[DeTomaso] Brakes!

[msm at portata.com]

Brake pads are made from various compounds with varying characteristics.  The pads vary in their durability, the amount of noise and brake dust they produce, and the speed at which they eat the rotors.  As with any part, you first need to figure out what it is you really want to do then find the compound that best meets your needs.  It is not a simple as just picking race vs. street.

 

Of course, the most interesting characteristic is the coefficient of friction - the grippiness of the pad on the rotor.  (There are different rotor materials, but that is a whole other issue.)  The coefficient varies with temperature.  Compounds that tend to be grippy at low temps are used in "street" pads, and compounds that are grippy at higher temps are used in "race" pads.  Naturally, it is not a simple binary issue.  The compounds have a coefficient of friction curves that vary in size and shape much like HP/Tq curves do.  Here is a comparison of several compounds.  The higher the "Cf", the better

 

http://brakepads.wilwood.com/02-graphs/ahjbc.html <http://brakepads.wilwood.com/02-graphs/ahjbc.html> 

 

The stock pads on my 300zx (commuter and sometimes track day car) were OK on the street but faded badly about 10 minutes into the first session of the track days.  I replaced the stock pads with the Porterfield R4S pads.  I now can go well into two sessions before getting significant fade.  However, when the R4S pads are cold, they are worse than the stock pads.

 

I have Wilwood PolyMatrix B pads on my Pantera.  The compound B material is considered a "race" pad, but it is good across a wide range of temperatures.  There are better race compounds which have even better grip at high temps, but they eat rotors quickly and/or only work at temperature that I will never see during a track day.  Interestingly, the compound B is better than the stock pads even when stone cold, though it is noisy.

 

Check out the compound selection guide and the compound graphs at http://brakepads.wilwood.com.


________________________________

From: detomaso-bounces at realbig.com on behalf of JDeRyke at aol.com
Sent: Fri 6/20/2008 10:35 AM
To: asajay at asajay.com; detomaso at realbig.com
Subject: Re: [DeTomaso] Brakes!



In a message dated 6/20/08 10:18:15 AM, asajay at asajay.com writes:

> I just got my Porterfield R4S pads for the Pantera.  A note on the invoice
> says the R4S pads are 
> -not- for racing use..... 
>
This is undoubtably a CYA note. Porterfield is located in California, home to
people who sue their grandmothers for not giving them a good childhood. The
R-4S pads were advertised as 'stock-car pads' when I bought them but in fact
they work well on the street- at least on our car. Having run tech inspections
for decades, I can tell you that no one ever looks at the brand of brake pads,
only their thickness. All 'non-racing' pads will do is maybe not last a whole
race.... but on a street car you really don't want race pads which typically
need several hard stops to heat up; not good on the freeway going out to the
track! Try 'em and see- I think you'll be pleased relative to OEM pads. Cheers-J
DeRyke



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