Rear brake (caliper) temp questions

[IamFODI]

I have F8x brakes up front with the stock rears, so the rears are working a bit harder than they ordinarily would (pressure bias shifts rearward). I’ve had Alcon temp strips on the calipers for a few events this season; at the last one, they ended up 1-2 squares from maxed out (450º - 500º F / 230º - 255º C).

2008 E90 M3
~Stock weight
No aero
245f/265r AD09 (endurance 200TW)
Stock power minus whatever has escaped in >172k miles
PFC 331/332 pads, OE rotors


Questions:

1. Are these temp readings normal?

2. Any concern about dust boots and seals at these temps? This page seems to think so, but I’d value people’s lived experiences here as well.

3. Without swapping to different calipers, is there anything I can do to manage these temps? All I’ve seen so far is this brake duct kit, and I have yet to see any posts about it installed on an E9x M3, let alone how effective it is.

[Obioban]

2) are they cracked/melted? Easy visual check when you're swapping pads.

3) ... I want to print something like that

[Estoril]

I would use something much more precise and measurable than temperature strips to determine true temperature. IME, OE caliper boots smoke pretty well when they are cooking.

Is this track or street experience?

[IamFODI]

2) are they cracked/melted? Easy visual check when you're swapping pads.

One was. But I'm not sure if that means much because it was original after 172k miles 😬

3) ... I want to print something like that

In!

I would use something much more precise and measurable than temperature strips to determine true temperature. IME, OE caliper boots smoke pretty well when they are cooking.

Got it. No smoke AFAICT, so I'll take that as a good sign.

I do have an IR thermometer with an emissivity setting. Wouldn't suck to calibrate that so I can use it....

Is this track or street experience?

Track.

[OPS]

Frenkit puts those temperature strips in every rebuild kit but like Estoril said, you need something more precise. Those oe boots are fine for the street but are not great at the track. DBA (Australian rotor mfg) did a great YouTube video comparing the dust boots. Seals also are measured on hardness (compression)

mike
ops