Charley Hoyt

Stoptech offers different piston sizes for the z51 (28mm, 30mm, 34mm) and the c6 z06 (30mm, 34mm,34mm). My delema is that my car is a z51 that has z06 body panels, suspension, and wheels/tires. The rear kits are the same. Which is the right front kit to use?

Thanks for the help,
Charley

JDIllon

Call Stoptech!! There technical dept can tell you why the difference and which they would recommend. They are really helpful. My quess would be because of the higher speeds of the Z. Thats just a quess! The Zs caliper has more clamping power. JD

Charley Hoyt

I did call Stoptech.... They recommended the z51 kit because "the rest of the brake system is z51". I know they are the pros...but, that didn't sound quite right. I would think that the wheels and tire sizes would make a bigger difference.

skxf430

You can also check with Zeckhausen. He is a nice guy and very knowledgable about both Stophtechs and Vettes.

fatbillybob

I think it is about managing heat and pad taper and pedal forces. A Z06 still has 100hp on you and that makes for more energy to stop so ST is probably right. The calipers are the same so if you really think you made a bad choice you could change to the other pistons later so it is not a fatal decision. ST has lots of data on vettes and what they need. These guys are really good at what they do. I don't think you have to worry about their recommendation. I'm sure they are right. Look at it this way too. You are running 6 pistons which will arguably control pad taper better than 4 pistons. The ST developed T1 kit on my car is all 4 piston front and rear and the rear calipers are smaller than the front calipers. I can tell you that I am over braked with near zero pad taper. It took me 2 years of racing to burn up the front rotors when I used to crack OEM rotors on the 3rd trackday!

KNSBrakes

The ratio of brake torque (radius times piston area) front to rear is what matters. This is bias

Bias is set to match wheel/tire. If the tire/wheel size proportion from front to rear change that greatly then I would assess what that change does and move on.

This is a relatively simple piston area/effective radius calculation - need help?

X25

They are trying to keep the OEM balance, which is why they recommended Z51 piston sizes. Now, you could buy StopTech front BBK for Z06, and replace your rear calipers with stock Z06 calipers (for very cheap), and tell your wife you're very smart about using your money

Charley Hoyt

I think your right Carl. Either kit should be fantastic...but when I am spending this much I want to make sure it is right.

Charley Hoyt

The part I don't understand is that If I have switched to Z06 wheels and suspension doesn't that affect the Brake Bias requirements? Or is a matter of there being a difference inthe master cylender or ABS? To clarify a little, I am going with ST-60s on the front and ST-40s on the back. The rear kits are the same for both kits.

Charley

Vettechris996

It (wheels and suspension) doesn't really affect the bias requirements that much. What is most important here is relative piston diameters (master and piston area at each caliper) since the brake system works on hydraulic principals those diameters dictate your bias (along with effective radius) to a much greater extent.

X25

I see your point. Yeah, if you've switched to Z06 wheel/suspension set-up already, I don't see the point of using Z51 spec StopTechs either. I'd go with the Z06 package.

JDIllon

And you think you are going to get better information here!!!
I'm just saying! It just struck my funny. LOL!!! JD

X25

I think he actually could. StopTech is pretty good on technical support, but sometimes vendors/manufacturers fail to read the details in an e-mail, and address your question with a generic answer. If you have the whole suspension/wheel package of the Z06, for instance, you're clearly better of with the brake balance of Z06 as well. The weight balance difference is negligible at best.

Charley Hoyt

I always think it is better to get as much information as possible when solving problems. Also, getting information from people that are heavy users of a product are good data points. When I talked to Stoptech yesterday I was apparently talking to someone in sales. That person said that the z51 kit was the right kit because it would match "the rest of the brake system in the car" when I asked him which parts it would match he couldn't answer. Today I called again and got their tech line.... This person didn't know and turned me over to someone that was very knowledgeable. He confirmed that both models use the same master cylinders and that the z51kit has more rear bias compared to the Z06 kit (he gave me the actual percentage, but i dont remember the specifics) . his recommendation was to get the z06 kit for my application. Either kit would have been fine.... But, I agree with him that the z06 kit is better for my application.

Thanks for the help
Charley

JDIllon

Per my suggestion, call the tech people!!! As I said, I love my Stoptech's and they have always been able to help whenever I needed them. For those that were not able to tell, my other post was joke!!!!!!! Information on this thread has been a great help to me in the past. JD

KNSBrakes

The Stoptech kits generally move bias a bit rearward as most vehicles are a bit front biased for safety reasons.

You can calculate the fr/rr bias by multiplying piston area times effective radius for each axle. Then compare this to the ST kit.