SLOTTED BRAKES.....12 or 6 slots

[TRDmod]

i am about to purchase aftermarket rotors for the front,

now, i wants slotteed ones, and i have been lookin at 6 slots or 12 slots,

what do you think i should get

i know that sometimes if you hae too much slots, you canabilise on the efficiency of your brakes, but too less might not be as good as lot sof slots under extreme braking conditions like track....

but anyone have any suggestions and facts to back it up....i would be interested and take it into consideration

[Stealer Of Souls]

Slots are more for "cleaning" the pads...

More slots would scrap the pads "clean" a lot more often. Mostly useful to help prevent glazing. Also help a little with de-gassing and cooling the rotor.

If you want real cooling/degassing then try looking for cross-drilled and vented rotors, or for just cooling ducting...

[pc]

I thought the purpose of slots was for de-gassing?
12 slots would give better coverage than 6... but would it increase pad wear?

[Stealer Of Souls]

Okay... I'm no expert. But I'd imagine that having 12 slots wouldn't necessarily make it any better at de-gassing than 6 unless your pads are gassing like a mofo. You need to "squeeze" the gas out from under the pad, and since the rotor is going at xxxrpm (say about 900rpm at 1:1 gear, final drive of 4:1) each slot will pass the rotor quite a few times. 12 slots would work better, but probably not really worth any potential increases in wear.

Like I said. No expert.
Try the TS sponsors 0800 RACEBRAKES and ask them all about it. They know what they're talking about.

[ROBODISCO_20v]

Slots are more for "cleaning" the pads...

More slots would scrap the pads "clean" a lot more often. Mostly useful to help prevent glazing. Also help a little with de-gassing and cooling the rotor.

If you want real cooling/degassing then try looking for cross-drilled and vented rotors, or for just cooling ducting...

Both slots and cross drilling are for de gasing. DBA did some testing and found that the stoping distance for both is the same. So there is no improvement in stopping with cross drilling its just and advantage for heat dispertion.
http://www.dba.com.au/default.asp
I have dba gold drilled & slotted on the front of my BZ-G with Lucas pads. Car stops on a dime, I Sell them at my work(appco) so if you like a price PM with your cars details or ph me at wk 444-1313. Carl

[Brolli]

With the cross drilled or slotted rotors, Does it affect the rest of the brake system and do you need to upgrade the calipers yada yada or get them certed ?

[Lloyd]

Nope, they're just replacement rotors. If you get direct replacements then you dont need to change anything, if you start playing around with replacement calipers and braided hoses and things then you need to get certs (as far as I know)

[GT4 20]

Common misconception - cross drilling is not there specifically for 'de gassing / cooling'. X drilled rotors were devised orginally as a means of reducing unsprung weight.
The 'holes' can lighten the weight of a rotor considerably, but at a price. With the surface area full of holes, you get uneven cooling of the material. This can (and often does) result in the rotor cracking between the holes, especially under hard use.
It is for this reason alone that I will never use x drilled rotors on an everyday car. I've seen the result of a car driving hard and then going through a big puddle. The thermal shock of the water hitting the already hot x drilled rotors was not good to say the least.
Fit grooved rotors by all means (bearing in mind that they tend to accellerate pad wear), but if you do go for x-drilled, check them often for signs of cracking.
Gary



ps Don't go posting lots of "But I've got cross drilled and never have any problems". I appreciate that there are cars out there which use them - but there are cars which do have problems with them - either from extremely hard use or poor quality rotors.

[GT4 20]

if you start playing around with ....... braided hoses and things then you need to get certs (as far as I know)

So long as the braided hoses comply with the relevant LTSA standard (forget now what it is) and the said standard is clearly labelled on each hose, then a cert is not required.
Gary

[ROBODISCO_20v]

ps Don't go posting lots of "But I've got cross drilled and never have any problems". I appreciate that there are cars out there which use them - but there are cars which do have problems with them - either from extremely hard use or poor quality rotors.

If what you say if true then why do companys like porsche fit them to most of their cars????? I'd like to know where you got your info from to make such a claim
http://www.giltrap.co.nz/porsche/frame-new.html

[TRDmod]

tge reason why porshe use cross drilled is cos firs tof all, the discs are cast and created or forged with holes, but cheap ones that dont cost thousands per pair are not liek that they are literaly drilled...hence weakening structure, also if you look at the thickness of a porshe or lambo o ferarri, the discs are THICK ASS AN IDIOT.....also they are big, i mean 14-16 inch discs with 4-6-8 pot callipers.....what ever they put on them depending ont he car....so thats why they dont crack, but!! but!! thats not always the case
did you know in america, ferarri enzos get their brakes replaced from brand new very frequently, in ratio to the number of enzos actually made, y? cos they dont bed them, and also, the brakes look good but not for EXTREME RACE SITUATIONS which some push it too hard......u say, why pay millions on a car and brakes fail, well, the carbon brakes they have are also experimental, similar to the cararra gt, and sometimes they need improving, touch ups and upgrades, these ppl dont care they are rich....

so that answers your questions, alot of factors into it, but if you are goin budget way, then cross drilled isnt that good, slots are
.....

[GT4 20]

As TRDman says. Top end market x drilled rotors are cast with the holes, aftermarket ones tend to be drilled after the casting process. You can't fight the law of physics as the rotor cools down at a different rate across it's surface which can weaken the material resulting in cracks.

And from the Wilwood website...

Q: Why are some rotors drilled or slotted?
A: Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching for ways to minimize unsprung weight. Drilling diminishes a rotor's durability and cooling capacity.

Slots or grooves in rotor faces are partly a carryover from the days of asbestos pads. Asbestos and other organic pads were prone to "glazing" and the slots tended to help "scrape or de-glaze" them. Drilling and slotting rotors has become popular in street applications for their pure aesthetic value.

[ROBODISCO_20v]

Well DBA make rotors for the new Ford GT-P & HSV's so they're not that budget.
You people that dont have these things on your car and just go on stories of my mate had this and it did this need to stop being such old woman. We've been selling DBA rotors for years and haven't had one back as a claim for cracking. Any rotor is going to crack/warp if you get it really hot then pour water on it, but you have to put heaps of water on it like a garden hose. Even when you drive thru a puddle the water generaly sprays away from the tyre ond not onto the brakes.

Anyway for all those out there thinking about putting drilled/sloted rotors on your car, DO IT. You'll be impressed with the improved stopping power, no point having a fast car if it cant stop in a hurry.

[Al]

Anyway for all those out there thinking about putting drilled/sloted rotors on your car, DO IT. You'll be impressed with the improved stopping power, no point having a fast car if it cant stop in a hurry.

Now this intrigued me. Why would my car stop quicker if I got better rotors? Arent better rotors there to just dissipate more heat and be able to break as hard for longer? Maybe lose some unsprung weight from the car?

Because my understanding of breaking is that if your current setup can successfully lock up your wheels then you cant stop any faster, no matter how big your rotors/calipers etc are. You need to change the other friction surface; the tyres, to slow your car down faster.

[ROBODISCO_20v]

Dude i wont even bother answer that its such a stupid question.
Sorry i guess i cant expect everone to be upto to play on these sorts of things. Have a read of the DBA web site, you should find some info on there to help you understand how this works

I found the info for you

Slotting increases pad bite, reduces fade and delivers better braking performance. The slotts continually de-glaze the pads improving efficiency. They wear evenly across the pad faces increasing the effective contact area. Slots help dissipate water as well as pump away dirt & dust. Slotting and drilling also combats "out-gasing", where gas from the pad bonding agents can form a cushion between pad and rotor, greatly reducing braking power.

There, i hope that helps

[Pelo]

If the upgraded discs etc. make more heat and are able to work efficiently at the higher temperature, and remove the heat created efficiently, you will stop faster.
All brakes do is convert kinetic energy into heat energy, so if they can make more heat quicker they will correspondingly remove more of the energy moving the car.

[Al]

Dude i wont even bother answer that its such a stupid question.
Sorry i guess i cant expect everone to be upto to play on these sorts of things. Have a read of the DBA web site, you should find some info on there to help you understand how this works

I didnt think it was a stupid question at all. I thought it was simple physics. You have two friction surfaces the pad/rotor and the tyre/road. If you can successfully lock the pad/rotor until you are stopped the only other way of slowing down quicker (without changing suspension/weight of vehicle) is with tyres that have more contact area on the road.

[Mr Revhead]

robo arnt you the guy that thinks generic aftermarket parts are better than factory ones? oh dear....


first up, brake performance is reliant on many factors, including tyres and suspension.

slots are as stated many times above, to dissapate gas caused by the fricton of the pad against the rotor.
holes are purely for weight saving, and the majority of major sporting brakes no longer have them as they do decrease braking perfromance and rotor life.

Dude i wont even bother answer that its such a stupid question.

not a question.... he's correct. if your currant brake set up can lock up the wheels with minimum effort then you will need to improve tyres and/or the things that manage the tyres. such as suspension.
improvimg the brake package may prevent fade over several stops, but wont make it stop any faster. simple physics.

DBA are an aftermarket company that makes everything from cheap nasty BNT replacements, to sporting type rotors. they rate below brembo and ap racing etc... they are good for road cars and amatuer racing, but you wont find them on any cars at le mans!!

[vvega]

Dude i wont even bother answer that its such a stupid question.
Sorry i guess i cant expect everone to be upto to play on these sorts of things. Have a read of the DBA web site, you should find some info on there to help you understand how this works

I found the info for you

Slotting increases pad bite, reduces fade and delivers better braking performance. The slotts continually de-glaze the pads improving efficiency. They wear evenly across the pad faces increasing the effective contact area. Slots help dissipate water as well as pump away dirt & dust. Slotting and drilling also combats "out-gasing", where gas from the pad bonding agents can form a cushion between pad and rotor, greatly reducing braking power.

There, i hope that helps

souldnd like you got nailed buy that rep too
dont spose he sells you your gates belts too

maybe if you went back to scholl go to uni and then get some idea on physics you would realise that what your saying is untrue

the holes are specifically for lightness...thats all
the slots are to were ther to wipe the pads
if you can lock your wheel your aplling maximun force
it dosent get any better than that
if you can explane how you can apply more braking force to the ground than locking a wheel then you are a lost cause
oh thats right we already desided that

please stop the regergataion of sale propgander
i know of 5 people that have cracked there cheap and nasty dba sport rotors or have had them warp
dba is cheap crap
thats it

maybe if you worked in a race shop you would understand what preformace is ...

v

[GT4 20]

Of course ROBODISCO_20v is going to say that dba rotors etc are great and they've never had one crack etc as he has a vestid interest being a vendor. Companies are always going to say that tehir product is the best. You want advice from somewhere that has experience and doesn't want to make money out of you

And R_20v, you may wish to think before you post comments - "You people that dont have these things on your car and just go on stories of my mate had this and it did this need to stop being such old woman." I have plenty of personal experience with cars - at nearly 40 years of age I'm not some spotty kid who talks out of his rectum.
Drilled rotors were, as I orioginally stated, developed to reduce unsprung weight - not to improve braking. At the end of the day they may (as well as grooved rotors) reduce heat build up, but as the surface area in contact with the brake pad is effectively reduce, simple physics will determine that you statement will not always be true. Al has asked a perfectly intelligent qiuestion. Shame you can't provide an intelligent answer
Gary