16" Vanco Big Brake Kit on 15" Steelies

Woodrow said:
More math: other things being equal, hydraulic pressure is proportional to piston area. The stock single piston diameter is 66mm so area is 325 mm sq. The BMB calipers have two 48mm pistons for 473 mm sq. So 46% more power than stock with an 11" rotor and 55% more power than stock with a 12" rotor?
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The area of a circle is pi x r squared . I have no idea where your numbers above came from
 
Yoda said:
Thank you sir!

I'll be going with 15x8's with 3.75" backspacing. I'd like aluminum rims to keep the weight down. I might have to buy an aluminum one and see if I luck out.

@mrblaine ... One last question. I plan to get your 16" kit with the new Master Cylinder, but I also plan to get your rear disc conversion. Does that MC in the 16" kit play nice with the rear discs or do you recommend another MC? And is a different proportioning valve needed?
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I put the 16" BMB kit on using ProComp 51 series 15" steel wheel with 3.75" back space and it all fit fine. I recently switched to an aluminum Outlaw 15" wheel. They still fit but there is very little room for wheel weights. A little patience is needed to get them balanced, but it is doable.
 
Plumber1 said:
I think you are both giving about the same numbers one is in mm squared and one is in inches squared
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You suck at math or reading. 5.60 is only about 7% larger than 5.22, not the 45% he states. And given that the duals are that much larger, you wind up with a 7% increase in pressure while only adding 7% pedal travel.
 
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Plumber1 said:
I think you are both giving about the same numbers one is in mm squared and one is in inches squared
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Nope . This math is not even close to correct .

Quote - “66mm so area is 325 mm sq“

The actual area is is about 3421.2 mm sq .
 
mrblaine said:
The stock piston is 5.22 square inches, the dual 48's are 5.60 square inches. Not that much of a difference. The piston area is only a small part of it.
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Yep. I get about the same numbers after re-doing the calculation more slowly. That's what I get for rushing to finish the post before doing something else. Very interesting that there is only around 6% hydraulic difference. So assuming same master cylinder and rotor diameter, what else is contributing? Pad contact area? Different friction materials? Better cooling design?
 
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mrblaine said:
You suck at math or reading. 5.60 is only about 7% larger than 5.22, not the 45% he states. And given that the duals are that much larger, you wind up with a 7% increase in pressure while only adding 7% pedal travel.
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@JDM
"Nope . This math is not even close to correct .

Quote - “66mm so area is 325 mm sq“

The actual area is is about 3421.2 mm sq ."

yeah. I don't know what button(s) I hit incorrectly, but the answer I got seemed like what I was expecting so, being in a hurry, I neither questioned or double checked it.
 
Woodrow said:
Yep. I get about the same numbers after re-doing the calculation more slowly. That's what I get for rushing to finish the post before doing something else. Very interesting that there is only around 6% hydraulic difference. So assuming same master cylinder and rotor diameter, what else is contributing? Pad contact area? Different friction materials? Better cooling design?
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A big factor is caliper design. We used an earlier Dodge 1500 front caliper before the new ones in 08 on the 17" kit. Later I saw the 08 version and built a test set. Everything else the same, the new caliper with same pad area and piston area as the old one worked much better. Enough so that I reworked the mold to update the 17" kit.

Rotor design has very little to do with it for some reason. We have tested most of them, none of it makes a short term difference.

The stock TJ pad has more surface area than the pad in the 16" kit.
 
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mrblaine said:
A big factor is caliper design. We used an earlier Dodge 1500 front caliper before the new ones in 08 on the 17" kit. Later I saw the 08 version and built a test set. Everything else the same, the new caliper with same pad area and piston area as the old one worked much better. Enough so that I reworked the mold to update the 17" kit.

Rotor design has very little to do with it for some reason. We have tested most of them, none of it makes a short term difference.

The stock TJ pad has more surface area than the pad in the 16" kit.
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Thanks. Once again, the situation is more complex than it seems.
 
mrblaine said:
You suck at math or reading. 5.60 is only about 7% larger than 5.22, not the 45% he states. And given that the duals are that much larger, you wind up with a 7% increase in pressure while only adding 7% pedal travel.
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I was only talking about the 5.60 and the 5.22 numbers not the percentages he listed. I guess I was not clear in my reply.
 
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