GOST

i just want some reviews and opinions on brakes before i purchase anything...

shoult

iTrader: (1)

What are you after? Looks or performance?

If you want performance go with OEM as they won't crack and will be less suseptible to warping.

Drilled/Slotted/dimpled look good and great for crusising put I wouldn't use one on the track unless I had the budget to replace them often.

Maxima-4DSC

iTrader: (1)

the cross drilled / slotted rotors stop faster due to they cool better.

AscendantMax

iTrader: (7)

I remember reading somewhere that those cross-drilled and slotted rotors were designed to remove the gas buildup created by the pads during the early years of brake systems.(don't quote me on that one as to i don't know much about brakes). not sure if they'll stop any faster than a nicely picked setup with solid rotors though.

anyhow, i personally think the cross drilled and slotted rotors are for looks. nothing wrong with going with a blank brembo disk with some good pads. that'll improve your stopping pretty well over stock components.

Menel

yes, cross drilled and all that bull**** will just leave your brakes weaker than they need to be, more prone to warping. leave them to the ricer crowd to blow their money on that ****. even if your doing autocrossing on a track slotted/crossdrilled isn't benficial

Get some standard brembo's i think they are around $40 each and some ceramic pads. nissan oem pads are nice but run around $70 for a set.

www.tirerack.com is a pretty good resource, the brembo's and oem pads are great!

LegitMafiaBoss

Why would Porsche put cross drilled rotors on their 911 cars if their was no performance enhancement and only for looks?

bgcease92

iTrader: (5)

good point?why would brembo and wilwood make only big brakes kits with crossed drilled rottors for looks? That one expensive ext modd. brembo and and powers stop work pretty good to me and the do improve stopping power alot. The crossed drills and slotted rottors these guys talking yap probably bought cheap ones.

Pervis Anathema

iTrader: (8)

Why don't you SEARCH the forum? This topic has been repeatedly BEAT INTO THE FREAKING GROUND.

93teg44444

Lets look at all the possibilities here. fist lets just dismiss almos all crosdrilled systems. ANytime you introduce holes into a part you introduce significant stress risers. These stress reisers are a protion of the metal that will crack very easily compared to other parts of the rotor. Mechanical forces, vibration and thermal variations all lend to excessive stress near the holes. I have never seen or heard of a slotted rotor cracking from the slots. But cross-drillled rotors often crack right at the holes. Porsche and some other big names don't actually drill their rotors they cast the iron with the holes there so that they can properly chamfer all the edges on the holes to minimize the stress riser. So basically drilling rotors is bad and the only real effect is that the holes are supposed to move the brake dust away from the wheel to reduce dusting.

On the comment of reducing warping, well from what i've read rotors don't really warp very often. Most times when rotors are diagnosed as warped it is actually brake pad deposits on the rotor. These deposits happen because of im proper pad breakin, and overheating hte pads and then holding the pads on the rotor causing some of the pads material to molecurally bond with the cast iron rotor. The pads have silicon and other elements in them that will due this under high heat. LIke after you run around fast and hard then come to a stop and set there with your foot on the brake. Very BAD.

Next lets discuss stopping distance. Stopping dfistance is based on just a few things pad material, the radius of the pad rotor interface from the axle centerline, and how hard you push on the pedal. THe surface area of contact between the pad and rotor has no effect on the frictional force between the pad and rotor. The surface area of pad rotor cantact is important in figuring out how fast the pads can dump their heat into the rotor.

Finally lets discuss the rotors thermal job. The rotor is a heat sink. Braking is the action of turning inertial energy into thermal energy through friction. all of the energy that you use to gain speed it turned into heat in the brakes. Remember energy cannot be created or destroyed only transformend. When you his the brakes alot of heat is created that heat should all transmitted in to the rotor. The pads do not sink heat to the air well at all. The first thing the rotor needs is volume. The large the volume the more energy it can absorb before getting hotter. It takes so much energy to make a CC of cast iron 1 degree hotter. the larger the number of cc's the more energy can be absorbed before the pads melt. Since large volume also generally relates to lasrger surface area we also have better heat transmission to the air around the rotor. Cross drilled rotors dont necessarily always increas the surface area of the rotor. It depends on the thickness of the rotor plates. since you gain the surface area of the circumference of a cylinder but you loose the tops and bottoms of that cylinder when you drill the holes. So all the holes might be doing is removing volume which is bad from a cooling perspective but good from a rotational inertia perspective (maybe another reason why high end system use it). Slots do decrese the volume but they alyays increase the surface area. Slots also supposedly remove vapor buildup between the pad and rotor. Any samll air pockets in the pad material would have huge axpansion once released because the volume of a gas is directly preportional to the temperature(PV=nrT). Supposedly the slotting also reduces the effect of the pad materail depositing because it removes the overhreated glazed layer on the pads.

So basically thats how I see brake systems. X-drilling is for top end systems that are properly cast and heat treated to reduce the effect of stress risers and even then it is most likely for inertia reasons due to large rotor diameters. Which are super important in how good the brakes work. Larger diameter rotors are possiblly the biggest way to majorly increase the rbaking energy of a car. the only other way is to use some super high friction pad. Slotting has no real down fall, decreased volume and increased surface area. Along with some other possible advantages discussed above. Good balnks aren't bad either. Good pads on good blanks should give almost all the performace of anything of the same size but at much less cost. If you want to brake good get good pads or get larger diameter rotors. IT would be much better to buy blank rotors and spend the extra on good pads and not use the standars autozone pads.

If I spelled stuff wrong too bad I have a degree in engineering not english. And it's tooo long already.

AscendantMax

iTrader: (7)

how long it took to type all of that? curious

shoult

iTrader: (1)

But they don't disapate heat as quickly as OEM (or solid) rotors because you remove mass from the rotor as you drill and slot it.

And they WILL crack if you put track day stresses on them.

Racers use them because;

1. They use HUGE rotors to make up for the mass the removed by drilling and slotting. (This is the REAL reason for using larger wheels to)

2. They use the holes and slots to remove unsprung weight.

3. They have budgeted to change out the rotors after so many laps

My statement still stands. Unless you have a racers budget and you drive hard (autox's, track days or canyon carving) you should stick with solid rotors.

If you want to look like a racer, get the slotted and drilled.

BTW, when I change rotors on my Max I will probably go with cad plated drilled and slotted because I know I will never push my Max hard enough to worry about warping or cracking the rotors.

shoult

iTrader: (1)

Porsche doesn't use crossdrlled rotors EVER! They use rotors with cast in holes. BIG DIFFERENCE! Any rotor you buy for your Max (or most ANY other car besides Porsche) is going to be drilled.

And also they are using 11-13" rotors on a 3000 lb car with 4-6 pot billet calipers. Not the crap one piston floating caliper design that most EVERY car on the road today uses work on a 6-9" rotor.

The number one way to improve your braking power is to increase the contact patch of your car to the road. That means wider tires with the right air pressure on properly sized rims with a good alignment.

If you want to understand braking systems and how they work there was a great article in Grassroots Motorsports call "Pulp Friction". Read it, learn it, live it, breath it. You'll thank me as you dive into that right hand hairpin at the end of the back stretch slowing from 100 to 15 mph during the 15th lap.

pezking4

Get some Brembo blanks. You'll be happy with your choice.

timebomb

also, the more surface area the pad hits, the better the results.

AscendantMax

iTrader: (7)