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Wilwood Forged Dynapro 6 Big Brake Front Brake Kit (what's on whoosh) vs Forged Dynalite Big Brake Front Brake Kit

Dpro

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#41
The brake balance you’re talking about is actually not related to the number of pistons at all, but rather the piston area. Wilwood has 4 pot calipers with more total piston area than some of their 6 pots. The advantage a 6-pot caliper (which usually has smaller pistons) gives you is that the pad can be longer, which allows larger area, increasing the wear life. Brake balance and “grab” is entirely a function of piston area and the resulting force applied to the rotor. Swapping in a 4 or 6 pot doesn’t inherently change the balance - you can have a single pot floater with a large piston that does the same job.
Correct which is way I am trying to find out the exact piston area of my original Whoosh’s for the sake of finding a comparable piston area in a Radial Wilwood.
 


Dpro

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#45
I have now found out that the original Whoosh BBK has the same piston area as our stock brakes , which explains while even with the 300mm rotor my pedal feels great and exactly like stock. Which is an 11.81 inch rotor size.
 


Fusion Works

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#46
https://www.wilwood.com/Search/PartNoSearch?q=120-12003-BK
This is the caliper I used in my brake package. Brakes feel just like stock from a normal driving standpoint, no extra travel or any weirdness. Using the BP20 pad and it dusts less than my stock summer pads on the rear. Its kinda funny how much less they dust.
 


Dpro

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#47
https://www.wilwood.com/Search/PartNoSearch?q=120-12003-BK
This is the caliper I used in my brake package. Brakes feel just like stock from a normal driving standpoint, no extra travel or any weirdness. Using the BP20 pad and it dusts less than my stock summer pads on the rear. Its kinda funny how much less they dust.
Ya that actually is got more piston surface area than our stock calipers. Though you probably balanced it out a bit by going larger in the rear.

I found out are stock calipers have a piston surface area of 54mm which comes out to just 2.12 inches
.
You can get Willwood 4 piston Superlites in a 2 inch surface are setup i.e. each piston has a one inch surface area or slightly over in 2.46 each piston having a 1.25 piston surface area.
Both sets of Calipers fit anything up to 14 in rotors . For roughly $750 a set from Wilwood , for the calipers.

Now if someone decided to retail to us we might get a better deal . Though that’s really not bad for 4 piston 3.2 pound radial mount Caliper for our cars. That would brake great and have close to if not stock feel backed up by a reputable company.

edit… after being called on this I talked to a friend who actually measured the pistons on the Whoosh Calipers which have the same surface area as stock . Doing the math after that I realized I did make an error above. I also since then found a Wilwood 4 pot dynapro that has a 3.46 surface area and comes in at a very reasonable price.
 


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Fusion Works

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#48
The caliper I am using has 3.46in of piston area. I am using the stock caliper in the rear. Have a 12.88in rotor in the front.

The OE piston area is 3.54in. You did your math wrong.
 


Dpro

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#49
The caliper I am using has 3.46in of piston area. I am using the stock caliper in the rear. Have a 12.88in rotor in the front.

The OE piston area is 3.54in. You did your math wrong.
I went off what I could find on the net. As for some reason I can no longer access the FSM to get the accurate size. So ya kill me if I am doing it wrong I will continue the research it now to just to know for sure because of what I got and what your are saying. Not saying you are not right I just want to know for sure since you are calling me on it.;)

P.S. I could alway go over to my storage and pull out my stock calipers and measure them . Though that’s a drive to Burbank.
 


Dpro

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#52
To calculate the area of a circle, 3.14*R^2.
(54mm) 2.12/2= 1.06in. 1.06^2= 1.124. 1.124*3.14=3.53in
yes and I got the numbers you are correct.

And with that I have now found. A 4 piston Wilwood Caliper that has a 3.54 piston surface area and will take a .81 width rotor or a 1 inch . Rotor diameters available are 10.75 , 11.75 and 12.19
https://www.wilwood.com/Calipers/CaliperProd.aspx?itemno=120-7328&appid=0
 


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#53
I have now found out that the original Whoosh BBK has the same piston area as our stock brakes , which explains while even with the 300mm rotor my pedal feels great and exactly like stock. Which is an 11.81 inch rotor size.
Rotor size by it’s self doesn't effect pedal feel or travel (except for maybe if the rotors are thinner than stock). Just the surface area of the pistons in the caliper. The master cylinder is of a definite size and pushes a certain amount of fluid down the lines. If we put brakes on that have a greater total piston surface area than stock, it will require more pedal travel to engage the brakes.

Rotor size comes into play in that larger rotors are further away from the axis of rotation so the caliper has more mechanical advantage to stop, and that larger rotors have more material to absorb the heat of braking, resisting fade.
 


Dpro

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#54
Rotor size by it’s self doesn't effect pedal feel or travel (except for maybe if the rotors are thinner than stock). Just the surface area of the pistons in the caliper. The master cylinder is of a definite size and pushes a certain amount of fluid down the lines. If we put brakes on that have a greater total piston surface area than stock, it will require more pedal travel to engage the brakes.

Rotor size comes into play in that larger rotors are further away from the axis of rotation so the caliper has more mechanical advantage to stop, and that larger rotors have more material to absorb the heat of braking, resisting fade.
Ya I know not sure why I typed that call me stupid.
 


Dialcaliper

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#55
https://www.wilwood.com/Calipers/CaliperProd?itemno=120-13435-RD

Its interesting the kit that Wilwood designed for our cars uses a piston area of 4.04in compared to the OE piston area.
My suspicion is it’s meant to balance the rear kit they sell, which has a 38mm piston (to our 34mm) on a 11.75/300mm rotor, which is kind of excessive for a 12.19/310mm front. I’m guessing they didn’t do a 280 rear on account of the SVT bracket swap. In fact a rear 11.75x0.81 (300x21mm) rotor in the rear is probably totally overkill for any big brake kit that will fit on this car. (It’s more brake than the factory Focus RS rear which goes with a 350x28mm up front and 300x15mm rear)

The only scenario in which you’d need that much rear brake is in something like a Rally/Rallycross car where you’re constantly on the rears with a line lock
 


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Fusion Works

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#57
My suspicion is it’s meant to balance the rear kit they sell, which has a 38mm piston (to our 34mm) on a 11.75/300mm rotor, which is kind of excessive for a 12.19/310mm front. I’m guessing they didn’t do a 280 rear on account of the SVT bracket swap. In fact a rear 11.75x0.81 (300x21mm) rotor in the rear is probably totally overkill for any big brake kit that will fit on this car. (It’s more brake than the factory Focus RS rear which goes with a 350x28mm up front and 300x15mm rear)

The only scenario in which you’d need that much rear brake is in something like a Rally/Rallycross car where you’re constantly on the rears with a line lock
Yeah have no idea why they did it. Could ask, but don't really care.

I used the stupidly large rotor for mine because I hated the look of the 17in wheel with the little dinky rear rotor. Mostly for asthetics. However after a few track days, they are lightly blued, so they see a lot of heat. The Torque Vectoring is putting a lot of heat in to the rear rotors a little more heat capacity isn't a bad thing. I pulled the rear brake dust shields so that should help get a little more air into the rear brakes.
 


the duke

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#60
Yeah have no idea why they did it. Could ask, but don't really care.

I used the stupidly large rotor for mine because I hated the look of the 17in wheel with the little dinky rear rotor. Mostly for asthetics. However after a few track days, they are lightly blued, so they see a lot of heat. The Torque Vectoring is putting a lot of heat in to the rear rotors a little more heat capacity isn't a bad thing. I pulled the rear brake dust shields so that should help get a little more air into the rear brakes.
I can’t say I ever had issues with heat in the rear. I’ve baked the front powder coat black, but m rears have never gotten that hot.
 




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