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Project C7 Corvette Stingray Z51: Improving Stopping With a Chevy Performance Big Brake Upgrade Kit

by Mike Kojima

 

When we did our baseline test of Project C7 at Buttonwillow Raceway configuration 13 CW, we were pretty impressed with the stock Z51 Stingray's on-track performance. We felt the chassis was set up pretty well for the wheel and tire configuration that came on the car, and the whole chassis calibration was matched to the amount of tire the stock car had and the power level of the engine. 

The only issue with the car we had at this point was the stock Z51 brake package in absolutely stock condition under racing conditions. Our test driver, Karla Pestonik, was able to induce brake fade after several hard laps and had to switch to a brake management driving strategy to not completely fry the stock brakes. This and a lot of traffic hampered her from getting a really good lap time. 

You can check out Karla's driving impressions here!  Project C7 Corvette Stingray Z51 Baseline Track 

Our Corvette came with the medium size of three possible brake options on the C7. You have the base brakes, which are probably suited for older guys going on brisk morning drives to the golf course. The Z51 brakes are the medium size option, which our car is equipped with, that are great for the autocrosser and canyon runner, but probably need a trackside switch to a racing brake compound for serious track use.

Finally, there are the Z06 size brakes which are the C7's world-class brake option. They are truly large brakes- the size of many race car brake systems. You can refer to the table below to reference the size of the various factory brake options. 

 

C7 Brake Configurations Base Z51 Z06 (non-ceramic)
Rotor Diameter (F) 320mm 345mm 371mm
Rotor Diameter (R) 338mm 338mm 365mm
Rotor Thickness (F)            30mm 30mm 33mm
Rotor Thickness (R) 23mm 23mm 25mm

 

Upgrading the brakes on a high-end modern car can be really tricky. The brake system is highly integrated into the car's electronic controls.  Messing with the brake piston diameters and overall area, pad area and rotor diameter can wreak havoc on the car's ABS, electronic brake force distribution, traction control and stability control systems. On a car as sophisticated as the C7, the programming for these systems is multi-layered and very complicated to give a lot of user adjustability and to make the systems seem transparent to the driver.

For this reason, we turned first to Chevy Performance for their factory engineered brake upgrade system for our C7. The fact that the system is factory engineered gave us a lot of confidence that we would not have issues with the cars sophisticated electronic controls.

Read more about our Project C7 Corvette Here!

 

The Chevy Performance big brake kit is very similar to the base Z06 Corvette brake system; it uses 371x33mm front rotors and 365x25mm rear rotors. These bigger rotors are paired up with big calipers and brake pads made by Brembo.
 

The Chevy Performance front brake is a work of art with its huge 365mm rotor and big six-piston Brembo caliper.
 

The Chevy Performance front caliper is made by Brembo to OEM specs, so it has all of the durability features like dust boots and anti-corrosive surface finish treatments that many racing calipers don't have. 

 

 

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Comments
ginsu
ginsulink
Thursday, September 21, 2017 6:45 AM
Such nice calipers, it's a bummer the monoblocks didn't incorporate an internal hydraulic feed line. I always think the external lines are a bit tacky in the looks dept. It's not always about looks though. I'm sure the performance doesn't really suffer much anyway, it might even be better because I'm not sure you could do it with with a monoblock caliper anyway (how do you internally machine that feature?)
SM_Clay72
SM_Clay72link
Thursday, September 21, 2017 8:04 AM
A little surprised that they did not use a aluminum drum/hat in the back or an aluminum drum/hat with steel liner.

Nissan Z cars and CRXs ran aluminum drums in their day for all rear braking duties.
Mike Kojima
Mike Kojimalink
Thursday, September 21, 2017 8:31 AM
The monoblocks on my evo and GTR have external lines as well. I wondered that as well.
Mike Kojima
Mike Kojimalink
Thursday, September 21, 2017 8:34 AM
My Z32 had a steel drum stock, I had an alloy drum/hat with a steel liner made back in the day. Aftermarket Brembo and Stoptech have a 100% aluminum drum but that probably won't pass GM's OEM level validation for durability or perhaps high-speed deployment testing.
spdracerut
spdracerutlink
Thursday, September 21, 2017 8:46 AM
On the rear rotor, I'm guessing durability in hard use as to why there is no aluminum. For sure, the steel is needed for the rear drums. Steel liner in an aluminum hat could pose fatigue issues under severe thermal cycling due to differences in thermal coefficient of expansion. So track use. I imagine a steel liner could come loose from the aluminum hat. Though... they probably could have figured out a solution but it just cost too much.
Dan DeRosia
Dan DeRosialink
Thursday, September 21, 2017 10:17 AM
I just have to say... I love that we live in an age where Chevy(!) is selling that as an upgrade part for one of their street cars.

The steel drum in the rear... just from eyeballing, in addition to what everyone else said, it looks like there's not a lot of thickness to do a steel liner for an aluminum carrier too.
SM_Clay72
SM_Clay72link
Thursday, September 21, 2017 12:59 PM
Yeah @mike You probably nailed it as a safety, high speed deployment type thing.
ThisGuy
ThisGuylink
Thursday, September 21, 2017 1:52 PM
Dan, If you look back onto the mid 80's racing was a whole different game, you had series like the Playboy Endurance Championship which in 6 months, 6 races, totaling 94hours!!! The Corvettes dominated and these were in Showroom Stock classes!!. They used stock equipt brakes with more aggressive pads. Chevrolet didn't find a need to offer upgraded parts.
bjokumura
bjokumuralink
Thursday, September 21, 2017 2:08 PM
Interesting, the front brake on the base model (which I have) is larger than the rear, which implies inducing over-steer under braking. But the Z51 and Z06 have larger front and smaller rear which implies inducing under-steer under braking. Does this mean that some chassis components need to be upgraded as well to keep the electronics working normally after upgrading the brakes on the base model?
bjokumura
bjokumuralink
Thursday, September 21, 2017 2:09 PM
I mean, "the front brake on the base model (which I have) is smaller than the rear"
Mike Kojima
Mike Kojimalink
Thursday, September 21, 2017 2:11 PM
Cars are bigger, faster and heavier now. Tire technology has vastly improved as well since then too all put more load on the brakes.
ginsu
ginsulink
Friday, September 22, 2017 7:25 AM
I haven't seen these for automotive application before, but I've always drooled over the nickel surface treatment on these guys. Has a cool 'Terminator' look, that I've always liked.

"In the GP4-RX version, the pads slide within the caliper body on special guides machined directly into the caliper body itself. This solution has made it possible to eliminate the pad pins. The GP4-RX is the first ever product to use a surface treatment adapted from MotoGP.

As well as giving the caliper an extremely attractive look, the nickel coating has made it possible to further reduce the already narrow machining tolerances, bringing benefits in terms of both performance and precision."

Your Image
ginsu
ginsulink
Friday, September 22, 2017 7:38 AM
Well, it took forever but I finally found them. I have no idea how they machine these but AFAIK it's limited to F1 so good luck getting any info on production.
Your Image

ginsu
ginsulink
Friday, September 22, 2017 7:39 AM
Your Image


ginsu
ginsulink
Friday, September 22, 2017 7:41 AM
Oh, that's a bummer, I think they still run an external brake line. Oh, well. Even F1 suppliers can't do magic.
Mike Kojima
Mike Kojimalink
Friday, September 22, 2017 9:16 AM
performance friction and willwood do nickel on some calipers.
daleong
daleonglink
Friday, September 22, 2017 11:47 AM
Hi, how did the stock Z51 wheels fit over the bigger rotors and calipers? GM performance states on the product website "These brakes will not fit under stock base or Z51 wheels. Requires a minimum 4mm wheel clearance between the outboard face of the caliper and the inner wheel spoke."

Did you guys just disregard the 4mm guidance? :)
erikl
erikllink
Saturday, September 23, 2017 6:50 PM
can you post a link to the kit? The Chevy Performance link is too huge to sort through. How much is the kit is what I am looking for.
Mike Kojima
Mike Kojimalink
Saturday, September 23, 2017 7:46 PM
We had to run a spacer
Jeff Naeyaert
Jeff Naeyaertlink
Saturday, September 23, 2017 8:06 PM
@erikl HERE you go... google the part numbers to find prices from various distributors.
V6er
V6erlink
Sunday, September 24, 2017 5:18 AM
I have two questions:
1) you state (multiple times) that are of friction pad is much bigger than stock pads.
Why is that important/useful? Correctly if I'm wrong, but every single formula I have seen(regarding brakes) takes into account friction coefficient, location of piston/s and are of them(pistons).
Only thing that comes to my mind - is thermal "capacity".
2) regarding brake electronics. Do you know where it is possible to read(book or good internet resource) in more details about brake electronics and their software?
P.S. you probably have already heard - but your site and articles are great! :)
V6er
V6erlink
Sunday, September 24, 2017 11:18 AM
area, sorry for typos :)
spdracerut
spdracerutlink
Sunday, September 24, 2017 1:43 PM
@V6er, bigger pad = more mass = more thermal capacity = reduced temperatures. As far as brake electronics, it's gotten WAY more complicated. Back in the day, it was simple ABS which just kept the wheels from locking up. Now depending on how good the engineers are determine how the car handles. So a situation is full braking while turning.

The brakes are now used for stability control and traction control. So a number of FWD cars (Focus ST comes to mind) don't use a limited slip diff but instead use the brakes to control wheel spin. Same with some RWD cars like a ~2007 Inifiti G35 I took on a road course. Car came in with the rear brakes smoking as they were trying to control wheelspin powering out of corners.
erikl
erikllink
Sunday, September 24, 2017 4:59 PM
Jegs sells the front kit for ~$2300. Not as expensive as I thought but a chunk of change. I wonder if you could do the fronts initially and the rears later? Probably not well balanced and cause the computers to get confused. What about sourcing the parts from a junk yard? Lot of research and work to find them I imagine.
spdracerut
spdracerutlink
Monday, September 25, 2017 9:25 AM
@erikl, likely need to do both front and rear at the same time to maintain the proper brake bias. If you can find a wrecked Z06 or Grand Sport.... If any car is going to be tracked, I highly believe larger brakes are a smart investment and should be one of the first things done. Granted, this is car dependent as a few cars actually do come with adequate brakes from the factory (Evos, higher trim Porsche 911s, etc). But all it takes is to be going down a straight at 100+ mph and have the brakes fade on you while trying to slow down for a turn to leave some brown stains in you pants and have you going straight for your credit card for bigger brakes. Happened to me back in the day, never again.
RedX
RedXlink
Tuesday, September 26, 2017 3:05 AM
Very nice detailed camera shots. It would be great if higher resolution pictures were available to readers.
warmmilk
warmmilklink
Tuesday, September 26, 2017 12:04 PM
for those looking to buy this kit for their C7's, I think the cheapest place to buy it is on Amazon, but you don't buy it as a kit, you buy all the parts separately. A friend of mine did this a year ago, I don't remember exactly how much he paid but it was considerably less than $2300. IIRC it was pretty close to what I paid for my front Wilwood kit for my Miata.


about the internal crossover tube, there are a decent number of aftermarket calipers that have this, but as far as I know none of them are monoblock, just standard fixed calipers. That being said, unless you're doing professional level racing, you're not exactly gonna benefit any going to AP's monoblock caliper with internal passages vs their standard Radi-CAL bolted caliper with internal passages
warmmilk
warmmilklink
Tuesday, September 26, 2017 5:26 PM
My friend with the C7 felt strongly about pointing out that the Z51 rear rotor is 18lb while the Z06 is 24.6lb
Mike Kojima
Mike Kojimalink
Tuesday, September 26, 2017 6:30 PM
Larger and thicker rotor.
Mike Kojima
Mike Kojimalink
Tuesday, September 26, 2017 6:37 PM
V6er, the amount of brake force that the caliper alone can generate is the coefficient of friction times the area of the pad, times the clamping force.
warmmilk
warmmilklink
Tuesday, September 26, 2017 10:08 PM
The front rotors are also lighter for the Z51 vs the Z06. 20.2 and 23.8 respectively.

Weights and links to pics of stuff on scales can be found in post 3 of this thread
https://www.corvetteforum.com/forums/c7-tech-performance/3829445-16-z51-arctic-white-track-build.html?styleid=147
V6er
V6erlink
Tuesday, September 26, 2017 11:32 PM
Mike Kojima, will recheck my sources. Because, if I remember correctly - are is from brake caliper piston, not pad area (pad perimeter doesnt get that clamping force that brake calipers piston "gives").
Mike Kojima
Mike Kojimalink
Tuesday, September 26, 2017 11:40 PM
I am talking braking force not clamping force. Clamping force is a function of piston area.
warmmilk
warmmilklink
Thursday, September 28, 2017 12:57 PM
so... uh... you guys gonna fix the claim that the Z06 rotor is lighter than the Z51 rotor on page 6?
Bba
Bba link
Thursday, September 28, 2017 6:35 PM
Dear Mike, performance friction and Wilwood only copied a small company that has been making internal fluid transfer calipers for many many years. TBM Brakes. They invented the zero drag caliper that performance friction claims they have. To be honest you don’t need 6 pistons to stop better, You need piston area to do that and and you can accomplish both caliper rigidity and prevent par taper that is caused by caliper flex from a long mono block caliper. One of the best kept secrets out there for many years.
Mike Kojima
Mike Kojimalink
Thursday, September 28, 2017 6:59 PM
Long, large area pad, multiple staggered size pistons control pad loading and control taper wear better. More pad area, longer life and if designed right, the potential to generate more braking force. What I wrote very clearly states that Wilwood and PFC have nickel finished calipers. I said nothing about internal fluid passages.
Bba
Bba link
Thursday, September 28, 2017 8:35 PM
That is correct. You said nothing about that. But the general public is under the assumption that you need six pistons in order to create better braking. And that is not true four larger size Pistons with more rigidity and a thicker pad will result in much more consistent braking.
Mike Kojima
Mike Kojimalink
Thursday, September 28, 2017 8:44 PM
You cannot say that in absolutes. The right answer is to design a brake system with the right capacity and the correct mechanical and hydraulic balance for the intended end use. It is not true that a large piston 4 piston caliper is always the best unless you are in the business of selling such systems.
Bba
Bba link
Thursday, September 28, 2017 8:52 PM
There are formulas that say it’s a good theory and then there is of course practice. I didn’t write this to sell the product. I use it and know racers that do. I sound silly when saying this but you should at least head over to their site and read the technical articles. Again. I don’t own stock nor sell their products. But I have done technical metallurgical processes for them and bought from them because of what I saw. I hope I haven’t been rude in any way. It was not my intention.
Bba
Bba link
Thursday, September 28, 2017 9:19 PM
Love the magazine BTW..
warmmilk
warmmilklink
Friday, September 29, 2017 11:06 AM
@Bba
I don't understand the claim that "thicker pad will result in much more consistent braking". I've seen a few kits on the market that offer smaller surface area than a stock pad but a thicker pad and they're saying its "volume" thats important. Ok, well thats all fine and dandy while the pad is new, but what about when the pad is worn down to its last 2-4mm? Then the bigger surface area pad has more volume. Or am I expected to never use a pad past the 50% point?
Bba
Bba link
Friday, September 29, 2017 4:14 PM
@warmmilk Well the thicker pad is for longevity... The rigidity of the caliper and the piston surface area will give you the clamping force you are looking for in a given application as well as lack in pad taper. There are of course other considerations here. The size of the rotor is an important factor. As Mike said, a well designed system will give you the proper feel and braking capacity. It's when things get HOT and aluminum starts to lose its rigidity is when the consistency comes to play. The point is to make fluid transfer very efficient for quick reaction feel and the drop in drag. drop in drag means less heat buildup as well. The transfer tubes usually suffer from hysteresis. A man Mike knows really well Robbie at robispec uses these brakes on his projects.
engineered
engineeredlink
Sunday, October 01, 2017 8:39 PM
Could another reason for an external line be to reduce heat soak from the caliper to the brake fluid?
KP1.5
KP1.5link
Wednesday, October 18, 2017 1:33 PM
@warmmilk Fixed! Thanks for catching that for us!
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