Cross drilled rotors???????

[kingman]

Hi

l hate to sound like a dweb, but what exactly are cross drilled rotors and what does it cost to be done?

Thanks

 

[LT1Vettepilot]

Cross drilled rotors have holes drilled across the the vertical line of the rotor. i.e. if you look at if from the side, the rotor looks like swiss cheese.
Reason, helps disippate heat faster basically. However there is a drawback. Do to the variations in how quickly areas of the rotor can disippate the heat, freaquently cracks appear near the holes.
Check here for more information
www.baer.com

 

[kingman]

Thanks Vette Pilot

l read some ads regarding the cross drilled rotors and they sounded good but they were only ads.

They look cool anyway.

 

[tntcorvette]

I think you only have to worry about cross drilled rotor cracking under sever driving.

I have the Mid America ZR1 front brake kit and the rotors are spot drilled. Basically they are dimpled versus drilled all the way through. So far im totally happy with them.

 

[LT1Vettepilot]

Hmm...I've never seen the dimpled ones. I don't see any advantage with just dimpling the rotors. This reduces the contact area between the rotor and pads without gaining the advantage of increased cooling efficiency. About the only thing I see that is advantagious over standard rotors is the dimples gives the brake dust a place to go...and that really isn't much of an advantage...its going to get on the wheels regardless.
Interesting concept though. Do you have any pictures or a link to them? I'm curious to see what they look like.

 

[tntcorvette]

I cant find a pic on the net, but I can take a pic of my rotors and post them.

BTW, since the cross drilled rotors and dimpled rotors are missing "surface area" then they both have the same contact area.

If memory serves me correctly the dimpled rotors are suppose to do the same thing as the cross drilled rotors (cooling, etc), but also reduce the chance of cracking the rotor and such. Sorta like the newer rotors with the "swirly" design on them.

BTW, this is a 13" rotor.

 

[Eagle85C4]

Nobody mentioned the ability of slots and or drilled rotors helping in removing gas from the rotors....

 

[tntcorvette]

Nobody mentioned the ability of slots and or drilled rotors helping in removing gas from the rotors....

Oh yeah, that too!

 

[tntcorvette]

LT1VettePilot

here is a link and pic to the ZR1 brake kit.


http://www.ecklers.com/product.asp?pf_id=33103&dept_id=1035&mscssid=Q9RCMNJW6XSR2LQF00N0SM2EP3QG3DVF

 

[LT1Vettepilot]

Hmm. Interesting.
However, if I'm not mistaken, starting in '95 all Corvettes came standard with the larger brakes from the ZR-1 and the ZO7 handling package.

 

[Chris N]

I believe that heat dissapation is a function of many things like mass, airflow, and surface area. Dimpled rotors have less mass, and more surface area in which to dissapate heat when compared to stock / smooth. Through drilled has less mass, more surface area and better air flow but more likely to crack or warp. Lower masses cool faster but can not absorb as much heat energy. Slotted rotors work like drilled ones. Although there is less pad contact area, all of the additional edges help the pad bite, but can shorten pad life.

I'm pretty sure about my theory, but not positive.

Engineering software is great for showing heat transfer and fatigue.

Engineers have to ballance cost, weight, life span, reliability, and manufacturing limitations on every part. It is tough because consumers don't all want the same things.

Chris N :cool

 

[tntcorvette]

you are right, eventually all corvettes came with 13" brakes, but unfortunately the '85 came with a set of lousy 12" skinny rotors.

 

[kingman]

Best Brakes!

Hi

If the cross drilled rotors are not the answer, what about the Bremo or something like that brakes for a 96?

 

[Eagle85C4]

TNT....

The 85 came with 11 1/2 " rotors...You can add the dual piston calipers and 12" rotors off of an 88 to the front of your 85. The only thing needed is a modified bracket to mount them. The brackets are sold by Carroll Supercharging.

You can email them for info.... supercar@bellatlantic.net

 

[tntcorvette]

11.5" rotors? Humm...not sure what GM was thinking when they put those brakes on a car that will do 150 from the showroom floor. But then again it was the 80's

I got the brake kit a couple of years ago at the Chevy Vette Fest. Mid America Designs usually has a booth there and offered free s&h and a 10% discount, plus their price was much lower than Ecklers at the time.

Since my car needed new brakes it was a good way to go. Next time (which wont be anytime soon) i'll proabbly upgrade to C5 brakes.

 

[Eagle85C4]

Tell you what I find amusing....is that the same brake pad is used for the front regardless which size rotor. The main advantage to the larger rotors is that they cool faster. The actual pad surface stays the same. And the calipers are dual piston for the upgrade. You are only going to generate so much force when applying the brakes. Instead of the pressure being exacted on one piston, the force is equally split between 2. By going to the 88 version brakes you get a bit larger rotor plus the dual piston caliper but you also get to keep the 16"rims and not have to change to 17" as with the 13" rotor.

 

[tntcorvette]

you are correct. The main advantage of larger rotors (13" in this discussion) is the ability to cool faster. The larger rotor area allows this. It is much more consistent. When I use to spend alot of time at the drag strip making back to back to back runs the oem brakes (when they were good) would fade after a couple of rounds of hard braking.

My rear brakes are replacement o.e.m. (I guess 11.5"??) rotors with new o.e.m. brake lines. In the front I run stainless steel brake lines.