b15 brakes same as....?

[Kevin J. Hart]

> the hole, the surface area lost by the drilling can be greater or less
than
> what is gained by drilling...

So you drill a hole say 1/4 wide....and the rotor is 1/2" thick....You are
going to pick up very very marginal surface area.  Ok then you multiply that
by the number of holes.  Ok you pick up a little extra surface area.  Which
on a daily driver means jack squat.  Why?  Because rarely do you heat up the
rotor to a point where it needs any extra cooling.  When was the last time
you faded on the street?  I cant think I ever have, well some of these
idiots around doing 90 on surface streets might but then again they end up
in a wall most the time and thats not on discussion.

> taking a bit more material off the flat part of the rotor and increasing
> surface area.  You cannot deny that.

the benifits from sloting have absolutely nothing to do with cooling power.
what the slot does is help clean off the surface of the pad of any glazeing
it may have created.  And help disapate gasses(which most pads made these
days do not put alot out) and water when they get wet.

> 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...

No Mike isnt blowing bananas.  And if he was, he would admit it.  But
re-read what he said..."Overall, I feel that drilled sport rotors are mostly
a cosmetic trick" show me any rotor on the market that isnt in this catagory
then ill show you the price tag of probaly hundreds per rotor.  I do not
contradict myself by saying what I said, misunderstood and poorly worded
yes.  What Im saying is on a street car, or even a lapping car, there is no
benifit to be picked up by crossdrilled rotors.  At high speeds that lemans
type cars see they use it for cooling along with proper infrastructure like
ducting.  Also these cars do not expect their brakes to last more than 24
hours at the longest, and at that they do make changes at times.

> 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.

The random cross drilled rotor(powerslot comes to mind for a distrubuter)
are not better and not "proper" rotors.  They are for show and end up
cracking anyway.  Oh god here comes the Porsche arguement.  Id like to see
the life expetancy of one of their rotors.  One reason they are on there is
people can afford such things.  They are not the standard rotor, one thing
the holes are cast into the rotor not drilled IIRC.  Doesnt mean they arent
prone to cracking.  Also Id like to see some data why they are on there.
Test a set of non holed to holed and see what happens.  On a street
car(which is what the majority of Porsche's end up as) it wont make a
difference.  Then on track it may make a hair...but if you are fadeing the
brakes, more than likely you will do it no matter what extra parts you throw
at it.

> 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.

Well most of the people see them on race cars and automaticly think they
will help them on their car even buying cheap ones.  It doesnt.  Hell i
remember GRM doing a study on it and even pulled out the math on it.  But
its almost impossible to find unbiased facts on anything these days.  I like
my smooth rotors they are friendlier on pads and can easily be surfaced, and
not going to crack as quickly or easily as cross drilled.  Slotted atleast
has some benifit not just conjector of it they work

I know this has been offered on the board before, if someone wants to back
it up then good.  We want to do some back to back testing of rotors in NC
and willing to make it totaly unbiased and as scientific as possible.  If
someone would donate a set of cross drilled and pads we would spec, which
they would get back in brand new shape, we would do some back to back
testing on the air field that Matt has access to.  See if they stop any
better or if we can get them to resist fade any better.  Totaly scientific
as possible and unbiased.  hell someoen show me the data and ill shut up.

Kevin
93 classic (Automatic, Stuff)
about tired of fighting