gkull

You got me thinking about this. So I went out and grabbed one of my stock 79 front rotors off a stack. It has been resurfaced and is ready to install on a vette with stock brakes. It weighs in at exactly 19 pounds. I had to look around for a colman 13.06 i had saved and it is worn from a race weekend with a visible ridge around the outer lip. It weighs in at nearly 3 #'s lighter at 16 pounds 1 oz.

Lets add in the aluminum hat and bolts with safety wire and call them at nearly equal in weight.

The Wilwood 8165's I'm using now even weigh less than the colmans because of the different diameter hat. You called it 12.3 almost 4 pounds lighter than the colman

I'm not sure where you came up with the 8.8 pound stock when my weight is 19 pounds

ignatz

I just happened to have two originals sitting around. On my bathroom scale that comes to 37 pounds, so I agree with your weights.

69427

The weights are from the Wilwood website (I didn't pull anything out of the air).

Please go back and read post #23, and the second paragraph of post #38. Let me know when you've read them, as I noticed a spelling error in post#23 and I'm itching to correct it.

The calculations are regarding the brake rotors on your car and mine, and the reasons why I'm running 11.75" rotors.

gkull

Stock size 11.75 with aluminum hats like jason stanley are indeed lighter than a 13.06 aluminum hat model. but both weigh less than stock 19 pound rotors by far.

69427

I agree. But did you go back and read my prior posts as I mentioned?

gkull

Yes, I m not sure what I'm missing. I was just very happy with my new lighter brakes. I also have the light weight billet aluminum rims

Your special 11.75 like Jason Stanley's weight 8.8 pounds

69427

My point of asking you to reread (or perhaps, read) my prior posts is that I never made the claim that stock C3 rotors weighed 8.8 pounds, as you put in bolded letters in your post.

gkull

With all the moment of inertia put aside. The reason for getting bigger brakes was because I would have brake failure within a few laps with stock brakes even with 3 inch ductwork and 600 degree motul fluid


So to use 8.8 pound small rotors was not an option they would fail even faster

I was looking at 14 inch but I couldnot find a kit

Big2Bird

http://www.wilwood.com/BrakeKits/Bra...tte&option=C-3

I don't know how good they are, but this is 14".

gkull

That kit was not available 12 or more years ago when I did the upgrade. Also i see on your posted kit the calipers are much smaller than mine. I have the Grand National calipers with 5.40 sq inches of piston area VS 4.04 sq inches or about a 25% reduction in clamping force

69427

Tons of guys successfully ran C3s with stock rotors and calipers in IMSA and SCCA "back in the day". Outside of extra vehicle weight, what is the reason your car has higher demands on those brakes than Corvette race cars years ago?

gkull

RedVettercr just showed you some what of what he did with J-56 and 12 inch rotors. They were so failure prone that they learned to install titanium thermal blocks between the pads and pistons. That is in lower class vette racing. You get up to the greenwood vettes Like I worked on and they all had world class aircraft inspired brakes like Alcon. the same thing as the fastest 24 hour racing cars from Europe

I worked around historic race cars for 10 years and some of them had extensive log books of testing and qualifying from back in the day. Their lap times are substantially faster now because of tire technology

redvetracr

36 vintage races and mine never failed except for the one time I experimented with O-ring pistons, complete failure, I also never used any type of titanium thermal block on my car.

gkull

I thought you had the thermal block titanium pucks. Sorry i looked into them from dontov racing for modified j-56. Local track and Miller race track near Salt lake city has a 3000 foot main straight . The high power cars were over 200 mph. I went to a Moto GP race and the bike guys were doing like 214 mph

69427

That's interesting, but irrelevant. I asked about your street car. Again, outside of being a heavier car, what is going on that your street car has higher brake demands than previous race versions of our cars?

gkull

Back when I had stock brakes with some of the best pads they scared me trying to brake from high speed. Over 150 mph stock brakes barely seem to slow you down and some where around 125 my rear tires might begin to alternately lockup and you would see blue smoke and black stripes out the rear view mirror

Around 80 the front tires would finally lock up and then you could finally let up some of pressure on the brake pedal

The first time it scared me and I started looking for alternative braking ideas

stock brakes are okay in Stock vettes because they can't go fast enough to exceed their ability

roscobbc

My '68 has 18" rubber on all four corners - I'm using 'O' ring seals on stock calipers - I have no power assistance - I am using Hawk HP+ pads. Everyone says that stock brakes on C3's are fine - and perhaps they are (on cars with 'old school' rubber and lower hp engines) - I'm just not convinced - compared with current day cars IMHO the brakes are barely adequate - however until someone can do a direct like for like measured comparison with two cars - one with a stock brake set-up and 'old' tyres and one with 18" or 20" rubber, big discs and calipers I'm not prepared to spend a huge bundle of cash on upgrading the brakes.

pauldana

What you need, if you want to stop faster... is the Wildwood adjustable distribution valve with the knee brake point...

Currently you only have about 30% stopping power in your rear wheels, this is due to the distribution/proportioning valve, This stopes your rear wheels from locking up and putting your car into a spin.

it is well under powered so as the rear wheel will never lock up and any standard combination of tires will work and GM will never get sued.

This proportion is way off for safety, and then you go put wider tires on the rear and then its even further off

When you add this valve and adjust it correctly, it will in fact shorten your stopping distance.. the size of the brakes will never have anything to do with stopping distance... just how long you can use them before they fade..

I road race, as well as my 2 sons... standard brakes will over heat very fast, boil the fluid and then start to lock up or completely disappear.

We were out racing the canyons one day last year, middle son runs a highly modified C4, suspension engine ... but he did not have his new BEAR brakes on yet... at the end of the canyon, my C3 was perfect, my sons C5 with C6Z brakes perfect, the C4... brakes were gone, to the floor... wait about 30 minutes to cool,,, brakes back... he changed them out the next weekend.

Big2Bird

I finally got some time off, and installed the Coleman rotors and alum hats, and the Wilwood units on the front.
I noticed they were not square to the world.
I removed the calipers per TimAT's idea, and measured the caliper brackets.
Both brackets were 1.06" from rotor to mount point at the top. (Tight to the spindle).
One was 1.08" at the bottom mount point, while the other was 1.11".(At the lower outboard point)
This helps to explain the taper in the old pads.
A few sledge hammer blows later, they were all 1.06"
Remounting the calipers showed equal spacing between calipers and rotors.
I always wondered about J-56, now I know. The stock brackets can and will bend, and need to be checked.

gkull

Anbody kind of east of the Rocky Mountains just don't understand "Mountainous roads" You from Florida, you don't realize mountains with such steep long grades that they build truck run off areas. 6 and 10 % grades. I've shut off my Vette and coasted in neutral before at up to 90 mph continually hitting my brakes for 14 miles. Locally I've come off the hill in my 4X4 and it fills the cab with burning brake smell

It is a @4500 foot drop from the mountain top to the valley floor. My 3000 pound vette does very well with bigger thermal barrier caliper brakes