Guest larkja Posted January 22, 2002 Share Posted January 22, 2002 I just put on the 4 piston calipers - pretty good. How much of a difference would the cross-drilled rotors make? Thanks Jim Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted January 22, 2002 Share Posted January 22, 2002 You mean strictly cross-drilled vs. non-drilled rotors in same physical rotor size? Little to NONE if not less braking force. Noone has proved 'outgassing' is an issue needing to be solved for our braking uses IMO. What are you looking to improve? fade resistance or braking modulation/force etc? Drilling and slotting reduce frictional surface as well as rotor mass so decrease fade resistance in that regard and available friction. Now some brembo rotors are cast with the holes in and those are a nice piece not prone to cracking at all as the metal orients itself as it cools when cast whereas drilling/slotting breaks the 'grain/orientation' of the surface (similar to forging/benefits etc). They're used a lot for show and on racecars, AFAIK (I'm sure Mike has more info) race use drilled rotors are usually drilled/stress relieved AND sometimes cryo treated as well. If for mostly show/looks then not a factor if your brake system isn't taxed too high. It can be a maintenance issue keeping the slots and crossdrilled holes clean and free of debris. I think they look great...just not convinced on function. Quote Link to comment Share on other sites More sharing options...
260DET Posted January 23, 2002 Share Posted January 23, 2002 As far as slotted rotors go, DBA (Disc Brakes Australia) claim that in tests their slotted rotors significantly reduce stopping distances. Can't find the leaflet but they did publish figures to back up their claim. The number of slots and their angle may have something to do with it. Their Z31 rear rotors for example have nine slots on each side, each at about 45 degrees to the direction of travel of the rotor face. Any advantage of slotted over cross drilled may be because the entire face of the pads is swept by the slots. Quote Link to comment Share on other sites More sharing options...
Guest Thurem Posted January 25, 2002 Share Posted January 25, 2002 And how much more do DBA charge for their slotted rotors? I think the whole drilled slotted deal is bogus, vented though is another story. Thure Quote Link to comment Share on other sites More sharing options...
260DET Posted January 25, 2002 Share Posted January 25, 2002 Further to my previous, DBA claim that on test from 100kph to stop, slotted reduced braking distance from 42.2 meters to 40 meters on average. Can't answer your question, therum. DBA do claim longer life as well for their slotted, hint at higher quality material but don't go into any detail. Apparently police tests for their vehicles confirm the improvement using slotted. Quote Link to comment Share on other sites More sharing options...
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