There are club racers (some who post here) who use this kind of data to improve their driving and car. I never said this was for everyone, I wanted to share what can be done. I wanted to share it so people can see what can and is done at different levels of driving/racing.

Let's let other people check it out with out our disagreement on who it's useful for. Everyone can look as much or little as they would like and I'm happy to answer any questions people have.

 

OK. What was the Blue pad and what was the Orange pad?

 

They are......Wait a minute, I see what you did there.

 

Very much appreciative of the intellectual debate and taking the time to post data - this is fun!

BUT Comparing cooked pads to new pads shouldnt be used to make any decisions, my guess if you put both the same pad one with 90% and one with 25% you would get (and I know from my butt data acquisition sensor) very different braking and duration of braking ability performance

All in all though, cool way of looking at the data.

I would suggest though you decide what you are solving for and chart accordingy

1. Qualifying - linear increase in long g's per brake PSI, ability to generate full lockup at moderate pressures - i.e. quick to get your braking ability required to get out there and knock out a lap

2. Racing - ability to stabilize rotor and brake temperature even multiple laps in, there you would chart similiar brake pressures over time and see if longitdual G's generated for given brake pressure remain close (and therefore allow for consistent driver inputs generating consistent outputs) - a 3 dimensional chart to the one you made with the x,y scatter. This is most important as many of us novice folks (DE myself here) do experience brake fade from under-cooled (and over used) braking.

Excited to rekindle my never used degree in auto engineering with this new SoloDL I bought and tinkering with this stuff - very fun and please continue to post stuff like this, it really sparks my imagination and enjoyment here

 

Posing a question: what influence does changing pads with different chemical/physical characteristics have on brake performance when the rotors have not been changed so only one set of pads are applied to its same matched rotors? The test description indicates that the rotors had "x" pads embedded material and then "y" pads were tested on rotors that had "x" pad material embedded in rotor. I was of the opinion that it is not a good practice to switch pad material without changing rotors. Could this accout for the high variability of the orange pads in long g vs brake pressure?

Just my 2 cents

 

I'd definately like to see the 2 pads I've been considering switching too with this data....I've stuck with the same pad for years because they work and don't melt my caliper seals
on the old cars the calipers seals are getting crappie it seams....new ones use sub par rubber...
I tried switching compounds twice and each time ended up with 3 or 4 leaking calipers...once was on a brand new caliper as well
went back to the old pad and troubles went away...yet I know others that run the ones that fry my calipers with no issues...and others with the same issue

 

Matt, thanks for posting the analysis. The data collection is something I use at every track outing. I enjoy pouring over the facts during and after the events. I suspect given two drivers of equal talent driving the same car, the one that consults with the data engineer will be the faster driver.

 

Very cool Matt, thanks for sharing. Would love to know which two pads/compounds you used for the comparison but understand why you would keep that quiet.

 

Which pad was faster? The orange pads seem like they would provide longer service life, but did either pad generate faster lap times for the driver?

I realize that driver preference is a significant variable.

 

Great question! You do have to bed each pad to the rotors. Essex has a great article on this at http://www.essexparts.com/learning-center/Bed-in Also read part 2. For this, both sets of pads were properly bedded.

We all know you love data as much as me!

I was trying to avoid having a battle of the data and figured not insulting people's favorite pad would help with that. Hopefully I'll have some more pads to test soon.

The blue pads were quicker, but the driver liked the orange more. The fast laps from the blue pads were from braking zones, so I don't think they were a significant variable. The blue pads did results in an octagon shaped tire though!

 

Great points! A better test would have been two new sets of pads, but that wasn't what we were able to do at the time, so this is the best we have. The difference in new and old pad performance is friction material oxidation (as explained to me by brake engineers). That is why old brake pads will sometimes not perform as well as new ones, even when their is plenty of material left. That was not the case here - the worn pads were not old and still performed with the same friction levels as when new.

I agree with your thoughts on the desired qualities of a pad, though I think you want significant overlap in qualifying and racing. We spend a lot of time building muscle memory, feel, and the brake system (MC size, caliper sizes, rotors, pedal ratios, etc) around getting a pad to work. When you switch that pad, all the other things may need to change to optimize the new pad. If nothing else, it takes an adaption from the driver, which is something I've found can be hard for many drivers.

 

PM me what you are considering and I'll tell you whatever I know about them. It's been interesting getting info from some of the brake engineers. Some of the most loved Porsche compounds are over 20 years old!

I agree on the quality of brake seals getting worse. I had some recently that I couldn't even get the pistons back in. It sucks to pay $15 for a fancy o-ring, but sometimes it's worth it to get good parts.

 

For sure the orange were preferred! Your decel v brake pressure plot, mixed with the temp data shows the orange is more linear in operation. Therefore, the orange is more predictable. A very worthwhile endeavor from my viewpoint.

So the blue was faster for 1 lap, but what about over the entire run? I would go out on a limb and suspect that the orange was actually quicker over continuous laps. Less variation and I assume more consistent lap times.

 

Great Analysis. I always like when you look at things as you have a little experience with this stuff!

Here is a graph of the lap time differences (% of best lap) for each of the tests. The times for the blue are compared against the blue and the orange vs. the orange. Hopefully that makes sense.

 

Definitely the orange is more consistent.

Even simpler what's the cumulative time for Blue vs Orange for Laps 2 thru 8? If the lap times are close (best vs best) than the orange would comparatively be the better race pad. The driver would likely be able to spend the first two laps building up a bit of a cushion. Especially as the best lap comes on Lap 2. The orange driver is building a lead early in the race.