RacerLex

What part of a BBK saves weight vs OEM? I'm guessing it's the calipers since the rotors are larger, unless BBK rotors are made from a lighter weight material ?

I ordered factory replacement slotted rotors from Rotora (not BBK) and they weighed about the same as the OEM rotors. I'm still using OEM calipers for now. I'll do a write-up on the Rotora's after they have broken-in and I can start punishing them .

lexforlife

iTrader: (7)

weight savings is in 2 forms with a true bbk rotaional weight savings and unsprung weight

my 6pot rotoras calipers weigh in around 9lbs loaded compared to arounfd 14-16lbs of stock the 2 piece 14 1/4 in rotor weigh about 3lbs lighter in rotaional weight

stopping power is out of this world

Neo

iTrader: (3)

Calipers are lighter. Better (more $) BBKs also have 2-pc rotors. These have aluminum hats in the middle of the rotor instead of a solid cast rotor. There is weight savings there too.

DaveGS4

iTrader: (2)

https://www.clublexus.com/forums/suspension-and-brakes/60803-some-good-info-on-brakes-upgrade-spec.html

stock gs brakes
font caliper - 2 pistons, 15lb
front rotor - 11.5" diameter, 18lb
rear rotor - 12" diameter, 12lb

supra tt upgrade (around a bit over $1000)
caliper - 4 pistons, 15lb
rotor - 12.7" diameter, 20lb

brembo GT upgrade (around $2800 to $3000)
caliper - 4 pistons, 7lb
rotor - 13.1"
piston area - 1.5"x2, 1.73"x2
pad area - 9.6"^2
rotor thickness - 1.26"

ap racing upgrade (around $3200 retail, there is a GB now for $2599 )
caliper - 6 pistons, 6lb
rotor - 13.5"
piston area - 1.1"x2, 1.6"x2, 1.5"x2
pad area - 11.8"^2
rotor thickness - 1.4"

stoptech upgrade (around $1800 to $2000)
caliper - 4 pistons (will fit in stock 17" wheel)
rotor - 13.1"

RacerLex

lexforlife: How did you measure rotational weight? Do you mean the rotors were 3 pounds lighter on a scale?

Neo: Didn't know that about the rotors, thanks.

DaveGS4: Great link, I'll contribute the weights of the Rotora factory replacment rotors to that thread.

Neo

iTrader: (3)

Just so that there is no confusion to anyone reading this. This line is from the above thread and there is no current GB.

lexforlife

iTrader: (7)

actual weight is about 3lbs lighter , they are 2 piece with hats being alum and rotor disk being steel rotational mass is amplified so three pounds of rotationl diff is like a added 30 lbs of weight spinning vs just unsprung weight

rominl

iTrader: (4)

about the rotational weight i was actually thinking. yes the center part is lighter now coz' it's the aluminum hat. but the outter is still cast and very heavy, and it's more on the outward now so the spinning weight is more outward, creating larger force. is that a good thing or they balance out?

lexforlife

iTrader: (7)

rotational mass is weighed as complete . so hat and disk together weighed

rominl

iTrader: (4)

umm..... i haven't touched my physics for a long time, but i think weighed mass has something to do with mass x distance from center of rotation? one very definite thing is, given the same mass (say 1kg), if it's spinning 1 in from the center (spinning at X rotations per second), it's going to be much easier to stop than the same mass being 12 inches away from the center (which is also spinning at X rotations per second)?

that's exactly why bbk has larger rotors, so calipers are more towards the outside, so they can exercise larger torque force to stop the car?

TLW

What!! No ENDLESS...

ENDLESS 6 pot Calipers 6lbs and sexy as hell

13.5 rotors as well
Price has been lowered actually

www.endlessusa.com

I

rominl

iTrader: (4)

they have 13.5" rotors now? i remember last time i checked they only had 13" rotors?