Slotted or Drilled rotors?

[ThUnDaKaT85]

i was looking at rotor upgrades for my 90 GSX, and slotted and drilled rotors are the same price. what exactly is the difference? is one better then the other?

 

[cait sith]

How about neither and just get blanks?

For what you're doing (Street driving), you don't need either of them.

 

[UCSLugRacerX]

For regular driving: "skip the bling and get the blanks." The Brembo blanks are great rotors.

In terms of the difference between drilled and slotted, according to Carroll Smith in his book, "Tune to Win" he wrote:
"Drilled discs...do the same thing as slotted discs, except that they do it better and they remove considerable mass from the disc itself. They also decrese pad taper by a considerable amount at the expense of increased pad wear. They are also prone to cracking around the drilled holes."
He also wrote: "...there are two theories...the Porsche pattern runs through the ventalated disc webs and the Automotive Products pattern does not."
-Carroll Smith

Also, drilled discs "supposedly" induce hot vapor evacuation, thus increase cooling characteristics. Although, the detrimental side effect to rotors with less material, results in a SMALLER heat-sink, which means the rotor will have a more limited heat capacity. This can lead to sooner brake fade. A slotted rotor increases the available surface area to provide better cooling, as does the dilled system.
Ideally, a performance dilled rotor should be a LARGE heatsink, while maintaining a light weight. (And this is often hard to achieve at a reasonable price.) Models such as these are AP rotors, or Brembo Gran Tourismo rotors.

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In any case, if your application is commuting, then get OEM blank replacements.

I hope any of this helps.

 

[Todd TCE]

I'll take a simpler approach; get whatever makes you happy. You won't notice the difference driving them anyhow. Neither is going to turn it into a boat anchor stopping machine. Get some reasonable pads, hoses, and rotors to your liking and run with it.

 

[UCSLugRacerX]

Didn't someone ask what the differences are? Isn't this a performance oriented forum? It's interesting how much attention is paid to getting a DSM from 0 to 60mph, but not 60 to 0mph.
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Todd TCE wrote: "You won't notice the difference driving them anyhow."
I doubt throwing on Brembo Gran Tourismo brake kits F and R, along with DOT 5 fluid, upgraded MC, and 275 width Hoosiers, will go unnoticed while braking at the edge of tire traction limits.

 

[14.5 drift]

werd.


however I read just the other day a write up contradicting caroll smiths theories. It said that the only benefit to drills was to loose weight. It said that it actually runs hotter due to less mass to absorb heat or some thing to that effect. Basically made drilling seem pointless but said that slots were helpful in rain and removing glaze but at the cost of pad life.

Give me a sec I'll post the link

 

[UCSLugRacerX]

Yeah, there are points in Carroll Smith's three books which contradict themselves. Race car tuning is almost never black and white. (Only exceptions are gravity, some of Newtons laws, etc...)

I personally think blank rotors are fine for street, and moderate spirited driving usage. There are other bigger factors involved other than big drilled rotors, which affect stopping power, such as tires.

 

[14.5 drift]

aight, here we go ......

http://scirocco.dyndns.org/faq/brakes/pulpfriction/pfpage1.html

 

[UCSLugRacerX]

Great article for the most part. I've read it before. It's a little overly drawn-out, but succinctly explains in Layman's terms. It eventually arrives at the conclusion that the tires are the most crucial component in contributing to stopping power.
Although Carroll Smith writes:
"...what actually stops the car? Some comes from the rolling resistance of the tires...most of it, however, must come from the vehicle's brake system which converts the kenetic energy of vehicle inertia into thermal energy which must then be dissapated into the airstream..." (Tune to Win, pg. 107).

Anyway, in sumation (and to state the obvious)--powerful and consistent brakes, coupled with wide sticky tires will usually result in good braking.