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Z51 Brake questions-

  • Thread starter Thread starter OLDGOAT
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OLDGOAT

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I would appreciate some help with some basic knowledge about the Z51's brakes. I apologize that some of these questions are very basic regarding cross drilled rotors but that's where I am at. Any insight/knowledge shared is appreciated.

1/ Is it correct that the basic advantage of cross drilled rotors is that heat is dissipated faster thus reducing brake fade in extreme conditions?
2/ In less than extreme conditions do cross drilled brakes perform any better than solid? Worse perhaps? Or....does the removal of all the rotor material by drilling the holes result in lower performance due to less actual surface area? Is this perhaps the reason that the size of the Z51 rotors is larger than standard?
3/ Does the removal of material in drilling the holes result in more warpage than expected from standard rotors? I understand that rotor warp was a problem on the C5 and that rotors were beefed up on the C6. Does the cross drilling compromise this? Do cross drilled rotors wear out faster than standard due to less surface area?
4/ Most who comment on the Z51 brakes seem to highlight how they "look"...larger etc. How do they actually perform vs. standard in normal ( for a vette ) driving conditions? Yes, on the "track" they would be better...how about "spirited" street driving?
5/ These question relate to the decision whether or not to choose the Z51 option. Yes, the brakes look neat. Yes, it's a value adding performance option. Yes, there are other upgrades in the package. However, there has also been comment in this forum about ride of the Z51 being rather harsh and brake noise ( which may be present on standard as well as Z51 ). It would seem a no brainer to select Z51 for almost any C6 ordered. But will this option really give added performance that will be noticeable in normal driving....and, are there downsides?
6/ Lastly, for someone who views the Z51 option MOSTLY but not entirely about getting better brakes what can we expect from aftermarket providers of upgraded brakes for the C6. Will these providers give us brake options for the C6 that are BETTER than those on the Z51? And how will the cost of aftermarket brake upgrades compare to the $1500 cost of the Z51 package? ( of course, for the real performance seeker I suppose that Z51 could be worth this relatively small amount of extra money for all the non-brake upgrades EVEN if they planned to upgrade the Z51 brakes )

I wish, like others have mentioned, that the Z51 option was "unbundled" so that portions of the package could be selected and perhaps combined with other ride options etc.

As an aside....thinking about the Z06 we have to believe that it will have substantially better/larger brakes than even the Z51? Perhaps the present Z51 brakes will become standard on the C6 next year with the much better Z06 brakes as the extra cost option? ( scratch this thought if the Z06 wheels are different and incompatible with the standard C6 )
 
OLDGOAT, I am gonna guess you're referring to the new C6? There is more to a z51 on any year than just the brakes. On the C6 it includes stiffer springs, different tires, I believe it also changes the roll bar rates/diameters and the valving of the shocks. Perhaps Hib can chime in to clarify. Are you gonna autocross, track days, race? Or do you just wanna cruise? These questions should help you in your decision. Good luck.

On you questions re: cross drilling. The basic concept is to allow better heat dissipation and to allow gases to escape the rotor surfaces. Cross drilled rotors can and do crack if severly overheated repeatedly. There is also such a thing as slotted, but not drilled rotors. I am not looking to start a rotor war, just pointing out a few differences.
 
I'm interested to read the answers to those questions.

From what I understand, drilled rotors are mainly for dispersing heat. I'm sure it would also depend on the quality of the rotors themselves. There was a member here who contemplated drilling holes in his rotors! Needless to say, we all suggested that he not do that. :(
 
Z51 Better yes...but BEST? Depends on application?

jwilliams said:
OLDGOAT, I am gonna guess you're referring to the new C6? There is more to a z51 on any year than just the brakes. On the C6 it includes stiffer springs, different tires, I believe it also changes the roll bar rates/diameters and the valving of the shocks. Perhaps Hib can chime in to clarify. Are you gonna autocross, track days, race? Or do you just wanna cruise? These questions should help you in your decision. Good luck.


Yes, I am referring to the C6. Also I understand all the other goodies that come bundled with the brakes. These are the items I wish we could select from to build a more custom car. A C6 for me would be a cruiser. Simply a car to enjoy driving on the roads and almost certainly not on a track or that gymK.......thing I can't even spell!

I start from the premise that the standard C6 is ONE HECK OF A SPORTS CAR. I understand that the Z51 would make it "better" . However, and this may seem a fine point, better does not always mean "best" for a given application. ( since the base car is a wonderful machine without the Z51).

It's tough because some people seem to be saying you have to have Z51 to have a great handling fun C6 for the highway. Yet, these same folks will admit that the base C6 is probably the finest handling ( and stopping ) vette ever built.

It Z51 would make my everyday cruising more enjoyable I will go for it. However, I want to understand the ACTUAL expected benefits as well as the potential downsides to the option package if any.

I guess my mindset is that if the average aspiring vette owner bought a base C6 with NO options of any kind they would be getting a fantastic car. With this as a starting point it makes selecting options like Z51 a decision for thoughtful consideration. If the base C6 were a dog then it would be different. However, for example, one of the items in the Z51 package is the closer ratio on the lower gears. So the Z51 owner will get a published 0-60 of 4.1 sec instead of 4.2 sec. Well, 4.2 sec is VERY fast for a street car....anyone disagree with this? Should I get the entire package with stiffer ride and all for .1sec in 0-60?

So I am simply trying to get a feel for Z51 brake inprovement....is it in the .1 sec range ( which I consider trivial ) or is it a major improvement?

thanks for your input, goat
 
HI there,
The Z51 or J55 braking system is more than just rotors and pads.
The rotor sizes are larger front and rear. Pad composition has changed also.
The cross drilling is not so much for cooling as they are for fade resistance.
The anomoly is called out-gassing, and this is what brake pads do when they get very hot when braking hard. The gasses that eminate from the pad usually will be sandwiched between the pad and the rotor. This reduces the contact between the pad and the rotor. Thus, causing what is known as brake fade.
Cross drilling or slots both help reduce or eliminate fade by giving these gases somewhere to go. In some instances, the large amount of cross drilling will lead to a weight reduction.
The performance of the braking is directly a result of tires and brakes.
As far as the rest of it, such as the acceleration and road holding, the transmission, swaybars, shocks and the tires all help in this instance.
If you are not a very aggressive driver, I would suggest that the average driver will not really take advantage or use the extra performance of the Z51 option.
IMO, I can only really see a differerence when I am driving very aggressively.
Allthebest, c4c5
 
From what you've said, OG, it sounds like Oregon roads and your driving would call for a MagRide car with a possible future brake upgrade, IF you don't find the stock brakes suitable, which I doubt. Personally, I would have to have the performance axle.
 

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