This is a question for TCE Todd, or any of the other brake guru's. I've read up on the cracking of cross drilled rotors, but wondered what your thoughs were of
diamond slotted rotors? This site states that the diamond slots don't cause the stress and cracking of cross drilled rotors.
Also, they show a different style of cross drilling that has rounded edges, unlike most rotors that have a sharp edge. What are your thoughts on those?
Thanks,
Mark
looks like the 'diamond slot' is just for the bling factor..
Slotting in general creates less of a stress factor than a drilled hole. Slotting is useful to scrape down the pad face, and keep it clean in applications where that may be necessary. Racing, and Rally etc type applications are the most notable examples.
Run, don't walk, from any drilled rotor that hasn't had the edges properly radiused. Radiusing the edges of the holes will decrease the stress concentration, but nowhere near eliminate it. So basically, its a little better, but not enough to make it worthwhile. Further, cooling benefits of drilled holes are minimal, and even possibly negative in a rotor not very specifically designed to make use of them. Very few rotors designed like that exist. Further, even when designed to use them, the benefit is minimal over a properly vented plain or slotted rotor. Plus, no matter what you do, a drilled rotor will still crack sooner than a similar plain faced rotor.
For durable reasons I'd pick the slots over the holes any day. That being said all four of the race car rotors are drilled. But I know that and pay attention to them.
The slot shown doesn't seem to me to offer and advantage over about a dozen other formats I have on file. *gotta add one more!
There are a number of patterns and designs that all claim to be the best or better than others. This way, that way, this design, those dimples yada-yada. One that did come to mind as both odd and worth a look is the factory Wilwood pattern that is no symetrical. This limiting harmonics at say 30 degree increments. Even by their own comments this is of minimal value to the average consumer under 150mph...
If I could find a way I'd really love to post all the patterns I have on file. I need to find a hosting site to put them into. It's really kinda funny.
I'll agree with RARA too but always point out that I know of no rotor that is truly relieved on all four sides. Most get two and thats the best you get.
Just the two people I wanted to respond. Thanks Rara & Todd! I just can't help but
over the looks of the cross drilled and slotted rotors. I think I may just go with the slotted and see how they workout. Just weighing my options before I spend a bunch of $$$. Thanks again!
Mark
I have been one of the most vocal about there being no benefit to drilled and slotted rotors except for looks. I still believe that is correct, however I did get seduced by the looks and now have drilled and slotted rotors on my own car. I did it for looks though, and I'm well of the potential pitfalls.
Whatever you end up using, if you do have slotted or drilled and slotted or slotted with some sort of dimple (like EBC or the diamond pattern you referred to) look for something that hase been liberally champhered to help cut down on the stress risers.
You would rally be better off with plain rotors that at the most you have had some color added (zinc plating, anadizing, etc.).
Mine are zinc plated and I have also painted the non friction areas with silver caliper paint. There are those that will say that the paint is not a good idea and will hurt heat transfer, but that is insignificant compared to the damage from drilling and slotting.
He's hooked. LOL
I won't ever say 'no benefit' but marginal enough for the average street driver to never know the difference. In a blind driving test....
Todd I'm wavering.
What benefit will I get with just bigger rotors with a stock caliper (As in FSVT setup) versus a full brake kit from you?
I understand lighter is better but how much better are the rotors in performance to justify the cost?
What about replacement parts and will I loose my pants on the first brake job?
On the other hand I'm tired of smoking out a set of brakes/rotors because I can go so darn fast and then I have to brake really fast too....
OT: Pudmunkie: weren't you JUST looking for a trubendz exhaust, and now your sig says bassani? lol
Can't make up your mind?
Ray
Shhhhhh....
And no I cant! Im actually pretty satisfied with my borla...
Rara, what are you some sort of brake engineer?
Thanks for all the info! I think for next season I'm going to try out the FSVT brake upgrade and see how I like it. I'll probably go to the Wilwood/Baer upgrade if/when I do any sort of turbo project. I think the FSVT upgrade will be nice for my street use.
Mark
Wow. Good writeup. I'm watering at the mouth and I'm beginning to look at the credit card.
Guess I owe RARA one eh?
He pretty much covered it all. (as he should be able to) I often suggest it's a matter of how hard you want to work the parts for the same given results. Would you put a small blower on a car and run it to the hilt or a slightly larger one that provides the same result with less effort?
Taxing the stock system to 98% may be equal to the larger rotor at perhaps 93%. Often with a nice complete package you net the same results at only 85% effort. Effort being a somewhat generic term here.
I didn't read how much larger the rotors are so it's hard to place a value on the cost to performance gains. But remember you're only talking half that for the torque numbers and maybe marginal swept area numbers for say 3/4" of dia.