SsTiNgEr77

iTrader: (4)

anyone know the weight of the oem rotors vs upgraded slotted rotors?


is it a significant amount like 2 - 5 lbs +/-?


or does anyone know the weight of the rotors for

F/R stoptechs

F/R DBA slotted

F/R OEM

any other brands? THANKS

Steppin Razor

iTrader: (5)

My intuition tells me that the weight differences in aftermarket, direct replacement, drilled or slotted, one-piece rotors is entirely insignificant.

Due to the very small differences in weight, in order to make an accurate comparison between these rotors, one would need access to a highly accurate scale (I'm guessing accurate to 1 gram or less). All rotors would also need to be measured on the same scale, one right after each other, and then measured again in order to get results that are even worth looking at.

wvjnky

iTrader: (1)

Last night on chop cut rebuild they were working on the binders on their WRX. They took off an aftermarket drilled/slotted set up and weighed the rotors. They were at a respectable 16 lbs. per corner. Then they pulled out these trick rotors that looked almost ceramic with a wavy cut to the rotor and they weighed 4lbs. per corner. Quick math says take 12 lbs. of rotating mass away from your binder set up and you are stopping loads less force hence better brakeing. The other upside would be excellerating would be easier as well do to less rotational weight. I got a phone call before I could get the specs. and the manufacturer. If anyone know of which I speak I wou;ld love to get these but I need info.

SsTiNgEr77

iTrader: (4)

thanks steppin razor and wvjunky,

but i agree with both u... brakes are made to stop the car, sot he best rotors would be the ones which stop the car the fastest, the manufacturers goals aren't to make the lightest rotors...

but as wvjunky said.. are their any brake rotors which are significantly lighter as he suggested?

and are they worth it?


or could u give me a hellov a deal on a stoptech stage II package steppin !!

symby

It is possible to make lighter materials that dissapate heat at a much quicker rate or even the same rate as regular. I imagine those rotors that wvjnky saw were probably quite expensive. The Enzo has ceramic rotors, yeah, super light, but at $25k a brake job.. oich. Of course thats pretty extreme.

I think one method used to lighten rotors is to make bigger vents in the middle. So, with bigger vents, you would also get better and faster cooling.

Steppin Razor

iTrader: (5)

Or even better yet, BrakeMan stuff. Those systems are awesome. Until you have to use them to stop the car. I don't even know where to start. First of all, any race car outside of F1 uses cast iron rotors. Heavy ones. We're talking 12 to 14 pounds per rotor for applications that require a large heat capacity, and that's not including the hat or mounting hardware. Combine that with the fact that these rotors are 320 to 380mm in diameter, and you've got a sizable amount of mass a pretty good distance away from the axis of rotation. Why? Because in order for these cars to keep the friction interface within the optimal operating temperature of the brake pads, the rotors have to be able to absorb a certain amount of heat over a given amount of time (I'm talking about the amount of heat that is generated on a per stop basis). That rotor must then have the ability to quickly dissipate that large amount of heat before the next corner, and do that hundreds of time per race without getting too hot. Now, conversely if the rotor is too big, the downside is that the added rotational inertia will prevent the car from turning faster lap times, and will actually start to slow the car down. Ideally, the rotors have just enough mass so that their temperature at the friction interface peaks at the top of the pads' optimal operating range. Any more rotor, you slow the car down with too much rotational inertia. Any less rotor, you slow the car down because the system is fading and can no longer achieve the same rate of deceleration.

Does any of that make sense? If not, ask a question.

Tim
www.stoptech.com

SsTiNgEr77

iTrader: (4)

awesome.. thanks for the response, so.. pm'd you!

go go go

iTrader: (2)

S202 has a special slotted rotors.
The material is different (CV iron) and its 7kg (15lb) lighter a vehicle.

I have CV iron rotor (Racing Gear brand) on my car but i forgot to weigh it..

s.g.d

i think of it this way.

when it comes to weight, the sum of the parts is what really adds up.

you have rotors that are say 5lbs lighter. alone that 5 lbs is useless and insignificant, but if you also get that forged control arm that is ~1 lighter, that becomes 6 lbs. and those wheels that were 2lbs lighter? 8....the tires that were 3? 11 and finally the lugs that were lighter....it all adds up and before you know it, you have saved 11 lbs each corner!!! 44 lbs over all.

thats how i look at it. save what you can
~SGD

OakosAutomotive

iTrader: (17)

It is important to understand that the brake rotor acts as a heat sink. The braking system converts energy from one form to another. During braking kinetic energy (the energy possessed by a rolling car) is converted into heat energy which is absorbed by the rotors before being dissipated into the air. Reduction of rotor mass (without the use of alloy center hats or exotic materials like ceramic or carbon) limits the amout of energy that can be transfered to it and, all else being equal, would result in higher rotor temperatures. Higher rotor temps will increase the likelyhood of both pad and fluid fade and also will accelerate wear on related items such as rubber seals and the wheel bearings.

Just for reference, here are some weights that I have measured with a Mettler Toledo PS60 scale that is legal for trade (ie. very accurate).
Carbotech slotted front rotor: 14.00lbs (likely identical to an unused OE rotor)
TWR Racing two piece slotted front rotor: 13.25lbs (Alloy Center Hats)
Stock front rotor, worn approx. 1mm + material lost to oxidiation in the vanes: 13.85lbs

-Dave