Question on the slotted rotors..

I got mine from VBP and I think they are swapped right/left.

They were delivered in two boxes, fronts in one box rears in the other. No directions. I did the left side of car first, then pulled the remaining rotors out of the box and found them marked with a sharpie as "left"..

I did press on and put the right rear together but now I'm having second thoughts..

So how importaint is it that I remove the rotors and swap them?

Is the directionality of the slots cosmetic or functional?

At least I stopped before I put the fluid back into the MC.

 

I just installed my cross-slotted and drilled rotors and they were left and right and the rear rotors had the extra holes for the e-brake adjustment. Not sure that it mattered which side but you should have the extra holes in the rear for the e-brake adjust. I installed mine to where the high side of the slot goes into the brake pad and tapers down as it goes through the pad. Hope this helps


Best Regards

 

i asked the same question on the c-2 listings and got good info back including a diagram--concencus is that the curve goes from the center then towards the back of the car as it spirals out toward the edge--Hope this helps or do a search on the c-2 forum--Glenn

 

I think it sounds like the same way I have mine installed.. right? Here are some pics.

Here is the front


The Rear


Close up of Rear, note the front of the car is to the left.

 

Thanks Glenn.. I'll look there.

 

My Raybestos Brutestop rotors were stamped L and R and the slots are directed from hub back. I chose these since Raybestos has been around forever and I felt confident in American made quality. They are slightly heavier than the OE rotors meaning more mass for heat absorption and dissipation. Even so, with the Wilwoods, I dropped 3 lbs per front wheel and 8 lbs per rear wheel.
The slots had very sharp edges which I chamfered with a Dremel to reduce the cheese grater effect. The drilled holes arrived chamfered. They were slightly out of true so i have them trued on a lathe before install. Average runout after install with only a total of 3 .005 shims used on all four corners was .002.

 

Usually they should be the other way around, what to check for first though is the vanes inisde the rotor, if they are radial/straight it doesn't matter but if they are either curved or not radial but angled they should angle back and away from the direction of rotation, the other way around they will not pump air properly from the inside to the outside.

 

 

Not trying to hijack, but on a street only car is there any reason for slots or holes (or both), other than asthetics?

 

Not a lot, it's cosmetic mostly. Modern street pads don't outgas much so there's not a big plasma issue trying to float the pads and requiring grooves to expell. If you want to get **** about it, the grooves even lower the rotor mas and with it the mass heat buffer meaning the overal running temp goes up compared to the same rotor without the slots. Now it's minimal with slots, not a whole lot of material has been removed, however with drilled rotors it can get quite significant, not even talking about the possible stress cracking issue with drilled holes....but having the drilled rotors to crack with normal street use would be improbable

 

I ran slotted rotors on the front of my Talon. I found that they kept the pads very clean.

 

I installed mine the other way ... oops. Then I started looking about at other cars etc. BMW's and Mercs and even 911's seem to have the rotors installed the other way from yours. Yet nearly everything else is installed as per your install.

carbster

 

I had a message into the supplier and got a call from them today. Thier advice agrees with what all of you have said, except he said I do not need to switch them for street use unless I want to.

Since I'm always trying to learn more and share that info, I will try to convey what he said.


Steve at VBP said that since I am not racing and this is a older style rotor with straight cooling vains (the ones between the rotor surfaces), it would not affect the function for street use. He did go on to say that on newer rotors with the curved vanes it is importaint to watch how the cooling vanes are oriented as they are more importaint than the direction of the gas slots. He also said only if I was racing would the angle of the slot become a critical factor. As the design of the slot is angled there is a difference in how it functions if not correctly orented. The angle allows the gas to be directed out away from the rotor as it rotates. The correct slot angle should be orentaited so that the edge of the slot closest to the hub is the leading edge that enters the brake pad first.

As seen in the pictures of how I have them now.. they are incorrect. Note the front of car is to the left in pic, so for correct gas venting they should be angled the other way (ie swapped to the other side of the car).



I did get them shimed for minimal runout .. which is why I've been reluctant to swap sides..

I'm running rallys so cosmetically not much will show.. but I kinda feel like "bubba " if I am not doing it "correctly".

Anyhow today I finally recieved the front bearing kit that was ordered when I started.. the shipper lost it for a week.

So I now have a reason to pull the fronts and swap them.. and might as well do the backs again too.. guess I get more practice setting the runout.

 

TT is correct, it looks like you need to reverse the rotors direction....

 

Yes the other way around so they point towards the back of the car--Glenn

 

This is in reference to their street performace rotors...

" Which direction should the discs rotate?

It is a popular misconception that the slots or drillings in a disc determine the direction of rotation. In truth, for an internally vented disc, the geometry of the vanes dictates the direction of rotation. There are three vane types in use:

Straight
Pillar vane (comprised of many small posts)

Curved vane
The first two vane types are non-directional, and can be used on either side of the vehicle. The curved vane disc, however, is directional. A curved vane disc must be installed with the vanes running back from the inside to outside diameters in the direction of rotation. Please see figure. Orienting the disc in the manner creates a centrifugal pump. The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This greatly enhances the disc's ability to dissipate heat.

Additionally, all of Brembo's slotted discs are directional as well, regardless of the vane geometry. The discs should be installed such that the end of the slot nearest the outer edge of the disc contacts the pad first. Please see figure."

AP Racings Tech manual agrees with Brembo.... He's got them on correctly according to VB&P as well.