Opinions on Front Slotted & Cross Drilled Brakes

[tone]

Hey peeps,

Was looking at upgrading my front brakes with something a little more impressive. Not going to buy a whole kit as they cost a tonne but something like :

Front DBA Slotted & Cross Drilled 4000 Series (pair)
http://www.mpsgarage.com.au/shop/pro...ries-pair.html

or

Rotora Front Drilled and Slotted Rotor Pair
Rotora Front Drilled/Slotted Rotor Pair: MS3

does anyone know if one is better then the other? or if I get a pair will i need to change anything else to make them fit correctly? or if there are any other costs associated with these. eg new pads etc etc.

My reasoning is that my current brakes are warped (been 2 years) and with new pads, they feel absolutely rubbish. I drove my friends Mazda 3 (2 years old) with just new pads. and It felt excellent compared to mine.

[2XS]

Slotted keep the pads clean and therefore help with braking, cross drilled can crack, not always the case, but the C/D allow better cooling of the rotors.

The questions are:
How hard do you really push your car?
Do you take it to the circuit at all?

[tone]

I tend to boot it around here and there. Nothing stupid though. I dont take it to the circuit, but I think i need something better as my current ones are just no good anymore. Took mums festiva for a drive to the shop just then. That has a better braking feel then my mps now.

So you think those might be a bit of overkill?

[Nuliaj]

Slotted chew through your brake pads. Think of them as cheese graters. Drilled are more likely to crack. Doesn't sound like you track (circuit not drag) so just go with the standard replacement (non drilled or slotted). Maybe change your brake fluid as well, should give you a better feel.

[tone]

so something like these?

http://www.mpsgarage.com.au/shop/pro...ard-pair-.html

or

http://www.streetunit.com/Rotora_Fro..._p/r.45078.htm

[Nuliaj]

Bingo. I would only go as far as slotted for the "race" look but remember you have to pay to play (in this case faster brake pad wear).

[Jmac]

Id go the DBA slotted only (not drilled)..

Personal preference, once slotted the bite is much better and less likely to fade..
+ bendix pads.

[MaN|aC]

Id go the DBA slotted only (not drilled)..

Personal preference, once slotted the bite is much better and less likely to fade..
+ bendix pads.

seconded......you can get away with slotted rotors and some harder pads like ceramic bendix or ebc reds.

technically you wont get more bite with slotted as there is less surface area, however you will be less prone to fade as they dissipate heat better. cross drilled rotors are a lot more fragile but dissipate heat the best. They also chew your pads the most. good for circuit racing if you plan on replacing everything after 40 laps

if i had to replace rotors i would do the same as JMac, DBA slotted but go ebc reds cuz i get them sooo much cheaper.

[Nuliaj]

As tone has mentioned though, he doesn't track his car and for a road going MPS brake bite, heat dissipation or brake fade are not common issues, but cost would be. You pay $100 more per pair of rotors and additional cost of going through brake pads quicker is for most people not worth the cost unless you really like the look of slotted brakes.

[tone]

In terms of braking performance, is there a notable difference between slotted and just standard non slotted or non cross drilled brakes?

[kmh001]

Brakes convert kinetic energy into heat energy. The greater the mass of the rotor the better it will work to absorb heat. If you remove mass from the rotor by cutting slots or cross drilling it be less capable of absorbing heat and fade will occur sooner.

The slots and holes do not aid cooling, the only technical reason they exist is to mitigate the effects of fade by providing a pathway for the gasses that cause brake fade to escape, but this is a band aid solution. It's better to design the brakes properly so they don't fade in the first place, and the MPS is pretty good in that area as long as the correct pad material is chosen.

The other reason slots and holes exist is because they have become fashionable, but trust me, they reduce braking efficiency and fade resistance. You would only choose slotted or drilled rotors if your stock brake setup is hopelessly inadequate and plagued by fade and you need to get the gasses out.

If your brakes have gone off it sounds like they need maintenance, not a redesign. Some things to consider include how many km have they done, whats the pad thickness and rotor thickness? Are the slides well lubed or dry? How long since the fluid was changed? Old rotors that have worn down by 2mm will have lost an awful lot of mass and will fade much sooner. That's why I prefer to discard rotors instead of machining them.

[rd415]

I wonder sometimes if the comments made are through experience or just somebodies perception or what they have read elsewhere. Having fitted DBA slotted discs all round to my VXSS Commodore, I firstly found that the warped disc problem of factory discs no longer occured. Warping discs is another topic, but there is a simle expanation for the warp and it can be difficult on some vehicles to prevent the warp occuring. Back to the slotted discs, pad wear didn't change, pedal feel and stopping ability felt much better. Exactly the same increase in performance on my son's VL with slotted disc's.
The variables are that it may not be the fact that the disc's are slotted, it may be that they are just manufactured from better quality material.
I would buy slotted discs, purely because of the quality, not because of looks

[spastic]

dude i have put slotted on my 99barina their wicked for what they are don't go with cross drilled as everyone has said they can crack and if you go slotted you will need new pads don't go ceramic tho they make alot of noise just go like top of the line bendex or ferdo but not the titanium strip bendex their no good for anything but standard. there is a deffenate diffrence in braking once you go slotted but be sure if you do go slotted bed them in first you'll need to do atleast 500km b4 you go jamming them on too hard unless you "have" to also when you change them mabey get a fluit flush as well

[Jmac]

I am speaking from experience from when I had my SSS.
Whilst I did have an upgraded brake setup (from GTIR) the slotted DBAs were better through the weekend natio run than the non slotted, I was using bendix advance pads.. Was a great setup so would be inclined to do the same..

For a little bit more dosh I personally think it would be worth while, though as it will be you parting with your money - your call

DO IT!

[Nuliaj]

You can't compare going from stock Holden brakes to aftermarket, as the stockers are a POS. The easiest way to explain this to people is - if you slam you brakes can you cause your ABS to kick in? If so going aftermarket brakes just means you're going to get ABS to kick in sooner. I'll say it again, the limiting factor when it comes to braking in our cars is the tyres, and unless you're going tracking, the standard discs are more than enough for daily driving.

[rd415]

You can't compare going from stock Holden brakes to aftermarket, as the stockers are a POS. The easiest way to explain this to people is - if you slam you brakes can you cause your ABS to kick in? If so going aftermarket brakes just means you're going to get ABS to kick in sooner. I'll say it again, the limiting factor when it comes to braking in our cars is the tyres, and unless you're going tracking, the standard discs are more than enough for daily driving.

Stock brakes are as you say, BDA brakes are a huge improvement over the stock brakes. Your theory on ABS is not quite accurate, do some research on ABS. Yes the tyres are the limiting factors on braking distances, that's the whole point, there are so many limiting factors that just fitting quality discs is a great improvement.
There is a theory with HSV vehicles that the ones fitted with premium brakes are involved in more accidents. The reality is that the driver takes greater risks because of thought of having better brakes. (Written in an investigation by insurance companies). I would still have the best brakes available, even for normal road use. Brakes and steering are the most important part of any vehicle.

[Nexus]

If you want to try different, I would go the slotted rotors and appropriate pads. If it turns out not be of your liking, Sell them and go the other way? If you don't see really excessive brakepad wear I'd bet you'd be preferring them.

In time it's likely I'll be trying DBA slotted. I wouldn't go crossdrilled more fragile - I think you'll find the slotted are street/track spec and the crossdrilled are street only.

[tone]

At the moment im using the HAWK HPS pads:
http://www.mpsgarage.com.au/shop/pro...s,-front-.html

it seems as if most people are saying to give the slotted brakes a shot. i was prepared to spend upto 500, so whether they are 200 or 400 i dont mind. just depends on which will perform better.

Is there any difference between the

Rotora
Rotora Front Slotted Rotor Pair: MS3

or the DBA's
http://www.mpsgarage.com.au/shop/pro...ries-pair.html

They are both the slotted pair.

---------- Post added at 10:39 PM ---------- Previous post was at 10:38 PM ----------

Brakes convert kinetic energy into heat energy. The greater the mass of the rotor the better it will work to absorb heat. If you remove mass from the rotor by cutting slots or cross drilling it be less capable of absorbing heat and fade will occur sooner.

The slots and holes do not aid cooling, the only technical reason they exist is to mitigate the effects of fade by providing a pathway for the gasses that cause brake fade to escape, but this is a band aid solution. It's better to design the brakes properly so they don't fade in the first place, and the MPS is pretty good in that area as long as the correct pad material is chosen.

The other reason slots and holes exist is because they have become fashionable, but trust me, they reduce braking efficiency and fade resistance. You would only choose slotted or drilled rotors if your stock brake setup is hopelessly inadequate and plagued by fade and you need to get the gasses out.

If your brakes have gone off it sounds like they need maintenance, not a redesign. Some things to consider include how many km have they done, whats the pad thickness and rotor thickness? Are the slides well lubed or dry? How long since the fluid was changed? Old rotors that have worn down by 2mm will have lost an awful lot of mass and will fade much sooner. That's why I prefer to discard rotors instead of machining them.

Well, the reason i want the new brakes, is because, since getting them machined, it feels like i have none. Maybe replacing them rather then spending 130 on machining would have been the better option.

[Nexus]

The differences would come down to quality of product. DBA is solid on reputation, and they're local, and reportedly great quality, Rotora?

Added a poll...

[Nuliaj]

Stock brakes are as you say, BDA brakes are a huge improvement over the stock brakes. Your theory on ABS is not quite accurate, do some research on ABS.

What exactly should I be researching? It's all good to say you disagree, but at least provide a reason. ABS in it's simplest form is the fastest you're going to stop in almost any situation. In a panic situation when you most need brakes (on public roads) if your brakes are sufficient enough to get ABS to kick in, then it doesn't matter if they're drilled/slotted or standard, you're going to stop in the same distance PERIOD. This is assuming all other factors being equal, as this whole discussion is on brake discs.

Yes the tyres are the limiting factors on braking distances, that's the whole point, there are so many limiting factors that just fitting quality discs is a great improvement.

The key to your sentence is quality discs which I agree with. However are you're implying standard discs are not as high a quality as slotted ones if they are manufactured by the same company? Let's use very simple physics here. Slotted discs at any given moment of braking will never have the same contact area with the brake pads given equal size discs. This is a fact. Less surface area = less friction. Assuming all things equal (pads, brake calipers, brake fluid etc), you cannot possibly argue that slotted will allow you to brake faster.

I don't mean this towards anyone in particular as this is just an observation in general, but it seems sometimes people feel the need to justify their purchases regardless of the facts.