size and benefit? dimenishing return?

[sharp67]

With disc brakes at what point does the diameter of the disc have diminishing returns? What I would think is, at some point the diameter starts to have adverse affects with moment of inertia, unsprung weight, etc. Additionally, with calipers, two, four, six, piston are the benefits outweighed by the additional cost? for an aggresively driven street car and occasional track day car where is the cutoff? does going from four piston to six piston gain you an additional 5, 10, 20 feet of stopping from 60 or is it more a matter of fade? would the money be better invested in fluid recirculators? Ive got a 67 camaro that will be 95% streer driven, and im trying to figure out how far to take it. the wilwood 4 piston kits are half the price of the six piston kit is the money spent worth it? I really like the look of the six piston setup but I dont want to blow an additional $700 bucks to pick up 2 additional pistons if the benefits are limited? Looking for thoughts or experiences so i can make an informed buying decision. Thanks. Jay.

[Apogee]

Just my $.02, but those are a lot of subjective questions that each person must answer for his/her self when evaluating their braking needs. Depending on the parameters you choose to prioritize (cost, weight, brake torque, availability, aesthetics, etc), the point of diminishing return will tend to vary.

How much brake one needs versus how much one wants also tends to vary, with the latter typically being more than the former by a significant margin IMHO.

Are 2-pistons worth $700? They are to some people, just as $10K kits are worth it to others. That $700 starts to look cheap if you compare it to buying parts twice to get what you ultimately wanted in the first place.

Tobin
KORE3

[sharp67]

iVE ACTUALLY BEEN LOOKING AT YOUR SITE AND THINKING ABOUT THE DIFFERENT SETUPS YOU HAVE. I printed the fitment forms and sized them appropriatly to scale. Ill be seeing what i can get away with on my 17" rims tonight. any specials for pro-touring.com guys? Are the performance gains significant when you go from the c6 calipers to the c6zo6 calipers. how much quicker will they stop you? Thanks again. jay

[Apogee]

All of our kits are deals ;)

The general performance differences between the C5/C6, C6 Z51, and C6 Z06 setups are fairly small. They all perform very well with each kit having its own pros and cons associated with it. Bang for the buck, the base level C5/C6 kits are very tough to beat. The larger rotor kits tend to have more thermal mass in the rotors and as such can take more severe beatings for longer periods of time before tapping out. The also cost more, weigh more, and require larger wheels...but most would agree that they look better too.

Stopping distances are typically going to be determined in large part by your tires and how well your car hooks up under braking. This is a function of your tire compound, weight bias, COG, spring rates, suspension geometry, etc in addition to the surface you're driving on. Getting any car to stop in less than 120 ft from 60-0 is a feat of no small proportions. Getting a car to do it 10 times in a row with minimal cool down time is where big-brakes come into their own and prove their worth.

Just like anything, there are a lot of options when it comes to brakes and no one right answer. Forums such as this are invaluable when it comes to getting lots of opinions on what's out there, so keep your ears open and keep asking questions but keep in mind what's important to you and you should be happy with whatever direction you end up going.

Rubber side down,
Tobin
KORE3

[Skip Fix]

Like Tobin said tires are often the limiting factor.

One of the late model GTO guys I bought his '05 calipers/brackets and rotors(my 04 has smaller rotors and a less beefy caliper) swapped on larger Harrop 6 piston/4 piston system. Same road same tires almost the same stopping distance, but also as Tobin said with multiple high speed stops it would probably outperform the stock GTO system-which is pretty similar to the C5s.

[Turbo67camaro]

Please correct me if I'm wrong, as I'm a noob.

But I've heard that more pistons = less petal effort.

This is likely to heavily influence my upcoming disc brakes choice.

I'm building a turbo based engine. I want to keep engine clutter down. Also, with boost, vacuum is lost, which is needed for traditional brake boosters.

More pistons in brakes decreases the need for power brakes. No power booster = more room in engine compartment, vacuum not needed, and more money for better brakes or other stuff.

Will I be happy without power brakes ? I'm guessing so if I go with 13 or 14" brakes with 6 pistons in the front, decent brakes in the rear, and the right master cylinder.

P.S. Having some mechanical engineering education, I do know that your brakes don't stop the car. The friction between your tires and the road stop the car (hence above comments make total sense). Good brakes are all about managing heat and providing durability.

[silver69camaro]

But I've heard that more pistons = less petal effort.
Good brakes are all about managing heat and providing durability.

No. Piston area as a direct relation to effort, no matter how many pistons there are. The two big benefits to multiple pistons is more uniform force applied against the brake pad, and often better pedal feel...which helps the driver modulate the brake application at the threshold of lockup.

Good brakes are all about managing heat and providing durability.

And threshold braking modulation, as above.

The downside to multiple piston systems is higher initial price and more parts to fail.

Off topic: Turbo 67, did I see your car at the XXX Root Beer show last year in Issaquah? I thought I saw a turbo'd small block at some point.

[Turbo67camaro]

Off topic: Turbo 67, did I see your car at the XXX Root Beer show last year in Issaquah? I thought I saw a turbo'd small block at some point.

Sadly, no. My car was in pieces.

Good news is that I found a good place to get my car done (Cobweb Specialties Rod and Custom in Edgewood, WA), and we're jamming ! I expect to be driving it this summer, and I'll attend some of the local events. Hope to see you around !

Thanks for the info. I'm trying to absorb as much of this stuff as I can as quickly as I can to make the best design and purchasing decisions.