racer I would bleed the brakes after every practice session and every morning. I wasn't alone.

You're asking a lot from street brakes that aren't serviced routinely to make repeated high speed stops. You generated a ton of heat which was trasferred through the pads to the calipiers and then the fluid, which boiled and made the brakes soft until the whole system cooled down.

 

I agree but I think in this case he ran into pad fade. With only 8mm left, maybe that's the reason they're fading so easily. Still sounds fishy though when my little 5at brakes would take what he was throwing at them.

 

I hate cars, you're making my point. Thinner pads equal greater and faster heat transmission to the caliper and then the fluid. Also well broken in pads shouldn't fade.

Again it's all about heat. Often new pads will fade because they "gas." They produce gases from the binding material in them. That's why most raceing pads have specific methods of heat cycling them to make them more effective.

Not being argumentative, just the facts gleaned from many years of racing.

 

I always enjoy reading your brake posts.

How high would you rank running a fresh set of pads (broken in but with the full pad thickness) for track use? The few times I've done it I've installed new pads but I was thinking about not swapping them this time.

 

Thanks, I've worn out a lot of pads in my day :-) Not to mention rotors. I have found that brake pads suitable for the street are not for the track and visa versa. Brake technology may have changed in the last few years so my comments may not be current.

Having said that I always used a fresh set of competition pads, carbon fiber back then, for the track and carefuly read the instructions for breaking them in. Using street pads, on the track especially on a poorly balanced car like the Acura with all the weight in the front just isn't a good idea.

They just won't do the job, will develop excess heat, and will deteriorate quickly. They will be ruined and you'll get deposits on your rotor that will produce shudder. They are also capable of warping rotors.

I will say that I certainly hated running competition pads on my car for street driving. For one they were really really noisy. They sounded like an 18 wheeler making a panic stop. Secondly they were ineffective until they heated up which was difficult on the street.

So the short answer is to use the appropiate pad for the usage intended. I know I was running rotor temps in excess of 1200 degrees on a well balanced car with excellent brakes. Think what that kind of heat will do to your street pads on an Acura. Of course it was so easy to change pads on a Porsche it was a no brainer. Not so on an Acura.

Hope this helps.

 

That helps a lot. At first I was thinking that my 13" front brakes were overkill on a 3,500lb car with only 258hp. But thinking about it more, with 70% of the weight on the front tires when static, I don't want to know the % of the braking the fronts are doing under hard braking.

I still have the debate going on whether to buy a track set and a street set or a very aggressive street set. I know what I should do but I'm hoping the larger rotors and pads will give me a little room for error in pad choice.

For what it's worth my fronts (1pc 13" Rotoras) and stock rears run about the same temps under normal to moderate braking. Under hard braking the fronts will run hotter. That's a huge change from the stock fronts. So far haven't gotten the fronts past 700F so that's what's making me think an aggressive street pad might be ok.

I have installed stock sized slotted Rotoras and an aggressive pad on the rear. It did raise the working temps of the rotor so hopefully it shifted some of the front bias toward the rear for shorter stopping distances.

On the bright side, this TL is a huge step up. I got used to 600hp and 10.5" rotors with drums in the rear.

 

LOL, you just can't have big enough front brakes and street or drag racing is a lot different than a 30 minute track run.

Think of it this way. Your brakes are nothing but a heat engine. For arguments sake say your Acura does 0 to 100 MPH in 15 seconds. How fast does it do 100 to 0? Probably in about a quarter of that 15 seconds.

So we can safely conclude that the brakes are way more powerful than the engine. How do the brakes accomplish this feat? They do it with friction right? What does friction generate? Right again, heat!

So you need to find a way to dissipate that tremendous heat corner after corner. It's not easy so compromises are futile or, at best, unsatisfactory. Big rotors are one way, air ducting is another, racing pads are yet another and by all means fresh racing break fluid is essential.

Guys had some unusual ways to cool their brakes. I remember watching one of my competition spuming large clouds of steam after every corner. I walked over to him in the pits and ask what was going on? he had rigged his window washer system to spray water into his brake ducts so he could cool them while on the straightaways. There was nothing in the rule book preventing him from doing that :-) At least that year.

Don't underestimate what your brakes go through on a daily basis and then imagine track usage.

 

I actually did a little figuring a long time ago on how much hp it would take to accelerate the car to the same speed over the same distance as the brakes decelerate. I don't remember the exact numbers but they were upwards of 700hp. That's a lot of BTUs for a rotor to dissipate.

It's no where nearly as interesting as water in the brake ducts but I saw a nearly 100F drop from high speed stops after removing the front dust shields.

 

Yeah I don't know the numbers but it's shocking how much horsepower it would take to equal the power of the brakes. I bet 700 is a bit low, or not, but you're right. It's a huge amount of heat to loose in a short time.

I forgot about the brake shields. they were the first to go and the bolt holes were used as mounting points for part of the brake ducting which sucked out into the ducts from the fog light openings.

Interesting discussion.

BTW I used to be an instructor for the Corvette Club for their high speed track events. Guess what their weak point was besides their unskilled drivers? I don't remember many that made it to the end of the day. Things have changed since then and their brakes are reasonably impressive now.

 

Wow, very interesting discussion.

I'm concerned that you say "only 8mm left." The dealer told me to get the rotors machined (or polished, or something?), and suggested to replace the pads while they were at it. I asked what the new pads came with, and was told 10mm... and that usually 3mm is the critical point to get them changed.

Since it was going to cost me like ~$500 for rotors+pads on JUST the fronts, I figured I'd wait. Should I reconsider?

But, to make sure I got this right... it sounds like the best solution would be to get the brake fluid replaced? Full flush? Any ballpark for how much it costs? If not, I'll start forum crawling. Thanks.

 

8mm is plenty of meat left for street use. I think a brake fluid change is an inexpensive first step. It's a DIY and the directions can be found on this forum. If you don't want to get dirty or don't have the tools any shop can do it for you,

It shouldn't be a big ticket item, much less than replacing parts and I think you'll see a world of difference. Yes a complete flush is the way to go. Make sure they are using premium, high temperature fluid.