I have been curious for a while now on how hot my brakes get while tracking the car. So I found a supplier that sold a special heat sensitive paint especially designed for use on brake rotors to track how hot they get.

On Monday and Tuesday the weather was perfect for a track event, temperatures hovered between 21C and 25C (70F and 77F) with no rain. It was an ideal situation in which to test the brakes.

I still don't have my front brake ducting kit completed yet so these reading are what anyone would see without additional cooling.


Heat sensitive brake paint by Genesis.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Brakes002.jpg">


Colour/temperature scale. A more detailed version is provided with the kit. Up to nine colours with their associated temperature scale is shown.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Brakes004.jpg">


Here the paint is applied to my rear rotor.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Brakes006.jpg">


Here are the results after tracking the car. The paint turned an orangy-yellow and after talking to the paint manufacturer we concluded the rotors hit the high 500C to low 600C (1100F) temperature mark... Pretty hot! Please take note that I was running with Ferodo DS3000 race compound pads in the front. As for the rear to my amazement they also hit the same temperatures! I would have never thought the rears would be as hot as the fronts on an Audi. In the rear I run with Ferodo DS2500 pads.

<img src="http://i17.photobucket.com/albums/b79/mlab601/Brakes024.jpg">


FYI, I don't get two full weekends of track use out of the DS3000. The last two events I averaged about 200 miles of track time at each event over 4 days (usually four 25 minute sessions per day). I needed to replace the front pads prior to the end of the second event.

Thanks for the info, Mike. Looks like those 3000 pads may be tough on your rotors from a wear point of view, also. I like the Ferodo 2500 pads on the RS4 as an all-purpose pad. Although changing pads is easy on the RS4, I do not think I would go to the 3000 pads unless I was convinced that it made an exceptional difference on the track and I was willing to swap pads on the paddock or in the garage at track events.

I'd like to hear about your pad changing routine and whether you feel it is really worth the effort.

You are getting.

If I may, I'd like to propose something to you. When we meet up at Tremblant at the ACNA event in September, I'd like to use my heat sensitive brake paint on your rotors to see what kind of heat the RS4 generates with the 2500s.

I believe Scott uses DS2500s and I'd like to propose that to him too. That way we would have two samples from RS4 owners tracking their cars with DS2500s.

I may want to try those (DS2500s) but STaSIS believes I'm pushing my car and its brakes well beyond the 2500s effective range. They actually tell me I'm running my rotors almost as hot as their race cars.

Anyway feel free to decline and I'm sure we will have plenty of time to discuss this prior and during the event.

So far the 2500's have stood up well to one track event at Lime Rock. This next week at Watkins Glen will be much more telling, since speeds are quite a bit higher.

Unless you have 370mm rotors ds2500 are not for you. I have 332mm brembos, ds2500 were not up to task on my 3,700 lbs A4.

I know that rs4 rotors are larger. But the car is heavier and reaches hgher speeds before braking.

I love ds2500s for street, and would recommend them to novices. They were great in rain. Dry day was not so kind to them.

I use street and track ceramics respectively. No need to re-bed when swapping. This has been working great so far.

Also I'm using DS2500s in the rear and they are reaching the same temps as my front DS3000s with no signs of problems.

My car weighs ~3200 lbs that's 800lbs less then an RS4 and I'm pretty sure I'll be approaching the braking point at almost the same speed so I have less brake energy to dissipate. I'm in the process of making and soon to test a brake cooling kit for the front so this should bring down the temperatures.

In any case I'm talking and working with STaSIS on the whole braking subject for my car. We'll see what happens.