Cadillac Brembo Front Brake Upgrade on a C5 Corvette - Information, Notes, and Testing!

Per my review of various upgrade brake options on the market for the C5, the option that stood out the most was utilizing the Cadillac Brembo 4 piston calipers with 14" C6Z06 calipers on the front. The price was reasonable, parts availability would be excellent, and it allowed utilizing much larger rotors (14" vs 12.6").  The upgrade was also preformed and documented on youtube first by another fellow Sam McLean and thus the parts and overall concept were documented enough to attempt this myself.Thus this upgraded seemed like a good way to reduce heat build up while also increasing braking ability, and it didn't hurt that this involved a bit of DIY fun and a fair bit of cost savings over other kits.

Parts list

Initial Installation - Issues & Success

My initial effort at installing these unfortunately was failure. The rotors fit great, and I was able to center the caliper on the 14" rotor with 2x 1mm M14 washer (linked above)... however the 18" "wagon wheels" did not clear the caliper. See the picture below. Also please note I did not drive the car like this, the wheels contacted the rotor just a few times attempting to check fitment chipped the cheap caliper paint. Such is life.

Other wheels may yield different results. I have also been advised that 5/8" spacers with extended wheel studs would allow a square setup with 4x 18" base model wagon wheels to clear as well. However, I went a different route.

As I want the maximum width tires I can get on this car anyways, I decided to go with 18x11 Apex ET57 SM10 wheels with 305/35R15 Federal 595RS-RR tires (200TW). These wheels are essentially the golden standard of wheel fitment for tracking the C5. It's the size spec Corvette utilizes, and you can't fit much more wheel/tire than this under the car without body modifications. These wheels also are specifically designed to accomodate maximum clearance for big brake kits, which in my case allowed for clearance of the Cadillac Brembo Calipers

The new Apex wheels cleared without any major clearance concerns at all. Not half bad and they do look pretty nice as well! Looks though take a back seat for me to performance!

Another factor with installing this kit that wasn't terribly well documented or investigated was there there is a small amount of pad overhang with these calipers. I grabbed my digital caliper and actually measured the overhang to be 2.66mm. This isn't enough to concern me, and the pad itself goes all the way down to the bottom of the friction surface of the rotor. These pads are making the most of what is available to them and then some. I have no qualms running these.

Speaking of pads, here is the Cadillac Brembo pads next to the C5 brake pads for comparison. The two seem to be pretty damn similar as far as stopping surface area goes. Add in that the Cadillac Brembos are 4 piston, this has all the symptoms of being an upgrade.

Anyways, beyond the pictures above, the install went smooth. I had the entire swap over done in an hour, with about 20 minutes of that me trying to determine exactly how the new pins work on the brembo rotors. Low and behold, you just wack them in. Want them out? Wack em out with a drift. Seems simple enough!

Initial break in testing

Having just installed these, I have to admit I was pretty excited to get out and try them. I took them to a remote desolate road that isn't very often traveled and began to follow the brake pads break in procedure. It called for 10x stops from 60-10mph at an aggressive pace, and then 10x stops from a higher speed to 10mph at an aggresive pace. We started performing these braking cycles in relatively rapid succession. As we were doing this, problems began to arose. First off, we started seeing sparks shoot we pulled over and checked everything and nothing seemed bad. Perhaps it was just because we were testing on a VERY dark night and it was new rotors and new pads?

We proceeded to break in the pads, and at several points we had to discontinue and go for cool down laps as the calipers started to make a distinct metal on metal grinding sound. We pulled over after a cool down and the sound going away and reviewed and yet again, everything seemed fine. Odd. Not sure if this issue would arrise at the track under heavy successive brakings from a high rate of travel back to 10mph back to back to back to back...

I took the Corvette home and next day I took everything apart to inspect. My theory was that perhaps the 2mm wider size of the Z06 rotors (The Cadillac rotors are 30mm wide, the Corvette Z06 rotors are 32mm wide) was perhaps causing the already tight side to side clearance of the calipers to rub. However, I could not find wear along these surfaces. However, I did find a bit of wear where the outside outward diameter of the rotor barely clears the caliper. Not sure if thise was perhaps braking material or road debris that got caught in there, but this clearance is also rather tight as well.

A spirited street test ride the next day confirm though that this works fine for spirited street driving withot issues. The brake break in procedure we followed was just quite aggressive, with the braking cycles done in rapid succession.

Baseline VS Brembo Caliper Stopping Distances & Rotor temps

In order to determine this upgrade has a functional and legitimate purpose besides like is to determine a baseline of what the car did with OEM brakes. We setup a simple enough test: Take an initial temperature reading after driving from my house to the test location. Drive down a largely untraveled road at 50mph. At the road cone, stop as agressively as I can. Repeat 5x. Take a cooloff lap, check temperature again, and then repeat some additional laps. This would let us know just how much distance the brakes allowed us to stop in, and what sort of temperatures we were seeing on the rotors, which in theory translates to temperatures in the system.

Here are the findings

 OEM CalipersBrembo Calipers
TestDistance (ft)Temp (F)Distance (ft)Temp (F)
Stop 17017066180
Stop 282*19765205
Stop 37523063220
Stop 47123565.5250
Stop 57428065.5240
Cool Off-280-195
Stop 67432068250
Stop 77632061270
Stop 87231064260
Cool Off 300-235
Stop 97630060250
Stop 106532061260
Stop 116732063257

* Outlier value, possibly incorrect reading or human error braking.

General Analysis:

Stopping distances were notably shorter with the Brembo Calipers, and rotor temperatures stayed lower the further along the test went.

Braking distance Comparison:

During the first phase of the test, average braking distance for the OEM calipers was 72.5, throwing out the outlier value. The average braking distance for the Brembo Calipers was 65, demonstrating the Brembo Calipers yielded a 10.4% improvement. In the second set of stops the OEM calipers averaged 74', while the brembo calipers averaged 64.3;, yet again showing the Brembos yielded a 13.1% improvement. In the final braking session however the OEM calipers averaged 69.3', and the brembos demonstrated an average of 61.3', demonstrating a final improvement of 11.5%.

Overall, it would appear safe to say that the Brembo calipers yielded at least a 10% improvement in stopping distance for this particular Corvette with wheel and tire combination.

Rotor Temperature Comparison:

During the first phase of the test, the Brembo calipers and rotors started with a higher rotor temperature and held a higher temperature until the 3rd stop, where the OEM calipers and rotors began to exceed the rotor temperatures of the Brembo Calipers. The OEM rotors held higher temperatures all the way until the cool off period, during which the OEM rotors also failed to decrease significantly in temperature during a cool off run.

For the remainder of the test the OEM setup would carry higher temperatures and achieved a highest temperature of 320 degrees. During the tests the Brembo setup peaked at 270 degrees.

During all cool down periods the Brembo configuration yielded the most improvements, dropping 45 and 25 degrees while the OEM setup dropped 0 and 10 degrees.

Overall, it would appear safe to say that the Brembo combination operates at a lower temperature despite starting at a higher temperature. It also appears safe to say that the larger rotors with the Brembo combination vent the most heat as the setup yielded significantly higher temperature drops between sessions.

A discussion on variability and the human factors involved:

There was definitely some variability in the testing, with a big part of that being the human factor. For example, on stop 2 with the OEM setup I clearly did not brake to full potential. There was also some variance in me getting up to speed and then setting cruise control. Sometimes I'd be a 48, sometimes I'd be at 52. I'd adjust the cruise control with 100 yards to go, but I can't be certain the car didn't vary in speed some amount between 47-54mph or so. I was also stopping as best as I could at a given marker, but there may have been several feet of variation there was well. When you consider the average human reaction time is 200 ms (.2s), and that  distance traveled when going at 50mph for that period of time is 14.6667 feet, you start to see that the margin of error isn't exactly insignificant.

Another factor is the manner of travel between braking stops along with the speed of the cool down laps. At times I found myself enjoying my Corvette a bunch, so I would be driving quicker back to the starting location. Another factor is that my familiarity with maximum braking likely improved as well during the testing.

There are factors in here to consider, but overall the trends appear significant enough to say that the Brembo combination outperforms the OEM combination.

Brake pad comparison notes:

PST-1001 for Brembos, OEM was PST-731. Same model, same compound from same manufacturer. OEM had two track days of driving on them already though. Bremo just brake in bedding + 500~ street miles. Some possible variation in there but likely not much?

Additional Clearancing

Reflecting on the  few issues I was having, I decided to investigate the caliper and rotor clearances on more time. An area I had not considered was clearance in regards to their radius. Measuring the clearance between the caliper and the rotor using a feeler gauge I was able to determine the gap was .015" or .38mm! That's snug!

This seemed to me like a likely culprit for clearancing issues when the rotor expands when hot, along with for extra material from the brake pad stick out to build up and then impact the caliper itself.

Being a highly scientific type, I decided to use the tried and true "Grind it until yer happy" technique to clearance the calipers. This yielded significant clearance gains.

Hopefully it's fairly obvious in the final picture that the clearance was increased several fold.

I took the Corvette out and went for a long session of practice braking. Sure enough... everything held up just fine and no more grinding after repeated intense braking, nor was I seeing sparks anymore. Not bad not bad!

Track Testing the Brembo Brakes

Testing occured at the Streets Of Willow track. I ran it both Saturday and Sunday, each day running a different direction (CCW and CW). I repeatedly hit 100+mph on the track with this configuration over and over, and not once did I experience brake fade. The brakes felt great and worked great the entire time. I was able to put down a personal best lap time, even with a blown coilover, of 1:28.162, over a second quicker than my previous lap times.

The biggest improvement of these brakes however was NOT that I improved braking distances or could brake any harder than before. The largest improvement was that I could acheive threshold braking with significantly less physical effort. This meant heel toe-ing was much much easier, and thus I found controlling the car both braking and shifting while brkaing to be a phenomenal improvement over stopping the car with the OEM caliper setup.

I then went and did yet another track day and had a great time as well. No issues with brake fade, and I again ran 1:28s despite the fairly cold track temperatures.

After three track days and all of the above aforementioned testing, here is what my brake pads looked like:

As you can see, the overhang on the top of the pad developed a slight lip. Most would also consider these pads unacceptable to continue to use at the track as the amount of pad material is less than the backing material. I'm inclined to agree and will likely be swapping these pads out every three track days.

Available Track Day Pads - Compared

So now having gone through two sets of the PowerStop brake pads... I'm interested in seeing what else is available out there and how it compares. Currently, I'm only getting three track days to a set of front brake pads. That adds a good chunk of change to my track day costs. The powerstop also throws up a TON of brake dust.

I'll document alternative track oriented brake pads for these calipers here and write about my experience with them as I get them.

Current brake pads I've been able to find but not yet test:

  • Hawk HB910G.590 - DTC-60 - $200 a set
  • Hawk HB910U.590 - DTC-70 - $230 a set
    • Medium/high wear ?
    • Notable braking power
    • Modest cold braking power
  • EBC DP51210NDX  - "Blue" Track Pad - $120 a set
    • Medium/high wear?
    • Good street manners ?
    • Supposed/reported brake fade above 600 degrees?
  • EBC SR-21 or EBC SR-11 (no part number yet)
    • Very low to low/medium wear ?
    • Not so great street manners, intense initial bite
    • Supposedly ultra low dust.

Answers to Commonly Asked Questions:

Now that I've done this write-up and am sharing it a bunch, I get a decent amount of questions. Some I never though to address as to me they are obvious, but eh you don't know what you don't know when research this, so I'll get all the questions and answers here.

Q: Can I use a rotor size different than 14"?

A: You cannot. You need 14". 14.125" would actually be ideal, but 14" is the biggest I could find.

Q: What brake bracket did you use in the front to make this work?

None. The "bracket" if you will is built into the body of the Cadillac Brembo Caliper. You will remove your OEM bracket, and just bolt the caliper directly onto the kunckle, with the appropriate amount of spacers to clear the rotor.

Q: Will this fit under any 18" wheel?

A: Wheel fitment is tight. I would say that unless others have confirmed it will fit a big brake kit, presume it won't. To test fit your wheel as cheap as possible, purchase just one caliper, remove OEM caliper, and bolt in the new one, don't bother breaking any brake lines or anything. Try and fit the wheel over it. If it clears, congrats!

Q: What about brake balance front to rear?

A: Good question. While I did not test this, this presumably adds more braking power up front. Given this is where the lions share of the braking power on most vehicles is at, should be fine. However, I went a step further and use C6 J55 / Z51 rear brake brackets and rotors. This let me upgrade the rear brake diameter as well, again increasing cooling and presumably bringing some balance back to the car. I cannot guarantee any of this though as I did not do any testing of this.

Q: How much does that pad overhang matter?

A: Per my testing, it does not, but bear in mind I am not a professional. I went a bunch of street miles and all of the above testing and three track days on a set of pads. The overhang, which is only minorly significant at 2.66mm, did not interfere with driveability at all and as best as I can tell influenced nothing.