b15 brakes same as....?

NX 2000 nx2ked@hotmail.com
Thu, 24 Jan 2002 17:17:34 -0600


>From: "Pat Griffith" <griffser@hotmail.com>

>How does removing material by drilling holes give brake rotors "extra
>surface area"??  Talk about contradictions ...

Let's go a little further on this.  By drilling a hole in the rotor you are
removing the radius times pi times 2 in surface area.  I believe that's the
formula for finding the area in a circle.  Feel free to correct me if I am
wrong about the correct formula here.
By drilling a hole, you have the circumfrance (sp) of the circle times the
width of the rotor.  Depending on the width of the rotor and the diameter of
the hole, the surface area lost by the drilling can be greater or less than
what is gained by drilling...

>Also, there is a difference between slotting and drilling.

I never said drilling and slotting are the same.  By slotting, you are
taking a bit more material off the flat part of the rotor and increasing
surface area.  You cannot deny that.

>>All this can be found in SE-R.net under brakes. I believe it was written
>>by Mike K.

>Alright, Mike says: "I myself think that drilled stock rotors or sport
>rotors may be somewhat questionable because since small stock brakes are
>run close to their thermal limit with high performance pads, the drilling
>can contribute to cracking  ... Drilled real racing brakes with sufficient
>thermal capacity are functional and useful ... Overall, I feel that drilled
>sport rotors are mostly a cosmetic trick and have never tested drilled,
>slotted and solid back to back."

Since you kindly added that in, my original reply was to Kevin who said
cross dilled rotors have no effect on braking unless you are talking about
above 90 mph speeds.  My reply was you are contradicting yourself by saying
no effect and yes effect above 90 mph.  And the link to SE-R.net allows
people to read the somewhat truths behind cross drilled and slotted rotors,
unless you are saying Mike is blowing bananas...

>Is that the part in question?  I have not tested this, but in theory, a
>cracked brake rotor will not help a car slow down better.

Now where did this come from?  You should have bought "Drilled real
>racing brakes with sufficient thermal capacity are functional and useful"

>In most SCCA-level (i.e., amateur) autocross and road-racing classes,
>cross-drilled rotors are not allowed, and nobody cares.  They whine about
>rules on seats, ECU's, restrictions on air dams, tires, etc., but none of
>them whine about not being able to use cross-drilled rotors.  Gee, maybe
>because they have seen/heard real-world experiences (not "in theory") with
>cross-drilled rotors and determined cross-drilled rotors aren't any better
>than non-drilled rotors.

Not where I am.  Cross drilled rotors put you into SP.  I never said cross
drilled rotors were better than stock.  I just said in theory they are
better and offered a place to search for more material to make their own
judgement.  BTW, Porsche use cross drilled rotors stock since this topic
came up before.

>It's a free country and you can go ahead and buy cross-drilled rotors for
>your car, but don't try and justify them as performance upgrades unless the
>rotors you're replacing are worn paper-thin.

What's with this bashing?  I NEVER tried to justify cross drilled rotors as
being a performance upgrade.  I just stated a theory and told to look up
se-r.net like everyone else should have done before posting questions on
this list.  Personally, I'd go for slotted rotors before cross drilled, but
that just my opinion.

Edwen