Slotted rotors on backwards?

[SimpleS14]

Ok...so I'm pretty sure I put my rotors on properly according to the label on the box..i.e. FR (front right) and FL (front left). So today I'm at a gas station and this guy tells me I have my rotors on backwards and he knows this cause he does tracking on the side. So I'm a bit confused because I can see how it can work one way vs. another. I'm making this thread to confirm if my rotors are indeed backwards, since I don't have a pic right now...here is a setup on another car on how my rotors are.....

http://images9.fotki.com/v165/photos/2/201040/2035460/DSC06624-vi.jpg

compared to this......

http://www.zeckhausen.com/images/brake_install/BMW/Z8/Front/118.jpg

[sean350z]

they should scrub the pad from top to bottom

[SimpleS14]

they should scrub the pad from top to bottom

I can see that happening if the slots are faced either way.

[Munch]

Yah I agree. I was 'toly watchin Street Tuner Challenge on SpeedTV yesterday and the guy doing the brakes on one of the cars said the same thing.

Really I'm not even sure what scrubbing it top to bottom does that bottom to top doesn't.

/me hasn't studied too much on slotted/drilled rotors.

[sean350z]

that porsche has the correct way...rotation is counter clockwise there for the part of the slot on the outside of the rotor will hit the pad first and scrub down towards the hub.

[sean350z]

Stoptech FAQ - directional slotted rotors (http://www.stoptech.com/tech_info/faqs.shtml#16)

[SimpleS14]

So basically I have them on backwards >_<

[drew935]

Blue car is correct. Silver is backwards. Ask Rotora, Mackin/ Project Mu...etc

[sean350z]

i'd check it just to make sure...the vane direction is key, i guess like stoptech says, different manufactors will slot/drill differently and it's not a good way to determine if a rotor is on correctly.

[SimpleS14]

well I'm using Powerslot rotors, so I guess I will search to see if I have them on correctly. When you say "vane direction" are you referring to the inside of the rotor when its cut in half?


EDIT: I just realized that I took pics of when I put on my rotors first time around and it clearly had an "R" or "L" for which side it had to be installed on. With that said....I have the right side...

http://www.ss14.net/pics/writeup/zbrakes/3.jpg

[Flybert]

Just align them based off the vents on the rotor. Vents face backwards to dispell heat.

[SimpleS14]

vents != slots

correct?

[ThatGuy]

Vents / Vanes are internal to the rotor. Look at it from the edge and decipher which way they point. Then orient the rotor on the side of the car that will allow those vents/vanes to dispell the heat "back" out of the rotor. :bow:

Slots are cut into the "face" of the rotor. Different manufacturers cut them in different directions.

[g6civcx]

Cliff's notes: check the vanes and make sure they scoop in air as you roll forward. If your discs were slotted at the factory (not by Ebay monkey), follow the direction listed on the package.


Okay, I know this topic is confusing because there is a lot of misinformation. I had very very long discussions about this with the design engineers at a popular brake manufacturer, who shall remain nameless as a courtesy.

First, you do not judge by the direction of the slots. Sometimes the disc is cut after it has already left the factory. People buy blank discs, cut them and/or drill them, and sell them at a markup.

This is the worse way to do it because the slots/drills have to be semi-cured at manufacturing. You do the final curing when you bed in your pads.

When you cut them like that, you expose raw edges of the discs. The slots/drills need to be treated at the factory. If you look at correctly drilled/slotted discs, and compared them to Ebay ones, you will notice the difference. The Ebay ones also warp and crack more easily. I know that wasn't your question, but I just wanted to give you some related background. I'll get to the point.

The thing that determines the orientation of the discs is the cooling vanes, not the discs. Pretend that you're lying on the ground, and the car is going to run you over head on. The part of the disc that you see is the vanes. They are little channels cut into the body of the disc to circulate air through.

Look at your vanes and see if they are straight or directional. If they are straight, it doesn't matter which way they rotate and you can install them on either side.

If they are curved and directional, they should be scooping air in as they rotate forward. It's hard to think of conceptually, but imagine if you had a claw, and you wanted to overhook as opposed to underhook your friend.

With people on Ebay, they'll buy the discs and cut the slots randomly. They can also swap packaging. I would not use the package labeling or the direction of the slots.

[Slidin240Wayz]

Stoptech says the bearclaw would hit you from above instead.

http://www.stoptech.com/tech_info/img/rotor_drilled_cutaway.jpg


http://i7.photobucket.com/albums/y264/Cdoria/Working%20on%20Cars/AirandBrakes.gif


Carlos

[chmercer]

yeah as people have said, the rotor direction depends on the vanes cast into the center of the rotors, the slots can go either way. tell captain gas station "haha yea ok bro" then roll your eyes at him. basically be as pompous and douche baggish as you can. maybe make some comment about how he works at a gas station.

basically the way in the first picture is supposed to be slightly easier on the pads, and the second way is supposed to bite slightly better. thats what ive read anyway. i call bullshit on that though, i doubt you could feel any difference at all.

http://superstreetonline.com/featuredvehicles/130_0303_9z+Nissan_Skyline_GT_R+Spindle.jpg

[drew935]

/\ WOW nice suspension setup with no upper A-arm, adjustable swaybar link, and a horizontal inboard shock setup :bowdown:

[HalveBlue]

Wow, this is confusing.

If the rotor vanes are supposed to be scooping air then the picture Slidin240 posted is wrong.

With the vanes facing the way they are on the Left Side Rotor the car should be traveling from Left to Right to scoop air. Not from Right to Left as indicated.

[Slidin240Wayz]

I am just going by what their pictures says, Left side rotor- USDM Driver's side.

Carlos

[upSLIDEdown]

Wow, can no one on here read or use common sense. The internal vanes are what determine orientation. Many vented rotors don't even have directional (curved) vanes, so it doesn't matter. As chmercer said, I doubt you will feel the difference in bite one way vs the other. The pic slidin240wayz posted is right. It's from STOPtech's website. In case no one bothered to read the link posted above, the vanes are made to draw air from the center to the edge, meaning you want air to go by the edge, pulling air out from the center, NOT forcing air in from the edges, into the center.

[SimpleS14]

AH....now I have a better grasp of what is going on and I'm 100% sure my setup is right.

chmercer - the guy was pumping gas for his SUV...he wasn't a worker and I can't act like a douche without laughing afterwards haha

g6civcx - I just followed what was on the Powerslot package and how the rotors were labeled. They are not knock-offs nor bought off eBay so I'm pretty sure I have them set up just right. Thanks for the info, it does add more to this thread.

[sean350z]

haha 'friend with bearclaw':keke:

[Slidin240Wayz]

the vanes are made to draw air from the center to the edge, meaning you want air to go by the edge, pulling air out from the center, NOT forcing air in from the edges, into the center.


http://i7.photobucket.com/albums/y264/Cdoria/Working%20on%20Cars/AirandBrakes-2.gif

Carlos

[S14DB]

Crap my vanes are straight. What do I do!?!?!?!?!
http://img.photobucket.com/albums/v108/S14DB/240sx/Brakes/Vanes1.jpg

[Slidin240Wayz]

Flip a coin. It doesn't matter.

Carlos

[S14DB]

Nope it's the right hand side rotor.
http://img.photobucket.com/albums/v108/S14DB/240sx/Brakes/RotorR.jpg

By my instructions the R side rotor goes on the Passenger side.
http://img.photobucket.com/albums/v108/S14DB/240sx/Brakes/install.jpg

[g6civcx]

Not related to your question, but this was the only AEM patent I found on their big brake kit: http://www.freepatentsonline.com/6305509.html

[SimpleS14]

S14DB - What kind of rotors are those?

[upSLIDEdown]

I don't think most stock rotors have directional vanes. Even stock Z32's look like the ones S14db posted (IIRC), in which case it doesn't matter. FWIW, mine are oriented like in the pics posted by chmercer and slidin240wayz. I think it looks more aggressive, and "looks" like it would bite a little better (whether it would is irrelevant and more than likely not even noticable).