Where does the Whoa!! come from.

[LVMarauder]

Im talking about brakes. What contributes more to braking ability? Is it the Diameter of the Rotors or is it the number/configuration of the pistons in the Calipers. Obviously im talking about what will get me more stopping power between 14" 2 Piston Baer's and 13" 6 Piston Willwoods. I went to howthingswork.com but it wasn't clear to me. Leverage or Pistons? what say you.

[gonzo50]

Bigger Rotors have more clamping area with less revolution per rotation, so I would think it stops quicker.:help:

[Master]

Multiple pistons give a more even pressure on the pads over the entire surface so the pad deflection is less and therefor allows for better contact across the face. More important than either size or pistons, though, is co-efficient of friction. I can run the tiniest rotors and pads on my race car with carbon kevlar material and heat treated rotors and they will outstop vehicles with much larger rotors and fancier calipers. However: My rotors will heat up till they glow red due to the limited surface area (as Carlos points out) and therefore do not disipate heat as readily. Nor do they offer as much surface area. Any one of the three improvements will offer you greater performance, but add pistons, area and friction and you have a deadly, synergystic combination.
Just my 2c. Lets see what everyone else says, now.

[ckadiddle]

I don't know much about the physics of braking, all I can tell ya is that the pads matter a good bit. I had mine upgraded to Hawk HPS pads when the OEMs wore out. It never stopped this good with the OEMs. The Hawks with stock rotors worked well at the drag strip during MVIV. They smelled a bit when they got good and hot and squeaked a good bit while hot, but never lost the least bit of stopping power while I did back to back runs.

[MitchB]

One very large factor is how much the calipers flex when it forces the pads against the rotors. Flex greatly reduces clamping force.

Mitch

[fastblackmerc]

If you do a search I believe Todd from TCE has discussed this more than once. Maybe he'll post here.....

[MENINBLK]

There are many factors that contribute to braking.

Master Cylinder design, and Brake Force Equalization.
Brake Fluid.
Brake Lines, Solid, braided, or rubber.
Rotor Material, Size, Vented or Not Vented.
Pad Material & Size
Caliper design and number of pistons
Wheels, Diameter, weight, and materials

And finally TIRES - Compound plays the most important part.

If your brakes create all of this friction to stop your vehicle
and the tires can't provide the traction to overcome the friction
then you ain't gonna stop on a dime or a half dollar... :eek:

[Grifter]

for the most basic explanation, outside of any thoughts of caliper flex, tire compound etc, think of it like this. take a small round object say a penny, and put it in a drill so that it spins like a rotor would. try to grab it with your fingers and get it to stop spinning. pretty hard to do, (and you will probably mess up your fingers!) now take a large diameter round object, say a vinyl record, and do the same thing. I bet you could stop it then, of not atleast slow it significantly down. with that being said, the only thing that changed was the diamter of the ''rotor". your fingers did not exert any more force, nor did the drill gain or lose any speed. you were able to stop/slow the record because you had more leverage on it.

[metroplex]

The GT500 uses quad-piston calipers up front with very large brake rotors. Venting helps keep the rotors cool, multiple pistons allow a more evenly distributed clamping force to the pads and also allow you to use very large pads. Cross-drilled and slotted rotors are just a fad inspired by the genuine deal used on race cars on the road courses (they don't last very long - just enough to finish a race).

[Master]

Nice example,Grifter. Also the comment about the tires needing to be up to the challenge. However, some of the other things in the list - master cylinder, brake line style, even number of pistons and material really - they can add dramatically to the "Feel" which in itself can aid greatly in controlled stopping. Its one of the key things in all motorcycle reviews - effort and modulation required for braking. When you are on two wheel and only one of them does 80% of the stopping, you really start to care about "Feel".

[magindat]

Keeping it simple....

Heat doesn't mean much to us unless we are road racing. A normal driver of an MM never generated the kind of heat generated while racing. So consider if you'll ever be using her at a track.

Pad compound, like tire compound, is important.

Bigger rotor means more leverage. More leverage means nothing without something to grip it with (pad compound).

More pistons means better distributed force on the pad. Again, means jack without the right compound on the pad.

Braided lines eliminate all rubber hoses from the system. They greatly increase feel and decrease fade. Result = more control.

There are many available improvements over stock. You must ask yourself what you'll be doing with the car.

My example:
I swapped to Baer Decela Rotors, stock size. Drilled and slotted. Slots wisk away the gas layer under the pad and drills dissipate heat. Heat I almost never generate, so they look good. They have a 3 year warranty against cracking. That tells me they'll last well.

I swapped to Akebo Ceramic compound pads. I had good success with these in my ricer days and was pleased to find they made our fitment. The dust is much less than stock.

I swapped to braided lines.

The entire combo has greater braking force (shorter distance and a great deal more CONTROL and FEEDBACK which hep me stop better and safer in any given situation.

There is no 'This is better than that.' I just has to do with what's best for YOU!

[metroplex]

A dedicated race car will have its brakes overhauled every few races, but the brakes on a daily driver can get very hot (800F+) depending on the driving conditions.

As for braided lines... are you referring to the braided hoses? The lines are already steel. It's the rubber hoses that tend to flex/expand at high pressure. The braided hoses are constructed to prevent this expansion or at least reduce it, so all of the required hydraulic pressure is diverted to the caliper piston(s). :coolman:

[jdando]

Pretty good stuff so far.

From a practical point, I do not think 14" Wilwood rotors clear stock wheels. The 13.1 are really tight.

Keep that in mind if you want to keep stock wheels. Do not forget stainless steel brake lines, they help with pedal feel and minimize mush.


Brake pad compound is very important. I burned through a set of road pads one weekend on the track. Scared the poo out of me and my instructor:eek:

Road pads are nice, quiet and dust free. Agressive road pads are okay, better stopping, quiet, but dusty. Track pads are :banana2:, noisy and dusty as a garbage truck, but fade free and incredible stopping with track tires.

As in most cases, it is hard to be a jack-of-all-trades. Knowing what I know, I would not run road pads on the track or track pads on the road.

Brakes are not cheap, but if you have the need they are great. I think for most, an upgrade to a better pad and stainless steel hoses would be a nice cost effective upgrade.

jeremy

[LVMarauder]

Sounds pretty good fellas, Thank you all for your comments. Right now I have some Cryoslot rotorrs up front with HPS pads. I think ive narrowed my choices down to the 14 baer claw system , or the more economical choice which is chaning to decella rotors ( the cryorotors has started to warp) , a ceramic pad compund and getting SS braklines all around.

[magindat]

Sounds pretty good fellas, Thank you all for your comments. Right now I have some Cryoslot rotorrs up front with HPS pads. I think ive narrowed my choices down to the 14 baer claw system , or the more economical choice which is chaning to decella rotors ( the cryorotors has started to warp) , a ceramic pad compund and getting SS braklines all around.

For all around general driving and an occasional track event, you'll be happy with the performance vs cost of what you've decided on.

[Architect]

Keeping it simple....
My example:
I swapped to Baer Decela Rotors, stock size. Drilled and slotted. Slots wisk away the gas layer under the pad and drills dissipate heat. Heat I almost never generate, so they look good. They have a 3 year warranty against cracking. That tells me they'll last well.

I swapped to Akebo Ceramic compound pads. I had good success with these in my ricer days and was pleased to find they made our fitment. The dust is much less than stock.

I swapped to braided lines.

The entire combo has greater braking force (shorter distance and a great deal more CONTROL and FEEDBACK which hep me stop better and safer in any given situation.

Magindat, How long have you been running this brake set-up?
Sounds like a good set-up.
Thanks, architect

[magindat]

Now at 49K.

Rotors and pads went on at 17K. Lines went on at about 43K. If you do it all at once, it WILL be a different car. I do about 25K a year.

Have one SVTOA track event on the pads. No noise or squeals or vibrations. Might be time for new pads soon. They're not worn out. It's just cheap peace of mind.

[Todd TCE]

Some good, some not so good info thus far.

Brake torque is achieved by rotor od (leverage), piston area (clamping) and pad Cf (how rough the pad is).

Some good points:

More pistons are better for spreading pad wear more evenly. Qty does not mean more tq however as it depend upon total area.

Larger rotors are a good start. They provide more tq but also increase mass and swept area.

Pad choice has a huge effect. Any good stock rotor fit with a good pad is worthy of most daily drive duty. Crappy pad= crappy performance all else being equal.

SS hoses increase performance. To the extent that pedal FEEL is improved. Pressure is pressure regardless of the hose.



Somre not so good points;

Larger rotors stop better. No, they only require less clamping to achieve the same effect.

More pistons and area is better. Not really. More area means more displacement and longer pedal travel. While tq is up for the same given input pressure it may well be too much front brake also thus negating rear brake application.

Slots and holes make for better braking. Sorry, but no. The holes and or slots while venting gasous build up don't make more brake tq but they can make the given tq more efficient. A better pad would do the same thing on stock rotor and thus most "packages" are sold with rotors AND pads- it's the pad that's making the change.

More pistons means more tq as it loads the pad more. Nope, only spreads the same psi over the pad plate in a different manner. Good for pad life and wear however.

Bigger pads do more work and are better. Nope agian. The pressure behind the pad is the same regardless of the pad size. Same tq on one or two pistons if the area is the same. Just placed in different areas.

You can learn more and see in real time the changes by using the brake bias calculaor here; http://www.tceperformanceproducts.com/brake_bias_calculator.html
forget "bias" for now and simply change the specs of rotor OD or piston sizes and see how the rotor tq changes for the same given LEG input. (multiple browsers help here)

[LVMarauder]

Thanks alot brake dude