slowV8berlinetta

is it worth it to buy drilled and slotted front rotors for my car for more than twice the price of standard ones? is it even possible to ever cut a drilled/slotted rotor? How much better would my car stop with them??

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'84 Berlinetta, LG4, 700R-4, starwars interior, falling headliner, T/A t-handle shifter, trans cooler, more to come in time and $$ www.hipergp@aol.com

Jza

It'll help very little if at all. I have drilled rotors, and they didn't make any difference in the stopping ability of the car. I only got them for the looks anyway. The only thing that will noticably increase your braking ability is increasing the actual diameter of the rotor, and that requires costly modifications. There are also some pads that might improve your braking, but it's a crap shoot.

Kandied91z

iTrader: (7)

I disagree, i bought drilled and slotted and it made a difference, especially if they were wet at all; it isn't the diameter of the rotor that makes the difference so much as the size of the caliper (# of pistons) or whatever their called. i know my stock ones were single piston, most baer setups are 4 or more which makes a huge difference.

personally, i wouldn't buy rotors looking to stop better; they are just to compliment the setup. unless your racing, you stock setup should be fine as long as it's in good working condition; if you really want more stopping power you will need an aftermarket setup.

Mista

think of it this way, the holes and slots REDUCE the swept area of your brakes. Nowadays they are a cosmetic item. Back when pads offgassed badly, they helped.

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86 T/A 5.0 A4 & 2.77 gear
15.62 @ 86 mph
93 Civic 1.6L
13.5 @ 100 mph

EvilCartman

iTrader: (1)

I beg to differ.. Larger rotors do make a difference in stopping power. If you ran 10 inch rotors with 4 piston calipers on your car and tried to stop, it would take longer than say a one with 12 inch rotors with 4 piston calipers.

88blkiroc

i thought drilled rotors where just to help with cooling, to reduce brake fade. not to increase stopping power.

John in RI

iTrader: (167)

"i thought drilled rotors where just to help with cooling, to reduce brake fade. not to increase stopping power. "


You are EXACTLY correct.

Under normal driving conditions the difference of "stopping power" between slotted / drilled Rotors and regular rotors is Miniscule. They were specifically designed to disburse heat under extreme driving conditions.... there-by reducing the brake "Fade" due to the overheated brakes.


Larger diameter rotors means more direct surface contact with the pads, That means MORE stopping power.

2 Piston Calipers also provide more even distribution of pressure to the pad/rotor - also causing MORE stopping power.


John in RI
Berlinetta@Prodigy.net

82camaro

If I locked the brakes up with stock brakes and then again with bigger brakes, the distance will be the same. The larger brakes increase stopping power, but if your stock brakes can lockup the tires the additional power isn't needed. The larger brakes do run cooler because of the increased surface area. Slotted and drilled brakes also run cooler.


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

John in RI

iTrader: (167)

"If I locked the brakes up with stock brakes and then again with bigger brakes, the distance will be the same."

Locking up the brakes is not even relevant - of coarse the disatance would be the same !

" The larger brakes increase stopping power, but if your stock brakes can lockup the tires the additional power isn't needed. "


Does that mean that Drum brakes are as good as Disk Brakes ??? The whole idea behind braking is NOT locking up the tires so that the brakes can actually perform. Look through the old Chevy Specs for a Z28 and then a 1LE car...... I'm sure the braking distance figures will prove that bigger is better !

clemsparks

iTrader: (1)

First off

The slotted or drilled rotors are made necessary dependent upon the pad compound used. As alluded to earlier, the slots or holes are merely gas reliefs (is "reliefs" a word?). Most pads don't require them. Most guys are running them for the WOW factor at the stoplight and such.

I've designed and developed braking systems for road racing vehicles. With most of the pad compounds out there, you don't need gas reliefs (again...releifs, relieves...little help?) even in all out competition. I'm drawing on my experience with heavy, tube framed cars like SCCA TransAm...brakes are IMPORTANT to these cars. (Big cars with Big power plus long straight and tight turns)

As for the wheel locking argument. Basically what 82 was saying is that, for one single stop, if you can lock the brakes you don't need more braking torque. The argument is valid...Assuming that you can lock the wheels and you have the skill to modulate and be just on the edge of the static/kinetic transition.

Again this is for one stop. Our cars are heavy. In a street driven situation, our brakes should be sufficient. However, if you want to go racing, the brakes will most likely leave a lot to be desired.

Also remember that when you take away mass from the rotor (light weight rotors) you take away their ability to store heat as well. Heat storage relates to braking "capacity" if you will. Heavy rotors are good for extended braking and severe useage, but they take more power to spin and they don't always let it go as easily.

I think before anybody with a thirdgen goes upgrading brakes, they should ensure that their stock system is operating correctly. It would probably be surprising to a lot of us how much a little maintenance in the brakes is worth.

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Clem
SCCA TransAm Series Race Mechanic/CrewChief
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1983 Z28 with LG4, 5 speed, and (unfortunately) T-tops
1983 Z28, NO T-tops, (unfortunately) Auto Transmission (hopefully not for long)

clemsparks

iTrader: (1)

and I forgot:

It all comes down to one important link. You can apply as much force as you want. If the tires lock, you can't stop. The tires are a VERY important part of the braking system, though it's not a popular concept.

If you can generate the force to lock up the wheels, you can ABSOLUTELY, for sure, generate the force required to slow the car at the maximum rate. It's all about physics.

Lets take two cars with radically different braking systems (lets say, stock and fully race prepped aftermarket) but which are BOTH capable of locking the wheels. If both cars are using the SAME TIRES they will be able to stop in the same distance, assuming that they are breaking on the threashold. The tires are the weak point in this single stop comparison.

again, things change when you want to do lots of repeated braking, like in road racing and autocross events

Clem

Matt87GTA

Exactly. Tires are a huge factor in braking. Locking up the tires is exactly what you don't want to do and really doesn't prove much about the brakes either.

The main idea behind drilled and slotted rotors is the dissipation of heat. This all comes down to energy. When the car is in motion it has a certain amount of energy contained in its motion and that energy must be transferred to the brake system in order to slow the vehicle down. So the brakes are just converting the energy of motion of the car into heat energy in the pads and rotors. Therefore, the better that those componants can dissipate the heat from the motion of the car out into the atmosphere, the better the braking performance of said vehicle.

That is why everyone is saying that drilled and slotted rotors are going to shine in a race condition and not give you any gain in performance during everyday street driving. Racing means extreme, hard, and repetitive braking which means the brakes are going to get very hot and stay hot and also be required to maintain high performance levels in those extreme high heat conditions.

The slots and holes also allow gases that form during the brakedown of the pad material during application, to escape and allow more friction to take place where the pad hits the rotor. But the main purpose of them is for heat dissipation.

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club