As many of you know about 2 1/2 years ago, I developed a new 13" brake kit to replace the C4 12" rotor upgrade for the 88 Fiero's (both of these kits use the stock 88 Fiero calipers). Since that time I have been slowly expanding the brake upgrade parts that I offer and have been selling the C4 rotors drilled to the 5x100mm pattern as well as the C4 concentric rings, so I only need the caliper bracket to offer a C4 12" Kit for the 88 Fieros that uses the stock 88 calipers and parking brake.
Prior to developing the 13" kit, I had R&D the 12" C4 kit. My 12" C4 caliper bracket design came from my own mockup of the 88 C4 12" front rotor on the 88 uprights to determine proper bolt spacing for proper caliper placement on the rotor. The exterior shape of my bracket design is also unique. The caliper mounting side is the exact same shape as my 13" bracket for the 88's and the upright side is made larger to increase the material around the countersunk bolt holes. Here is a drawing of my 88 C4 caliper bracket:
I have to give credit to Rockcrawl for originally developing the "dogbone style" bracket for 12" C4 kit for the 88's as this style of bracket eliminated the caliper to upper a-arm interference issue that the other "rotated style" had - especially with lowered cars.
Currently there is no vendor selling the dogbone style kit for the 88 Fieros to use the 88 Corvette front rotors, even though it used to be the most popular brake upgrade for the 88's. So if there is interest in the C4 12" kit being reintroduced for the 88 Fieros, I can make that happen pretty easily and make sure they are readily available for years to come. The dimensioned print has already been sent to the machine shop that does my 13" brackets for quoting and the initial run will be 20 brackets, followed by a 100 bracket run for all subsequent orders.
Why would I offer this kit when I have my 13" kit already? 1: The rotors for this kit are lower priced, so the kit can be more economical. 2: This kit fits 16" wheels (my 13" kit requires 17" ones). 3: The C4 rotors are about 5 lbs lights per rotor (20 lbs. per car) than my 13" kit.
The two downsides to this kit are: 1: You will need to grind the nose on your lower a-arm for clearance to the back side of the rotor. Some stock height 88's can get away without doing this, but I recommend everyone do it as there is nothing more aggravating than installing brand new rotors and gouging the backside before you even get the car out of the garage... 2: This kit will not be compatible with Rodney Dickman's lowering ball joints. Once the lower a-arm becomes vertical, these lowering balljoints make the a-arm nose move toward the backside of the rotor at a quicker rate than stock.
Estimated Pricing:
Hardware only kit - full car: $200 shipped in the lower 48 states (Canada will cost more) Full Kit with plain rotors: $400 shipped in the lower 48 states (Canada is $75 more) Full Kit with drilled/slotted/zinc coated rotors: $475 shipped (Canada is $75 more)
Anyone still looking for the 12" C4 brake kit for the 88 Fieros (retains stock 88 brake calipers)?
Currently there is no vendor selling the dogbone style kit for the 88 Fieros to use the 88 Corvette front rotors, even though it used to be the most popular brake upgrade for the 88's.
Do they use front or Rear C4 rotors? I was under the impression it was rear rotors. I have this setup on my car already or I'd buy a kit(12" or 13")
2: This kit will not be compatible with Rodney Dickman's lowering ball joints. Once the lower a-arm becomes vertical, these lowering balljoints make the a-arm nose move toward the backside of the rotor at a quicker rate than stock.
FML...
I purchased the hardware for the 12" rotor upgrade some time agao... and the 1" lowering ball joints installed three years ago. This is a complete no-go?
Wait, doesn't the 1" lowering ball joint force the spindle into negative camber faster, by raising the upper control arm?
[This message has been edited by carbon (edited 02-13-2014).]
Guru, I would rather have the 12" kit. It opens up many more wheel options and is a little lighter in weight. FWIW, I had a 12" corvette brake setup on my last Formula and it was awesome! I could lockup the fronts at a pretty high speed.
Originally posted by KissMySSFiero: Do they use front or Rear C4 rotors?
For the 88 Fiero kits, they use four 88 C4 FRONT rotors. The C4 front rotors are about .32" deeper than the stock 88 rotor, so there is room for a 5/16" bracket. The rears are only .1" deeper than the fiero rotors, so there is only .1" for the caliper bracket and that is way too thin.
The confusion may come in that the 84-87's kits must use the C4 rear rotors in the rear of Fiero because the fronts are too deep and interfere with the upright.
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Originally posted by carbon: FML...
I purchased the hardware for the 12" rotor upgrade some time agao... and the 1" lowering ball joints installed three years ago. This is a complete no-go?
With stock ball joints, the nose of the lower a-arm has a tendency to make contact with the backside of the C4 rotor at the extremes of suspension travel in compression. Some people have installed the C4 kit on the 88's w/o doing anything and never had the grinding issue. Maybe they got lucky, maybe they never hit a bump hard enough to bottom out on the bump stops, who knows how they were able to have success, but I know that some of them are out there. I also know there have been a lot of issues with the interference as I had it when I installed my first C4 kit back in 2005, and have posted in the threads where people have had issues and provided guidance on how to resolve it. The interference issue is most common on Fieros that are lowered (by shorter springs) because their suspension range of motion is more biased to the compression side.
Now shift the nose of the a-arm down 1" while keeping the ball joint pivot in the factory position (this is how the lowering ball joints work). As soon as the lower a-arm passes the horizontal plane and the ball joint pivot becomes higher than the center of the a-arm bushing, the nose will approach the backside of the rotor at a much quicker rate (it now 1" further away from the pivot point).
What I do not know is the exact point at which the interference will happen when the lowering ball joints are used with the C4 kit (is it after 1" of compression, 2", 3" or more), but I know several people who have had the issue and it gets worse the lower the car is.
Now if someone really wanted to use the lowering ball joints and the C4 kit together, then they should remove the front shock and spring and compress the suspension while turning the wheels lock to lock. Once you find the point at which contact happens, then you can start grinding and remove as much material from the nose as you feel safe doing. Try to get as much suspension travel as possible. If you still can't make the bump stop contact its stop plate before contact, then you can start raising the bump stop, but this might cause you to hit the bump stop more often, which makes the car ride rougher.
Since you have the ball joints installed already, you can check for clearance using the stock rotor, just raise the suspension until the bump stop makes contract and then see if you can slide a 3/8" piece of steel bar between the backside of the rotor and the nose of the a-arm. If you can't, then start lowering the susension until you can and that will be about the point at which the interference starts.
It is possible for someone to do all this work and possibly reach a decent compromise allowing the use of the lowering ball joints and C4 rotors together but I can't guarantee it will work, nor would I expect a customer to have to do this to use one of my products. As a vendor I would rather market my kit identifying the incompatibility and lose some potential sales, than risk selling a kit to someone who can't use it due to fitment issues with other parts.
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Originally posted by eunospeed:
Guru, I would rather have the 12" kit. It opens up many more wheel options and is a little lighter in weight. FWIW, I had a 12" corvette brake setup on my last Formula and it was awesome! I could lockup the fronts at a pretty high speed.
Thanks!
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Originally posted by hiwil88formula:
I would be interested in this kit. The lower cost over your 13" kit would make me more inclined to buy this one.
Thanks, I am hoping there are more people like you both!
[This message has been edited by fieroguru (edited 02-13-2014).]
It is possible for someone to do all this work and possibly reach a decent compromise allowing the use of the lowering ball joints and C4 rotors together but I can't guarantee it will work, nor would I expect a customer to have to do this to use one of my products. As a vendor I would rather market my kit identifying the incompatibility and lose some potential sales, than risk selling a kit to someone who can't use it due to fitment issues with other parts.
Oh I hear ya! I'll have to look into it when the time comes I guess, thanks for taking the time to post all of that. I still need to buy new wheels before anything is going to happen, regardless.
Hardware only kit - full car: $200 shipped in the lower 48 states (Canada will cost more) Full Kit with plain rotors: $400 shipped in the lower 48 states (Canada is $75 more) Full Kit with drilled/slotted/zinc coated rotors: $475 shipped (Canada is $75 more)
Anyone still looking for the 12" C4 brake kit for the 88 Fieros (retains stock 88 brake calipers)?
Yes, I plan on purchasing a set late spring / early summer.
I have 12" vette brakes with Rodney's lowering ball joints on my '88. They clear fine, but I did have to do some cutting on the end of the a arm. I really took my time and didn't take any more material off than I had to.
I can respect the OP not wanting to condone this with a formal product, but for people willing to take it on, it can be done.
[This message has been edited by onesexyfiero (edited 02-13-2014).]
I have 12" vette brakes with Rodney's lowering ball joints on my '88. They clear fine, but I did have to do some cutting on the end of the a arm. I really took my time and didn't take any more material off than I had to.
I can respect the OP not wanting to condone this with a formal product, but for people willing to take it on, it can be done.
Are you using stock ride height springs? Did you check the clearance at full compression with the bump stops resting on their stops after the clearance work?
Yep, good to full compression, barely. I did a lot of checking to make sure I didn't take off any more than I had to. Been running the setup for a couple of years with no issues. I've checked the inside edge of the rotors for signs of contact periodically, and haven't seen anything.
On Friday I sent the drawing to the machine shop for quoting an initial run of 20 brackets (5 full kits) and 100 brackets (25 full kits - my normal purchase quality).
I will likely place the order for the initial run of 20 brackets sometime this week and its normally about a 2-3 week turn around.
Hopefully by mid March I will be able to offer this kit.
I need just 2 brackets for my 88 cradle swap. I sent drawings to my machine shop to do in their spare time (for the right price) but they're pretty backed up and it's been a while.
On Friday I sent the drawing to the machine shop for quoting an initial run of 20 brackets (5 full kits) and 100 brackets (25 full kits - my normal purchase quality).
I will likely place the order for the initial run of 20 brackets sometime this week and its normally about a 2-3 week turn around.
Hopefully by mid March I will be able to offer this kit.
I already have the brackets that I bought years ago but now I need the C4 rotors. I need some that look close to your 13" setup as I'm planning to run 13/12 setup on my (two) cars.
I already have the brackets that I bought years ago but now I need the C4 rotors. I need some that look close to your 13" setup as I'm planning to run 13/12 setup on my (two) cars.
Thanks
If you buy them from the same vendor, then there is a "chance" that the patterns will be "similar".
I sold a C5/C4 rotor combo that both rotors had a similar pattern (C5 on Left, C4 on Right):
Here is one of my 13" rotors that are from the same vendor:
Originally posted by Tom Slick: Sweet... I need to order some C4 rotors from you. I looked on your website but I didn't see anyway to order except by calling.
Yeah, I still have some work to do on the website to allow ordering from it directly... I sent you a PM on how to purchase is set.
The machine shop I use has been slammed, but I spoke with them yesterday and the first 5 sets of brackets should be completed this week. So if all goes as planned, the first 5 sets could go on sale in the middle of May.
The first batch of brackets arrived today... 30 of them instead of 20. Laser cut, tapped, and counter sunk... now I need to QC them to make sure they are right, install a set to verify fitment, write the installation instructions, and then they will be ready for purchase!
The brackets were produced within specified tolerances, so they are ready for a test fit. I didn't want to pull my 13" kit off either of my 88's, so I test fitted them on the loose suspension uprights I have in the garage:
Bracket bolted to upright. The critical thing here is the heads of the bolts need to be flush with the bracket so the caliper will bolt on parallel to the rotor. You can also see that I increased the overall size of the bracket so there is more material around the countersunk bolts:
Then I put on the rotor and caliper with new pads. Check for placement of the pad to the edge of the rotor - the pads should be flush or slightly inboard, which they are:
Also need to check for clearance between the caliper bridge and the OD of the rotor, and there is plenty on both sides:
Then I bolted on a stock lower a-arm... this kit is know for having interference issues between the nose of the lower a-arm and the backside of the rotor and here is why. When the a-arm pivots are about horizontal (picture is slightly higher on the chassis side, which increases the clearance), there is less than 1/8" clearance between the bottom edge of the nose and the backside of the rotor.
Rotate the lower a-arm down (like when the suspension is loaded, or the car is lowered, the lower corner of the nose makes contact with the rotor.
The nose contact is holding the a-arm up:
The fix for this is to trim the nose of the a-arm. I take some tape and wrap it around the nose of the lower a-arm leaving about 1/4" of the nose exposed and taper the sides back.
Using a cutoff wheel or grinder, remove the marked section of material and clean up the cut.
With the lower portion of the nose notched, now within the range of the ball joint rotation, the nose of the lower a-arm never makes contact with the rotor.
As you can see with how close the nose of the a-arm is to the rotor, I will not recommend this kit to those who have or are planning to install Rodney's lowering ball joints. Those will greatly reduce the clearance and will require more material at the nose to be removed. Some will say they have both the 12" C4 rotors and Rodney's ball joints on their car and it works, but it requires more work than I am comfortable expecting my customers to do. So I will not recommend the kit to those with lowering ball joints.
The Full Kit will consist of the following parts (shipped in 2 boxes): • 4 - 12” rotors drilled to the 5x100mm pattern • 4 – steel caliper brackets to relocate the stock brake calipers, painted semi-gloss black • 4 – plastic expandable concentric rings • 8 - grade 10.9 M12 bolts • 1 – strip of sand paper • 1 – set of installation instructions with pictures
The Full Hardware Only Kit will consists of the following parts (shipped in 2 boxes): • 4 – steel caliper brackets to relocate the stock brake calipers, painted semi-gloss black • 4 – plastic expandable concentric rings • 8 - grade 10.9 M12 bolts • 1 – strip of sand paper • 1 – set of installation instructions with pictures
The brackets and bolts are more expensive than my 13" kit, but with the rotors being less expensive, I have been able to keep the price of this kit between $150 and $190 lower than the full car versions of my 13" kit. Below are the prices and purchase options for this kit.
If you compare my "shipped" prices to the other vendor selling the 12" C4 rotor upgrade for the 88 (priced w/o shipping and the website pricing tends to be lower than actual pricing), I think you will find my pricing and options to be highly competitive (just like my 13" kit!).
Pricing Summary: All prices shipped for US and Canadian addresses unless noted.
Hardware Kit only – Front:.....................$100 Front Only w/ plain rotors:.....................$200 (+$35 shipping surcharge to Canada) Front Only w/ Drilled/Slotted/Zinc Rotors:$225 (+$35 to Canada) Hardware Kit Only – full car:...................$200 Full Kit with Plain Rotors:.......................$400 (+$70 to Canada) Full Kit with Drilled/Slotted/Zinc Rotors:....$450 (+$70 to Canada)
It will still be a couple of weeks before I am ready to start selling these kits, but feel free to let me know you are wanting a kit and to reserve one of the 7.5 kits that I have in this first batch. Once it looks like 5 or more of these will sell, I will place the order for 100 more brackets (25 more kits). I just hope it doesn't take as long for the next batch to be produced.
[This message has been edited by fieroguru (edited 05-04-2014).]
Those look great! The brackets I have on my Formula use a cap screw instead of the countersunk screw like you are using. I like yours better, looks much cleaner and stronger. How much are your Slotted Front and Rear Rotors, just the rotors? I will probably get the whole kit later in the future as I plan on stripping down the Fiero once I get my own garage.
I don't know if you mentioned it earlier in the thread, but your instructions should include using "Locktite" on all of the Caliper attachment bolts, as well as the new bracket bolts.
Originally posted by Ravant: Honestly, if you did these for a car with an '88 rear and a pre-'88 (1985) front, I would be all over them like white on rice. And then some.
PM Sent
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Originally posted by craigsfiero2007: Those look great! .... How much are your Slotted Front and Rear Rotors, just the rotors?
$265 shipped when purchased separately. They will come already drilled for the 5x100 pattern.
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Originally posted by California Kid:
I don't know if you mentioned it earlier in the thread, but your instructions should include using "Locktite" on all of the Caliper attachment bolts, as well as the new bracket bolts.
The use of locktite and the specified torque for the bolts is already part of the instructions.
Originally posted by fieroguru: ... I will not recommend this kit to those who have or are planning to install Rodney's lowering ball joints. Those will greatly reduce the clearance and will require more material at the nose to be removed. Some will say they have both the 12" C4 rotors and Rodney's ball joints on their car and it works, but it requires more work than I am comfortable expecting my customers to do. So I will not recommend the kit to those with lowering ball joints.
Wouldn't "lowering" springs or cut springs have much the same issue? Before I received my 13" kit, the 12" rotors looked like they were very close to the LCAs, although I never had it on the ground.
Edit - After looking again at the bottom pic... perhaps not.
[This message has been edited by Raydar (edited 05-04-2014).]
Wouldn't "lowering" springs or cut springs have much the same issue? Before I received my 13" kit, the 12" rotors looked like they were very close to the LCAs, although I never had it on the ground.
Edit - After looking again at the bottom pic... perhaps not.
Once you trim the nose, then you have proper clearance for full range of motion of the stock ball joint - so it will work with shorter or lowering springs.
The lowering ball joints effectively add a spacer between the lower a-arm and the ball joint pivot. This change in geometry makes it so the nose of the a-arm will move towards and away from the rotor a further distance and at a quicker rate.
I am curious on how much you would have to trim off the Lower Control Arm with Rodney's 1" Lowering Ball Joints. It looks like it would have to be alot, like you would be trimming into the ball joint area.
Here is a drawing I made to show how a 1" lowering ball joint changes the rotation of the nose of the lower a-arm and how it changes the available clearance to the backside of the C4 12" rotor. It isn't exactly to scale, but it is a good visual indication of the differences.
Thinking about upgrading and using your kit but I run 17" wheels all around. . Figuring out how to retain the eBrake would be a plus.
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