brake disc venting-curiosity

[Sygh2k]

just out of curiosity really something i noticed over the weekend replacing front brake discs. maybe somebody has some info, or maybe not, just curious.

whilst changing front discs i noticed the vents on the old can be seen in the middle from the wheel side whereas on the new the vents in the middle cant, see piccy.

does anybody know if there is any impact on one way or the other if at all?

 

[Charlie Farley]

I think you mean the on the new discs the vents can be seen on the inner centre but not on the older discs.

I assume the new ones are m-tech j hook , what about the old discs?

 

[Sygh2k]

it was more the difference i was trying to point out

the new are mtec j hook, but i also have some mtec groove and dimpled which vent the same as the old ones in the pic, those in the pic are original audi

 

[Charlie Farley]

are they the drilled 320 ones by some chance?

 

[Sygh2k]

no just dimpled n grooved

 

[Charlie Farley]

I think you'll find the oem ones use the drilled holes to vent the discs via the centre vents as they don't go right through , i'm not sure they work that well to be honest as the holes soon become clogged thus reducing the air flow/cooling almost completely, the vents that go right through will work better as air can pass right through and draw heat away.

 

[Charlie Farley]

Ok, if your old ones don't have any holes and the centre vents don't go right through then I doubt they will be as effective as the new ones, they will get cooling air and have a limited effect but wont dissipate as effectively .

 

[Sygh2k]

the centre vents on all 3disc variations i have go right through, its just some vent towards the wheel and some vent away from the wheel.
the surface of the disc isnt an issue.

 

[Charlie Farley]

Ok, I cant see the inner vent on the old discs though , in that case I think it just a design thing then .
I cant see any of the three working any better than the other on our cars really , the basic concept is the same and they work the same albeit one may have a marginally different air flow exit angle , can't see it making a shed load of difference though chap.