i'm waiting for someone to drill the stock bolts out and replace them with arp studs...

 

The studs that come on the Radial mount brackets are ARP. At least that is what I used.

 

bolts vs studs... you know that story.

 

IIRC, the dynapro-6 lug mount that is a direct bolt-on replacement for the dynalite-4 lug mount has the same piston area. In some cases, a 4-pot actually has a better pressure spread over the pad than a 6-pot with smaller individual pistons. Not a lot of improvement to be seen there.

Bigger reason to upgrade calipers would be for additional rigidity (better mounting method i.e. radial vs. lug OR stiffer caliper) and/or for a different piston area than is available from the dynalite range.

-Ryan

 

A larger rotor will increase brake tq...why?
because it's a bigger heatsink?
something something larger radius?

 

Tau = F x R

 

Which is the engineers way of saying a larger rotor provides more leverage, hence more torque.

 

Bigger reason to upgrade calipers would be for additional rigidity (better mounting method i.e. radial vs. lug OR stiffer caliper) and/or for a different piston area than is available from the dynalite range.

-Ryan[/QUOTE]

I agree. But additional rigidity usually comes with more weight. How much caliper and rotor weight increase before the scale tips and it starts to become a negative rather than a positive. Miata front calipers are a little over 8 lbs and a stiffer, non Willwood caliper say, is another 4lbs heavier. Then a Mini Cooper upgrade rotor is about 14lbs. So, for most people (fun street/the odd track day) car is about compromise. Weight is the trade off until more money overrides the weight. God, I'm just rambling........

 

Dynalite 4 is 3.4 lbs (shipping weight, real weight is even a bit less), Dynapro 4 (stiffer) is 3.8 lbs, Superlite 6 (all the beef) is 5.3 lbs

Any way you go, lighter than OEM.

-Ryan

 

more leverage, kinda. the answer is in heat.
During acceleration Fuel + air is turned into heat. that heat is tuned into forward movement via the engine and drive train. That movement is a form of energy. Emery that comes from heat. The law of conservation states that energy cannot be created nor destroyed. The car accelerates by tapping into the energy in the fuel. When a vehicle decelerates it needing to convert that energy (movement) into something else. Some of that energy in a moving car is lost to drag from the air, some is lost to rolling resistance, during a crash that energy is given into the chassis causing it to crumple. Under braking the friction from the pads + rotors convert that energy (movement) into heat. The rotors job is to simply dissipate the heat. A larger with more thermal mass then a similar rotor of a smaller size. Thermal mass provides inertia against temperature fluctuation. The extra thermal mass helps the rotor dissipate heat faster than a smaller rotor with less mass. So a larger rotor will convert energy to heat and return to normal temperature faster than a smaller rotor.

 

Right but if you make the rotor twice as thick you've doubled its thermal mass but done nothing to increase brake torque, and the question was about brake torque.

 

I agree. But additional rigidity usually comes with more weight. How much caliper and rotor weight increase before the scale tips and it starts to become a negative rather than a positive. Miata front calipers are a little over 8 lbs and a stiffer, non Willwood caliper say, is another 4lbs heavier. Then a Mini Cooper upgrade rotor is about 14lbs. So, for most people (fun street/the odd track day) car is about compromise. Weight is the trade off until more money overrides the weight. God, I'm just rambling........[/QUOTE]

this thread is 99.999% rants. don't worry your ranting in the right place.

You are forgetting about what the calipers are made of, and how they are made.
A stock caliper is iron. And it’s made to be mass produced. AKA cheap

Aluminum calipers like the wilwoods are made for motorsports and to be built to a price. So quality of the aluminum will be not as precise as a much more expensive motorsports caliper.

2pice vs 3 piece v monoblock
The strongest caliper on the market is a mono block caliper. One made entirely from one piece of aluminum. The molecular structure between the two sides of the caliper are unbroken, making the structure very strong. This is also the hardest to produce and will cost more due to the extra machine work they need to be created.
2 piece calipers are easier to create. Splitting the two sides are easier to be machined. Because the molecular structure between the two halves of the caliper are cut they will only be as strong as the bolts holding them together. The two sides will lean on each other but the bolts provide most of the strength. The bolts are also made from steel and as we all know the steel is heavy. 3 piece calipers are even cheaper. They are a 2 piece caliper with a spacer installed. This is bar far the softest of the 3. The molecular structure has been broken twice between the two side and gives the caliper even less structure to hold itself together.

Is a stiff caliper heavy? You would be surprised how light and stiff the F1 calipers are. The price would also make you faint. This is more a story of you get what you paid for..

 

i got a negative prop? wtf


guess you guys want to tell me how a thicker rotor has double the thermal mass? Converting energy is brake TQ. Look if you want my help i'll give it to you. if you don't want it just go away. Run you jank ebay brake kit and wonder why your brakes suck. i don't care..

 

I have no problem countering neg props with a positive one of my own. :cheers:

 

Dont look at me. I didnt negative prop you. But plain and simple, torque is force time radius, it doesnt care how much thermal mass is kicking around. Now that force term is going to change with the friction coef of the pad as the temperature changes but thats not what the dude was asking. A rotor thats thicker is going to be more massive and thus will have more thermal mass, but you're not going to generate any more braking torque with a thicker rotor excluding the case where the thinner rotor has over heated while the thicker one has not. The case is not the same with the larger diameter rotor, sure it has more thermal mass and wont overheat as soon, but using the same pad compound and caliper the larger diameter rotor will produce more braking torque but thats because the effective radius of the braking force is larger than the smaller diameter rotor, not the larger thermal mass.

Now I'm not trying to argue with you or talk down to you. I'm not sure why I even needed to mention this since you've shown in other post in this same damn thread they you completely understand the concept of what I'm saying. Maybe today's just an off day.

 

" This is more a story of you get what you pay for."
Thanks Johnny,
Yep, that is so true. ( I personally would need to spend money toward suspension then eventually toward wilwood's) If you had to choose caliper stiffness or larger rotor, which way would you lean? Slightly larger caliper would be stiffer and slightly more pad area. More torque/thermal dissipation from larger rotor, but more rotating mass. You still have a weight/mass increase, but it seems like the rotating mass would be a bigger negative than the caliper increase.
Thanks,
-Jeff

 

Hi!

Have a 99 miata (full weight). Mostly daily driver but sees 4 to 5 track day's a Year. I'm soon on 200whp with a small TD04. 390lb front 280lb rear coilover's and FM front ARB. 2.5" cooling duct's atached to front fog's.

My initial idea was for a Willwood upgrade but $ to € is not helping right now, so i have to stick with stock callipers for next couple of pad's.

I'm now on EBC yellow stuff. They where "fine" on stock power, exept for terrible modelation. I use a front pad set every 6k miles including trackday's, and my rear pad's do like 3 to 4 front's set's.

I'm upgrading to a willwood adjustable brake proportioning valve but have some doubt's regarding brake pad compound.

I would prefer an all around pad that i could use on street and track but i know it can be dificult. I'm excluding carbotech excatly because if i find them to be too noisy, i can't change to a street pad without resurfacing my rotor's.

Our circuit's are similar to Laguna Seca, regarding braking usage so they're realy hard on the brakes.

Regarding all this, do you think i can try PFC 06 all around for dual dutty or they really won't be any less noisy than PFC 11 and i really should forget dual dutty pads?

Thank's in advance!

 

you'll feel the effects of a rotor before you feel the effects of a caliper.

When a rotor gets hot it will start to deform. 1st phase of deformation it will look like the brim of a cowboy hat. 2nd form of deformation it will start to look like this

it goes on to 3rd, 4th, 5th ect... forms of deformation.
With a cheap rotor it doesn't take much heat for this to happen.
the picture below was from a autocross.


What this Feels like.
when a rotor starts to deform you'll get what the industry calls a "LONG PEDAL" that's when you put your foot to the pedal, and it just keeps going further and further away. Boiling brake fluid can give similar feeling. what is happening is the Pad is getting kicked back into the bore of the caliper. the first forms of deformation will make the pedal feel soft, and the more forms of deformation you get, the worse the pedal will feel. if you have a deforming rotor the stiffest calipers in the world will still feel like crap.

 

yes those should be fine. they are a race pad. so with any race pad expect noise. if your in Europe contact PFC UK it should help with the strong $ PFC Brakes Europe | PFC Brakes

 

Another pad question.

1.6 Turbo Miata.
Track/auto-x and street usage
Cheap 205 all-season tires on 15x8 wheels.
180-220hp (haven't dynoed)

Stock 1.6 brakes.

I'm a relatively novice driver and am hoping to survive this track season on 1.6 brakes, then upgrade to a BBK next winter. My current brakes are StopTechs and I have a feeling they will be running out soon. Right now I'm thinking that Hawk DTC-60 will be my best bet.

Also I'm cheap, less money = more better. Thats one of the reasons I'm not considering cobalts.