Moparts
Is 380 mm rotors large enough for you?
Posted By: astjp2
Is 380 mm rotors large enough for you? - 12/31/13 08:00 AM
I found 380 x 34 mm (15" x 1.375") rotors that will fit on my drum brake spindles with Brembo calipers for $600 plus about 120 for .400" thick chromoly steel adapters. Would this be too much for a street car? What size wheels would I have to run? I am really considering this because its off the shelf parts with an adapter that I can get cut out on the water jet. Tim
Posted By: 72Swinger
Re: Is 380 mm rotors large enough for you? - 12/31/13 02:11 PM
Quote:
I found 380 x 34 mm (15" x 1.375") rotors that will fit on my drum brake spindles with Brembo calipers for $600 plus about 120 for .400" thick chromoly steel adapters. Would this be too much for a street car? What size wheels would I have to run? I am really considering this because its off the shelf parts with an adapter that I can get cut out on the water jet. Tim
19" wheel minimum. 2010+ Mustang wheels have a few options in that diameter.
Posted By: 70Cuda383
Re: Is 380 mm rotors large enough for you? - 12/31/13 04:11 PM
If the rotors are cheap enough, you can always cut them down so they don't need as big of a wheel.
Posted By: BigBlockMopar
Re: Is 380 mm rotors large enough for you? - 12/31/13 05:19 PM
At what point becomes a discrotor just a flywheel with stored energy for the car in question?
Big enough?
Not quite sure about the cheap part though...
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 12/31/13 06:07 PM
As long as you don't might the weight of a rotor that size may be, or running the 19" or 20" wheels...sounds like a decent deal for rotors and calipers (depending on just what Brembos they are?)
I stick with 360mm rotors on mine along with the 8 piston Brembos as I don't want to run larger than an 18" wheel on my car..
Posted By: Mopar Mitch
Re: Is 380 mm rotors large enough for you? - 12/31/13 06:08 PM
Now THAT's "Handling on Rails"
Best wishes for the New Year!
Posted By: jcc
Re: Is 380 mm rotors large enough for you? - 12/31/13 06:11 PM
So what is the goal? Bragging rights, bling, mechanical mounting challenges, etc? Too big of brakes may make you warm and fuzzy and peace of mind, while you study the bumper of the guy that just passed you. Unsprung weight, and the flywheel effect mentioned which is valid at BOTH ends of the straightaway, and normally cost, which the Op has overcome. are all concerns, bottomline, the wrong solution at a good price, is still the wrong solution. Now if the OP is overheating his ducted brakes repeatedly, step up, but might want to figure out how to lighten the car, which has many benefits, reduced braking requirements being one.
Posted By: Viol8r
Re: Is 380 mm rotors large enough for you? - 12/31/13 07:09 PM
I much prefer moderate size rotors that are available at any moment and not an arm and a leg. We run cooling to our brakes, to me this is a lot cheaper then dealing with 14"+ rotors. For us it comes down to the Caliper, pads and cooling.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 12/31/13 07:23 PM
Quote:
I much prefer moderate size rotors that are available at any moment and not an arm and a leg.
FWIW...my rotors were about $165 each for genuine Mercedes ones. 
If you can design a brake package around some OE components at least, you can do it for a pretty decent price.
Could always go with some carbon rotors to save some weight I suppose. 
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 12/31/13 07:29 PM
I actually like doing the research and figuring out how to make things work. I like thinking outside the box and finding applications that I can make fit. It takes a lot of money to but caliper brackets and rotors just to see if I can make them fit, so I have been just doing the math and calculations lately.
I have laid out the rotor brackets in cad and had them cut on a water jet for the ones that are presently on my car now from 4140, I am still wondering if I should make a set from aluminum. They are .375 thick if aluminum, .400 in 4140 precision ground plate. I could do the same thing with the 380 mm rotors, the hat height on the 380's would require me to use 2 brackets that are bolted together to offset the caliper bracket to get the right offset.
The 305mm rotors that I have now have brackets that are 1 piece and require 17" wheels to clear the calipers. The 380's would require 19" wheels. I like the idea of larger wheels for better handling but I hate the rubber band look. I am just pondering about this as a project. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 12/31/13 07:35 PM
A cad and a water jet sure would be nice..I made my brackets the "old fashioned" way
Posted By: MuuMuu101
Re: Is 380 mm rotors large enough for you? - 12/31/13 07:51 PM
Quote:
A cad and a water jet sure would be nice..I made my brackets the "old fashioned" way
With super-precision eyeballs and hands accurate enough to the closest tolerance of .050"?
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 12/31/13 07:54 PM
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 01/01/14 02:25 AM
My 360 mm rotors tip the scales at 37 pounds. EACH.
Are you sure you want to go larger?
I bought my brakes 9 years ago when big brake kits were not readily available for our cars.
Scrounging around in our inventory gave me a 4 wheel big brake kit cheaper than the 13" front-only brakes offered at the time.
Keep it at 13" or less and make your life easy.
Also, don't forget to check the caliper clearance for the back of the wheel. That was a major issue for me (and Oz).
Posted By: PHJ426
Re: Is 380 mm rotors large enough for you? - 01/01/14 02:42 AM
Here is some info on Formula 1 carbon rotors with ERS energy recovery system sounds $$$$$$
http://www.formula1.com/inside_f1/understanding_the_sport/5284.htmlFirst one on Moparts with these brakes wins
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/02/14 07:50 AM
I was just thinking that I could do this because its fairly cheap (under 1200), I can match the fronts and rears from the original vehicle, and there is some cool factor to having rotors that fill the wheel well. The rears are 13"
along with a hydroboost and a system that is designed for a 6000# vehicle.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/02/14 08:01 AM
Ignore the arrows!
Posted By: BigBlockMopar
Re: Is 380 mm rotors large enough for you? - 01/02/14 10:13 AM
Nifty little brake pad you're holding there.
Looks a bit glazed over though...
Hey at least I ignored the arrows...
Posted By: AlexP
Re: Is 380 mm rotors large enough for you? - 01/02/14 07:45 PM
Quote:
I was just thinking that I could do this because its fairly cheap (under 1200), I can match the fronts and rears from the original vehicle, and there is some cool factor to having rotors that fill the wheel well. The rears are 13" along with a hydroboost and a system that is designed for a 6000# vehicle.
Are those calipers on a Cayenne Turbo S?
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/02/14 08:21 PM
Nope, large SUV, they have the largest brakes of any 1/2 class ton suv out there....
Posted By: Uhcoog1
Re: Is 380 mm rotors large enough for you? - 01/02/14 10:46 PM
Quote:
Nope, large SUV, they have the largest brakes of any 1/2 class ton suv out there....
.... and that is?
Posted By: Consulier
Re: Is 380 mm rotors large enough for you? - 01/03/14 05:12 AM
Quote:
Quote:
Nope, large SUV, they have the largest brakes of any 1/2 class ton suv out there....
.... and that is?
SRT8 Grand Cherokee
Why a secret i have no idea.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/03/14 10:16 AM
I just wanted to have some fun with it..
Yep, the SRT8 GC...
Posted By: 70Cuda383
Re: Is 380 mm rotors large enough for you? - 01/03/14 02:38 PM
Those F1 cars with their carbon fiber brakes are impressive for sure.
talking to a ferrari owner who abused his car the way it was built for, said that his carbon fiber rotors cost him $15,000 to replace when they were finally worn out.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/05/14 06:31 AM
Carbon brakes are old technology from the 1980's The energy conversion is newer...
http://www.boeing.com/commercial/aeromagazine/articles/qtr_03_09/article_05_1.html
Posted By: jcc
Re: Is 380 mm rotors large enough for you? - 01/05/14 04:32 PM
That was an interesting link
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/05/14 06:58 PM
I think I may build this combination, I found some 18" steel wheels that may fit if I cut the centers out and move the back spacing to the center. If I use the discount rotors and get a rebuilt caliper, I can fit it up quite well before it ever goes on a car. Tim
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 01/07/14 02:23 AM
Quote:
I think I may build this combination, I found some 18" steel wheels that may fit if I cut the centers out and move the back spacing to the center. If I use the discount rotors and get a rebuilt caliper, I can fit it up quite well before it ever goes on a car. Tim
That must be a really impressive steel wheel.
I haven't seen one yet that will clear a caliper that size on a rotor as shallow as those.
I strongly suggest you find a SRT Jeep and break out a measuring device. The center hat of the rotor is less than an inch away from the rotor surface. The caliper sticks out nearly three inches from the surface of the rotor.
Your wheels are going to smash the caliper before you can get the lug nuts on. There's a good chance it will contact the outer radius of the caliper too.
Mission: Impossible.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/07/14 10:31 AM
These are the rotors I have now, the caliper clearance sucked but I found stock 17" steel wheels that cleared the calipers. I cut the centers out of the wheel, recentered them, and welded them in. Its a 17x7.5" wheel with 3.5" of back spacing. The reason I used these if the fact that I can bolt the brackets on the drum spindles and everything clears. Modern brakes for 200.00 in salvage yard parts. Comes with dual piston calipers and 12" rotors. Tim
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/07/14 10:33 AM
This is the mockup of 12" rotors before they are put on the car.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 01/07/14 10:38 AM
Bracket and spindle installed...
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/01/14 09:35 AM
So I was poking around Amazon yesterday and found Raybestos pro grade rotors 380mm for $43.99 each, so I dropped the hammer and ordered a pair and with prime it was free shipping. Now I just need to find calipers in a salvage yard...Then its measure up and make new brackets....for the largest brakes I can fit on a 68 Charger. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/01/14 06:13 PM
Are you going with 6 or 8 piston calipers with those rotors?
And obviously it will be 19" and up wheels..
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/01/14 09:11 PM
The grand Cherokee has 6 piston calipers. I am going to try a high clearance 18" wheel first, if not, then I can look at 19" wheels. I will have less that 700 in the whole project. I have made the setup for 12" rotors with dual piston calipers that bolted up to the drum spindles and hubs. Its the challenge of making something different that I enjoy. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/01/14 10:03 PM
That would be mighty tight with an 18" wheel I would guess. My rotors are 360mm, and with how the 8 piston calipers sit on them...it is does fit under an 18, but not a ton of room to spare. With the extra 20mm in diameter...so 10mm on one "end" so to speak pushing the caliper out further be interesting to see how it goes squeezing into the same sized wheel. (and depending on the shape of the top of the Jeep caliper too
)
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/03/14 03:16 AM
Rotors should be here by wed morning. Amazon was awesome for that price and free shipping.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/03/14 03:26 AM
Those rotors are pretty flat too...probably have to make sure you use a wheel with a thick enough mounting pad to get the spokes,etc far enough away for caliper clearance, or just wheels that curve outward somewhat.
They are a little thinner than the ones I use, so at least that helps offset the weight with the extra diameter.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/03/14 04:26 AM
I wish Feets would do some of the math so I know what size master cylinder I should run. I was looking at Marauder wheels. 5x4.5 with the same register as mopar. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/03/14 04:34 AM
I use a 1" with my setup.
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 02/03/14 08:58 PM
Quote:
I wish Feets would do some of the math so I know what size master cylinder I should run.
I don't know what size pistons you're playing with.
Did you try get the numbers and plug them into the spreadsheet?
Posted By: MuuMuu101
Re: Is 380 mm rotors large enough for you? - 02/04/14 12:58 AM
Quote:
Those rotors are pretty flat too...probably have to make sure you use a wheel with a thick enough mounting pad to get the spokes,etc far enough away for caliper clearance, or just wheels that curve outward somewhat.
They are a little thinner than the ones I use, so at least that helps offset the weight with the extra diameter.
A wheel like this may help. It's from Volk Racing, I believe...
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/04/14 01:37 AM
I will probably need a 0 offset and 4.5 backspacing on an 8" wide wheel to fit in the wheel wells without rubbing. Tim
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/04/14 01:39 AM
Quote:
Quote:
I wish Feets would do some of the math so I know what size master cylinder I should run.
I don't know what size pistons you're playing with.
Did you try get the numbers and plug them into the spreadsheet?
I dont have the brake assemblies out so I can measure the pedal ratio's, its a 68 B-body that origianlly had power brakes. I was planning on using 98 explorer rears also. I will have to see what I find on piston sizes.
Found that the rears are single puck 48mm and the fronts are not listed anywhere.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/04/14 02:44 AM
Quote:
I will probably need a 0 offset and 4.5 backspacing on an 8" wide wheel to fit in the wheel wells without rubbing. Tim
Just make sure what ever you use will have caliper clearance of course..
I built my brakes to suit my wheels. (I found the exact wheels I wanted first, so built to fit them, and hence needed a certain rotor height)
Feets did it the other way around, he built the brakes and then made me have wheels built special to be able to fit.
And funny thing is, we both had the same rotors and calipers in the end. My wheels use a flat spoke made for large brakes basically, he went with ones that curved back, so the wheel needed a custom mounting pad height to be able to get the spokes to clear the caliper.
With your caliper being a tad further out, you'll just have to make sure you get a wheel to clear obviously.
(Let alone what back spacing you need to fit that car, the actual center of the wheel itself will have to fit the brake assembly...)
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/04/14 04:09 AM
I am starting to have second thoughts on this project....I was hoping to find a wheel that would clear and do this on the cheap....in a 18-19" wheel size. I can have the brakes for less than a grand all the way around.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/04/14 04:31 AM
You can probably find a cheapy china 2 piece cast wheel like would go on a Jeep, etc in a 19" maybe that may clear ? the problem is getting the offset you want I would guess at though?
A 2 piece wheel will let you get the offset just where you want it, but cost will be higher of course and as mentioned..you just need to watch for caliper clearance.
With a pretty 'flat' rotor like the specs on the ones you picked out, is it pushes the caliper further out towards the wheel. Again not the end of the world...you just have to plan ahead for the entire combo.
And the larger the wheel is...the slightly more forgiving the shape of the spokes,etc will be to the caliper clearance. The smaller you try to go the more critical it will be.
PS. You could always ask them if they know if their wheels have caliper clearance for the SRT Jeep...but who knows if they will know off hand?
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/04/14 04:33 AM
By the way...if you already have a wheel in mind...if you know anyone who happens to have one already, just lay your brake rotor when they come in, inside one and take some measurements between it and the wheels, both on the brake face an along the edge. Then you can double check to the caliper measurements before you go any further. That can save you buying the calipers if the wheels you want will not clear and you are only out a little bit for the rotors.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/04/14 06:29 AM
Coy wheels is not to far from me, I can try to see if he has something that is to my liking and fits. I have a spare spindle and hub from when I set up my last brakes I made, I can use them to create something mobile and do the test fit. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/04/14 06:34 AM
No need to lug a spindle and all around..all you need is the rotor and a few studs (or the hub if it's handy) to locate it in the wheel.
Just lay the wheel upside down, and lay the rotor on it with a few studs to center it, and you can take some measurements. (You may need to tilt it up some to measure further towards the center of the rotor if the caliper is going to be in contact with the spokes of the wheel in that area..depending on wheel shape) If you already had a caliper of course you can try that, but it sounded like you hadn't got those yet?
His stuff is pretty much all china but I suppose the price is cheap.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/04/14 09:48 PM
One rotor was delivered today, gwad are they heavy! It weighs more than a wheel...
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 02/05/14 12:13 AM
Quote:
One rotor was delivered today, gwad are they heavy! It weighs more than a wheel...
I told you my 360 mm rotors weighed 37 lbs.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 02/05/14 12:21 AM
Quote:
Quote:
One rotor was delivered today, gwad are they heavy! It weighs more than a wheel...
I told you my 360 mm rotors weighed 37 lbs.
So double the weight of my wheels..
(My 18 x 10.5" rears are about 18 - 19 pounds each)
Posted By: MuuMuu101
Re: Is 380 mm rotors large enough for you? - 02/05/14 12:31 AM
Quote:
Quote:
One rotor was delivered today, gwad are they heavy! It weighs more than a wheel...
I told you my 360 mm rotors weighed 37 lbs.
Bro... Talk about mass moments of inertia... 
Posted By: AlexP
Re: Is 380 mm rotors large enough for you? - 02/05/14 12:46 AM
In for him to produce a readily available bracket....
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/05/14 02:39 AM
If I did go through the headache of making brackets, would anyone even want to buy them? I know its not a get rich thing, but the 4140 moly steel that I used for my last build was almost 90 per pair. I can only find it and pay full retail, no deals on the metal. Plus the cost of the waterjet to cut them, probably 200 for the brackets... that fit the drum brake spindle. Tim
Posted By: AlexP
Re: Is 380 mm rotors large enough for you? - 02/05/14 02:53 AM
Quote:
If I did go through the headache of making brackets, would anyone even want to buy them? I know its not a get rich thing, but the 4140 moly steel that I used for my last build was almost 90 per pair. I can only find it and pay full retail, no deals on the metal. Plus the cost of the waterjet to cut them, probably 200 for the brackets... that fit the drum brake spindle. Tim
I'd buy a set.
Posted By: cudazappa
Re: Is 380 mm rotors large enough for you? - 02/05/14 04:39 AM
Quote:
If I did go through the headache of making brackets, would anyone even want to buy them? I know its not a get rich thing, but the 4140 moly steel that I used for my last build was almost 90 per pair. I can only find it and pay full retail, no deals on the metal. Plus the cost of the waterjet to cut them, probably 200 for the brackets... that fit the drum brake spindle. Tim
If you aren't heat treating the 4140 I don't see any benefit to using it over 1018 or A36. Unless 4140 anneal plate has a stronger tensile strength. Also, if you go with low carbon you could get it laser/plasma cut without worrying about work hardening (like what would happen with 4140). Laser is usually cheaper than waterjet.
Posted By: AlexP
Re: Is 380 mm rotors large enough for you? - 02/05/14 04:59 AM
Quote:
Quote:
If I did go through the headache of making brackets, would anyone even want to buy them? I know its not a get rich thing, but the 4140 moly steel that I used for my last build was almost 90 per pair. I can only find it and pay full retail, no deals on the metal. Plus the cost of the waterjet to cut them, probably 200 for the brackets... that fit the drum brake spindle. Tim
If you aren't heat treating the 4140 I don't see any benefit to using it over 1018 or A36. Unless 4140 anneal plate has a stronger tensile strength. Also, if you go with low carbon you could get it laser/plasma cut without worrying about work hardening (like what would happen with 4140). Laser is usually cheaper than waterjet.
Either a ME or Metallurgist here. 
Posted By: MuuMuu101
Re: Is 380 mm rotors large enough for you? - 02/05/14 08:09 AM
Quote:
Quote:
If I did go through the headache of making brackets, would anyone even want to buy them? I know its not a get rich thing, but the 4140 moly steel that I used for my last build was almost 90 per pair. I can only find it and pay full retail, no deals on the metal. Plus the cost of the waterjet to cut them, probably 200 for the brackets... that fit the drum brake spindle. Tim
If you aren't heat treating the 4140 I don't see any benefit to using it over 1018 or A36. Unless 4140 anneal plate has a stronger tensile strength. Also, if you go with low carbon you could get it laser/plasma cut without worrying about work hardening (like what would happen with 4140). Laser is usually cheaper than waterjet.
We've laser cut plenty of parts of various thicknesses mostly being 4130 and 6061 Aluminum. Laser cutting from what I understand isn't a very hot process. It shouldn't work harden your part too much. Plus it doesn't leave as much of a taper as water jetting does.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/05/14 10:22 AM
Quote:
Quote:
If I did go through the headache of making brackets, would anyone even want to buy them? I know its not a get rich thing, but the 4140 moly steel that I used for my last build was almost 90 per pair. I can only find it and pay full retail, no deals on the metal. Plus the cost of the waterjet to cut them, probably 200 for the brackets... that fit the drum brake spindle. Tim
If you aren't heat treating the 4140 I don't see any benefit to using it over 1018 or A36. Unless 4140 anneal plate has a stronger tensile strength. Also, if you go with low carbon you could get it laser/plasma cut without worrying about work hardening (like what would happen with 4140). Laser is usually cheaper than waterjet.
Well the 4140 is precision ground, the A36 or 1018 doesn't have as nice of a surface. I am also having it cut on a waterjet, it does a nice job but I finish the holes with a reamer. Laser is too high tech for me. I also get a precise thicknesss that is absolute consistent at .400 thick, +- .001 That is way tighter than what I am able to hold with my precision eye. Tim
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 02/05/14 08:46 PM
You guys are going WAY too deep on this.
Finishing caliper brackets down to the micron is not necessary. If you can get the bracket mounting surfaces flat to the hundredth and bolt holes to the same degree you will have a perfectly usable bracket.
The factories cast the parts, spin off a few flat spots, and send them down the line.
Sure, perfectly machined parts are pretty but these are brake parts. Function over form. The stress loads they see are easily overcome with 1018.
Mine are made from Scrapbinuim and work great.
You guys are going down the overengineering drain. Step back and think about it.
Samy, here's your homework assignment. Using a friction coefficient of .75 for the brake pads figure out the force applied on a caliper bracket. Use common values for variables such as vehicle weight, speed, and tire contact.
Posted By: MuuMuu101
Re: Is 380 mm rotors large enough for you? - 02/05/14 09:11 PM
Quote:
Samy, here's your homework assignment. Using a friction coefficient of .75 for the brake pads figure out the force applied on a caliper bracket. Use common values for variables such as vehicle weight, speed, and tire contact.
Lovely, more homework on top of my homework...
Edit: Thinking about it real quick while studying for a midterm. I'm not sure if I'd be more worried about the force exerted from the pad creating a bending stress on the caliper bracket or the torque/moment acting on the bracket due to the clamping force and the dive of the car. Either way, I think 1018 should be fine as I'd assume it should be pretty thick.
Here's a quick powerpoint I found on brake noise... Page 23 has some torque calcs.
http://www.sae.org/events/bce/honeywell-liu.pdf
Posted By: cudazappa
Re: Is 380 mm rotors large enough for you? - 02/05/14 11:11 PM
Quote:
Mine are made from Scrapbinuim and work great.
You guys are going down the overengineering drain. Step back and think about it.
Like I thought 3/8" thick 1018 is plenty. If you really needed that .400" thick, buy the 7/16 or 1/2 plate and have it blanchard ground after cutting.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/06/14 04:00 AM
I dont need it that thick, it is just comes that way as a prehard material. I used it because I didnt have to mill the surface, I just had it cut to shape and install. I have them on my charger now, using 2006 crown vic rotors and dual piston calipers. The calipers were 50 each, rotors 90, the adapters were about 200 with travel and cutting, pads are what you want...I spent 40 for the napa gold ones. That is about as cheap of a modern dual piston disc brake setup as you can get. Tim
Posted By: Pool Fixer
Re: Is 380 mm rotors large enough for you? - 02/06/14 06:09 AM
Quote:
I dont need it that thick, it is just comes that way as a prehard material. I used it because I didnt have to mill the surface, I just had it cut to shape and install. I have them on my charger now, using 2006 crown vic rotors and dual piston calipers. The calipers were 50 each, rotors 90, the adapters were about 200 with travel and cutting, pads are what you want...I spent 40 for the napa gold ones. That is about as cheap of a modern dual piston disc brake setup as you can get. Tim
those look like rotor sliding over hub.... what are you using for hubs? summit has 2006 crown vic rotors sllotted/drilled for 55 each. besides the rotor being a litttle bigger than the standard 11.75 stuff, seems like the consumable pieces will always be cheaper and dual piston caliper is nice too. you should mass produce those brackets
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/06/14 08:07 AM
I asked Andy if he wanted the cad layout and he politely declined because he had enough brake kits already. I can have more made if someone is serious about the crown vic stuff, Its just materails and time on the waterjet. This is an option for the drum brake spindles and hubs for a b-body. The rotor hat is not very high though and you need to put disc brake wheel studs in. I have not done the final assembly on the car yet, only mockup. Its beefy~!
Posted By: AlexP
Re: Is 380 mm rotors large enough for you? - 02/06/14 06:53 PM
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 02/08/14 05:20 AM
Quote:
Quote:
I wish Feets would do some of the math so I know what size master cylinder I should run.
I don't know what size pistons you're playing with.
Did you try get the numbers and plug them into the spreadsheet?
Fronts are 32/38mm with a 380mm rotor, the rears are 48mm with a 280mm rotor. Now I just need to get measurements for the 68 b-body power pedal and I can figure out what is a fair number for braking bias. Tim
Posted By: 68cuda440
Re: Is 380 mm rotors large enough for you? - 02/08/14 06:17 AM
Quote:
Lovely, more homework on top of my homework...
Edit: Thinking about it real quick while studying for a midterm. I'm not sure if I'd be more worried about the force exerted from the pad creating a bending stress on the caliper bracket or the torque/moment acting on the bracket due to the clamping force and the dive of the car. Either way, I think 1018 should be fine as I'd assume it should be pretty thick.
C'mon Samy, let the old dynamic systems T/A help you out:
Assume Kevin's car weighs 5000lbs (that is a lot of slugs), peak decel of 1g, and the rear brakes contribute nothing... just to make you metric kids happy we will round that off to 2300kg. The bracket doesn't care about dive... Let's assume Kevin's tires are 26" diameter. Torque = I * Alpha. alpha = 1g/13". What is the average lever arm of the brake pad... man, I am making this too easy for you. Now pin the face of the bracket to the spindle and load all that geometry into your favorite FEA package and safety factor > 10... I would guess 1018 at that thickness would be extreme overkill. Post your assumptions and your FEA output plot and I will grade it later.
Posted By: 68cuda440
Re: Is 380 mm rotors large enough for you? - 02/08/14 06:28 AM
Quote:
Post your assumptions and your FEA output plot and I will grade it later.
For extra credit model it using Simulink, show me your input for your theoretical tire model, the assumptions for contact area and road surface. How would you approach an ABS algorithm to keep you close to maximum friction coefficient. Can you test that with different dynamic loading simulations and traction conditions? What sensor inputs would you want for your ABS system?
You want to be an Engineer? The unfortunate thing you will discover in practice is that the presentations and finances become more important than the raw engineering in too many cases. Your constraints and boundary conditions will not be just the ones you discussed in your dynamics class.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/17/14 10:34 AM
Well I took an old hub from a b-body drum brake system. I made a few drill fixtures so now I can redrill the 380mm rotors. The rotor diameter is about .060 larger than the hub register, so I took some safety wire and wrapped it through the original bolt holes. It now has a nice fit and is centered. Next, I need to figure out what drill bit I need to drill the holes to. I am thinking that I may use a roto broach to bore the holes. I am making progress, not as fast as I would like but its still progress. Tim
Posted By: dickdale
Re: Is 380 mm rotors large enough for you? - 03/17/14 02:15 PM
Use a 9/16" bit.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/18/14 06:36 PM
Quote:
Use a 9/16" bit.
SO what you are saying is that I don't want the wheel studs to also press into the rotors? Just slip over the threads? The knurled section of the hub is 5/8" so I was going to get studs that also pressed into the rotor too. Is this not what I want to do? Tim
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 03/19/14 07:24 PM
The lugs do not need to press into the rotor. The OEMs use a single screw to hold the rotor in place. You can drill and tap your hub to match if you like.
The size hole will depend on the lug used. If the shank poke out the front side of the hub the rotor will need to clear it.
A properly sized lug will not have splines protruding above the hub.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/19/14 09:08 PM
Quote:
The lugs do not need to press into the rotor. The OEMs use a single screw to hold the rotor in place. You can drill and tap your hub to match if you like.
The size hole will depend on the lug used. If the shank poke out the front side of the hub the rotor will need to clear it.
A properly sized lug will not have splines protruding above the hub.
So Feets, should I just use a .505 reamer to finish sizing the holes since the hub center is about .060 smaller than the hole in the rotor to keep it centered? Tim
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 03/20/14 09:12 PM
That's a good place to start if the lugs drop down in size at or before the hub surface. A 1/2" lug is under .500" but you need to be dead on with your new lug holes. 5 thousandths is pretty tight if the holes are off.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/31/14 02:45 AM
Well I was able to start boring the holes, I made some drill bushings and was able to center the hub. I got the pilot holes drilled and went to bore the 1/2" holes and broke the broach. Now to get a replacement broach...which the repair part costs more than the kit did. Tim
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/31/14 02:46 AM
Pic 2
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/31/14 02:47 AM
pic 3
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/31/14 02:48 AM
Pic 4
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/31/14 08:34 AM
This was expensive...the blair company only sells replacements in quantities of 3...
Posted By: brads70
Re: Is 380 mm rotors large enough for you? - 03/31/14 01:56 PM
Why didn't you just use an ordinary drill bit?
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 03/31/14 06:44 PM
They walk and create oversize holes, this way, they are bored and stay round. I just let the drill get cocked and the cutter snapped like a twig.
Posted By: cudazappa
Re: Is 380 mm rotors large enough for you? - 03/31/14 09:40 PM
Quote:
Why didn't you just use an ordinary drill bit?
It doesn't look like he's using a bridgeport or even a drill press.
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 03/31/14 10:06 PM
Quote:
Quote:
Why didn't you just use an ordinary drill bit?
It doesn't look like he's using a bridgeport or even a drill press.
My thoughts exactly.
I could knock that out on my mill rather quickly but shipping rotors isn't cheap.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 03/31/14 10:25 PM
Might be easier to just find a local wheel repair/modify place and have them toss the rotors in their mill or what ever they use to redrill wheels and get it done in a few minutes.
My wheel guy drilled my rotors out...took me longer to drive there and back to pick them up then to have them done.
(in hindsight, I should have drilled my hubs to Mercedes bolt pattern and have the wheels drilled the same, save having to modify the rotors..but oh well.
)
Posted By: dickdale
Re: Is 380 mm rotors large enough for you? - 04/01/14 12:25 PM
Quote:
Might be easier to just find a local wheel repair/modify place and have them toss the rotors in their mill or what ever they use to redrill wheels and get it done in a few minutes.
My wheel guy drilled my rotors out...took me longer to drive there and back to pick them up then to have them done.
(in hindsight, I should have drilled my hubs to Mercedes bolt pattern and have the wheels drilled the same, save having to modify the rotors..but oh well. )
If you do that then you must change the rear aswell. Best thing to do is adjust the MB rotors by going to a machine shop and let them dril the holes. Bring the hubs also so they can adjust the center hole on a lathe...
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 04/01/14 04:49 PM
Quote:
If you do that then you must change the rear aswell. Best thing to do is adjust the MB rotors by going to a machine shop and let them dril the holes. Bring the hubs also so they can adjust the center hole on a lathe...
I had to open the center register on the rotors. They're smaller than the old Mopar stuff.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/01/14 05:10 PM
Quote:
Quote:
Might be easier to just find a local wheel repair/modify place and have them toss the rotors in their mill or what ever they use to redrill wheels and get it done in a few minutes.
My wheel guy drilled my rotors out...took me longer to drive there and back to pick them up then to have them done.
(in hindsight, I should have drilled my hubs to Mercedes bolt pattern and have the wheels drilled the same, save having to modify the rotors..but oh well. )
If you do that then you must change the rear aswell. Best thing to do is adjust the MB rotors by going to a machine shop and let them dril the holes. Bring the hubs also so they can adjust the center hole on a lathe...
Wouldn't have been any need to change the rear really in my case at least. It is not like I would ever rotate the wheels, so different bolt patterns wouldn't have really mattered. (I run 8" wheels up front and 10.5" in the rear. )
Either way, it's no big deal to get the front rotors redrilled in my case when I happen to need to change them.
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 04/01/14 10:09 PM
Quote:
Either way, it's no big deal to get the front rotors redrilled in my case when I happen to need to change them.
Same here. I don't even have to leave the house.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/02/14 05:00 AM
My lathe is not up and running nor is my mill, both are getting a full rebuild and rescraping. I can hold a .005 tolerance with the tooling I have made. Tim
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 04/02/14 09:30 PM
Quote:
My lathe is not up and running nor is my mill, both are getting a full rebuild and rescraping. I can hold a .005 tolerance with the tooling I have made. Tim
How dare you take both machines down at once?
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/03/14 10:39 AM
One was given to me in pieces and the other was one that I bought and in the process of rebuilding. The lathe is a 11x36 Rockwell from 1957, the mill is a mid 1970's to late 1980's 6x26 from tiawan. I need to scrape both in and then I can start using them. I am waiting on a few parts for the lathe, a couple of gears, belts and then what ever I find in the varidrive that is not working and need to fix. Its just time and money! tim
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/12/14 09:15 PM
Well I came up with enough for 1 caliper, this thing is frikn huge! I am wondering what the hole at the top of the caliper is for? That is a size 11 foot to compare it to!
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/12/14 09:16 PM
6 each 40 mm pistons, they are all the same size!
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/13/14 12:03 AM
Only six piston?
8 is nicer.
As for that hole....my calipers have a bridge across the center (since they are larger I assume?) but maybe it was for a pad wear sensor of some sort maybe for your's?
Feets would probably know.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/13/14 02:19 AM
The pictures online show a special bolt, now where I am going to find one of those? They are not on the dealership listing....
Posted By: brads70
Re: Is 380 mm rotors large enough for you? - 04/13/14 03:14 AM
I agree the hole is for a bridge spacer and bolt. I'd just use a socket head capscrew and a tube spacer (simple lathe job) if you can't find the proper parts.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/13/14 04:16 AM
Here is what mine look like..
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/13/14 04:40 AM
These are a stretch bolt for this caliper, I have seen them used on aircraft before. This is what I need....
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/13/14 04:44 AM
Another view...
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/13/14 05:03 AM
Different setup than my calipers then..
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/13/14 05:11 AM
Yep, but for 225 per caliper, I think they are still a steal of a deal!
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/14/14 07:52 PM
Well Brembo does not sell service parts for OEM calipers and Mopar only sells the bridge bolt with the calipers. So I called Ford, they list the anti Rattle kit for the 2013 GT500 as a 2b164 part number, I ordered a kit for $31.00, so I hope it comes with the bolt. Tim
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/17/14 12:16 AM
The kit from Ford had the bridge bolt, I will have pics when I get home. Now to make adapters once I finish drilling the rotors. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/17/14 01:45 AM
That is cool you were able to find the bits for them seperately.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/17/14 03:59 AM
Its kinda disappointing that Mopar doesnt support their products better!
Posted By: Consulier
Re: Is 380 mm rotors large enough for you? - 04/17/14 05:00 PM
Is the GT500 the same caliper?
Also, what's the full part number? This is what I found with that extension...
No Bolt
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 04/17/14 11:47 PM
I'd make my own bridge and call it good.
Once you get the calipers installed you need to do something about those girlie sized feet.
Posted By: brads70
Re: Is 380 mm rotors large enough for you? - 04/18/14 12:15 AM
Quote:
6 each 40 mm pistons, they are all the same size!
I missed it? What are these off of?
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/18/14 07:52 PM
The GT500 is supposed to be the same caliper, they are made for the OEM's and are not the same as the GT6 series calipers. I got one for a 2013 SRT8 Grand Cherokee. They are listed on Ebay for about 300 each. The Ford Part number is DR3Z-2B164-A for the anti rattle clips and bridge bolt. For 32.00, I could not build the bridge bolt, considering my time. Since my lathe is down, it is more of a pain than its worth. I still have to drill the rotors, I should see how the mustang rotors fit compared to the GC rotors. Projects like this get expensive if I start buying parts just to see if they fit. Tim
Well the rotors are thinner on the GT500, the bridgebolt is too short...by about 3/8", but at least now I have a pattern to work from...crap, another 30.00 wasted unless I modify the bolt I have and making it work. Tim
Posted By: Consulier
Re: Is 380 mm rotors large enough for you? - 04/18/14 08:11 PM
I usually use Rock Auto or one of the other sites only to get some basic dimensions.
GT 500 Rotor
Posted By: Consulier
Re: Is 380 mm rotors large enough for you? - 04/18/14 08:15 PM
Another rotor to look at might be the CTSV rotor. You'll have to drill the bolt pattern, but I believe they are the same thickness as the GC rotor. 10mm smaller diameter should work.
CTSV Rotor
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/18/14 08:15 PM
Yep, too short, maybe I can make a bushing and open up the recessed area and make it work. Tim
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/18/14 09:30 PM
Rock is handy for that.
Here are the ones I use (and feets used to as well)
I notice the AMG rotors are thicker than most others out there.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/18/14 09:32 PM
Bummer the pins didn't work out...but should be able to over come it, it looks like with a little work.
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/20/14 08:28 AM
Here is the info on the Jag XKZ
Descripition:
UPC: 018575357276
Style: Full Cast
Bolt Circle (in): 4.252
Bolt Circle (mm): 108.00
Overall Height (in): 1.890
Overall Height (mm): 48
Outside Diameter (in): 14.961
Outside Diameter (mm): 380
H&R / R: Disc Only
Solid or Vented: Vented
Nom Thk (in): 1.417
Nom Thk (mm): 36.00
Min Thk (in): 1.34
Min Thk (mm): 34.00
No. of Stud Holes: 5
Stud Supplied (in): No
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/22/14 01:52 AM
Well unless someone from here is willing to provide some technical support, I am starting to lose interest for now on this project. I feel that I am not making much progress on finding wheels to fit our older cars with big brake kits that dont cost a fortune. I enjoy projects like this but my resources are running dry...Tim
Posted By: 72Swinger
Re: Is 380 mm rotors large enough for you? - 04/22/14 02:52 AM
American Muscle sells affordable wheels in 19" sizes in 5-4.5 patterns.
Posted By: OzHemi
Re: Is 380 mm rotors large enough for you? - 04/22/14 02:58 AM
How much are you realistically looking to spend on wheels ?
Going with the diameter of rotor you have chosen means of course you need 19"? or 20" wheels, so that is going to raise the price over 18" stuff.
You might have to reverse engineer the direction you go, in picking the wheels first and built the brakes to suit, again depending on your wheel budget.
They are still some decent priced 2 piece wheels out there if you look which lets you built the back spacing you need to fit everything properly.
Or of course try and find a one piece wheel that just happens to be about the right back spacing and then you need to build a hub and rotor and caliper package to fit under the car ok for the wheel. (plus then get the diff width right too)
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 04/22/14 03:36 AM
I think that 2-400 per wheel is ok, anymore it defeats the price of doing the brakes on the cheap. I am just struggling with having to drop lots of cash on a project that seems to almost not be worth it. I enjoy building things but maybe I over stretched myself. Tim
Quote:
How much are you realistically looking to spend on wheels ?
Going with the diameter of rotor you have chosen means of course you need 19"? or 20" wheels, so that is going to raise the price over 18" stuff.
You might have to reverse engineer the direction you go, in picking the wheels first and built the brakes to suit, again depending on your wheel budget.
They are still some decent priced 2 piece wheels out there if you look which lets you built the back spacing you need to fit everything properly.
Or of course try and find a one piece wheel that just happens to be about the right back spacing and then you need to build a hub and rotor and caliper package to fit under the car ok for the wheel. (plus then get the diff width right too)
Posted By: feets
Re: Is 380 mm rotors large enough for you? - 04/22/14 03:40 PM
Get off the 15" rotor.
One reason I went with the 360 mm rotors was fitting them under 18" wheels. The 2005 S-class rotor also has a deep hat that moves the calipers away from the wheels.
Your biggest enemy with these brakes is making sure the back of the spokes don't hit the caliper. That has a major impact on the style of the wheel. My wheels had to be made with an extra deep mounting pad to provide clearance. The mfg got it wrong the first time and a second set had to be made.
Forget you ever heard of 15" rotors. Leave those to the Bentley boys and find a smaller and much lighter rotor.
The rotors Oz and I use weigh 37 lbs each. That's 74 lbs of rotating mass that doesn't help acceleration or unsprung weight. Going bigger just makes it worse.
Quote:
I think that 2-400 per wheel is ok
Seriously?
You want a $400 19" wheel that won't come apart with an old heavy car bouncing around on it?
Hello, China? I'd like to buy your best wheels...
Posted By: astjp2
Re: Is 380 mm rotors large enough for you? - 05/02/14 07:54 AM
So I did a little measuring tonight, I need to clear 1.75" between the wheel mounting surface and the caliper, and the center of the spindle to the outside of the caliper is 8" so now I have a few measurements to see what is out there for wheels. Tim
