JohnAlley

I am in the process of setting up my 2004 Z06 for NASA TTA next year. I have read a lot about the various SS brake lines and am now totally confused. Since I am VERY new to all this any suggestions as to which SS brake lines work best on the C5 Z06

CHJ In Virginia

I have used the Goodridge SS lines on my 03 Z06 for the last 6 years. Totally reliable and help with a good solid pedal. They cost about $120 for the set of 4 lines and are worth the $. Some users reported wheel sensor code problems with the grounding on another brand. No such problem with Goodridge.

gmccreary

I have Goodridge on my 01 C5Z as well. StopTech also makes a good SS brake line.
http://www.stoptech.com/Products/sta...al_lines.shtml

andrewdonald1

I've been running the Goodridge lines on the street for over a year with no problems.

gkmccready

I like the DRM SS lines. They're modular, too, so if you change to a BBK with a different fitting you just buy the fitting and not whole new lines. (I did this going from stock to Wilwood calipers.) HardbarUSA is also selling some fancy coated lines that look nice and keep the grim out of the SS braid.

RacePro Engineering

DISCLAIMER: Absolutely NOT a C5 "Expert" in any manner of speaking.

However, we work all the time with attempting to get brake systems more effecient (not just larger!!) We are not familiar with the Hardbar coated lines mentioned above, but GENERALLY any coating over the metal acts like an insulation, retaining heat in the fluid - a very bad thing!

A number of years ago, when we prepped our 1987 for racing, Earl's made a very nice set of stainless lines that were not braided, and could therefore be cleaned easily.

Ed LoPresti

Solofast

The abraision between the braid and the hose is a bad thing too, and if you get some abraision you won't have any heat transfer between the braid and the hose because you won't have good contact between the two. Then you have flexing in the teflon inner liner and you've back to a sofer pedal.

By the time you get to the hose, the big fittings on the caliber act as heat sinks and you're not going to be boiling the fluid near or in the hose anyway. Besides, the hose itself (not the braided part but the rubber or teflon liner in the hose) is a poor conductor of heat, so there isn't much heat coming out of the hose in the first place.

RacePro Engineering

Let's see - we could test this theory by grabbing hold of a brake line immediately after coming off the track (perhaps not as dramatic at an autocross.) Some heat is being transferred from the caliper, and still a good deal of heat from the fluid itself.

Ed

Solofast

If you aren't taking the heat away, anything eventually gets hot and the conduction from the caliper along the hose is why the stainless steel hoses get hot, the amount of heat transferred from the fluid, through the hose is next to nothing.

The thermal conductivity of teflon is about 1,060 times less than aluminum, and about 65 times less than that of steel. Bottom line is that the number of BTU's that are coming out of the hose through the teflon are very close to nothing, when compared to the other heat rejection in the braking system.

Any of the elastomeric hose materials are excellent insulators, so the amount of heat that comes out of the hoses is orders of magnitue less than the similar area of the caliper. And since the caliper has (or should have) in any racing application a blast of air on it, the amount of heat lost there is literally 10,000 times greater than you are getting from the hose. You can sit down and do a few calculations on it, but it isn't worth the time. Just a quick glance at the relative heat transfer coefficients tells the whole story.

RacePro Engineering

At the risk of hijacking poor John's thread -

I was not in any way comparing the thermal conductivity of teflon, iron, steel, aluminum, kevlar, or any other material. My point was that any metal brake line, encased in something else (other than ice), will retain more heat than one without that casing.

How much more heat? Well, water at 211 degrees (F) is not boiling. Now add one-half-of-one-percent, and presto!

Ed

Solofast

Sorry Ed, but I do think you are missing the point. All of the flexible lines that go from the chassis to the brake caliper are made from elastomeric materials. The stainless braided ones have a sheath that protectes the outside of the hose and helps keep it from expanding under pressure, but the surface in contact with the fluid is either rubber or teflon. Those materials have very low conductivity. That is, very little heat is coming out through any of these hoses because the hose itself is made from a material that is a very good insluator. Changing the conductivity at the surface by wrapping the steel isn't going to make an appreciable difference, because, as a practical matter there simply isn't any heat that goes through the hose in the first place. You are assuming that it is a bad thing to cut the heat flux on the outside of the hose, but really, it doesn't make any practical difference because the fluid is already insulated by the hose liner.

BTW your boiling analogy is really a bad one. While it takes 1 degree of temperature to boil water from 211 degrees to 212, it takes 970 btu's per pound of water to actually do it. That is instead of 1/2 of 1% of temperature rise you actually need to add the equivalent amount of heat that it would have taken to raise the temperature an additional 970 degrees to actually boil the water. Small point, but in heat transfer, the the amout of heat that you can move is more important than the temperature in some cases.

Heat transfer is sometimes not a very intuitive subject. You have to look at what is happening and how the heat is leaving the respective surfaces, and then figure out what is important and what isn't. Getting air moving on the outside surfaces of the cailper, plumbing air to the center of the brake disk, and adding a heat barrier under the pad, as well as using things like titanium pistions are ways that you can significantly effect performance of the braking system.

The effect of heat transfer out of the hoses are a second order player at best, and in reality doesn't make any difference in how your system is going to perform. When you consider reliability and the effect of grit getting under the stainless sheath, it is very likely that after a few seasons the heat transfer from the covered line will actually be better than the uncovered hose with grit under the braided steel line. That's because the hose will wear under the braid and the contact area gets reduced, which cuts the heat transfer between the hose and the braid.

In short, John needn't worry about what hose he uses, he can pick a wrapped hose and it isn't going to make any practical difference in his fluid temperatures. If he wants to have good brakes for a complete track weekend, he needs to upgrade his pads, fluid, and hoses, add spindle ducts and hoses, and put a thermal barrier under the pads. If he does all of that he should be in good shape, and the hose he picks won't be an issue.

RacePro Engineering

Solo,

I am certain we are all very thankful for the physics lessons.

The way I read John's "question", he wanted non-confusing information about stainless brake lines. Nothing more.

From years of successful racing, our empirical findings are that any sort of covers on the outside of the brake lines, braided or not, tend to block air that can potentially help cool the lines AND the fluid. Whether the lines themselves are hot from the calipers, or from the fluid, or from close proximity to the axles, makes little difference.

These are our findings. And, I'm certain we are missing the point here, too . . . . .

L98Terror