Brake pad friction coefficients

[pmbrunelle]

So for my new Fiero brake setup, I was wanting to choose brake pads.

Of course, there's a multitude of choice in the D154 form factor (Zettner-style setup).

There's almost too much choice, and all the marketing wank in the world couldn't help me select a suitable pad.

Of course, the most basic parameter of a brake pad, its friction coefficient, is typically found nowhere, except for some boutique pads from Wilwood, EBC and the like.

Anyway, so I found this:
http://faculty.ccbcmd.edu/~smacadof/DOTPadCodes.htm
Edit for dead link repair:
https://web.archive.org/web/20190907185 ... dCodes.htm

The 250 °F and 600 °F friction coefficients are built into the code that is marked on the brake pad. On a track the temperatures could go higher than this, but some data is better than no data!

When shopping online, sometimes you are able to read the code in the product photo.

I don't know if y'all know about this already, but I just learned this today.

For reference, here is an old Delco pad set for the Fiero that was given to me:

IMG_5618.JPG (184.57 KiB) Viewed 1678 times

[The Dark Side of Will]

That's pretty awesome! Like sidewall markings for tires.

//

Porterfield R4S pads are good street/track pads, although Steven Snyder did cause a set to disintegrate through dedicated track use.

[pmbrunelle]

Porterfield is nice enough to publish friction vs. temp curves in this pdf:
https://www.porterfield-brakes.com/imag ... _41_04.pdf

For my Fiero project (street, but I would like to go to the local autocross-style event), I think that pads with a higher friction coefficient might give a nice result.

I will most likely try PowerStop Z26 pads. They appear to be GG-rated.

[The Dark Side of Will]

Porterfield is nice enough to publish friction vs. temp curves in this pdf:
https://www.porterfield-brakes.com/imag ... _41_04.pdf

For my Fiero project (street, but I would like to go to the local autocross-style event), I think that pads with a higher friction coefficient might give a nice result.

I will most likely try PowerStop Z26 pads. They appear to be GG-rated.

Porterfield makes some good product.

Oooh, snazzy on the PowerStop Z26's.

[Honest Don]

This is good info!

Does powerstop have something that fits the 84-87 cars?

[pmbrunelle]

I ordered the PowerStop Z26 pads (for GM Metric calipers) from Summit Racing. I'll be able to confirm soon enough if my internet sleuthing was accurate in determining that they are in fact GG.

PowerStop doesn't seem to have anything for 84-87 Fiero. EBC seems to sell stuff for 84-87 Fiero though, and I heard of places where you can send you stock pads, and they reline them with another friction material. I haven't spent too much time looking for 84-87 Fiero though.

One 84-87 Fiero project I think would be interesting would be to install the vented GA rotors, but using the Fiero calipers at all four corners to maintain bias and the parking brake.

To accomodate the wider rotors, two Fiero calipers could be cut in two, the bigger halves of each caliper being bolted together to create a wider assembly. Dunno how feasible that would be.

[The Dark Side of Will]

Not sure there's enough section thickness in the bridges to make that feasible.

At that point, there are other options that make better use of resources.

[pmbrunelle]

The PowerStop Z26 is indeed GG.

Brake Pad.JPG (460.3 KiB) Viewed 1568 times

On Rockauto the same PN is listed for front and rear of the Seville... that's not a total lie, but the inner pad has a riveted retaining spring which goes inside the front piston.

This retaining feature will have to be ground off to use the pad with the flat-faced rear piston. Additionally, I'll probably have to remove the shim on the inner pad, so the anti-rotation pin can engage deeper into the parking brake piston.

On the front, I probably have some tweaking to do to make the pads work with the dual-piston Wilwoods, but that's OK, as this constitutes an off-label use.

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Who makes these massive auto-parts cross-reference lists?

They seem to be centrally controlled, in that every parts store seems to have the same mistakes in their list.

I'm sure it's not every auto parts store that has to redo this on their own.

[The Dark Side of Will]

Good find!

I thought pretty much all the interchange info came from Hollander.

[The Dark Side of Will]

Where did you find the friction coefficient rating? The Bug Out Van is due for brakes, and GG pads that don't chew rotors up like Dremel tools would be nice.

[pmbrunelle]

I go on Rockauto, and then I click on the Info button to get more information on a candidate pad.

Step 1.jpg (311.21 KiB) Viewed 1415 times

Then, I cycle through the photos... sometimes you'll get lucky enough to see the markings there.

Step 2.jpg (205.24 KiB) Viewed 1415 times

Not all pad listings have photos of sufficient quality / viewing angle to see the DOT code easily.

I'd suggest going through the pad listings one-by-one until you find the GG you're looking for.

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The AMECA list of pad codes sold in the United States can be found here:
https://ameca.org/handbook-of-compliant-safety-devices/

It's kind of a useless list for our purposes, because I have not found a way to cross-reference the manufacturer part number (what we see in retail) to the compliance number (the AMECA list).

It follows that I have no recommendation that is better than viewing the code (either in-person or via photo) on the pad itself.

[The Dark Side of Will]

Ah, ok. Yeah, the pad itself should be marked, but for the few I checked that's typically not visible until the pads are in my hand. I looked at pics of the Akebonos for the van and they do not show the pad markings.