There are always a couple of threads going on about brake pads. It's always interesting to hear what different people like, what works best in their car, and what the manufacturers say.

I thought I'd share some of the way you can use data from the car to help make a decision. Here is data on brake rotor temps, brake fluid temp, and brake pressures. The data is all from the same track, same driver, similar lap times, etc. Also, I could have probably chosen better colors for the graphs. Despite the orange and blue colors, these are not Pagid pads. All the orange lines are the same pads (set 1) and the blue are all the same set (set 2). I will say the blue lines are from a very popular compound that lots of people run. The orange lines are not as popular, but the people who do use them really like them.

I thought the rotor temp difference was very interesting. The blue set puts significantly more temp in the rotors and has a larger spread from the max and min. The difference in the brake pressures used is directly related to the hot friction values of the pads. Since the pads are from two different manufacturers, I don't have data on the CoF for each pad. I can say one is around .4.

What I thought was most interesting was that the orange lines are from a set of over 1/2 worn pads and the blue were brand new, but the temp that was passed into the brake fluid was not very different even though the blue pads ran so much hotter. It would be interesting to do this with new pads for both sets.

Anyone with a brake pressure sensor can look do a similar analysis of brake aggression, release smoothness, max pressures used, etc. There is some really interesting data in brakes and different ways to use it.

 

You aren't going to tell us which pads were tested? What a tease..

Interesting that there is such a wide spread in rotor temps for the blue pads, relative to the orange. The averages are about the same despite the significant differences in max/min temp. Also interesting that the orange pads caused a greater temperature increase in the fluid, despite having lower peak temperatures than the blue. Maybe having a new set of orange pads, with more thermal mass, would change that story.

Cool stuff. You can really see the value in data driven decisions over just going by feel. Makes me wish I had more time to collect and review data at the track. I haven't even downloaded the data from my last event and it has been almost a month.

 

This is definitely post event analysis. At the track, I'm usually checking car vitals (oil pressure, temps, over revs, etc) and working on immediate driver development. Stuff like this is done after events when there is more time and deeper analysis can be done.

I've found that most times the data mimics what the driver says - data is after all just a recording of the events. The data/video really helps to reconcile the drivers perception with the reality out on track. Many times, it helps the driver to quantify and further refine their feel of the car.

Analysis at the track is critical to being able to improve your driving. Even a quick review looking at speeds traces for variability, brake pressure/long G traces for braking performance, and combined G for checking that you're using all the grip available to you will give you great thing to work on while out on track.

 

Does that data actually help you go faster or does it overwhelm one with useless data? Just because you can collect certain data does not mean it is useful. Paralysis by analysis is what I worry about here. Even after the event.

Assuming my brakes (i.e., pads, rotors, fluid) function properly during the race, going faster is all I really care about and I don't need brake rotor or brake fluid temperature data to tell me that. I can look at the rotors and pads to see how they are doing and I can certainly tell if the fluid is overheating without data.

Trying new pads is the only way to know if there are better pads out there and the lap times will tell you if they work better for the driver or not.

Seems like a real waste of analysis time to me. At least at the club racing level.

 

I suspect the orange pads conduct heat better than the blue, and as a result give higher fluid temps and lower rotor temps.

It might be interesting to plot longitudinal deceleration vs brake pressure for both pads. That might tell you something about how the two pads differ in modulation.

Will it make you faster? Probably not, but this is a hobby, and some folks like delving in to things like that. Actually I don't generally dig that deep. It's too much like what I do for a living. But for some it's enjoyable.

Others like to argue...

 

DO NOT !!!

 

http://youtu.be/k80nW6AOhTs

 

Now, THAT'S a great, simple and worthwhile analysis! Expediency rules...

 

The orange pads were much thinner (probably 25% remaining) versus the blue pads that were brand new (>90% remaining). I think it alone that made the difference.

The braking aggression and average release smoothness graphs are better measures of modulation than pressure vs long g. But, it's interesting to look at all the different ways to analyze things.

To answer the question of does all of this make you faster? An unquestionable YES. Knowing the actual brake temps can make sure you are in the best operating temps for the pads you choose (which on this car they were not), which will increase braking abilities and driver confidence. Also, you can use this to figure out the best pads for the driver based on the modulation and brake pressure required to get full braking performance.

But, like you said, you have to have someone who likes to do it and has the time. Data is knowledge. Knowledge is power.

 

Not everyone is into data, no problem. I can show you professional racers, car builders, and more who do not value data. I can show you Lemons racers that love it. Different folks for different folks.

For me, the teams I work with, and my customers, this sort of data does not lead to paralysis by analysis. This leads us to make the best decisions we can with the most information.

You're right that at our level of sophistication, you have to try different brake pads, cooling setups, etc. to determine what is best. But, at a certain level, that is not the case. You know why F1 doesn't run adjustable shocks? Because they have far more data than this, run simulations constantly, and know what will work when the car rolls out of the trailer. The same holds true for the top teams in Tudor, DTM, WEC, Indycar, and more.

Different strokes for different folks.

 

Matt,

You and I both know that the stop watch is the ultimate answer to what is faster. This no way you can say that this particular brake data will certainly make you faster. It might for some but certainly not all. If I had a team with a data engineer it would certainly make sense to track. But for most of us, the extra sensors and the extra data are probably not going to help us get any faster and not be worth the cost or the time.

You can track and analyze that data if you want.....I have much more important data to digest.

 

Wow there's a LOT of scatter in the orange points. The blue pads are pretty linear with the exception of one datapoint that doesn't quite make sense. But the Orange points are all over the place. Any ideas why?

 

We each speak from our own experience. I have used this sort of data to make people faster, improve qualifying times, and finishing positions. I can tell you one of the fastest cars on the East Coast, driven by a name that everyone would know, has used this data to go faster and get better brake performance.

Brake friction engineers walk around with thermocouples so they can get brake temps when you come in from a hot lap, just like tire engineers do for your tires. This data is much better than what you get on pit road, just like the IR tire temps are more accurate than what you get from a probe on pit lane. Whether you collect it, how you collect it, and what you do with it is up to the driver/owner/crewchief, etc.

 

Matt,

For the club level racer, to whom you are catering here, that brake data is of dubious value. Some may benefit from tracking and analyzing it. But not most and certainly not all. At the club level, I can guarantee that most of us have bigger fish to fry.

 

Good catch!

I do know what caused it. This is the same graph from the orange pads on a different day / different track, but show how linear they normally are.