When I mentioned bedding the brakes in, I was referring to the discs and pads. Heat cycling / bedding the pads following the recommend procedure is one thing. However, if you have installed new discs at the same time they need to bed in correctly too. Discs as finished from their machining and manufacturing processes have a rough surface if viewed under a microscope. This rough surface can initially create very high temperatures leading to warping unless it is given time to bed in correctly. Which is often longer than the pad bedding procedure. Sam, how heavy is your car and what sort of power is it running? Mk3 Golfs with 239mm brakes had those little scoops fitted.
I've been through several sets of Brembo 280's and DS3000's. Had to cut a few days short due to seemingly warped discs. I'm looking into better cooling to the discs and maybe changing away from the DS3000's although i don't really want too as i love the feel and stopping power they give. I think Performance friction, Hawk and EBC do pads to suit my Dynalites so may try some of those. I've also looked at different discs, there is a company in the states that does floating discs in 280mm but they worked put quite expensive, will check my emails for more details. Another company Nitrac does cryogenic discs that claim to have a higher resistance to warping. danster also supplied some good info on discs & pads which i need to follow up on.
Beware hawk pads, as a set I used took 2mm off the discs in 1 60 mile rally. My cooling ducts are nothing special, just fabbed alloy scoops on the wishbone. I dont run a low front airdam though, as with my crap driving i'm always hitting parts of the chicanes , scenery etc.....
The bedding-in procedure isn't the problem, pretty sure of that. They have been given all the time in the world to bed-in. My Old man must have bedded-in 1000's of pads, maybe even 10's of thousands, and never has issues with warping. It's 910kg with me in it. Around 150bhp. Big sticky tyres. Larger servo of course. Its surely just a temperature thing.... Just wanted to see if others have had the same problem, and any solutions of 'super' discs out there Sam
I would advise a 2 piece disc. Also have you checked your calipers are not sticking on slightly, this would cause the disc to warp mid race.
I couldn't see 280mm to suit the G60 listed so have sent them an email asking if they do a set or would consider making them. Will check my calipers over to see if a piston is sticking.
I spoke with CompBrake a while back about a floating 280mm disc setup. They do make one, but the offset of their disc may differ from the std G60 280mm discs because their kit used 4 pot calipers. Should be possible to amend the bell drawing to suit though. Also, one of the Lotus Elise use a 280 two piece disc in 4 x 100. Might be worth checking up on for the offset and bore centre too. I can't see how 280mm discs on a 150bhp Mk1 are not sufficient when a suitable pad and disc combo is being used. EDIT: Come to think of it Sam, are you using 16v / G60 type pads and calipers, or the 239mm setup with caliper carrier extension brackets?
My pal has a set of the Compbrake bells and rotors on his car so if I get chance I will remove one and compare against the standard setup. Compbrakes only 10mins away from me so should be able to get some decent info hopefully
I'm coming late here, but my experience on my race Oettinger ( > 180 hp) fitted with G60 discs (drilled Zimmermann) & callipers is quite positive. The only time I warped the discs was on a track day when I went down to less than 1mm on the brake pads (DS3000). Grinding 0.1 mm was enough to make them as brand new ! Before the pads had about 4.5 hours training/racing + 2hours playing on track days. Just have to add that I generaly use to brake 0.1 m before the "too late" panel ! On another side I used to run durability tests on the N'Ring with BMW's, and less than 5 laps were enough to feel vibrations on new discs & pads. On my 320d E46, (305 mm discs) I only had to look hard at the brake pedal to warp the discs ! Something to see with the wear on the steering arms, says BMW ???
I'm using proper G60 calipers and pads. 280mm. Picture here; http://media.fishontrack.co.uk/2011/04/IMG_2000.jpg I know what you mean though Danster, 280mm should be enough, no idea why they are warping. DS3000 are quite a harsh friction. They didnt warp my 239 stanard discs though. The 280mm set-up can't be getting hotter than the 239mm discs, surely. Pretty certain there isn't any pad dragging on the disc...
I've just spoken to compbrake and they are interested in producing a 280x22mm 2 piece disc as a straight replacement for the 1 piece G60. They need a disc new or old to measure up, I could post one up but it I expect the postage cost would be quite a bit, anyone close to Preston that has a G60 disc they could drop in?
280mm should be getting hotter as they are travelling faster at the pad area than 239mm for any given speed.
Good point! I'm not sure If I can use a 2 piece disc in Class B VAG. Brakes have to be from the VAG parts bin. Not sure where the discs fall. I would only really be interested in a floating disc, as I dont think there will be much benefit in a bolted rotor.....?
Physics! Under identical test conditions the same amount of heat will be generated regardless of disc, caliper, or pad substitutions
More physics! Surely the 280's will be cooler than the 239's, as there is more material on the 280's to dissipate the heat.
If different brake systems are tested by stopping the vehicle under otherwise identical conditions, each system will generate the same amount of heat The greater the mass of components absorbing that heat, the lower their initial temperature compared to lighter substitutes - - however, prolonged use will result in very similar component temperatures unless one system - - usually that with greater mass - - has a larger surface area to more effectively dissipate heat Thus one of a suspension engineer's conundrums - - less unsprung mass for superior tyre contact, vs greater mass for superior prolonged brake performance
I can confirm the Compbrake rotors and bells are not 280mm G60 fitment, they are 285mm and have a slightly different offset. I`m going to take a G60 disc along to see if they can make some up.. anyone advise of the best setup to ask for??
