cross drilled rotors Scott Williams is WRONG!

[mkii@nycap.rr.com (Josh Able)]

Total BS!!

The author drives a Saturn!!!!!!!!!!!!


:D


Josh Able

----- Original Message -----
From: "Brett Van Sprewenburg" <brett@netacc.net>
To: <scirocco-l@scirocco.org>
Sent: Saturday, March 23, 2002 1:11 PM
Subject: RE: cross drilled rotors Scott Williams is WRONG!


> >Hehehe that got your attention ;-)
> >
> >I don't know about performance, I think everyone is missing the point.
> >Rotors have holes drilled into them in order to increase air flow,
> >thereby reducing heat in hard driving conditions (such as racing on a
> >track). That's the theory behind that. I would say (not from experience
> >since my car isn't done) that they would work...It just makes sense.
> >Will this increase performance? I don't know, but I do know they would
> >have to be cooler (temp) no? Of course it could take a couple of seconds
> >for the pad to grab the cooler rotors (so I've heard). That's why you
> >would want to get the braided lines to get a better bite in the
> >caliper...As far as Scott being wrong, I think I have a better chance on
> >finishing my car today than proving him wrong...
> >
>
> I really need to post that brake article... :)
>
> Anyway,  I'm afraid the above opinion is incorrect.  I'll paraphrase from
> the GRM brake article again...
>
> Crossdrilling your rotors does nothing in most situations now-a-days,
except
> look cool...so please don't say it's for higher performance. (And
> they do look cool) ;)
>
> Rotors were first drilled because early brake pads from the 40's and 50's
gave
> off gases when heated to racing temperatures.  The gasses then formed a
thin
> layer between the brake pad face and the rotor, acting as a lubricant and
> lowering the coefficient of friction.  The holes were implimented to give
those
> gasses someplace to go.  Todays friction materials generally do not
exhibit
> the same gassing out as the early pads.
>
> The holes have carried over more as a design feature than a performance
one.
> Contrary to popular belief, they don't lower temperatures.  In fact,
> by removing
> weight from the rotor, they can actually cause temperatures to
> increase a little.
> These holes create stress risers that allow the rotor to crack
> sooner, and make a
> mess of brake pads - sort of like a cheese grater rubbing against them at
every
> stop.  Need more evidence?  Look at NASCAR or F1.  You would think
> that if drilling
> holes in the rotor was the hot ticket, these teams would be doing it.
>
> Ok, let's debunk the bigger rotors = better here also (again).
>
> Bigger rotors will make your friends think you are cool, bigger
> rotors look sexy, but
> bigger rotors do not stop the car.  What a bigger rotor will do is
> lower the overall
> operating temperature of the brakes - which is a GREAT idea IF your
> temperatures
> are causing problems with other parts of the braking system. (It can
> also changes how
> the brakes are modulated by the operator, which might be better for them).
The
> quick motto is bigger is better until your temperatures are under
> control.  AFter that
> point, you are doing more harm than good due to the load of steel
> hanging on the
> wheel that needs to accelerate each time the gas pedal is pushed.
>
> Finally, SS brake lines only remove compliance from the braking
> system, which really
> affects only the pressures and forces applied, not so much how cool
> the rotor is
> running...
>
> Again, this is an excerpt from a rather extensive braking article
> from Grassroots Motorsports,
> written by an anti-lock braking systems engineer with the Robert
> Bosch Corporation who
> is a Saturn racer for scR motorsports.
>
> In my opinion, this probably doesn't matter to the most of us
> anyway...very few of us
> are pushing are cars hard enough to get into the perfomance areas
> where these kinds
> of details actually make a difference very often.
>
> ==Brett
>
>  \/  '84 Scirocco (ITB racer 2B) | "Hot VW's, take two home. They're
small"
> \/\/ '88 Scirocco 16v (Show), '92 Passat 16v (Winter+) | -
brett@netacc.net
>
> _______________________________________________
> Scirocco-l mailing list
> Scirocco-l@scirocco.org
> http://neubayern.net/mailman/listinfo/scirocco-l
>