Disc brake conversion (70 Dart)

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I Like the part about tires.
Most of us run 235s or less up front, and even 10" drums can lock those up at 35mph, maybe more with better than cheapo shoes. And the speed limits anywhere in My province are 70 or less.
Like Blu said, the tires are the limiting agent, and in Manitoba,lol, the roadways would be the next limiting factor. And nobody needs to be an ME to figure that out.
If I had an extra G to spend, it wouldn't be to improve any factory DB system on a streeter.
BFG radial T/As and Cooper Cobras, are great looking tires, but they are so easy to overpower. Learning to drive on them, with 350/400hp,is a whole nuther story.
 
Just curious, why does this chart compare '73 OEM front brakes to Wilwood rears ? Weird comparison or did I miss something ?

Apples and Oranges...obviously fronts have more impact on braking capability.

I'm definitely NOT an engineer or rocket scientist, but is it a coincidence that all HP cars have an multi-piston brake caliper...must be a reason for it.

moparVSwilwood.jpg
 
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oi81b4uu812b4 said:
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!
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Dude..........WTF ?
You dig willwood brakes, thats Great ! We're all happy for you !
Share your opinion, and move on.

I see you are new around here (2016).
Theres absolutely no reason to disrespect the members of this Great site.
And you "Have" disrespected a few on this thread alone.
Its a big family, and your type is not welcome here. Dont be a richard.
.
Its guys like you that would make me want to keep my 13" wheels, and drums in spite.

Cheers
 
Scotish said:
Just curious, why does this chart compare '73 OEM front brakes to Wilwood rears ? Weird comparison or did I miss something ?

Apples and Oranges...obviously fronts have more impact on braking capability.

I'm definitely NOT an engineer or rocket scientist, but is it a coincidence that all HP cars have an multi-piston brake caliper...must be a reason for it.

View attachment 1715206662
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It compares front to fronts. The calculator I used was set up for calculating front and rears. The calculations are all the same, it just was labeled differently so I used the “rear” calculator for the wilwood specs to get a side by side comparison. I changed the labeling on most of the fields, but I guess I missed that one. It’s just a label on that field, it doesn’t change any of the calculations.

As for multi vs single piston brakes, you apparently haven’t actually read this thread very well.

Fixed, multi piston calipers are generally more efficient than single piston sliding calipers. With the single pistons some of the clamp force is lost to flex in the sliding mechanism and uneven clamping on the pads. Less of that force is lost on a fixed multi piston caliper because there’s less flex and more pistons.

But that’s in GENERAL. It doesn’t mean that every fixed multi-piston brake caliper is better than every floating single piston caliper. Which is why you still have to look at the clamp force. If it’s within 10 or 15%, you can safely assume that the fixed multi-piston caliper will actually put more force to the pads. But if the difference is much more than that, you can’t safely make that assumption anymore, you have to actually test the calipers and see what you get.

In this case, the OE calipers produce 24% MORE clamp force than that particular set of wilwoods. You can’t safely assume the wilwoods are that much more efficient. And even if you did, that would mean paying twice as much money for the same brake force.
 
Not trying to start a rumble 72B&B.

Just trying to educate myself and saw a discrepancy...that's all. I will most likely put single piston O.E. style brakes on my A Body.
 
Johnny Dart said:
Dude..........WTF ?
You dig willwood brakes, thats Great ! We're all happy for you !
Share your opinion, and move on.

I see you are new around here (2016).
Theres absolutely no reason to disrespect the members of this Great site.
And you "Have" disrespected a few on this thread alone.
Its a big family, and your type is not welcome here. Dont be a richard.
.
Its guys like you that would make me want to keep my 13" wheels, and drums in spite.

Cheers
Click to expand...


WAA WAA WAA...lmfao:rofl::rofl::rofl:
 
I'm reading Andy Finkbeiner's b body book. Excellent chapter on disc conversions. He mentions the advantages of wilwood, 1994 viper, and even mustang cobra conversions. Having said that, he does claim that the "disco tech" and master power (like Dr Diff brakes) are a very well engineered and great performance for the money. He gives lots of praise to Chrysler engineers for the single piston disc system.
 
How does a person get to be like that? And why do you stick around? What pushes you forward in the face of such obvious error. Can you not see it? Have you blinded yourself to correction, hardened your heart, become your own god? Why do you lash out so?
You know, most people just say sorry and get on.
 
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Viper Caliper Mounting Brackets for Mopar DRUM Knuckles

That's another great option to upgrade too if you have good drum spindles. Use the D100 rotors and buy the Dr. Diff Viper/Brembo adapter kits, it's affordable enough. Just look around for a set of 1st Gen Viper 4 piston Brembo calipers. They are all over Ebay and Viper owners love to pull them off and upgrade leaving us perfectly good usable caliper cores. Every once in a while there are rebuilt cores at autopart stores.
 
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stroked340 said:
Why waste your time with rusty OLD parts get yourself a Wilwood conversion kit you get all NEW parts and NO need to change the upper control arms installs really easy and looks better and works BETTER then ANYTHING the factory produced..
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Wilwoods all the way!!!
 
Using 72bluNblu’s Calc sheet with corrected piston count, swept area and taking into account this calc sheet doesn’t work for sequential piston diameter multi piston calipers ( had to add them together and take average)

Here it is with no Vodoo or bullshit lying applied.
upload_2018-8-14_8-57-27.jpeg


upload_2018-8-14_8-57-41.jpeg
 
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Wow! The OP has 9" drum brakes. If he replaces them with OEM small bolt pattern 11" K-H front discs, he will think he has died and is in heaven. Same for the single piston big bolt pattern "A" body 73 up conversion. Going with the big bolt pattern 11.75 OD 2.75 piston pin calipers and good pads on a 1970 "A" body, he will be afraid to touch the brake pedal. All the calculations and theoretical BS is amusing, but let's get real. For me, as soon as you start with aluminum hubs and aluminum caliper adapters for the street, I'm out. I don't care for the lack of hardness, or the coefficient of thermal expansion of aluminum. I've seen too many aluminum parts fail. If you want to race with that stuff, that's fine with me. You're not using it enough and replacing stuff often enough you should not get into trouble. I have run all of the above, and have driven Porsche's and Vette's and was not wowed by any huge difference in braking. I also have the AR Engineering Viper conversion, but frankly have not felt compelled to swap it for what I already have, yet. I'm sure all the newest wiz-bang stuff works better, but mine will be still be working fine for the next 50 years. To the OP, see if your rotors will clean up, replace the bearings and races, use your calipers for cores and get some 71 Barracuda Calipers and flex lines and have at it. Best of luck. Notice I did not attack or ridicule anyone?
 
Unfortunately, you both miscalculated. With the single floating caliper you have to double the normal force on the rotor, and multiply that times the surface area of the brake pads. Then the friction coefficient times the distance from the center of the caliper piston to the center of the hub to get the friction force on the rotor.
 
72bluNblu said:
Yup, you've got it. DoctorDiff will have all the parts you need to refurb/replace everything for the 73+ mopar brakes.

Also keep in mind your tire choice. If you're planning on running 15" wheels and BFG T/A's, you can put the biggest, most expensive brakes you can afford on there and it won't make a lick of difference, because you'll be traction limited before you're braking force limited. Doesn't matter how much clamp force you generate at the rotor if you can't put it to the ground.

And, the "new tech" thing isn't really accurate. The old Kelsey Hayes calipers that were used on the A-bodies from '70-'72 are actually 4 piston fixed calipers, just like the Wilwoods are. The biggest drawback to them isn't their braking performance, it's the scarcity of reproduction parts available to rebuild them.



I'm not sure what your problem is. I don't "play" a Mechanical Engineer, and I wouldn't claim to be an ME anyway because it would be selling my education short. I hold an Aerospace Engineering degree from UCLA, which required me to take every class a ME would take and then Fluid Dynamics on top of that. I participated in Formula SAE for two years while I was in school, and then a couple of Aerospace competitions after that. I left the industry after college, but let's face it, brake calipers are not rocket science and I'm more than qualified to weigh in.

I would have no problem understanding any data you posted. Of course, you haven't posted any, not in any of your threads here. I know if I worked at a "suspension R&D shop" and had access to that kind of equipment I would be testing the crap out of all the stuff I was installing on my car, but I guess you don't bother.

And I certainly didn't "make up" any data. I used the specifications right off of Wilwood's site, as well as the dimensions I pulled off of an extra set of the Mopar 73+ calipers that I have. Hell I even linked to the specs.

I DO understand why clamping force is a benefit. And I said in post #12 of this thread that multi-piston, fixed calipers are more efficient at transferring force at the piston into actual clamping force. They lose less of the generated force at the piston to flex and have more even pressures across the pads, both of which improve the clamping force. But, the Wilwood calipers in questions have a significant disadvantage because of their smaller pad and piston area. They generate less force at the piston than the Mopar calipers, that's just the reality of their piston area. I have NEVER argued that single piston sliding calipers are better than fixed multi-piston calipers in general. But that's not what we're talking about, we're talking about two specific calipers, and while the Mopar calipers do have a simple, less efficient design they also have a lot more piston area.

Now, neither one of us knows for sure if the actual clamping force is better for the 73+ Mopar brakes or the Wilwoods. That number can't be calculated like the force generated at the pistons, it has to be measured because you have to know how much force is being lost to flex and uneven pad pressures. No caliper will transmit 100% of the force at the pistons to the rotors. The 73+ mopar calipers would need to lose an extra 24% of the generated force at the piston though, which is a lot, to end up having less clamp force than the Wilwoods we're talking about, because that's what the Wilwoods are giving up for piston area. Is it possible the Mopar calipers are losing that much force? Sure, it's possible. But again, someone would actually have to test it in order to know that for sure.

Now, if you've tested every OEM brake system available since 1996 why don't you actually test a set of 73+ Mopar calipers against the Wilwood Dynalite's and post up the actual clamp forces? You can easily do that if you have the equipment and experience you claim to have, and personally I'd LOVE to see the testing results. Even if they prove me wrong. At least then people can make an educated choice between the 73+ mopar calipers and the Wilwoods, weighing the cost of the Wilwoods against their actual performance.
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YOU are the one that claimed YOUR Brake Force Calculator was the best thing to use to evaluate a braking system. And you are also the one who claimed to be a Aerospace Engineer?

Now you have a problem with admitting you calculated the Wilwood calipers which are (4) piston and not (2) to get wrong info.

Just admit you were wrong and be done buddy!

i have tested almost all these brake systems on our brake dyno with brake pads and solid steel replacement pads. I work at an R&D OEM and everybody comes to us for evaluation. I don't have to look much further than your amateur numbers you came up with to know you had a mistake in obtaining your data. Your numbers weren't even close. But just using it to prove you didn't calculate your numbers right will never be enough for 72bluNblu will it.

Where is your data? As always, it's just you opinion and a Brake Force Calculator you screwed up and won't admit you calculated wrong. You yourself admit you have never taken any of your cars to a race track and claim to drive like a little old lady everywhere on the street, so where are you getting your testing results? And your correction numbers are wrong too. But I like the fact you took my reasons where multi-piston calipers benefit a braking system and retyped it on here like you discovered that info.

If your an Aerospace Engineer and machinist like you say you should be able to build your own brake force dyno on your lathe, then post REAL data here instead of your opinion that hurts our aftermarket. I'm sure it won't be up to SAE parameters for testing, but it would be real data, a big step for 72bluNblu!

Until I see REAL data you have collected, this is all just your opinion. As usual... So just suck it up like a big boy and admit you were blowing smoke out your ***.

Most of the people on this forum are happy with drum brakes or stock disc set ups. So that's really all they need here about.
 
I will say this one time, and one time only, stop the bashing in this thread NOW !!
 
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