cagotzmann

Over the past 2 years I have been looking at upgrading the performance of my stock 1978 brakes. The car is mainly used for road track driving.

The first graph is using semi-metallic standard auto shop pads.
Max 7.4 G


The second graph is using ac delco organic stock pads
Max 8.95 G


The Third graph is using Hawk HPS Plus Race Pads.
Max 9.2 G


With the metallic pads I could not lock the tires as shown with the steady G Graph. The ac-delco did lock up and was harder to control a smooth stop. The varying G ready shows me trying to threshold brake.
Same goes for the Hawk HPS Plus Pads. The ac delco pads would only lock up at lower speeds and the HPS Plus pads I could lock up and any speed.
As far as brake effort the metallic pads required the most brake pedal pressure, the ac delco required initial hard break pressure then threshold braking, and the HPS plus required little effort but threshold breaking to start with. It was too easy to lock the tires. I am very happy with the Hawk HPS Plus pads. Everything else is stock, calipers and rotors. With these pads the weak link is the tires. They are 255-60-15 BF TA's. I will be adding Michelin Super Sports 245ZR4518's once I find a 18x8 wheel that fits my 1978 without adapters. Anyone else have any brake stories / testing.

I was looking at getting bigger brakes but until I have better tires I don't see the point.

noonie

Interesting results.
Same tires as yours, but using the Autozone cheapy pads (20 bucks), I could lock up at 70mph, don't know about multiple times heated, but I doubt it. Modulated pretty well too.
Of course pavement and temp has a lot to do with it too.

cagotzmann

I can lock up the cheap pads but not stopping from 85 MPH. These tests were stopping from 85 MPH. Total 4 Runs each. The metallic pads were starting to soften by the 4th pass. Ac Delco's were best 2nd and third pass. The HPS Plus were best 2-4th pass. They needed some heating to work best but no change in breaking.

427Hotrod

I've got this one where I did some testing with my stock brakes and then some Wilwoods. It was a lot of fun and interesting!

JIM

http://www.carsandparts.com/Articles...e-braking-test

cagotzmann

Thanks for sharing. What kind of pad material was used during testing ?

427Hotrod

It has the BP-10 Wilwood lining. I don't road race it. I street drive and drag race. It's a very heavy car (3850 Lbs at the line). When I'm drag racing the brakes are cold when I pull to the line...so they need to do all they can on the first hit at the end of the track in the 145+ MPH range. No time for warming them up.

JIM

jb78L-82

Nice Analysis! The C3 brake system when functioning correctly is an excellent system for the street-they can fade though in road racing. Like you, I have a completely stock system with SS calipers and stock rotors BUT use Performance Friction Carbon Metallic pads (for years now) with SS braided steel lines and have found the system to be terrific on the street. Also, like you, I have found the limiting factor for braking to be the stock 255/60/15 tires which are all basically just a standard passenger car tire dressed up with nice white lettering. I switched to SLP 17 inch rims with 255/45/17 ZR ultra high performance summer only tires about 5 years ago and holy smokes did these tires change the braking, steering and handling of the car-I would never use the OEM tires again!

MIKE80

I use a vacuum pump for my booster due to my engine's low vacuum. I have been considering adding hydroboost so I can remove the vacuum pump and should add a quicker response to my braking. My entire brake system is new with all stainless steel lines (solid and braided), VBP stainless steel o-ring calipers, and Hawk HPS pads.

I haven't done any testing, but maybe I'll do a before and after if I do the hydroboost. Tires are 275/40 ZR17 Nitto NT555 Extreme Performance.

jb78L-82

I would be interested in seeing your results since i would not predict any difference in brake performance with and without hydroboost just like there is no brake performance difference between manual and power brakes-hydroboost will only effect the brake feel, not the actual performance which is limited solely to the actual brake components-calipers, rotors, brake pads, and tires. the physics of these basic brake components solely dictate brake performance-no way around it.

0Todd TCE

Temperature range has a huge impact on some of this also. Here's a chart on some of the lower Cf compound street pads which shows the above BP10 as well as some other compounds.



One of the most difficult things is trying to find one pad that does it all. That won't really work out the best as pads are a compromise of things; temps, Cf (Mu), wear rates, rotor wear and cost. For most folks you'll soon find that your best results are pad specific applications.

MIKE80

I think it's a pressure issue that I'm not getting the response I would like to see. Plus, it seems like I need to work the pedal harder than I should. Everything is new and functioning properly. Maybe it's because the vacuum pump needs to kick on every time I apply the brakes, not sure. What I'm thinking is that the Hydroboost should speed up the braking response time with the added pressure from the hydraulics compared to relying on manual or vacuum assist, and take less pressure to work the brake pedal.

But, on the other hand, maybe you are right and it's just me, wanting more out of my brakes.

jb78L-82

It's sounds like in your case that Hydroboost may help since your issue seems to be not enough brake boost from a lack of vacuum and a delay from the external pump kicking on. Let us know what you find.

cagotzmann

Yah the tire issues. I want to run with Michelin super sport 245x45Zr 18
I don't think you can buy the SLP 17" anymore. I am having a hard time finding a nice looking 18x8 0 offset wheel. I don't want to add wheel adapters for road track driving. Its bad enough I have higher maintenance on tires / Pads / Rotors I don't want to add bearings and spindles buy using wheel adapters, I believe the wheel adapters move the load bearing stress to far out from the bearings adding more stress, unless someone can convince me it doesn't matter. But simple engineering tells me other wise. What tires are you running in 17" did you match the overall diameter to OEM's ?

jb78L-82

255/45/17 ZR Kuhmo Ecsta SPT front
255/50/17 ZR Kuhmo Ecsta SPT Rear-same overall diameter as 255/60/15

cagotzmann

That would be good if you could post some results. I think this helps everyone who thinks there brakes are not good enough. I am going to run the same G-Force test using my C6 2010 GS and see how this compares.

cagotzmann

Here are my 2010 GS G's Graph.
Max G's 1.055

Big difference due to ABS a much nicer smooth slow down at high G's

Stock GS Calipers Hawk HPS Pads Michelin PS2 ZP Tires.


So it seems the C3 Brakes could do very well with practice at threshold braking. Next test is when I get better tires.

vette427-sbc

The bearings dont care what spacers you run on your wheels as long as the centerline of the wheel is in the correct spot. If you ran flares and used a spacer to push the centerline of the wheel way out, then your bearings would be under more load. And if youre tracking the car, get some meat under the front fenders! As seen by mike80 and myself, you can get a 275 or 285 tire to fit up front.
HP Plus pads, titanium thermal backing plates, 3" brake ducts and some high temp fluid with manual brakes here. Love everything about this brake system except the weight (and by association of cast iron, the ability to shed heat)

cagotzmann

Adding a wheel adapter is moving the center line of the weight transfer out and away from the fulcrum point the bearings. While the center line of the tread may remain the same with a offset wheel + adapter, but I think it is still moving the load transfer point outward and therefor creates a greater torque at the bearing and wheel assembly. But this may not be enough force to cause any problems with a few inches but I am not sure yet. What did you use for brake ducts ?

Sayfoo

[QUOTE=jb78L-82;1584684733] Like you, I have a completely stock system with SS calipers and stock rotors BUT use Performance Friction Carbon Metallic pads (for years now) with SS braided steel lines and have found the system to be terrific on the street.

I'm looking at these also, but can't seem to get a definative answer as to how they handle when cold.
Your experience right out of your driveway?

Jason Staley

Here are the results from the last time I was at the track in my 76'.

I'm running aluminum calipers (stock size pistons) and stock size rotors with brake cooling ducts and Hawk HP Plus compound. Using fresh DOT3 SSBC fluid. So basically a factory sized brake system upgraded to reduce weight and manage temperatures better.

I have no brake fade yet, but I haven't pushed the brakes to their absolute limits either. I may get it eventually, but so far so good. I'm pretty happy with this system at the moment.

The graphs from two brake zones have filtering to take out momentary spikes, but the table doesn't so there is a slight difference in the numbers. Obviously ignore the one extraneous line where I was off throttle coming into the corner with a whopping 0.2 g's in braking.

And yes, I know, I'm not very consistent yet with my braking. Some laps I feel more daring than others.