vettman10

Has anyone noticed a difference between brake rotors with straight vanes and those with curved? A rotor with directional curved vanes will obviously run cooler as it is always pumping air through it when moving, but is it enough to make a difference in brake performance when on the track? The factory rotors on my '02 Z06 have curved vanes and so are side specific. And most standard replacement aftermarket rotors, even the popular NAPA rotors have straight vanes.

CHJ In Virginia

I have run multiple sets of both varieties over the past 5 years. I can't tell any difference in longevity or cooling between the two. I just go with the ones that I can find cheapest.

vettman10

Thanks for that info. Apparantely it doesn't make much of a difference. I have noticed that the drilled and slotted factory rotors that come on some C6's (including the Z06) are all 'left side' rotors. Take a look at the orentation of the slots and drill holes, which mirror the orentation of the inner vanes. They are correct on the left but backwards on the right side. I guess they wanted to save a few bucks and only use one casting design, and/or the difference in braking performance is minimal. I bet lots of folks haven't noticed this.

Solofast

This has been talked about, do a search. Bottom line is that the amount of air pumped by a curved vane is actually less than a straight vertical vane. The curved vane has advantages in that the thermal stress situation is different, but it's probalbly not a big advantage. These are actually pretty low speed compressors so it doesn't matter that much.

Painrace

It is far more important to get forced cool air through the vanes that how the vanes are configured.

Jim

RacePro Engineering

That is a very interesting observation.

And I bet here's something else that lots of folks have not paid attention to: It is far (FAR!) more important to run the rotor that is lightest weight, rather than worrying about curved or straight vanes.

Ed

Gering

These are nice rotors that are very light.

http://shop.performanceafx.com/Brakes_c2.htm

Screamin Z

This...

If your worried about "hardcore" cooling. Your air flow should be going from the inside of the rotor and blowing out the outside of the rotor via spindle ducts and duct work.

curved or straight vanes wont show any diffrence in cooling at all if no air is forced through them.

Bill Dearborn

The directional vanes in the C6 rotors have been talked about quite a bit. Some people say it makes a difference but I never noticed any difference and when you read info that came out of GM;s testing at the Ring it looks like their instrumented testing didn't show any differences either. The C6 Z06 rear rotors are straight and they front rotors are just curved in one direction. It seems like the curved vanes would act like a turbine and help move air through the rotor but there may be a much greater contribution to air flow due to the heat of the rotor causing air to expand and thus getting a pressure differential from the center of the rotor where the air is cooler to the outside where it is hotter. The curved vanes may serve no greater purpose than increasing the cooling surface area since the vanes are longer.

Bill

frcc

Without real data it's really hard to say which rotor design is best.
See this: the author used computational fluid dynamics to see which of pillar, straight, forward or backward curved vane designs work best. It really is a complex matter and the results are somewhat surprising. Even more analysis and real life testing would be required before reaching a final conclusion.

https://waveydynamics.medium.com/com...r-970008425ccd

romandian

thats interesting. a fact to consider is that he disregards conducton and radiation heat fluxes, that together usually equal the convection flux for most rotors.

tommyc6z06

fascinating article...and quite unexpected conclusion. thanks for sharing.
Frankly, I've always shied away from the 'kangaroo paw' pillar vane rotors because i presumed they wouldn't pump as much air through them, and because apples to apples they were often heavier than the directional, curved vane rotors that i prefer....although that usually means they're a larger heat sink.
Lots of food for thought here, and while some of it may be splitting hairs, or inconclusive, its a good for argument for trying the inexpensive DBA rotors instead of necessarily upgrading to an alternate 2pc directional radial design

Still...can't help but wonder how all the leading aftermarket racing brake manufacturers don't go in this direction for their iron discs