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Discussion Starter #1
Tarquini is up for some new discs soon. Depending on how much of my hard-earned the tax man wants, I will replace the whole lot.

My question is; Does anyone have any recommendation?

I don't have any preference at all except I don't like those little slots everywhere. I can deal with a few grooves but my ideal disc is going to have a million holes in it and no grooves at all.

Red Dot do those Sport Japans which seem to be in pole position at the moment but I'd be interested to hear what other people have to say.

Tarquini is a V6.


Ralf S.
 
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I know very little about discs but one word of warning. Grooves are supposed to be better in the long run. I've seen pictures of discs that have failed due to cracks appearing inbetween the holes through wear and overheating.

Dunno how they are put in the disc, if its by drilling that is not good for the metal. If they are cast in then it will be stronger.

wrinx
 
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I believe that cross-drilled disks are, as the name suggests, drilled rather than cast. However it is possible that the disks are heat-treated after drilling which should remove some of the stresses.

Having said that, I wouldn't choose disks with lots of holes in them. I am using Forza grooved disks from Autodelta - they have been on the car since 20,000 miles (when the originals wore out, I gather) and have survived 40,000 miles of hard driving. They will need replacing soon (getting a bit thin) but they seem to offer good performance.

Choice of pad is at least as critical (if not more so) as choice of disk - some pads offer brilliant braking but wear fast, others offer brilliant braking but wear the disk out fast. I've got Tarox pads on the Alfa and used them on a 33 and an X1/9 as well - they seem to offer good fade-resistance, long life and reasonable disk wear. A good compromise.

Ian
 
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Discussion Starter #4
Just for reference, the grooves and holes are there in the disk to dissipate the gas produced at the interface of the disk and pad, personally I prefer grooved disks as Like wrinx I have heard horror stories about drilled disks.

As for what to go for, Tarox, brembo, etc...

And at the moment Evo Eng are having a brembo sale, I think they are offering Brembo disks + EBC or other quality pads at £134 + Vat per Axle

Steve
 
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Discussion Starter #5
Grooved again, got some 'free' Red Dot on my 75 3 litre, 20 grooves plus Red Dot pads, still look like new after 18 months and about 10K miles, very pleased. 75 brakes are rubbish as standard, the discs and pads made a very noticable improvement.

I won them at the Italian day at Donington summer 2001. I think they felt sorry for me, 17inch Momo sport wheels, and some well worn and puny standard discs showing behind.
 
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Discussion Starter #6
Ian Spring:
I believe that cross-drilled disks are, as the name suggests, drilled rather than cast. However it is possible that the disks are heat-treated after drilling which should remove some of the stresses.
Drilling is the problem, being cast with holes which are then tidied up is preferable, this is what I'm not sure about. Drilling through metal destroys the molecular structure and thefore weakens it. Also heat treating would not stop the smaller area of metal between holes becoming hotter quicker than larger areas of metal, increasing the risk of cracking/warping. Metal must be heated evenly to prevent this........even then its not gauranteed! :confused:

wrinx
 
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Discussion Starter #7
I've got Tarox sport japan disc on mine. These are "drilled & slotted" however if you look closely at the holes it would appear that they have been cast with the holes.

I may be completely wrong, this is just how it looks to me. :D

BTW these and tarox pads give superb braking, they do work better when warm though.
 
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Discussion Starter #8
i have black diamond drilled and grooved on mine theyre not dear and are very good.done track day with them no problems.
alan.
 

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I've read somewhere that quality drilled discs are cast with holes in and cheaper ones are just drilled and not that good, because of possible fracturing.

As for the slot / drill debate, all high performance road cars that you see (Ferrari's, Porsche's etc.) have drilled rather than slotted discs... does this tell you something?
 

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Take a look here

Porsche drilled discs

This didn't take a lot of finding under secret 'non slotted discs' parts of the website either... and it looks like it's just the cheapy boxter that gets plain discs.
 
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Discussion Starter #11
I think that grooved disks throw off more pad material, my 20 grooved Red Dot are bad for that with the semi-race pads, although the fast road ones don't do it so much. But they don't stop as well. I think if you buy decent disks they should be OK drilled or grooved.
 
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Discussion Starter #12
I had sport Japan Discs and the tarox pads on my 33, the holes did appear to be cast and not drilled.
Oh and they were a big improvement and didn't show much sign of excessive wear.
In short I would thouroughly recomend them!
 
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