RB5DOCC

Want to uprate my brake discs, nothing to radical.

Have noticed that most upgrade kits consist of grooved discs however, most if not all of the high end proformance cars have x drilled discs.

What is the major difference?? Why are grooved discs not fitted as standard, does this mean x drilled are better???

Scooby-Mark

From what I understand the X Drilled discs help reduce heat in the discs and grooved provide more friction against the pad for more stopping power ( I may be totaly wrong though )

On my two previous cars 95 Clio Williams and an 02 Clio Sport 172, I fitted the Black Diamond "Combi" discs which are X drilled and grooved and couldn't fault them one bit, dramatically increased the stopping power on both cars and look cool through the alloys with that slightly unsual look of both grooves and holes

I also found them to be excellently priced comparied to other brands that only offered the single option for the same price !!

Will definatley consider fitting them to my MY05 Scoob when the time arises for new brakes !!

Mark.

willy

Its down to noise...
Drilled discs are quieter..
Grooved discs allow gases to escape and clean the pads more... but are noisy.

Thats why high end cars have x drilled discs..

*****

7 Foot

Drilled discs are also more likely to crack. Have a look at the grooved and vented Godspeed discs - great quality.

warrenm2

as above - drilled can crack - go grooved

Mike P

There's been some debate about the robustness of drilled discs on scoobs. The discs are relatively thin, and the combination of this with the holes can result in cracking, especially with some of the more agressive aftermarket pads.

Unless you're doing serious track days or are already maxing out the brakes I'm not sure if they bring that much benefit.

After a remap I'm going to try a pad upgrade on standard discs, for two reasons.

1) Standard discs are cheap so if I knacker them I'm not bothered
2) If a standard disc is good enough for a group N rally car it'll probably do for me

Mike

lee green impreza

ive just fitted ebc turbo grooved which also have dimples instead of cross drilling and ebc red stuff ceramic pads make a hell of a diffrence to stopping.

p1doc

as i understand it-group n discs are the best 10% of all standard discs so they are an improvement on standard
martin

awd wrx

Group N discs are just standard discs , and as I rally a Gp N Impreza can confirm that the discs last maybe 1 or 2 rallies ! we would put grooved ones on there but arn't allowed under the regs...

RB5DOCC

Have to agree with Mike, if standard is good enough for Group N, then good enough for me. Although the black diamond disc do seem to be rated.
As i dont drive my car to hard and it will never see a track, drilled may be the best compromise for me, will have to ask a specilist like Godspeed i think.

I have used EBC on two previous cars (not scoobys) and was not impressed. The red pads and disc are recommended, but something in my head wont let me do it.

RB5DOCC

Also AWD WRX, just want to ask why you would go for grooved over drilled if the rules allowed?

Are drilled really that weak?

awd wrx

For normal fast road use the drilled discs wouldn't be a problem , if you are hard on the brakes , or do track days then you will end up with cracks around the holes , and this is with any make disc , With the rally car I left foot brake a lot , which serously overheats the discs , so grooved discs wont crack like drilled ones would

Fat Boy

The only "drilled" ones that are ok are those with cast in holes as per Porsche for example for track days and/or hard road use.
The drilling causes stresses in the disk that are increased when it gets very hot and will cause cracking and, in the extreme, the shattering of the rotor. Bigger disk equals more area for bigger pads to work on and better heat dissipation, that doesn't necessarily mean you'll stop harder but it does mean you can keep stopping...

awd wrx

Have a look at a Porsche that does track days with someone who 'drives' it , they will have cracks in them , I dont mean the posers on the track !

Fat Boy

I'm not disagreeing with you, I'm just trying to stop someone buying a halfrauds kit or whatever with cross drilled rotors by pointing out that only the most expensive kit should be considered if you really really want this look. For instance, Movit cross "drilled" brakes on a scooby work pretty well given the big difference in weight betwen a porker and an impreza, and proper race brakes with "holes" done properly are ok, but, as you know, these are treated as disposable items to be binned after each event, not for some bloke in his 6 week old shiny 911 Turbo to ponce around silverstone in and then do another 10k miles in before he looks at his brakes again....

Me, I'm happy with my Alcon Calipers and 330m grooved rotors, Goodridge hoses, uprated fluid, with DS3000 pads for the track and Pagids or DS2500 etc for the road. Mind you, still been through 3 sets of these rotors in 40k miles...

Mick

iTrader: (1)

Just put EBC 'sport' rotors all round on my Disco (V8 not TD5 ) - dimpled and grooved - used with SUV equiv of 'greenstuff' pads - worthwhile upgrade I think - looks cool too

Found best price at www.brakes4u.co.uk - quite a well set up site.

Mick

anfywills

WHAT EVER YOU DO ONLY PUT THE RED CERAMIC PADS ON

DO NOT PUT GREENS ON OR YOU WILL GET BRAKE FADE

Aztec Performance Ltd

iTrader: (234)

I run some cheap OE discs (cost about £30-40 each) and they work well with EBC Ceramic pads, braided lines and 5.1 fluid.

Previously went through two sets of pagids cracking and warping both within a year (low miles).

IMO drilled and grooved discs are overhyped.

Will be sticking with the same set-up on the next change too as they havent let me down yet and this include some heavy miles with heavy useage and some track-work also.

Bob