Disc brake conversion (70 Dart)

72bluNblu said
Ok, since I've been called out for lack of "Data", here's all the calculations for braking force. This uses a 15/16" master cylinder for both system, the stock pedal ratio of 6.5, a modest foot input of 70 lbs, the same brake pad coefficient and the same wheel diameter. The effective diameter for the rotor is slightly different because of the 10.95 vs 11" rotors, but I did include it. You can clearly see which system generates more clamping force, and which has more total force at the wheels.
View attachment 1715195958

Now, this calculator assumes 100% of the force generated at the pistons is transferred to the rotor. That never happens, and as I have said previously the Wilwood multi-piston, fixed caliper will be more efficient- it will not lose as much force to flex in the caliper, pads, etc as the Mopar single piston sliding design.

The question is, how much less efficient is the Mopar caliper? Do you think it loses 744 pounds of clamping force in flex? I don't. Now, that last part is my opinion, and you'd need a brake dyno to figure out how much force is actually being applied to the rotor by each caliper. But quite frankly, there's no way it's losing that much force to flex.

Here's the source of my calculator, all I did was input the Wilwood and Mopar numbers for the calculations. The spreadsheet is set up to calculate front and rear, I changed the header titles to match the brake systems I was comparing, and added the "bold" to the clamping force calculation results.
http://norcal-cobras.com/misc/brake-formula-mod.xls

For those of you curious about the equations used in the spreadsheet, there's a really awesome article by StopTech that includes all of the equations, as well as a pretty good amount of brake theory. It should be attached at the bottom.

So, there are the numbers. Make your choices, spend your money.

That's a lot of write up for still not understanding even caliper clamping force on the rotor. I really don't care if a caliper clamps with 3000, 5000 or 10,000 pounds of force. If it ain't putting it down evenly, it's not efficient. And if it clamps the pads unevenly and can't do it repeatedly with consistency, it's inefficient. A smaller brake pad making parallel clamping contact with the rotor will always be more efficient than a large pad being clamped unevenly. I think you need to review the Statics, Dynamics and Materials classes you should have taken to earn your claimed Rocket Science degree.

Once again, you really don't understand why a multi piston caliper would have sequential piston sizes either.

And sorry a Aerospace Engineering degree from UCLA is about as good as a used piece of toilet paper. Probably why you're a firefighter instead.

But,everyone else posting on here would probably be happy just swapping to an old single piston Mopar caliper and it will meet the needs of their application. Even drum brakes stop great just driving around with, if they are driving like a little old lady, which is what 72bluNblu says he does, they will be fine. They just don't work the greatest when hot.

And yes, we have tested Willwood brakes here! They work great!