13" Mustang Rotors

[xtremerevolution]

This was brought up in another thread. Strange of me to to be the one bringing it up considering I already have drilled w-body rotors, but anyways.

 

Can you fit mustang rotors on a w-body...

 

I have a cousin who has a nice machine shop. Basically a 3-dimensional tool that will cut anything out of a block of metal. He said he wouldn't charge me for any of the work I could ask him to do.

 

That being said, can I use 13" rotors off a Mustang using the w-body calipers if I had a bracket machined to spec? Is the mustang rotor a different offset than the w-body rotor?

 

According to calculations, I would need to have the brackets made 7/8" or 15/16" longer (the latter for safety). He said all I would need to do is send him one of the brackets that I have and he can get the stuff put together without a problem.

 

Any ideas? Would I notice any performance increase going from 11.25" Drilled rotors to 13" standard rotors? Unless of course I could get 13" drilled rotors for cheap.

 

Needless to say, I'd be selling my 11.25" drilled rotors. I'm sure a few people around here would love to get their hands on them for cheap.

 

I'm not planning anything for now, just trying to get ideas and opinions on the issue.

 

I already know that the bolt pattern is different, but have heard that since the center bore/hub is the same size, it won't make much of a difference.

[Psych0matt]

hmmm, you might be onto something here...

[intern8tion9l]

you'd have some definate interest if you could get some custom brackets made up and could get the guy to make quantities of them

[Psych0matt]

brackets would be realatively cheap, and then they could come up with the rest on their own, seems like a good start

[GutlessSupreme]

Should work. I think the bolt pattern differences are 5x115 vs. 5x114.3 or something like that, so it's not huge.

 

If the rotors fit it'll be a great upgrade. I assume your cousin will know what he's doing, but be aware if you have to machine the rotors and you don't do it right, they could crack. Shouldn't be a problem with the proper equipment I guess.

[alphagtp]

I'm first in line for those drilled rotors !!!! just saying, if you get to that point lol, but seriously....

[BXX]

I was the one who brought up the 13" Mustang rotors multiple times... Yes, measurements allow it to fit along with the hub offset is very close... Fabbing a bracket shouldn't be an issue.

 

The best bet is to use a Wilwood caliper. Summit sells them as well as many other places. Of course measurements need to be taken.

 

 

[xtremerevolution]

Should work. I think the bolt pattern differences are 5x115 vs. 5x114.3 or something like that, so it's not huge.

 

If the rotors fit it'll be a great upgrade. I assume your cousin will know what he's doing, but be aware if you have to machine the rotors and you don't do it right, they could crack. Shouldn't be a problem with the proper equipment I guess.

 

Bolt pattern won't be the least bit of an issue since the center bore is the same. I know they'll fit perfectly.

 

Also, I'm not planning to machine the rotors. I'm planning to machine new caliper brackets for the left and right and using existing two-piston front w-body calipers. I want this to be as cost effective as possible. As it is if I can get this to work, all I'd need to pay for is a new pair of mustang rotors, since the caliper brackets I can get made for free.

 

The only thing I'm wondering is about the offset of the rotor. I know the first pair of EBC rotors I ordered (slotted and dimpled) came in as a wrong order (12" with a much bigger bolt pattern), and had a huge offset. It looked kinda like the one on the bottom:

 

 

The w-body front rotors are relatively straight and flat from the braking surface to the center

 

 

Notice the difference? I'm not sure what mustang rotors look like, but there would be a lot more to calculate in regard to the position of the caliper to compensate for the offset if there was the slightest difference. I'm sure I could get those kind of brackets manufactured, but it would be that much more difficult.

 

Basically, I'd be planning on using the existing w-body calipers and brake pads with these rotors. I wouldn't really get these installed till the snow stopped falling in Chicago since I can't get the 17's on the car till then and 13" rotors wouldn't fit under my stock 15's.

 

I was the one who brought up the 13" Mustang rotors multiple times... Yes, measurements allow it to fit along with the hub offset is very close... Fabbing a bracket shouldn't be an issue and calipers from a Toyota Truck (RN chassis) are a probible to use, they are 4 piston and are readily in stock at most part stores.

 

The best bet is to use a Wilwood caliper. Summit sells them as well as many other places. Of course measurements need to be taken.

 

Another option are rear rotors from a Lincoln Limo... They are 13.2", but I think they may be solid rotors... Unfortunately the rotor catalog I have didn't know show whether they were solid or vented. I will check on that when I dig out my newer rotor catalog. It shows all sizing and such for all rotors..

 

I think the other option I found were rotors from a Toyota Supra TT. But I think at 12.8" the cost was better for the Mustang 13"

 

If you're right about the closeness of the offset, I might just go ahead and give this a try. It would be pretty nice to get w-body caliper bracket to allow someone to install a 13" mustang rotor, which I'm sure you can get drilled/slotted as well. Now that would be pretty badass behind an open rim.

[Olds W31]

I am so in! I wanted 12"s, and you have given me hope for 13"s! I wonder if these will fit behind the stock 16" wheels

 

The difference in braking force between a 10.5, 11.25, 12, and a 13, due to the leverage that can be applied would be TREMENDOUS. I am imagining 12 to 13 in rotors and a slighly bigger dia MC to give a solid, confident brake feel to the W body.

 

PLEASE MAKE THESE BRACKETS! Cobra rotors are <$25 each on ROCKAUTO.com

[RangeStang]

I am so in! I wanted 12"s, and you have given me hope for 13"s! I wonder if these will fit behind the stock 16" wheels

 

The difference in braking force between a 10.5, 11.25, 12, and a 13, due to the leverage that can be applied would be TREMENDOUS. I am imagining 12 to 13 in rotors and a slighly bigger dia MC to give a solid, confident brake feel to the W body.

 

PLEASE MAKE THESE BRACKETS! Cobra rotors are <$25 each on ROCKAUTO.com

 

Not sure on this but I think you have to have a 17'' wheel to make them fit.

[Andrew]

I am so in! I wanted 12"s, and you have given me hope for 13"s! I wonder if these will fit behind the stock 16" wheels

will not fit. you'll NEED 17's for 13" rotors

[xtremerevolution]

In that case, if the 13" rotors are good to go, I'm sure I can also have him make something for 12" rotors.

 

I'll look into it a bit more. Any help would be appreciated. I'll definitely buy myself a mustang rotor and play around with it a bit some time soon to see how it would work out. I can't promise I'll have anything too soon, especially since I can't put my 17's back on the car till Chicago snow goes away, but I'll see what I can do. If the offset is the same as on a w-body rotor and all that needs to be changed is the spacing on the caliper, then this whole thing shouldn't be too difficult.

 

Any other opinions/research on this topic would be appreciated. 13" rotors on a w-body would be pretty badass. 13" drilled/slotted/dimpled rotors on a w-body would be simply insane.

[BXX]

Yes, but just think, you can run the stock Mustang rims with these brakes...

 

K, here's a bit of a lowdown. The Mustang rotor is very very close to the hub offset as the W-body. I think it has a bit more though which helps with rim clearence... The bracket should be pretty easy to fab, I have already looked into it. But you will not want to run the W-body caliper as you will see little or no braking gains as the friction surface of the W's pad is much smaller... Another break down of things will also put weight into perspective. We are talking about unsprung weight here, and the W's suffer from a huge amount so keeping the weight to a minimum and also giving the car the braking power is very important. Most of our cars are heavier than some Mustangs... I have a weigh slip that shows my 96 CS without me in it and running outta gas is a little over 3700lbs

 

Another possible rotor is a rear rotor from a Lincoln Limo. It is 13.2" but I have not been able to tell if it is vented or solid. I will have to check my updated rotor catalog for some measurments. Another possible rotor is from a Toyota Supra TT, but at 12.8", they are pretty pricey and the calipers are as well.

 

 

 

W-body Brake part weights and the prices from AutoZone in USD

 

Rotors, both sides - $68 30.8lbs

Pads, both sides - $30 3.4lbs

Calipers, both sides - $64 16lbs

------------------------------------------------

Total (no tax) $162 50.2lbs

 

 

Mustang Brake part weights and the prices from AutoZone in USD

 

Rotors, both sides - $128 40.2lbs

Pads, both sides - $45 4.3lbs

Calipers, both sides - $162 10.5lbs

--------------------------------------------------

Total (no tax) $335 55lbs

 

With only ~5lbs heavier, it's not really unacceptable, but the brake power will be immense compared to the stock W. Notice how the W's caliper is much heavier. The Mustang is aluminum whereas we all know the W's is iron.

 

Of course I also have reasearch and full plans of 14" brakes on a W, but seeming someone is currenty taking my idea of the 13" mustang parts to make prolly make some cash, I will keep the 14" setup to myself. Yeah, 14" rotors that use dirt cheap ($30 each) and readily available 4 piston calipers

 

 

 

 

[slick]

If you really want an upgrade, reman Corvette caliper's aren't that expensive. Obviously your gonna have to run a much larger wheel though.

 

Why not F-body calipers? They aren't expensive either.

[BXX]

If you really want an upgrade, reman Corvette caliper's aren't that expensive. Obviously your gonna have to run a much larger wheel though.

 

Why not F-body calipers? They aren't expensive either.

 

The Mustange Calipers are more superior, not to mention it is a guarenteed fit over the Mustang rotor...Remember, pads and rotor widths have to be taken into account to make sure it fits correctly and does just what it's supposed to do... The Mustang rotor is also wider than the Vettes and F-body.

[BXX]

Also, here are pics, even though small, that might help ya

 

Mustang on top, 96+ W on bottom

 

 

 

 

 

Another note, the Ws master cylinder is crap... A larger one will also net sufficient stopping gains. Also, with the larger brakes, the ABS WILL NOT FUNCTION CORRECTLY, therefor for safety, it needs to be disabled, or even better since GM ABS systems are complete shit, get rid of it and at least run a standard non-ABS master cylinder.. I know a much better master cylinder to run, but at this time that has to stay a secrect for safety issues (I haven't tested it yet )

 

 

[slick]

2nd Gen w-body guys upgrade to F-body calipers, rotors, pads, etc... Plus, why would you use Fbody calipers with mustang rotors anyways?

[Euro]

If you really want an upgrade, reman Corvette caliper's aren't that expensive. Obviously your gonna have to run a much larger wheel though.

 

Why not F-body calipers? They aren't expensive either.

 

The Mustange Calipers are more superior, not to mention it is a guarenteed fit over the Mustang rotor...Remember, pads and rotor widths have to be taken into account to make sure it fits correctly and does just what it's supposed to do... The Mustang rotor is also wider than the Vettes and F-body.

 

He was talking about F-body calipers along with the GM rotors.....

 

And F-body calipers are much easier to use with w-bodies(at least with 2nd Gens)

[BXX]

Mustang calipers with Mustang pads on Mustang rotors are a guarenteed fit. That and Mustang pads are pretty damn beefy and the calipers are big and light.... Seems like a no-brainer

[GutlessSupreme]

Bolt pattern won't be the least bit of an issue since the center bore is the same. I know they'll fit perfectly.

 

Just because the center bore is the same doesn't mean that they fit. If the bolt spacing doesn't fit, it doesn't fit.

But like I said, the difference is so marginal that they should.

 

I'm planning to machine new caliper brackets for the left and right and using existing two-piston front w-body calipers.

 

I was hoping you weren't going to come back and say this. I didn't mention it before because you said you'd be trying Mustang calipers. But as BlackBird said, this will be pretty much useless as our calipers and pad area are way too small for rotors that big. Consider this: Our front calipers did not change from 1988 to 1999 for 1st and 1.5 gens. In 1996, rotor size increase from 10.5" to 11.25"

 

So you want pads that were designed to cover a 10.5" rotor to cover a 13" rotor?

 

Approximations:

Inner hub area: ~19.25 in2

Pad surface area: ~12 in2 ? at most?

Pad contact surface area of the 10.5" rotor: ~134 in2

Pad contact surface area of the 11.25" rotor: ~160 in2

Pad contact surface area of the 13" rotor: ~227 in2

 

I don't have time to finish this, but figure the pads are only cover the last outer 1" or so of the diameter of the rotor.

You get the idea.

 

F-body's have never had the same bolt pattern as 1st gens and would require machining the rotors.

[mra32]

blackbird, not to be a dick, but what evidence do you have that w-bodies have too much unsprung weight? everything about my car says that its fine or on the too small side (relatively low spring weights relative to the car, the way it handles bumps in the road, etc...). I was just wondering if you took measurements or something to quantify your statement. I would be nice to have some numbers about suspension components, as opposed to going gung-ho and having people choose arbitary spring rates for new suspension setups.

[xtremerevolution]

Bolt pattern won't be the least bit of an issue since the center bore is the same. I know they'll fit perfectly.

 

Just because the center bore is the same doesn't mean that they fit. If the bolt spacing doesn't fit, it doesn't fit.

But like I said, the difference is so marginal that they should.

 

I'm planning to machine new caliper brackets for the left and right and using existing two-piston front w-body calipers.

 

I was hoping you weren't going to come back and say this. I didn't mention it before because you said you'd be trying Mustang calipers. But as BlackBird said, this will be pretty much useless as our calipers and pad area are way too small for rotors that big. Consider this: Our front calipers did not change from 1988 to 1999 for 1st and 1.5 gens. In 1996, caliper size increase from 10.5" to 11.25"

 

So you want pads that were designed to cover a 10.5" rotor to cover a 13" rotor?

 

Approximations:

Inner hub area: ~19.25 in2

Pad surface area: ~12 in2 ? at most?

Pad contact surface area of the 10.5" rotor: ~134 in2

Pad contact surface area of the 11.25" rotor: ~160 in2

Pad contact surface area of the 13" rotor: ~227 in2

 

I don't have time to finish this, but figure the pads are only cover the last outer 1" or so of the diameter of the rotor.

You get the idea.

 

F-body's have never had the same bolt pattern as 1st gens and would require machining the rotors.

 

My impression was that if the caliper is spaced farther out, the mere additional circumference to brake against will make a noticeable gain. Also, my car has the 11.25" front rotors. I'm not sure if my pads were designed to be 10.5 or 11.25, but I just thought I'd throw that out there.

 

I'll keep thinking about this for a while. I have till the spring to come up with something anyway.

 

Most of our cars are heavier than some Mustangs... I have a weigh slip that shows my 96 CS without me in it and running outta gas is a little over 3700lbs

 

Yeah about 500-1,200 pounds lighter!

 

 

lol. I'd say *some* w-bodies are heavier. Mine certainly isn't. Weighing in at 3223 lbs stock, I think mine is much lighter than a mustang. Mustangs are tanks. Seriously.

[RangeStang]

 

 

 

 

 

 

 

 

 

Yeah! about 500-1,000 lighter depending on year/model/weight reduction you do fox bodies anyways.They are light little cars thats what makes them so quick they have a good power to weight ratio.

[GutlessSupreme]

Also, my car has the 11.25" front rotors. I'm not sure if my pads were designed to be 10.5 or 11.25, but I just thought I'd throw that out there.

 

Consider this: Our front calipers did not change from 1988 to 1999 for 1st and 1.5 gens. In 1996, caliper* size increase from 10.5" to 11.25"

 

So you want pads that were designed to cover a 10.5" rotor to cover a 13" rotor?

 

*-I meant to say rotor size here, not caliper

 

The calipers never changed, the pads never changed. Your (all of our) pads were designed for 10.5" rotors.

 

My impression was that if the caliper is spaced farther out, the mere additional circumference to brake against will make a noticeable gain.

 

Again, without changing the contact size with the rotor (i.e. proper calipers/pads), upsizing the rotors isn't going to actually improve braking capability all that much. The biggest difference will be in cooling. The forces towards the edge of the rotor are obviously not as concentrated as those near the middle, so it should be easier to stop, but I think to really get the most out of this you should go with the proper (Mustang) calipers.

 

I'm not putting this down or anything, I just think the gains will be much more worthwhile if you go that route rather than with stock calipers.

[Euro]

Mustang calipers with Mustang pads on Mustang rotors are a guarenteed fit. That and Mustang pads are pretty damn beefy and the calipers are big and light.... Seems like a no-brainer

How do you know for sure they'll fit on a w-body?