TW: 13" Rotor, Caliper Brackets

[JRas]

Originally Posted by sil80drifter

The reason people go with the Cobra rotor is because the AREA of the rotor is larger than the 300ZX rotor. The contact patch is the same, for both rotors, the pads are completely covered by the rotor (for the Cobra upgrade this requires slight grinding of the caliper edges so that they sit closer to the rotor).

Bigger brake upgrades are very rarely about stopping faster. Stock 240SX brake are sufficient to lock up the wheels (which means all the braking power you need to stop).

Nowhere in this thread have people claimed faster stopping times. The advantage of bigger brake rotors and pads lies in their heat dissipation abilities. Being able to stop from 100-0 is no large feat. Being able to do so multiple times over without experiencing brake fade and fluid boiling is what counts. This is achieved by maximizing the area of the rotor and pad.
The EVO/STi combo is also great. The EVO rotor is not 13" though, so fade may occur faster.

sil80

if this is just for heat dissipation, I'd rather build myself some brake ducts... willing to bet that would be more efficent way of heat dissipation, not to mention inexpensive.

the rotors would also have uneven wear because the caliper doesn't properly cover the full surface but mainly the outside.

[sil80drifter]

by that logic, we should all just have brake ducts and not even bother with larger brake rotors. what about smaller circuits, or bumper to bumper racing where you don't have air just going to the brakes? brake ducts only work when thee is air flow, and at good speeds nonetheless.
No, we need as big a rotor as our wheels and weight concerns allow us. Obviously the weight of the car matters a good bit, an AE86 won't need a 13" rotor, while a heavier, turbocharged, sometimes fully equipped s13/s14 will definitely benefit from one on the track. IMHO heavy track use requires both ducts and larger rotors.

Btw, the caliper NEVER covers 100 of the rotor up to the hub mount. There is always a bit of space there (a few mm at least), and the reality is that it doesn't matter; there won't be an "edge" issue due to rotor wear.
Basically, if you can get the cobra brakes, you should get them, this is the best big brake kit for the buck. If you need one, at all, that is.

sil80

[JRas]

Originally Posted by sil80drifter

by that logic, we should all just have brake ducts and not even bother with larger brake rotors. what about smaller circuits, or bumper to bumper racing where you don't have air just going to the brakes? brake ducts only work when thee is air flow, and at good speeds nonetheless.
No, we need as big a rotor as our wheels and weight concerns allow us. Obviously the weight of the car matters a good bit, an AE86 won't need a 13" rotor, while a heavier, turbocharged, sometimes fully equipped s13/s14 will definitely benefit from one on the track. IMHO heavy track use requires both ducts and larger rotors.

Btw, the caliper NEVER covers 100 of the rotor up to the hub mount. There is always a bit of space there (a few mm at least), and the reality is that it doesn't matter; there won't be an "edge" issue due to rotor wear.
Basically, if you can get the cobra brakes, you should get them, this is the best big brake kit for the buck. If you need one, at all, that is.

sil80

Air at low speeds is surprisingly more than most people think. A car may overheat idling or while sitting in traffic but may not overheat driving at 15mph. I doubt anyone here has brake fade issue at normal driving anyways :P at the track you're obviously going to be driving faster and cooling the calipers/rotors quicker.

I know the caliper never completely covers the rotor. My point is there a sufficient amount of free space on the rotors friction area not being touched by the brake pads at all.

I personally wouldn't spend my money on this "upgrade", not to mention I already have an Evo setup waiting.

[INeedNewTires]

not only does the larger rotor cool better, but it DOES have more square inches of contact patch. Not on the caliper itself but on the outter dimensions of the rotor. In other words it takes more material to go around the outside of a 13" rotor than an 11" rotor. So more surface area.

Another benefit is the further out you space the caliper the inertia has more stopping power. Spin a disk of some kind, and with your fingers grab it near the middle, then try near the edge. stops alot easier the farther you go outward. I'm sure someone with more technical knowledge and vocabulary can tell you the physics behind this, but you should get the idea.

Where can i buy just the brackets?

[timtiminy]

i have the z32 calipers to cobra rotor brackets, problem is the cobra rotors need a hub ring in order to stay centered and i dont have the hub rings.

[sil80drifter]

I know you are defending your choice of the EVO/STi kit. That's fine. If I had to do it over again, I'd still go with the Cobra kit. You cannot beat it's bang for the buck. Both the calipers and rotors are much cheaper, and I feel the performance will be just as good if not better. That's just my opinion.


sil80

[timtiminy]

as well as bigger rotors having a higher thermal capacity because of their size, cobra rotors have curved vanes which also assist in cooling and are alot cheaper to replace than evo, sti, or 350z rotors.
Ineednewtires: i think you are refering to the additional torque that having bigger rotors gives you on braking. torque is expressed as radius times force so if you have a larger radius (bigger rotor) more baking torque is made so it should make a difference in how quickly you decelerate; that is before the time the tires lock up.

[JRas]

Originally Posted by sil80drifter

I know you are defending your choice of the EVO/STi kit. That's fine. If I had to do it over again, I'd still go with the Cobra kit. You cannot beat it's bang for the buck. Both the calipers and rotors are much cheaper, and I feel the performance will be just as good if not better. That's just my opinion.


sil80

I like how the brackets can be had for the cheap, along with the rotors but unless I see some hard evidence showing it actually increased braking and brake fade by a substation amount I have my doubts. I have no first had experience with this setup, so I spoke to gumball who told me over aim that he did in fact try all three setups and there was an increase in performance with the cobra rotor, however he did state his STi setup is superior :P

I won't knock it anymore, but I'd still like to hear a before and after story from someone in the thread.

[INeedNewTires]

if anyone has the bracket for Z32 caliper and Cobra R rotor i'll pay them just for a detailed measurement or trace outline of one! otherwise WHERE CAN I BUY THE BRACKETS ALONE?!

Someone needs to set up a group buy on these bitches, their worth the money imo

[timtiminy]

i have the brackets alone. you will have to figure out hubrings and hardware though..