Another discs and pads query

[aporschefan]

I need to change both front discs and the pads on all 4 corners in the next week or so on my '91 turbo.

I use the car as a daily drive but will be tracking it every now and again.

The callipers are M030. 

Bearing in mind the use, can you recommend what the best options are for discs and pads for each of the below options?

1. Money no object
2. Best value for money
3. Best performance

Someone suggested I consider upgrading to cross drilled variant 304mm diameter discs. Should I do this or will the difference be negligible/insignificant?

Based on what little I know, its worth getting decent discs but good pads can make a bigger difference. Is that right?

 

[edh]

I would stick with OE or Sebro discs (not Zimmerman) - I usually get Sebro from Bert at Berlyn http://partsforporsche.co.uk/ . Don't bother with cross-drilled

Pads - Porsche pads are pretty good actually - and will stand up to moderate trackday use. It's really all about how hot you get the pads, and how they perform at elevated temps

A moderate upgrade to something like Mintex 1155 at the front will improve trackday performance - Camskill are pretty cheap on Mintex pads

Ultimate performance will either be Pagids (RS29?) or Performance Friction (PF97). Be warned though, the PF pads will leave corrosive bake dust on your wheels & down the sides of the car. These pads will set you back over £200 for the fronts. PF97's are astonishingly good []

The other cheap mod to look at is brake cooling - getting more cold air to the pads/discs/calipers. The late turbo has a metal deflector plate on the strut. The Turbo S had ducts that fitted in the front bumper and directed air onto those plates. These can be retrofitted to later Turbos I believe (Promax have them on their website)

The 968 is slightly different, with a 2 part plastic setup. The first part attaches under the lower arm (won't fit 944 arms, but your car might have 968 arms if you're really lucky - check the part numbers cast on the arm and the numbers on PET) and directs air to a second part on the strut, which fires it into the centre of the brakes. This is cheaper and better than the 944 setup IMO, but does depend on having the right wishbones

 

[chrisg]

Beaten to it ! I just going to say stick with standard discs, (sided and different part number) for good track performance 1155,'s with decent fluid and Ss lines will stop u anywhere. I've used this setup at the ring etc no problems but yet they'll also work very well from the cold for road use

 

[edh]

Chris are you coming to Bedford?

 

[Copperman05]

Echo the above although I did go for cross drilled disks on my S2 when upgrading to m030, mainly for looks tbo but they seem to perform well too, the issue is that the Porsche disks are very expensive and aftermarket versions tend to crack. So general consensus is that solid disks are cheaper, longer lasting and perform nearly as well (in regards to heat dissipation).

Another pad setup you may want to consider are the Ferodo DS2500, I did I load of research of what pad to use for a fast road/track car and came up with these, its probably the best track/road compromise pad out there, it has great bite from cold and are just awesome when heated a little. Not as good as the all out PF97's on track, but for mainly road use I would suggest the PF97's are a bit much, take longer to warm up, have alot of corrosive dust and are expensive. Ive had the DS2500 on for while now and had not had even a hint of fade out of them so far, even on track. A cheaper alternative would be the Ferodo DS Performace pads which are billed as road pads, perhaps similar to Ds2500 on the road but not as good for track use.


Edd

 

[edh]

DS2500 are very similar to 1155's - but have a bit of a reputation for leaving deposits on the disc.

btw - PF97's work fine from cold - I wouldn't use them on a concours car though []

I think the Porsche discs might be cast with the holes in, rather than drilled later, which might make them less likely to crack. Sebro discs stand up well even to the heat of PF97's, which are also very abrasive - I found I wore a set of discs out before the pads. Not as bad as it sounds, because the discs are cheaper than the pads.

as an aside, the PF97's for non m030 calipers are available for under £100 from design 911 - a bargain!

 

[Copperman05]

No deposits here, I think this must be a consequence of not bedding in the pads properly, Ferodo have a very detailed specific bedding in procedure that many don't bother with. I think they are great pads, but not cheap.


Edd

 

[zcacogp]

ORIGINAL: chrisg
I just going to say stick with standard discs, (sided and different part number)

Interesting - why are the disks sided, if they don't have grooves or holes? The only reason I can guess is that the vents in them are vane-shaped, and mirror images of each other on the two sides ...


Oli.

 

[Diver944]

You're right Oli.

The M030 disks have slanted internal vents in them that are designed to 'suck' air in at the centre and back of the disk and expel it through the outer edge of the disk. If you mount them on the wrong side it defeats the purpose of the design as the vents then slant forwards

 

[T3rra]

Interesting, so the vent need to run towards the rear off the car? In the opposite direction off rotation? Will check mine when I get the chance

 

[MarkK]

Pagid RS29s are my favourite track pad,they are more off and on than PF 97s but they do stop you!!
They can squeal a bit on the road.

 

[bmnelsc]

ORIGINAL: edh

I would stick with OE or Sebro discs (not Zimmerman) ...

Just for information - why not Zimmerman? Known issues? Issues for track use or road use also?

Thanks

 

[Eldavo]

I believe there are well reported issues with them cracking across the drilled holes.

 

[MarkK]

If you are tracking it solid Porsche discs are the way to go,mention your club membership and get a discount.

 

[edh]

ORIGINAL: bmnelsc

ORIGINAL: edh

I would stick with OE or Sebro discs (not Zimmerman) ...

Just for information - why not Zimmerman? Known issues? Issues for track use or road use also?

Thanks

I have never used Zimmerman myself, but have read reports of warping / cracking. I trust Bert @ Berlyn Services, who recommends Sebro.

The Sebro discs were still in good shape when worn down to their limits after heavy track use - fine surface cracking but nothing major

 

[aporschefan]

Thanks for your feedback everyone. I bought Ferodo DS2500 with Sebro discs. Will have to read into the bedding in process for the pads.

Edd, you mentioned you have followed a specific process. Where can I find this information?

 

[Copperman05]

Instructions are usually in the box with the pads. I can't remember exactly but I think it was 30-40 4 second 50% braking periods every few hundred metres or so, then let cool whilst still driving, when disks have no deposits they are ready for use.

What I did was find 2-3 roundabouts on a dual carriageway that you can drive between, gradually braking later and harder. Basically I think you have to cook the pads a little, get them smoking and let them cool by braking lightly whilst driving. It's not really that difficult, if its not done the pads tend to fade on their first use and leave deposits, this is normal and why the bedding in is done before you really need to use the brakes.

Once done I found these pads awesome, work well cold but fantastic when heated up a little. I'm sure you'll bevery happy with them, let us know how you get on.


Edd

 

[edh]

Sounds about right. The usual bedding procedure for track pads is progressively harder stops to almost stationary (but not quite), from higher & higher speeds until you have got things really hot & you can smell the pads. Then a slow drive home, park & leave the pads to cool right down - obviously with a 944 you can put the handbrake on because it's using separate shoes.

lots more info here

http://www.stoptech.com/technical-s...ions-and-procedures/stock-brake-system-bed-in

and here

http://www.stoptech.com/technical-s...-theory-definitions-and-procedures/bed-in-faq