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Discussion Starter #1
Oki doki chaps.. I have the AP racing 6 pot kit with the Ferodo DS2500 pads.

Since there refit I have done a hot day at Goodwood and most recently the Brandshatch GP circuit, along with a fair amount of fast road driving. At Brands I found the brakes making strange sounds and viabration coming throught the steering wheel and the car itself (as passengers commented) .

So whats the answer? Floating discs? Pros and cons please.

..Ian
 

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Ian,

Floating discs are a big no no for road cars. They need to be rebuilt regularly to ensure they float, so I was told by those that know about these things.

Peter.
 

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Discussion Starter #3
Peter you have the same kit as me , do you get the same results after a while? My discs weren't warped and there is plenty of depth on the rotor and the pad!!

I know its a heavy car but these GT boys are running metal rotors in the FIA series (GTS class) for 3 hours no problems!!!
 

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There are a couple of GTRs out there with floating discs, I think Charlie has them for one and Rupert as well?

The BMW M3 and M5 also use floating discs as standard, so they must be capable of being road usable.

I think the AP floating discs make a bit of noise though.

Guy
 

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Ian,

As you know, I've had my problems with brakes but since fitting the DS2500s with the APs, they've been 110%, no judder, only marginal fade under extreme conditions. OK they've cracked now but given the absolute torture they've had over the last year, I count myself lucky they've lasted so long especially when you think of other people's experiences, Jamie, Chris Wilson, etc.

It may be that you've a duff pair of discs with a flaw which is only presenting itself on track. Road driving never ever compares with track driving as you know so I guess whilst there are many poeple on here who have APs, there don't seem to be many who track their cars regularly so perhaps I just got lucky with this pair...?

I'll soon find out when I get the new ones on.

Peter.
 

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Guy said:
There are a couple of GTRs out there with floating discs, I think Charlie has them for one and Rupert as well?

The BMW M3 and M5 also use floating discs as standard, so they must be capable of being road usable.

I think the AP floating discs make a bit of noise though.

Guy
Possibly Guy but I had lengthy discussions with Abbey, Tim @ SVS and Alcon last year and the idea was a complete non starter then. Not sure how this would benefit Ian anyway?

Peter.
 

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Discussion Starter #7
Peter,

Only because I am on my second set of rotors after having them skimmed due to a dodgy set of pads i tried, so I can't see any design fault! there just must be something better out there!. I can put up with the sound but the feel thru the wheel is too agressive!.

Guy tyhe new M3 has floaters? one of my clients bought his M3 down to Goodwood last month and was disapointed in the difference due to him having to brake so early. They weren't uprated in anyway though!

What sort of noise would I expect from floating discs?

..IS
 

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Give me a call Ian and I'll tell you what I have done. Its to long to list here.

07771 535653
 

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Discussion Starter #10
I have spoken to someone else (not Jamie) and they have vsuggested that trying DS3000s on track could help! Has anyone tried this full race/track compound? I would imagine what with the weight of the car the would get up to temperature quite quick and may be be suitable for road use?

..Ian
 

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No, I haven't Ian but I have tried the Mintex F4 pads which I'm lead to believe are very similar. It's not so much dust, more a mixture of iron filings and glue! :eek: They might, only might, help you stop quicker, I can't see how they would cure brake judder though and all at the expense of your gorgeous Nismos. Don't do it....
 

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Discussion Starter #14
may be not then..

Going back to the floating dics I have got advice from some and thought Id post his view which hopefully will enlighten others who read or do a search on the item in the future.

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As a disc gets hot, it expands.

If the discs are floating, they are less prone to warping, as there is no imposed stress from the location points that connect it to the bell. The disc is free to expand.

Any two piece disc is connected to the bell by bolts that connect to one of the two friction plates, normally the outer one. Whilst most of these are designed to allow a fraction of movement, there is a limit. A floating disc does just what you would imagine. It is losely located onto its connection points and can expand as much as necessary without collecting any stress. It is also the best design for stopping heat soak, through the bell, into the hubs.

In a solidly mounted disc, some stress is also relieved by the aluminium bell, although cooler than the disc, having a greater rate of expansion per degC temp rise.

The solid mounted version is preferable, in all but the most extreme cases. It is much quieter in use - floating discs can "clonk" when used on the road, and it is maintainance free - floating discs must be periodically cleaned to stop dirt clogging the floating connections. If they are not cleaned, the float can jam and this will wreck a disc very quickly.

Don't think I am knocking solid mounted two piece set ups, they are substantially better than one piece discs and are more than adequate for my own fast road/track day use, even with full race pads.

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Im still none the wiser as to cure the problem , do I have to spend £50 have the discs skimmed every 2 track days!
:rolleyes:
 

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Great explanation there Ian, who is he/she? :) I don't think pads are the issue so I'd stick with the 2500s if I were you.

Not sure what to advise, when I've got new rotors on, I'll let you know if they are as good as the last set.

Peter.
 

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Discussion Starter #16
Peter..

..it's Pete Croney who runs Scooby Sport (the Subaru tweakers).

I'm not so sure what my next move is, the viabration didn't actually make the car stop any slower it just throws you out a little and the passengers think somethings wrong to.
 

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Discussion Starter #18
Peter E..

Yes he was actually, it would seem that the more heat treated the disc get the better they are and the less they warp, so to get them skimmed every two or so track days would be the answer and to run them down thru the grooves (like you did) is fine. So the less rotor material left the better. Obviously they will crack eventually (as u know).

The rotors are nearly £500 (without hubs) so to get them skimmed 3 or 4 times at £50 a go is cheaper but a pain in the butt.

The answer is ..there is no answer ...You can have high maintainance and noisy road going floating discs or if you can afford it ..£10k worth of carbon fibre discs and race bits.

...Ian
 

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The only thing to watch out for is piston pop when your pads get low. The discs start life at 32mm, at 30.5mm they need to be binned. So that gives you 1.5mm for wear and skimming, not much is it....
 

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Discussion Starter #20
Peter..

..someone has sugested that the viabration could be caused by unbalanced wheels/set up? I think that its poppy **** but thought i'd ask!

...Ian
 
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