Slotted Rotors - Directional?

WhiteKnight · 10-11-06, 03:09 PM

Does it matter which direction the slots rotate on slotted rotors?

Artsvette73 · 10-11-06, 05:51 PM

They are directional rotors. The arc should run in the direction of the wheel. If that helps you.

WhiteKnight · 10-11-06, 06:03 PM

Thanks.. that helps, and I think means I have more work to do..

I just installed a set on my car 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 side..

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?

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

Artsvette73 · 10-11-06, 10:59 PM

I wouldn't drive it, I would change it.

WhiteKnight · 10-12-06, 12:47 AM

Now I'm more confused.. like that's a stretch.. I just recieved other advise that the slots don't matter but the cooling fins in the rotor do. However the rotors I have don't seem to have directional fins. ??

Artsvette73 · 10-12-06, 10:53 AM

I have slotted on my 73 and cross drilled and slotted on the 77. The slots help expell the brake dust away from the center of the hub. Other than that I don't know what to tell you.

Twin_Turbo · 10-12-06, 11:00 AM

Quote:

Originally Posted by WhiteKnight

Now I'm more confused.. like that's a stretch.. I just recieved other advise that the slots don't matter but the cooling fins in the rotor do. However the rotors I have don't seem to have directional fins. ??

Actually you read that wrong, the slots matter but the vanes are much more important and should be checked first. The slots will work best if they sweep back against the direction of rotation but the vanes will really mess up the coolig if installed wrong. Most C3 rotors however are straight unidirectional vaned.

The slots are there to help plasma escape, this plasma is craeted under braking when the apds outgas..now here's the kicker, modern street pads don't outgas any amount worth mentioning...the slots are mostly cosmetic.

WhiteKnight · 10-12-06, 11:20 AM

Thanks TT..

I had a message into the supplier and got a call from them today. Basically his advice agrees with what you said and he said I do not need to switch them for street use. I'm always trying to learn more and 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. 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 small difference and the angle alows 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.

Here is a pic of how I have them now.. front of car is to the left in pic, but for correct gas venting they should be angled the other way (ie swapped to the other side of the car).

Twin_Turbo · 10-12-06, 11:55 AM

exactly, I myself would swap them so they face the right way, IMO it also "looks" wrong the other way around, like having sawblades (or any C4 wheel) the wrong way around (which also affects brake cooling)

Did you shim and dial them all out yet?

WhiteKnight · 10-12-06, 12:16 PM

yeah I did get them dialed out .. which is why I'm reluctant to swap sides..

I'm running rally's so not much will show.. but I kinda feel like "bubba

" if I am not doing it "right".