Rotors with curved vents, directional?

sambo · #1 (**permalink**) 08-15-2007, 07:17 AM

As I was fitting my new rotors tonight I noticed that while the slots had been milled to give a left and right rotor, the curved vents (vanes) inside the discs did not present a left and right side. That is, with the slots lined up correctly, the vents on one side pointed backwards and the other side forwards.

I've searched the web and found conflicting views on whether this is a problem. Eg, should the vanes point forward when the wheel is moving (in order to 'scoop' air) or the other way, or does it not matter?

I'll be calling the shop tomorrow but I'm interested to hear what people have to say. Here's the link to the brakes on eBay.

Thanks,
Paul

Jac Mac · #2 (**permalink**) 08-15-2007, 02:07 PM

Vanes pull the air from rotor center to OD, therefore OD of vanes should trail with respect to rotation. Grooves in face of rotor if correct should be machined to 'cross' vanes to avoid stress points, if they are machined parallel to vanes it can create a weak area.

Jac Mac

Chrome · #3 (**permalink**) 08-15-2007, 02:32 PM

HI Sambo,
I agree with Zac Mac, the vanes should be in the direction that pulls air from the inside of the rotor to the out side.

The grooves are less of a problem, ideally they should start on the inside and as the wheel rotates the slot/ groove moves to the outside.

Sounds like you have 2 left or right rotors not a left and right.

I also had his wrong untill someone pointed it out for me.

400TT · #4 (**permalink**) 08-15-2007, 08:34 PM

Regardless of slotting, curved vein rotors should point backward as Jac Mac posted above.

So sounds like you have left and right slotting, but your rotors themselves are from the same side.

Curved vein is unusual in aftermarket rotors. The best form of ventilation design if you duct air to the centre of the rotor. If you don't duct the front brakes, then there are better ventilation designs like DBA Kangaroo Paw. V8 Supercars and premium sports cars run curved vein rotors. We had Skyline GTR oem curved vien cross-drilled rotors on the front of the Cobra when we first built it and they were left and right hand side

sambo · #5 (**permalink**) 08-15-2007, 08:54 PM

Well it seems there were more than a few shadows in the shed last night because in the clear light of day I have to report that they are in fact straight veins, which means they're uni-directional.

Go to the back of the line Sambo.

Thanks for the replies lads.

Craig - I have a question for you on the R32/R33 rear ends. Geof Hemphill seems to recall your brother John 'refurbishing' all the bushes/rubbers/boots on the GTR rear end after heavy track use. Do know much about what was involved? Mine's in decent condition but I'm thinking of taking preventative measures.

400TT · #6 (**permalink**) 08-15-2007, 09:02 PM

Yeah, that makes sense. Haven't seen anyone selling curved vein rotors here.

Actually had to solid mount the carrier in the cradle as it flogged out the bushes. That's all that has been done, well except for wearing out everything every 12 months or so.

Is yours GTR(GTS-4) or GTS-T? GTS-T mount carrier in the cradle in a totally different manner and might be fine.

Keep in mind everyone that has raced GTS-T rear-end Harrisons have not had a problem so far.

sambo · #7 (**permalink**) 08-15-2007, 09:19 PM

Yes mine's GST-T, R33 with the wider mounting points according to Warwick. Looks like pretty solid gear so I might just paint it up and forget about it until something starts making noise.

400TT · #8 (**permalink**) 08-16-2007, 12:31 AM

Yeah, especially since it's going to sit basically unused while you build the car. See how it performs once the Cobra is on the road.

acecob · #9 (**permalink**) 08-16-2007, 04:09 AM

hey chrome

Thats not bad knowledge for a gal , what's the go there?, can we be sure its mr phils work on that car of his, is there something you havn't told us.

Chrome · #10 (**permalink**) 08-16-2007, 08:02 AM

Hi Peter

It is Phils knowledge (like i would know any of that

) he used my computer and forgot to change the Sign in details.......His computer also died last week so it was a very good week for him! So between the car, oven, microwave, jug, fridge, computer, hire car, tow trucks and the Cobra being finished and the bill needing to be paid yesterday i think i will have to get another job! I did try sleeping with the boss but he still wouldnt give me a pay rise!!!: