Poll question: Have you noticed any difference in braking ability with slotted and/or drilled rotors?

Perhaps I’ve been over thinking this (Proof I’ve been over thinking this:

I’ve got the flu, hence why I’m doing engineering equations on a Saturday night. I’m usually not this pathetic.)

I’m thinking of ordering the www.raceconcepts.net slotted and dimpled rotor, but after seeing this picture mcgyvr posted

of the rotors I’m worried that too much of the surface area of the rotors has been removed. The braking torque is directly proportional to the contact area between the brake pad and rotor. How much of the surface area has been removed I don’t know. Is it enough to make a difference? My car will never see track use so the slots and dimples are strictly cosmetic. I don’t want to decrease the stopping ability of my car for the sake of looks. The “cheese grater” effect of the slots that some people have talked about before will only be there for a short period of time because eventually the slot edges will become rounded.

-J

it's too early to tell, i was expecting the pedal to be firmer and have better bite but it seem to brake like stock but seems to fade less. So it must be doing its job. I think these stock pads stink though, I saw smoke coming out of them after I stopped off the road after mountain racing... I want my metal master back :(

Bump

But let me also add I gave this some more thought and my initial thoughts were wrong. The force applied to the brake pad is determined by the cross section of the brake piston, so regardless of what size the contact patch is between the pad and the rotor the force will be the same. So in theory loss of contact area will have no affect of braking ability. But to quote Homer Simpson: "In theory communism works."

I still would like to know what your personal experience has been with slotted and/or drilled rotors.

I noticed an improvement with the powerslot rotors. My car defenitely works better than stock.

I just put the raceconcepts on, (perfect fit by the way) and the braking is much better that with stock, much better, I also have some nice carbon/metallic pads (Autozone with lifetime warranty when they are gone I get new ones free) total cost to greatly improve braking 100 for rotors and 49 for pads. Money WELL spent.

Hades the pedal feel/braking will increase after a little time, I put 500 highway miles on this weekend and on the way back I noticed the braking has improved greatly. No brake fade what so ever.

i have a slotted and drilled brembo with ceramic pads and i noticed a great improvement over stock even my mechanic who drives my car from time to time noticed it
to someone saying that ebay stuff is b/s i bought this on ebay for 130 shipped can't beat that

what was the symbol in the final equation?

The squiggly looking thing? Proportional
Or the three points? Therefore

Try bleeding your brake fluid and gettin metal master pads first. Get valvoline syntec brake fluid. That will make a difference in that it will be firmer. The slotted or cross drilled rotors don't really make a difference for the typical driver, who doesn't fade their brakes mnuch. It would make a bigger difference at the track. It looks good though. If you want a real bigger difference in braking, get a big brake kit (AEM, Wilwood etc).

>Bump
>
>But let me also add I gave this some more thought and my
>initial thoughts were wrong. The force applied to the brake
>pad is determined by the cross section of the brake piston,
>so regardless of what size the contact patch is between the
>pad and the rotor the force will be the same. So in theory
>loss of contact area will have no affect of braking ability.
>But to quote Homer Simpson: "In theory communism works."
>
>I still would like to know what your personal experience has
>been with slotted and/or drilled rotors.

That is inaccurate. If you increase your pad's contact with the rotor, you will increase stopping power. It's simple physics. More friction=better stopping.

Any reduction in contact area because of drilled and sloted rotors would be trivial. Besides, when you swap out your rotors you'll probably be upgrading to a pad with a better compound anyway, so any minimal loss would be offset by the pad.

Chris

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Simple physics dictates that the friction force is equal to the normal force times the coefficient of friction. Nowhere is the contact area involved in the calculation of friction force. Look it up in any physics book and that’s what you’ll see. In my initial (incorrect) calculations I factored in the contact area by saying that the contact area would determine the force applied by the hydraulic system when in fact it’s the cross section of the brake piston that determines the force applied. However that’s not to say that in real life the contact area plays no part on friction. It’s a proven fact that wider tires give better traction. Theoretical physics and real life don’t always mesh perfectly.

> Nowhere
>is the contact area involved in the calculation of friction
>force. Look it up in any physics book and that’s what you’ll
>see.

I ain't a physisist, but I know if you've got more shit rubbing against some other shit, you're going to have more friction.

Fuck the formula. If you rub your two hands together as opposed to your two pinky fingers, you're going to generate more friction.

(I should write a book, Physics for Rednecks. :) )

Chris

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Hahaha

Sorry man, but a Mechanical Engineer buddy of mine from Indiana is already working on that book.

>Hahaha
>
>Sorry man, but a Mechanical Engineer buddy of mine from
>Indiana is already working on that book.

Damn. There went my thousand dollar idea!

Chris

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LOL, I see you are like me squid. You should have seen the mathematics I pulled out of the net and my physics book to find out the best way to sound proof my car. (Sound Transmission Coefficients and NRCs, loaded barium vinyl, closed cell foams and energy diffusing patterns etc ad nausea.) We'll see how that turns out this weekend.

Anyway, the whole idea behind the slotted, cross drilled rotor is that the recesses and holes remove the gas that is built up between the pad and rotor as you brake, which would keep the pad from contacting the rotor. In theory there should be more friction between a crossdrilled rotor and the pad now.

As for performance, my crossdrilled/ slotted rotors at the very least feel a lot smoother than the OEMs. I think the OEM's warped within 10,000 miles. I also like the complements I get on them :)

hehe yep your right they do bite a little more and the pedal got a bit firmer. I miss my metal master pads :( I'm runnin stock mitsu pads, I think I shoulda bought some metal masters :( Ne1 wanna buy mine. Yes I do believe the new rotors run much cooler than the stock ones also, the bite feels kinda weak though I'm guessing it cuz they're not broken in yet (haha I raced them already smoked the pads too :P ) and I'm using crappy stock mitsu pads.

Hehe Yeah i know I went a bit overboard.

I know about the gas that develops when the pads are over heated, but highly doubt that I heat my pads up to that extent in my everyday drving, or even on my more enthusiastic driving moments. In theory friction has nothing to do with contact area, yet we all know that wider tires give better traction.:wary

I'll probably be ordering the rotors later today.

-J

Stillen. If you can't feel a difference with Stillen's big brake upgrade, your lying. Cause I can throw a passenger without their seatbelt on right through the windshield if I bite down on them.

NICE

>Stillen. If you can't feel a difference with Stillen's big
>brake upgrade, your lying. Cause I can throw a passenger
>without their seatbelt on right through the windshield if I
>bite down on them.


Unless you switched to a really agressive pad or got rotors that are much larger than stock, you're experiencing a bit of a plecebo effect.

Here is a really long discussion that took place on LS1.com about cross drilled Baer Eradispeed rotors for the LS1 F-Body. Remember, braking physics work the same for every car, you cannot simply write off the information contained in the thread by saying, "Well that's only true for F-Bodies." By the way, several of the guys participating in that thread are avid autox racers who have spoken with people such as Lou Gigliotti (http://www.lgmotorsports.com/page.cfm?id=1&folder=race) on the matter.

http://www.ls1.com/forums/showthread.php?s=a7494a76b2b7334fba5d436c0ee09eba&threadid=120564&highlight=brake+rotor

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>Stillen. If you can't feel a difference with Stillen's big
>brake upgrade, your lying. Cause I can throw a passenger
>without their seatbelt on right through the windshield if I
>bite down on them.
>
>
Hope you don't have a mother in law!

>Anyway, the whole idea behind the slotted, cross drilled
>rotor is that the recesses and holes remove the gas that is
>built up between the pad and rotor as you brake, which would
>keep the pad from contacting the rotor. In theory there
>should be more friction between a crossdrilled rotor and the
>pad now.

Take a look at that thread I posted from LS1.com. Here is a quote that you may be interested in:

"Truth is brake fade is almost always caused be exceeding the temp of the pads, or boiling of the brake fluid. I have spoke with racers like Lou Gigliotti about this. According to Lou, modern pads do not outgas. He said the only advantage to drilled rotors is the slight weight savings. He said he would use them for qualifying, but that since they are prone to cracking he would not use them for a race. Larry Narcus from Carbotech also told me that modern pads do not outgas."

Chris

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i've mentioned a couple times about my raceconcepts rear rotors, mine look even cheesier than the ones you posted. I have powerslots in the front and they are better, they are thicker and wider. the raceconcepts are shinier so a little nicer in that aspect but i still like the powerslots better since they are more upclose and look slightly bigger.

Baer talks about the benefits of a crossdrilled and/or slotted rotors on their site. They say as far as a street driven vehicle (with no plans to seriously auto-x or anything) the benefits are purely cosmetic. You don't generate enough heat and what not to benefit from the gas release of these rotors. Larger rotors with a bigger diameter and/or width would help, but again it wouldn't matter if they were smooth or drilled/slotted. I say if you don't want to buy a complete system or anything, just go and get some good pads and good fluid and you will notice a significant difference.

>I say if you
>don't want to buy a complete system or anything, just go and
>get some good pads and good fluid and you will notice a
>significant difference.

I agree 100%. If all you want is cheap increase in braking performance, that is the way to go. If you want some great looking rotors and can afford them, then I say go for it, but they won't increse your performance unless you get those aggressive pads and good fluid.

Chris

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well I'll tell you this good pads are good to have. When I got my metal masters I was very satisfied. I think the first brake upgrade you should do is to get better pads. With racing pads on stock rotors you can make your car a stopping monster. Haha I learned that leason when I put these crap mitsu pads on I should bought some race pads instead, but i do notice less fade most the slots and the drills help and the fact that the rotor is bigger and the pads contact patch is larger it helps. But it doesn't bite as hard as my metal masters did :(

Hey Hades, did the Metal master pads make any noise at all? Any screetching? Where can you get them for a good price? I'm wanting to get better stoping power soon..haha damn turbo :)

Does anyone have any pics of the raceconcepts rotor installed on their car? I like the rotors, but our stock sized rotors are just so small and the raceconcepts are the same size, right? My stock rotors look dwarfed by my 17" rims!

My raceconcept rotors ($153 front rotors and pads with shipping) were shipped out last night and I should get them by Wednesday. Unfortunetly I don't have a digital camera so I probably won't be able to supply pics. Maybe mcgyvr has some.

different rotors aren't gong to increase or decrease your braking power. to increase braking power you need bigger brakes or more pressure. the point of crossdrilling and slotting rotors is so they releive themselves of heat and prevent brake fade for more predictable braking and better braking results during hard driving.

>Hey Hades, did the Metal master pads make any noise at all?
>Any screetching? Where can you get them for a good price?
>I'm wanting to get better stoping power soon..haha damn
>turbo :)

Metal masters are 55 dollars from http://www.roadraceengineering.com. I had them with my stock rotors, and now with teh power slots. I like them, definitely much better than stock. They don't usually squeak much, but sometimes a little when coming to a stop. Definitely get them, best pads for the money.

With just front cross drilled KVR rotors and pads. I see a much better pedal feel and stronger braking... and with a full braking power from say 120+ down to like 45 no warping of the rotor. I am impressed and pleased wiuth the set up, now I just need to install and convert the rears.

Una salus victus.
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Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
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All motor in the making.

Injen CAI, 55mm TB, P&P Intake Manifold, Hooker Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, Crane Fireball HI-6DI2, SS Clutch Line, NRG Susp. Motor Mount Ins., FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730, Front KVR Cross-Drilled Rotors & Carbon Fiber Pads

To Be Installed: P&P Milled Head, Rear Disc Brakes, Rear KVR Cross Drilled Rotors & Carbon Fiber Kevlar Pads, SS Brake Lines