F/R brake temperature?

andy_meng1024 · 09-27-2019, 11:33 AM

Quote:

Originally Posted by osbornsm

No... don't think so.

70% of braking is done with the front wheels... it's the same reason the front rotors are bigger than the rears. Different inputs = diff temps.

The front brakes are about twice as big so they have about twice the heat volume. I sold many Brembo race kits here in Taiwan as well as the GT, GT-S, and GT-R kits on street cars and race cars, and they all behave the same.

iPhoneTapatalk

cv129 · 09-27-2019, 02:22 PM

Just wanna add this little bit here via AP Racing’s website

https://www.apracing.com/Info.aspx?I...&ProductID=976

“In order to achieve optimum racing brake performance and prolong disc life it is essential that the brakes operate at the correct temperature. In general discs should run at similar temperatures front and rear and from side to side, dissimilar temperatures will lead to varying brake balance.”

Also wanna point out, Andy’s method of temp sticker indicates peak temp, where as Obender66 seems to be measuring temp after a cool down lap, so the different rates of heat dissipation may also cause a bigger variance than there is.

Another thing is, was Obender66’s temp taken after many successive laps where rotors and calipers’ temp were stabilized, or after just a couple quick laps?

cv129 · 09-27-2019, 02:45 PM

Don’t know if Obender was measuring caliper or rotor temps.

For rotor temp measurement after a cool down lap, assume OEM Akebonos and no brake cooling ducts: the front rotors are just tiny bit bigger than the rear in diameter (355 vs 350mm), but thickness differs greatly (32mm vs 20mm). The front rotors carry a much greater volume of heat with not much more surface area to for heat dissipation. With a method like using an infrared temp gun, which measures surface temp, I would not be surprised there is a temp difference, even if the peak temp during braking may be the same between front and rear rotors.

obender66 · 09-27-2019, 05:15 PM

Quote:

Originally Posted by cv129

Don’t know if Obender was measuring caliper or rotor temps.

For rotor temp measurement after a cool down lap, assume OEM Akebonos and no brake cooling ducts: the front rotors are just tiny bit bigger than the rear in diameter (355 vs 350mm), but thickness differs greatly (32mm vs 20mm). The front rotors carry a much greater volume of heat with not much more surface area to for heat dissipation. With a method like using an infrared temp gun, which measures surface temp, I would not be surprised there is a temp difference, even if the peak temp during braking may be the same between front and rear rotors.

Yes, there was some cool down, and I agree, they cool off differently. My fronts probably cool off quicker as they are Wilwood 2 piece with aluminum hats and rear are off the shelf Z33 brembos.
I expect to see rears to be cooler, but question is how much cooler? Thank you for AP Racing link-they do not give precise answer, and it cannot be precise due to all the parameters mentioned by other posters. It's understood, but 40%?

cv129 · 09-27-2019, 05:25 PM

Quote:

Originally Posted by obender66

Yes, there was some cool down, and I agree, they cool off differently. My fronts probably cool off quicker as they are Wilwood 2 piece with aluminum hats and rear are off the shelf Z33 brembos.
I expect to see rears to be cooler, but question is how much cooler? Thank you for AP Racing link-they do not give precise answer, and it cannot be precise due to all the parameters mentioned by other posters. It's understood, but 40%?

I think your best bet is to now find peak temp via temp paint/sticker, see if the difference is nearly as big.

Rusty · 09-27-2019, 07:43 PM

Get some different temp paints and paint stripes on your calipers and on the edge of the rotors. Also, you can put some paint on your rotor hats to see how temp is there. Because that heat goes to the bearings.

https://www.pegasusautoracing.com/pr...p?Product=3161

09-27-2019, 02:22 PM	#2 (permalink)
cv129 A True Z Fanatic Join Date: Jul 2011 Location: Dallas, TX Posts: 3,262 Drives: 09 Nismo, 16 Nismo Rep Power: 163995	Just wanna add this little bit here via AP Racing’s website https://www.apracing.com/Info.aspx?I...&ProductID=976 “In order to achieve optimum racing brake performance and prolong disc life it is essential that the brakes operate at the correct temperature. In general discs should run at similar temperatures front and rear and from side to side, dissimilar temperatures will lead to varying brake balance.” Also wanna point out, Andy’s method of temp sticker indicates peak temp, where as Obender66 seems to be measuring temp after a cool down lap, so the different rates of heat dissipation may also cause a bigger variance than there is. Another thing is, was Obender66’s temp taken after many successive laps where rotors and calipers’ temp were stabilized, or after just a couple quick laps? andy_meng1024 and Rusty like this. __________________ Setrab \| RE-71 \| SPL \| JRZ \| Nismo \| ARK \| Whiteline \| RacingBrake \| CJM Oil Pan \| Ti shield

09-27-2019, 02:45 PM	#3 (permalink)
cv129 A True Z Fanatic Join Date: Jul 2011 Location: Dallas, TX Posts: 3,262 Drives: 09 Nismo, 16 Nismo Rep Power: 163995	Don’t know if Obender was measuring caliper or rotor temps. For rotor temp measurement after a cool down lap, assume OEM Akebonos and no brake cooling ducts: the front rotors are just tiny bit bigger than the rear in diameter (355 vs 350mm), but thickness differs greatly (32mm vs 20mm). The front rotors carry a much greater volume of heat with not much more surface area to for heat dissipation. With a method like using an infrared temp gun, which measures surface temp, I would not be surprised there is a temp difference, even if the peak temp during braking may be the same between front and rear rotors. Rusty likes this. __________________ Setrab \| RE-71 \| SPL \| JRZ \| Nismo \| ARK \| Whiteline \| RacingBrake \| CJM Oil Pan \| Ti shield

09-27-2019, 07:43 PM	#6 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 69 Posts: 35,386 Drives: 2011 Nismo GM 6M Rep Power: 2684438	Get some different temp paints and paint stripes on your calipers and on the edge of the rotors. Also, you can put some paint on your rotor hats to see how temp is there. Because that heat goes to the bearings. https://www.pegasusautoracing.com/pr...p?Product=3161 andy_meng1024 and Hotrodz like this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

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