CTS-V brakes, something different
#281
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I pulled one of my Firehawk rims and measured the hub to spoke clearance at 7" out and it was only 1.375". If it needs 1 7/8" it's not even close.
Anyway, Fast377 are you saying the only problem with the Chrysler rotor is the bolt pattern? That's an easy fix.
Vernon
Anyway, Fast377 are you saying the only problem with the Chrysler rotor is the bolt pattern? That's an easy fix.
Vernon
Yes, the only problem with the Chrysler rotor is the lug pattern. The only problem with the Cayenne rotor is the hub center. So we might have something with the rotors I mentioned above. Fingers crossed...
Anyone know how far back the rotor can be before we run into problems hitting the spindle or something?
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The closest component on the back side is the lower control arm end. I'd guess it's around 0.400".
I measured my rim flange to spoke depth based on what you said it would take to fit it. When you gave the 1 7/8" spec wasn't that based on a z06/CTSV mock-up? I didn't even check against my rotors or calipers.
Vernon
I measured my rim flange to spoke depth based on what you said it would take to fit it. When you gave the 1 7/8" spec wasn't that based on a z06/CTSV mock-up? I didn't even check against my rotors or calipers.
Vernon
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So from what I have been reading, you can use cts-v calipers without any brakets using the factory mounts on an ls1 car. So is it possible to use spacers to make it work with c5 rotors?
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On your current LS1 rims, you need about an inch of spoke clearance to clear the CTS-V calipers and Vette offset rotors.
If you measure the LS1 rotor to LCA clearance you'll see that you can only push the rotors friction surface back 30mm. Any more will hit the arm.
If you measure the LS1 rotor to LCA clearance you'll see that you can only push the rotors friction surface back 30mm. Any more will hit the arm.
#285
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Well, I didn't have to pull a wheel off, but I got under there and checked. Looks like bad news for most of us. The closest obstruction is the lower A-arm. I don't think even 15" rotors would clear it. Anyway, there is about 1/2" or 12mm of room there with my 12" F-body rotors. If you already have the C5 rotors then the gap would be .7" or 18mm.
![](http://img.photobucket.com/albums/v335/JasonWW/Misc%206/RotorClearanceatA-arm0.jpg)
This means that for some of you, you will have to use a spacer on the front to clear your spokes. No way around it.
It also means those above hats won't work as they are too tall. We need to find one 1.2" or about 30mm or so. I found one from Coleman, but it's a lightweight part designed for solid discs and would have to be drilled for our bolt pattern. I doubt this would work for us.
http://www.colemanracing.com/catalog...15a7cea32a57bf
If we can't find a hat then we'll be forced to use the rotors we have now (LS1, C5) and then just get spacers to push our rims out to clear. Maybe we should look at the OEM rotors again looking for about a 30mm offset.
![](http://img.photobucket.com/albums/v335/JasonWW/Misc%206/RotorClearanceatA-arm0.jpg)
This means that for some of you, you will have to use a spacer on the front to clear your spokes. No way around it.
It also means those above hats won't work as they are too tall. We need to find one 1.2" or about 30mm or so. I found one from Coleman, but it's a lightweight part designed for solid discs and would have to be drilled for our bolt pattern. I doubt this would work for us.
http://www.colemanracing.com/catalog...15a7cea32a57bf
If we can't find a hat then we'll be forced to use the rotors we have now (LS1, C5) and then just get spacers to push our rims out to clear. Maybe we should look at the OEM rotors again looking for about a 30mm offset.
#286
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Something else just occured to me. For the guys who want to run the 13" rotor it may actually be hard to mount the caliper due to the mounting lugs being so long.
If you look at this pic of the stock spindle you will see that the CTS-V caliper mounting holes would be approximately 1/2" closer to the hub.
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/BrakeupgradewithPOR157.jpg)
Something like this:
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/BrakeupgradewithPOR158b.jpg)
Even with a new bracket, can those lugs be cut off enough to allow this caliper to fit? You guys may be better off going to a radial mount caliper. It looks like this:
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/bira71.jpg)
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/hlubb31.jpg)
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/hlubb21.jpg)
Perhaps the viper caliper as was mentioned on post #66 would work better.
Post 66
Or a compromise for making the CTS-V caliper s fit would be to use a conventional bracket and see if the Z51 13.4" rotors would fit under your 17" rims. Then the holes would only need to move back 1/4", which would require less cutting on the spindle.
Did we ever find out the GTO rotors size and offset?
If you look at this pic of the stock spindle you will see that the CTS-V caliper mounting holes would be approximately 1/2" closer to the hub.
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/BrakeupgradewithPOR157.jpg)
Something like this:
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/BrakeupgradewithPOR158b.jpg)
Even with a new bracket, can those lugs be cut off enough to allow this caliper to fit? You guys may be better off going to a radial mount caliper. It looks like this:
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/bira71.jpg)
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/hlubb31.jpg)
![](http://img.photobucket.com/albums/v335/JasonWW/Big%20Brake%20Kit%20Pics/hlubb21.jpg)
Perhaps the viper caliper as was mentioned on post #66 would work better.
Post 66
Or a compromise for making the CTS-V caliper s fit would be to use a conventional bracket and see if the Z51 13.4" rotors would fit under your 17" rims. Then the holes would only need to move back 1/4", which would require less cutting on the spindle.
Did we ever find out the GTO rotors size and offset?
Last edited by JasonWW; 05-29-2008 at 11:51 PM.
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Jason, when you checked the rotor to lower control arm gap did you have the front end raised up? With mine on the ground there's no way I could get fingers in there like your picture. That gets me to thinking that at full compression it's even smaller.
Vernon
Vernon
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I can drive one of my wheels onto a curb to compress it and check again. If the gap becomes tiny then that really screws things up for the guys who were needing more spoke clearance.
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Jeez, I already pointed out the reason that won't work. Post 117
Ed says we might be able to use a "Bob Bishop" style bracket to fit the 13.4" Vette rotor, but any smaller and you run out of room. Even though the GTO rotor might help a lot of guys get their spoke clearance, it's just too small in diameter to mount with these calipers.
Ed says we might be able to use a "Bob Bishop" style bracket to fit the 13.4" Vette rotor, but any smaller and you run out of room. Even though the GTO rotor might help a lot of guys get their spoke clearance, it's just too small in diameter to mount with these calipers.
Based on your control arm interference measurement, the BMW X5 rotor is dimensionaly a perfect fit...but it is too thick. I think we can only go 32mm thick and the BMW is 36mm.
Last edited by fast377; 05-30-2008 at 09:32 AM.
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I am interested in the end result of this! I have been looking into better stopping power but dont have the money to blow for name brand kits, so this may be the way to go! Can you guys PM me all the necessary stuff?
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Hey how are you guys compairing rotor dimensions? Is there a web site like Brembo's but more specific and easier to navigate? Or are you guys useing printed information and who's catalog should I order?
I'm getting in on the test fitting myself. I have some standard Chrysler hemi rotors here and should be recieving some CTSV calipers today. All from salvage yards, $300 total investment so far. These rotors are like the SRT-8s but only 13.6". If I can't figure them out in a few weeks I'll see if Jason wants to help, we must be pretty close to each other.
Vernon
I'm getting in on the test fitting myself. I have some standard Chrysler hemi rotors here and should be recieving some CTSV calipers today. All from salvage yards, $300 total investment so far. These rotors are like the SRT-8s but only 13.6". If I can't figure them out in a few weeks I'll see if Jason wants to help, we must be pretty close to each other.
Vernon
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Hey how are you guys compairing rotor dimensions? Is there a web site like Brembo's but more specific and easier to navigate? Or are you guys useing printed information and who's catalog should I order?
I'm getting in on the test fitting myself. I have some standard Chrysler hemi rotors here and should be recieving some CTSV calipers today. All from salvage yards, $300 total investment so far. These rotors are like the SRT-8s but only 13.6". If I can't figure them out in a few weeks I'll see if Jason wants to help, we must be pretty close to each other.
Vernon
I'm getting in on the test fitting myself. I have some standard Chrysler hemi rotors here and should be recieving some CTSV calipers today. All from salvage yards, $300 total investment so far. These rotors are like the SRT-8s but only 13.6". If I can't figure them out in a few weeks I'll see if Jason wants to help, we must be pretty close to each other.
Vernon
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Basically the LS1 rotors are about as far offset as you can go already. The vette rotors stick out a few more mm. I doubt it's worth the trouble to find a different rotor that has a few more mm of space in exchange for having to re-center the hubs and re-drill the lugs. So as far as I can tell, the vette 13.4 rotors are the only real choice as far as fitting it with a 17" rim.
I measured the gap between the rotor and the A-arm on my 12" rotors with the tire extended and got about 30mm, but that almost goes away when the suspension is fully compressed. (Someone needs to verify this)
So if you already don't have around an inch of spoke clearance now, your going to have to space the tire out. I don't think a "magic" rotor is going to fix this basic problem.
So the tire sticks out more, what can you do? Maybe a shorter upper A-arm will pull the top of the tire closer in as well as give you some good negative camber. If the fronts are still further out than the rears, then space out the rears some so they match.
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Last edited by JasonWW; 06-05-2008 at 11:51 AM.
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Fast, the 2004 Audi A8 had a mid-year production change for front brake rotors. I hate to be a pain but can you confirm if it's before or after the production VIN# change.
Vernon
Vernon
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I'm out of town right now, so I don't have my brembo catalog. I've been using dba's online catalog for most of it recently. It's pretty user friendly. But I think the BMW rotor I mentioned above is going to be a better fit then the Audi one. And it's priced about the same as the z06 rotor.
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Agreed. These calipers need at least the 13.4 rotor to fit right. Did you ever measure your spoke clearance?
Based on your control arm interference measurement, the BMW X5 rotor is dimensionaly a perfect fit...but it is too thick. I think we can only go 32mm thick and the BMW is 36mm.
Based on your control arm interference measurement, the BMW X5 rotor is dimensionaly a perfect fit...but it is too thick. I think we can only go 32mm thick and the BMW is 36mm.
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The minimum thickness on the BMW rotor is 34. I don't know how I feel about turning past that...especially for street/track use. They have a minimum recommended thickness for a reason.
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I think that since the rotor was designed for a much heavier car, they would recommend a thicker minimum. But since we are using it on a f-body, it should be fine. And can you use the rear caliper with the stock f-body rotors?