Drilles/grooved disks.

[Technonotice]

The disks need changing on my mates car. Is it worth using drilled/grooved disks(oem size) or just using standard solid ones.

cheers

[GreenV8S]

Use plain discs unless you have an overheating problem. If the brakes are fading consider using higher temperature pads to reduce gassing. If that isn't an option, grooved discs dissipate the gasses but at the cost of more noise and pad wear, and reduced friction area.

Don't ever use drilled discs. They dissipate gases the same as grooved discs but are substantially more prone to cracking which can eventually lead to catastrophic failure. If your brakes are hot enough to drilled/grooved brakes to be necessary then they will be hot enough for cracking to be an issue.

[Technonotice]

GreenV8S said:

Use plain discs unless you have an overheating problem. If the brakes are fading consider using higher temperature pads to reduce gassing. If that isn't an option, grooved discs dissipate the gasses but at the cost of more noise and pad wear, and reduced friction area.

Don't ever use drilled discs. They dissipate gases the same as grooved discs but are substantially more prone to cracking which can eventually lead to catastrophic failure. If your brakes are hot enough to drilled/grooved brakes to be necessary then they will be hot enough for cracking to be an issue.

Apologies for the silly question, but you do see Porsche and the like with drilled disks as standard. Are these prone to failure? Or are the oem drilled disks as safe as solid ones?

will advise to stick with solid oem's. cheers

Edited by Technonotice on Tuesday 14th April 15:12

[GreenV8S]

Technonotice said:

Apologies for the silly question, but you do see Porsche and the like with drilled disks as standard. Are these prone to failure? Or are the oem drilled disks as safe as solid ones?

will advise to stick with solid oem's. cheers

Some of the more expensive OEMs use discs with cast holes rather than drilled. These still suffer from cracking, although not as severely as drilled discs.

[tertius]

Technonotice said:

GreenV8S said:

Use plain discs unless you have an overheating problem. If the brakes are fading consider using higher temperature pads to reduce gassing. If that isn't an option, grooved discs dissipate the gasses but at the cost of more noise and pad wear, and reduced friction area.

Don't ever use drilled discs. They dissipate gases the same as grooved discs but are substantially more prone to cracking which can eventually lead to catastrophic failure. If your brakes are hot enough to drilled/grooved brakes to be necessary then they will be hot enough for cracking to be an issue.

Apologies for the silly question, but you do see Porsche and the like with drilled disks as standard. Are these prone to failure? Or are the oem drilled disks as safe as solid ones?

will advise to stick with solid oem's. cheers

Edited by Technonotice on Tuesday 14th April 15:12

And my 993 has just destroyed another set of cross drilled discs - that was after two track days. They are fine on the road.

I'm struggling to find a grooved option that I've heard of - only one seems to be Black Diamond? Anyone any experience?

[Huff]

I'm using grooved BD discs on the front of an E34 540 - they needed replacing anyway, and its a heavy car driven fast.

Hum like a bugger under moderate braking, but really haul-down when used in anger. Better than stock. 10k miles in, they are wearing well and no complaints - they're showing no cracking, heat-checking or most especially the warping which afflicts stock rotors.

[PJ S]

tertius said:

And my 993 has just destroyed another set of cross drilled discs - that was after two track days. They are fine on the road.

I'm struggling to find a grooved option that I've heard of - only one seems to be Black Diamond? Anyone any experience?

Steer clean of BD - heard many a horror story about them.
Tarox or DBA would be my choice.
What pads are you using?

[Kylie]

Cross drilled rotors will fail only if you punish them bady say at track days where the heats builds behind the caliper if left to stand still. My 350 has rather large cross drilled rotors and always make sure I rock the car forwards or backwards when coming back into pits to park up so the heat dosent build up in one spot. My mate had this failure on his racing Porsche but these precautions will help. Everyday day driving you should be sweet. Cross drilled rotors do look sexy

[GreenV8S]

Kylie said:

Cross drilled rotors will fail only if you punish them bady say at track days where the heats builds behind the caliper if left to stand still.

It's not just a matter of stationary heat soak. They also suffer cumulative cracks from thermal stresses as they heat and cool in use. All discs do, but drilled discs in particular tend to concentrate these stresses and the resulting cracks around the holes, as a result they tend to suffer far worse cracking than plain or grooved discs.

[tertius]

PJ S said:

tertius said:

And my 993 has just destroyed another set of cross drilled discs - that was after two track days. They are fine on the road.

I'm struggling to find a grooved option that I've heard of - only one seems to be Black Diamond? Anyone any experience?

Steer clean of BD - heard many a horror story about them.
Tarox or DBA would be my choice.
What pads are you using?

I'm using Pagid Blues (RS4-2). I can't find a Tarox (or indeed any other except the never previously heard of Black DIamond) listed for the std 993.

[PJ S]

The Tarox discs you need, are the F2000, NOT the G88, since you're tracking the car.
Part # 9303 Fr and 9444 Rr

DBA don't make one suitable off the shelf, but you could go with their 2-piece 5000 series, but that may require a custom hat. Might still be an option, but I'm thinking not really unless you're tracking the car a lot.

An alternative to the Tarox is Nitrac, with their cryogenic treatment, and black phosphate coating option - website certainly makes a good case for going with them.
www.nitrac.co.uk

[Huff]

PJ S said:

Steer clean of BD - heard many a horror story about them.
Tarox or DBA would be my choice.

Got any links? A quick search here only suggest probs with the pads.

[tertius]

PJ S said:

The Tarox discs you need, are the F2000, NOT the G88, since you're tracking the car.
Part # 9303 Fr and 9444 Rr

DBA don't make one suitable off the shelf, but you could go with their 2-piece 5000 series, but that may require a custom hat. Might still be an option, but I'm thinking not really unless you're tracking the car a lot.

An alternative to the Tarox is Nitrac, with their cryogenic treatment, and black phosphate coating option - website certainly makes a good case for going with them.
www.nitrac.co.uk

Cheers, that is a huge help.

[PJ S]

Huff said:

PJ S said:

Steer clean of BD - heard many a horror story about them.
Tarox or DBA would be my choice.

Got any links? A quick search here only suggest probs with the pads.

Anecdotal unfortunately from a number of Scooby and Evo guys at a recent detailing meet - mentioned them, and they fell about laughing.
Think I might have read something on one of the Civic forums - but then as a lot of other members use/recommend EBC greens, I have to wonder if maybe their expectations were too high.

http://thaoc.ipbfree.com/index.php?showtopic=1589&...
http://bbs.scoobynet.com/group-buys-356/333651-bla... - although it is almost 5 years since originally posted!
http://www.pistonheads.com/gassing/topic.asp?t=199... - cracked drilled and grooved Black Diamond discs