i have had my k sport big brake conversion fitted but the grooves on the discs are facing the way of the rotation of the wheel ,

i.e the groove ( which is an arc from the centre to the outside edge of the disc ) looking at the disc through the wheel go from centre and curve to the right , wouldnt this wear the pads more agressively or am i being paranoid ?? it was Mario who spoted it when he was up at mine for a weekend ....top top bloke by the way sorted my stereo and faulty central locking....cheers Paul :)....do i need to get my discs swapped around as all the wheels are the same ??:sad:

there not directional and how there fitted is correct to the way the manufacture say's ....

they should disperse the water and crap better but under hard braking u may get a little rotor noise

I got K sports aswell. If you look at the actual internal vents they go the right way to disperse cr4p and heat etc. but the grooves on the outer surface are there more for just roughing up the pad surface a bit and aesthetics but yes I agree they appear to go the wrong way on K sports and you'll get lots of 'mechanics' telling you they're on the wrong sides of the car....they're wrong.

If your discs have curved cooling vanes, then the discs themselves are directional and should be installed with the cooling

vanes running back from the inside to outside diameters in the direction of rotation.

 

-Andrew

 

Hi Steve,

 

I trust you're keeping well chap! :)

 

In my past life, as proprietor of DTA-Motorsport UK et al, I did quite a bit of research into the benefits/drawbacks of grooved/slotted and/or drilled discs.

 

Firstly, and most importantly, as AndrewG posted above, cooling of the disc is aided by the inclusion of curved cooling vanes sandwhiched between the two outer surfaces of the discs. It's not so much about getting cool air INTO the discs as it is about getting hot air OUT of them. This is done primarily through centrifugal forces hence the discs being "directional". I can't quite remember whether the K-Sport discs have these cooling vanes but I would be surprised if they didn't. By comparisson, DBA discs have what is known as "kangaroo paw" cooling structures inside the discs (they look like triangular "islands"). These also aid cooling but are located in such a way that the discs are not directional.

 

Secondly, external grooves/slots cut into the disc surface are generally there to help expell gasses that form when brake pads are subjected to extreme heat through friction. Again, centrifugal forces ensure that these gasses, as well as any brake pad material and water on the disc, is ejected from the disc as quickly as possible. In order to do this most efficiently the grooves should be cut in such a way that when the disc is rotating in the driving direction the grooves will expell the particulates rather than scoop them up. So, if you're looking at the top section of the disc, the groove starts at the centre of the disc, curves outward to the right and then ends further to the left than the starting point. I hope this makes sense. Furthermore, the more grooves/slots are cut into the disc, the less surface area is available for actual contact with the brake pads. There is no concensus on the optimal number of grooves but I have always maintained that 10 grooves is more than adequate.

 

Fully drilled discs are much better at expelling gasses and cooling discs than grooved discs. However, these types of discs are far more prone to cracking when used "spiritedly". This is of course also dependent on the disc casting material. If you look at the drilled discs made by Brembo for say our 300ZX versus discs made for a Bentley GTC (pre- carbon ceramic brakes) the massive difference in price (approx. £110 and £580 respectively) is not only down to size but is very much down to the purity and strength of the casting. The 300ZX disc is far more likely to crack/warp than the Bentley disc. Anyway, I digress.

 

If you're still reading this, the most important factor in mounting your discs correctly is to ensure that the cooling vanes between the discs are pointing in the right direction. I believe that EBC discs and AP discs have their cooling vanes going in the same direction but their external grooves in opposite directions. Fitting either of these discs therefore depends on the direction of the internal vanes and not the external grooves.

 

My apologies for this long-winded post but I do hope it was of some interest and help to you.

 

All the best,

 

Dan

thanks guys , all the replies were very very helpful my mind is well and truly put to rest,

 

Nice to see your still about Dan , hows it going matey ? .... the car has ended up everything i wanted it to be ..only needs mapping now

not sure on how to go with that one, i could go stand alone ECU or ask nicely if a certain chap on here ( Mr Dixon ) can map the nissan ECU to accomodate my mods and squeeze the power up to the 400+ rwbhp figure i had in mind when i set out on this journey all those years ago.....

 

got to say that for all the "meh" press the k sport brakes got, i am very very pleased with the series two 8 pot fronts and 6 pot rears.....awsome stopping power

 

 

have left some Rep for you guys as a thank you

 

kaza steve