Discs Drilled Grooved Or Both?

[brumster 135 1 Cars]

I run the 285mm AP 4-pots. The calipers weigh naff all and, well, put it like this - you won't catch me putting a standard caliper and disc back on there any time soon (maybe when the money runs out!)....

 

Only problem I have is the relatively narrow 21mm disc that these older spec calipers run; discs are starting to craze now, mind you they've done a good 6 years of service so can't complain. But while I'm toying with the idea of having to buy new ones, I'm considering moving up to thicker discs while I'm at it...

 

I ran them briefly with the standard master cylinder and servo. s*it me you could stand the thing on it's nose big-time then!

[CopperBottom 1]

I have no experience on a pug, but my 300zx now runs DBA5000 2 Piece slotted rotors with Mintex 1155's with Brembo Ferrari F50 4 pot Calipers. I used to run DBA 4000 single piece plain disc which I changed to the 5000's during an open pitlane day at Bruntingthorpe (i picked them up from the seller at the track day and took the opportunity to do back to back tests)

 

After bedding the discs in, in terms of overall performance the only real difference i found that the slotted 5000's gave a better intial bite that the 4000's, which on a reasonably heavy car like the zed, gave a bit more confidence on corner entry. In terms of how they handled heavy braking, i didnt manage to set off the highest heat thermographic paint on either disc, so they both were competant discs.... i just prefered the feel of the 5000's (and they offer a lower unsprung weight compared to the 4000s)

 

Oh, and EBC, personally i wouldnt use their discs as paperweights! I know so many people who have warped them.

 

For the pug i'd more than likely either go for DBA4000 plain discs (if they do them for the pug) or Brembo plain discs

 

Oh and the usual pub talk of "porsches' etc run drilled disc, they must be good".... the difference is that those discs are CAST with holes in, not drilled..... Drilled discs WILL crack. FACT

 

Just in IMHO of course

Edited October 26, 2012 by CopperBottom

[oonip 4]

Just to clarify for the people that are giving advice without any real background knowledge ... A grooved disc does affect the braking feel. The various different groove patterns are designed to improve bite whilst limiting the increased wear.

 

As for the claims 'race guys use plain discs'. I'm guessing they are low level, low budget racers that need discs to last longer than a few sessions.. There are gains to be had from grooved discs (note you never see drilled disc's on a race car anymore - a good one at least), the grooves will increase pad wear, which quickly gets expensive if you are really giving them some abuse.

 

As an added extra they will also help the release of gasses built up but as somebody has said it's not as big of an issue as it use to be.

[commievid 8]

 

Just searched for some low level, low budget racers.

 

http://www.fmcgcollectables.com/memorabilia/Carbon-Brake-disc-used-during-the-2006-season-on-the-Red-Bull-RB2-RB06RB2M-000003.html#aRB06RB2M_2d000003

[CopperBottom 1]

You can't really compare a carbon disc to a steel one!

[Mad Scientist 106]

I used to sell brakes through my own company. Spent lots of time talking to manufacturers and suppliers. Grooved or drilled discs have no advantage with modern pad compounds. Fact.

 

My 911 carrera s has drilled discs. They are known to crack between holes, and Porsche consider it normal. At 400 quid a disc, it's a bit of a joke!

[Batfink 201]

Just to clarify for the people that are giving advice without any real background knowledge ... A grooved disc does affect the braking feel. The various different groove patterns are designed to improve bite whilst limiting the increased wear.

 

As for the claims 'race guys use plain discs'. I'm guessing they are low level, low budget racers that need discs to last longer than a few sessions.. There are gains to be had from grooved discs (note you never see drilled disc's on a race car anymore - a good one at least), the grooves will increase pad wear, which quickly gets expensive if you are really giving them some abuse.

 

As an added extra they will also help the release of gasses built up but as somebody has said it's not as big of an issue as it use to be.

 

My customers don't like wasting money on minute gains they simply cannot notice when racing. Plain discs are usually around £13-50, Grooved discs are £150-200. When the pad material makes a significantly greater difference to braking performance and feel, then using a higher friction co-efficient on the pad and replacing the discs more is a better economy.

Also many modern race pads simply do not need the cleaning effect of grooved discs, all these achieve is greater pad wear. Some pad manufacturers even discourage their use.

Edited November 3, 2012 by Batfink