JeffP1167
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Would ZR1 brakes be a great upgrade verses my stock 12 inch brakes on my 1990? Will these slear my stock 17" inch wheels?
zr1 brakes on my 90?
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MYBAD79
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Even the stock C6 (Z51) brake calipers are a tight fit on the front 18" rims, doubt that 17" rims work...
JeffP1167
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were the 17's on the front of a zr1 different then the base vettes 17 inch wheels? I though just the back wheels were different.
If you are talking about the C4 ZR1, I think the difference is rotor size (12" vs. 13")? I think the caliper is the same.
J55 option brakes were available for the base C4 also.
J55 option brakes were available for the base C4 also.
JeffP1167
Well-known member
Diameter and thickness is both different and appears to be casting differences in the calipers.
But yes a C4 Zr1
MYBAD79
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you're talking about C4 ZR1 brakes ??? I thought you were talking about C6 ZR1 (Z06) brakes...
Many upgrade from standard C6 brakes to Z06, standard C6 calipers are not very hard to find - that would be a serious upgrade over what you have but won't fit 17" wheels...
C4 ZR1 rims are 9.5x17 and 11x17, I used to run these on my Z28. Not sure if the front offset is different from the stock C4 rim but it probably is... what's on there stock ? 9x17?
Twin_Turbo
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The 12" rotor is only about .9 wide, the 13" rotor (Grand Sport and maybe ZR1??) is 1.1" wide. I have the same setup from Baer on my Camaro. I know for a fact that the Grand Sport caliper is the wider one. If the ZR1 is narrower it's only suited for the .9 wide rotor (if there is a .9 wide 13" one) the abutment bracket and the caliper for the .9 wide stuff are different.
I have a J55 setup from a 92 here. It uses 13" rotors 1.1 (28mm) thick. Like Marck said, the abutment bracket and caliper are probably different. Looks like Rock Auto has the rotors and calipers pretty cheap.
Twin_Turbo
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This is a set of the wider Grand Sport calipers. The abutment brackets are the wider ones, w/ the adapter brackets these are for 1LE camaros (modified stock spindles)
The GS caliper is similar to the J55 but the J55 has a couple of differences in the ribs, there are more ribs but they are smaller. Also there's some other small casting differences. The biggest difference of course the the Corvette script. The JL9 (12") and J55 caliper are very similar, the only readily noticeable difference is the width of the caliper itself, of course for the .9 vs 1.1 width rotor.
The GS caliper is the exact same core as the Baer one (apart from the logo) with the smooth front, no ribs on the front and the wider ribs on the back.
The GS caliper is similar to the J55 but the J55 has a couple of differences in the ribs, there are more ribs but they are smaller. Also there's some other small casting differences. The biggest difference of course the the Corvette script. The JL9 (12") and J55 caliper are very similar, the only readily noticeable difference is the width of the caliper itself, of course for the .9 vs 1.1 width rotor.
The GS caliper is the exact same core as the Baer one (apart from the logo) with the smooth front, no ribs on the front and the wider ribs on the back.
Twin_Turbo
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Here's some good info:
C4 Corvette Caliper Pictorial
Below are some pics and descriptions that show some of the differences between the later ('88-'96) C4 calipers.
Pics of the JL9 (12") caliper:
Pics of the J55 (13" Non-GS) caliper:
Pics of the GS (13") caliper:
Noted differences between JL9 (12") and J55 (13") Caliper:
As you can see below, the major difference between the J55/GS and the JL9 caliper is the width of the throat where the rotor resides. The J55/GS caliper is the one on the left and is about .5" wider than the JL9.
Noted differences between J55 and GS Caliper:
It's very hard to tell in this pic but you may notice that the rib running between the piston cylinders is deeper on the J55 caliper then the GS caliper however the GS calipers rib is a bit wider.
There are a couple of differences noticeable in this pic. First, the ribs on the top of the calipers. The J55 has more ribs but they are thinner than the ribs on the GS. Second, notice that the triangle shaped leg on the J55 caliper is not present on the GS.
Main difference here is that the GS caliper is smoothed with the "CORVETTE" logo unlike the plain, ribbed J55 caliper.
Another view of the top of the calipers showing the difference in ribs.
C4 Corvette Caliper Pictorial
Below are some pics and descriptions that show some of the differences between the later ('88-'96) C4 calipers.
Pics of the JL9 (12") caliper:
Pics of the J55 (13" Non-GS) caliper:
Pics of the GS (13") caliper:
Noted differences between JL9 (12") and J55 (13") Caliper:
As you can see below, the major difference between the J55/GS and the JL9 caliper is the width of the throat where the rotor resides. The J55/GS caliper is the one on the left and is about .5" wider than the JL9.
Noted differences between J55 and GS Caliper:
It's very hard to tell in this pic but you may notice that the rib running between the piston cylinders is deeper on the J55 caliper then the GS caliper however the GS calipers rib is a bit wider.
There are a couple of differences noticeable in this pic. First, the ribs on the top of the calipers. The J55 has more ribs but they are thinner than the ribs on the GS. Second, notice that the triangle shaped leg on the J55 caliper is not present on the GS.
Main difference here is that the GS caliper is smoothed with the "CORVETTE" logo unlike the plain, ribbed J55 caliper.
Another view of the top of the calipers showing the difference in ribs.
Twin_Turbo
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This is a Camaro 1LE caliper 7 abutment bracket (and adapter bracket + modified spindle, just like stock 1LE). The 1LE uses a 1.1" wide 12" rotor, it's the same caliper as the J55. The abutment bracket is different though, it uses the smaller mounting hole distance like in my 1st pic of the GS calipers.
The abutment bracket itself is also what makes the difference between a 12" and 13" setup, the bolt holes are simply in a different location.
This is the abutment bracket like used on Corvettes. See how it's got the bolt holes spaced wider? The 1.1 sized abutment bracket also has a wider clearance slot for the rotors and is wider overall. On a 12" bracket the 2 bolt holes will be drilled closer to the caliper.
White racing sells the correct bracket
http://www.whiteracingproducts.com/index.php?main_page=index&cPath=6_170
The 1LE abutment brackets won't work, they also have that bowed center, that was done to clear the hub on the 12" rotors (a 1pc rotor/hub), if you see that hump, you know they are the wrong brackets
The abutment bracket itself is also what makes the difference between a 12" and 13" setup, the bolt holes are simply in a different location.
This is the abutment bracket like used on Corvettes. See how it's got the bolt holes spaced wider? The 1.1 sized abutment bracket also has a wider clearance slot for the rotors and is wider overall. On a 12" bracket the 2 bolt holes will be drilled closer to the caliper.
White racing sells the correct bracket
http://www.whiteracingproducts.com/index.php?main_page=index&cPath=6_170
The 1LE abutment brackets won't work, they also have that bowed center, that was done to clear the hub on the 12" rotors (a 1pc rotor/hub), if you see that hump, you know they are the wrong brackets
JeffP1167
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Ok so now GS calipers come up as well. Seems like a never ending option list thats for sure.
OK .... Here is the intended use for my car 80-100 on freeway with occasional fast stops for gridlock. Quite a bit of around town use and 3 times a week through a twisty canyon road full of morons, no competetive racing nor street racing of any kind .
Perhaps my friends 90 had serious brake issues that he didn't realize but one thing is for sure his has the same 12" brakes and FE1 suspension that mine does and his brakes would start fading fast after 3-5 quik stops. Almost to the point where you didn't think it would stop in time. No ABS codes or anything on his car. My mini-vans brakes seem better and in fact long ago when I was using my 82 corvette he had mentioned it could out brake his 90 with ease but I though he was kidding till I had his 90 for 3 weeks.
Is what his is doing normal ???? Or will mine be just as bad ????
I have a lead on the whole F & R brake things from a ZR1 but am a bit skeptical that they aren't really J55 parts ... Can any ID these parts for sure or am I better off just buying rebuilt ones ????
OK .... Here is the intended use for my car 80-100 on freeway with occasional fast stops for gridlock. Quite a bit of around town use and 3 times a week through a twisty canyon road full of morons, no competetive racing nor street racing of any kind .
Perhaps my friends 90 had serious brake issues that he didn't realize but one thing is for sure his has the same 12" brakes and FE1 suspension that mine does and his brakes would start fading fast after 3-5 quik stops. Almost to the point where you didn't think it would stop in time. No ABS codes or anything on his car. My mini-vans brakes seem better and in fact long ago when I was using my 82 corvette he had mentioned it could out brake his 90 with ease but I though he was kidding till I had his 90 for 3 weeks.
Is what his is doing normal ???? Or will mine be just as bad ????
I have a lead on the whole F & R brake things from a ZR1 but am a bit skeptical that they aren't really J55 parts ... Can any ID these parts for sure or am I better off just buying rebuilt ones ????
Twin_Turbo
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if that's a 13" rotor, and it looks like one..it's a ZR1 setup.
JeffP1167
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I can get all 4 calipers 100.00
4 rotors 150.00 freshly turned and not used since
the front brackets 100.00
rear calipers rebuilds with 17K miles on them,.
Good deal or should I pass ?????
JeffP1167
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I believe mine are all 17x9.5 tires are all 275/40/17
Twin_Turbo
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JeffP1167
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He claims its all from a 90 ZR1 .... however everything looks like whats on my 90 base car. I know for a fact mine isnt a big brake car unless my stuff has been changed.
anyways Ive seen pics of 12 & 13" calipers now look at his picture.
This must be a front caliper but now look at the 13 inch caliper notice the ribs end at a casting line where his dont and look more like the 12 inch caliper. Also notice the more pronounced "square" shape verses the rectangular shape of the 12" caliper that is beteen the holes you can see the pistons in.
anyways Ive seen pics of 12 & 13" calipers now look at his picture.
This must be a front caliper but now look at the 13 inch caliper notice the ribs end at a casting line where his dont and look more like the 12 inch caliper. Also notice the more pronounced "square" shape verses the rectangular shape of the 12" caliper that is beteen the holes you can see the pistons in.
JeffP1167
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I know ny his rotor pictures it is hard to tell but they also resemble 12" rotors just by there thickness which looks like mine as well.
what do you guys think? is this really big brake stuff he has or possibly did his car loose everything before he got it? My cars stuff looks like the small brake stuff and what he is selling matches mine perfectly
these are supposedly 13" rotors
what do you guys think? is this really big brake stuff he has or possibly did his car loose everything before he got it? My cars stuff looks like the small brake stuff and what he is selling matches mine perfectly
these are supposedly 13" rotors
Twin_Turbo
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The left are the 13" 1.1 wide rotors for sure.
The caliper behind the wheel has the bowed casting, not the straight. That bow, like that in the 1LE abutment bracket is there for rotor clearance.
The caliper in this pic is a J55 caliper
These are the 13" HD 1.1 wide rotors:
The rotor vent size is an immediate clue, the stock ones are much thinner
These are the 12" HD rear rotors:
The caliper behind the wheel has the bowed casting, not the straight. That bow, like that in the 1LE abutment bracket is there for rotor clearance.
The caliper in this pic is a J55 caliper
These are the 13" HD 1.1 wide rotors:
The rotor vent size is an immediate clue, the stock ones are much thinner
These are the 12" HD rear rotors:
JeffP1167
Well-known member
by bow you mean it is curved in this area? like the other caliper?
mine are perfectly flat like the one pictured and not curved like the other caliper in this area.
So they are indeed 13" calipers so will they also fit the 1.1" wide rotors?
mine are perfectly flat like the one pictured and not curved like the other caliper in this area.
So they are indeed 13" calipers so will they also fit the 1.1" wide rotors?
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