The thicker ap discs (5000 series) are heavier and have proportionally less cooling. This makes them less able to be used on track rather than more. The 3000 series discs made of a higher quality material allowing the walls to be thinner and the cooling vanes to be wider, they are also therefore lighter. This means they are better for track/race use but will wear out sooner
The air, having travelled through the cooler exits through slots in the wheel arch liner. Its this air that then finds its way to the disc…it certainly cannot help.
The air, having travelled through the cooler exits through slots in the wheel arch liner. Its this air that then finds its way to the disc…it certainly cannot help.
Any idea of the temp difference between a) air exiting the cooler & then passing through slots in the liner & b) the discs under braking? A couple of hundred degrees C would be my guess! Copied from Mintex site re: FR4 pads (probably equiv. to Pagid RS14)
[image]http://www.mintexracing.com/pics/f4r_chart.gif[/image]
Well, I know I wouldn’t dream of touching the discs with my fingers, but I wouldn’t hesitate in putting my hand in the flow of the aforementioned air coming through the liner.
![http://www.mintexracing.com/pics/f4r_chart.gif[/image]](http://www.mintexracing.com/pics/f4r_chart.gif%5B/image%5D){kind=link}
From Pagid’s website:
[color:“blue”] RS 14 Black
This is a medium high friction value ceramic type compound with very good modulation, high fade resistance, low heat conductivity, and a good wear rate up to a temperature of 650�C (1.200�F). It is kind on discs, with visible grooving, but a limitation of hairline cracks. Applications: NASCAR, CART, F3, Touring cars, GT cars, WSC, Trans Am and Rally.
[/color]
Uldis
Excellent modifications, mon amigo
The thicker ap discs (5000 series) are heavier and have proportionally less cooling. This makes them less able to be used on track rather than more. The 3000 series discs made of a higher quality material allowing the walls to be thinner and the cooling vanes to be wider, they are also therefore lighter. This means they are better for track/race use but will wear out sooner
I thought that you could get a full range of thicknesses for the 5000 series. From their website, they list the following:
CP5000 Disc range :- These discs use different castings through the range according to the size of finished part.
The list below details the number of vanes and air gap used.
CP5000-312/3CG8 30 Vane x 12.7mm Air Gap.
CP5000-510/1CG8 24 Vane x 9.3mm Air Gap.
CP5000-212/3CG8 36 Vane x 15.3mm Air Gap.
CP5000-112/3CG8 48 Vane x 19.5mm Air Gap.
CP5000-210/3CG8 36 Vane x 15.3mm Air Gap.
CP5000-206/7CG8 30 Vane x 15.5mm Air Gap.
CP5000-218/9CG8 48 Vane x 19.5mm Air Gap.
CP5000-110/1CG8 48 Vane x 19.5mm Air Gap.
CP5000-177CG4 solid brake disc.
Although I don’t see how they can all weigh the same 5.4kg?
The thicker AP discs (5000 series) are heavier and have proportionally less cooling. This makes them less able to be used on track rather than more. The 3000 series discs made of a higher quality material allowing the walls to be thinner and the cooling vanes to be wider, they are also therefore lighter. This means they are better for track/race use but will wear out sooner
I can see your point, but bear in mind that extra disk mass will lead to a bit more thermal capacitance, i.e. stability.
The changes in temperature will be slower and this means that while on the straights the lighter disk (bigger gap inside) will cool more, under heavy breaking they will reach a higher temperature, possibly going over the pad’s maximum and therefore fading.
The heavier disk, with its slightly narrower gap will not cool down as much as the lighter one, but will not get as hot instantaneously as the light one.
Also, it will be less propense to hot spots, maintaining a more even temp all across.
This was the mistake of the Eliseparts I got initially (Hi-Spec), they were fairly light because the overall disk thickness wasn’t as much as they could be (don’t know if they’re like that anymore). Basically, giving being narrower the inside gap was also smaller that it could have been, decreasing the possible cooling it could have had.
Mutts Nuts got the balance right, and I’m sure at least one of the AP’s will be perfect.
My point is that although the lightest disk may be appealing, it’s not always the best, the best is the most mass but with the biggest cooling AREA (not gap).
For the same certain gap, the widest one but with more vanes (heavier) will cool better just because the cooling air will touch a bigger inside AREA.
Weight can then be limited by machining the inside diam of the disks so that no unswept material is wasted.
See my point?
I see also what people are saying but would a 3000 spec disk be better for track days as cars only do 10 laps max at a time.
A 5000 spec disk might be better for a 50 lap race
it might be better for you if you only do 10 laps at a time but i know lots of people who do 1 hour stints on trackdays or until they run out of petrol.
it might be better for you if you only do 10 laps at a time but i know lots of people who do 1 hour stints on trackdays or until they run out of petrol.
I have Alcon disks on mine which are supposed to be equivalent to AP 3000’s. With RS14’s I managed to cook them at Bedford and actually get some pad material transfer to the disk - I guess the pads working above their operating temp for the reasons Uldis mentions.
I am going to put some new pads on before I go out again this season…I was thinking about the Performance Friction ones Sean raves about…better check their thermal properies. Any other suggestions??
Mine is an S1 but with a boat-anchor Honda ,…and I drive like a girl …Bedford is a bit of a shocker on brakes though.
I run RS15’s now, harder pad, works perfectly, but not great from cold on the road… not a problem either, just loose some of the initial feel till they have some temperature.
If you want brakes to perform like a race car on track (or harder as our cars are normally heavier!) then you sometimes have to make compromises!
Works for me anyway
I see also what people are saying but would a 3000 spec disk be better for track days as cars only do 10 laps max at a time.
A 5000 spec disk might be better for a 50 lap race
10 laps max?
Where’s the fun on that?!
Like Neill says, plenty of us do full tank stints. Yes, open pit lane only here.
If you definitely drive such short stints, I would say you can use whatever you want then.
If I go for the Lotus AP Big Brake upgrade will I still have the ABS?
Yep
I run RS15’s now, harder pad, works perfectly, but not great from cold on the road… not a problem either, just loose some of the initial feel till they have some temperature.
If you want brakes to perform like a race car on track (or harder as our cars are normally heavier!) then you sometimes have to make compromises!
Works for me anyway
What discs are you running? Need to change mine soon too