As some of you may or may not remember from past threads, I'm not a fan of drilled rotors after seeing them crack over and over at the racetrack. I ran into a thread on brakes on track oriented forum (http://www.corner-carvers.com) that turned into a discussion of drilled rotors. In the opinion of a Brembo brake engineer:
"My personal opinion is with today's materials its mostly for bling. there are some slight benifits to it, but there are also some negatives. There have been Brembo/Porsche tests to show that x-drilled rotors increases first effectiveness in wet conditions. Assuming there is enough mass for thermal capacity of the application, X-drilling can save a slight amount of weight (although any unsprung, rotating mass savings help) and offer small increases in cooling speed. However, they are prone to crack more, especially propagating from the drilled holes. This can be accounted for with a proper rotor design (i.e., pillar and hole location/orientation) to prevent small cracks from propagating all the way to the disc edge. If the rotor is designed correctly and sized properly for the application cracking is minimal. That being said, many designs on the market (I won't name any specifically) arent designed properly (arrangement to prevent crack propagation), machined properly (poor or no chamfering), and are under-sized for the application (thermal mass). This is especially true of those popular in the ricer community."
In other words, if the rotor is adequately sized for the weight of the car (which Q45 rotors definitely are not), and the rotors are designed to accomodate drilling (most certainly are not), then drilling isn't a big problem and you may get some small benefit from it. Otherwise, it's a bad idea.
He also mentions that the "Porsche rotors have cast holes" theory is an urban legend. They are drilled, but done so on rotors that have extra material cast around the location of the holes to reduce the probability of cracking, they chamfer the holes, and the rotors are enormous, so they are able to adequately dissapate heat even under hard use.
Eric
Cross drilled rotors
elwesso wrote:INteresting information.... What do you think about slotted rotors???
I've seen those crack at the racetrack too, but it is a lot less likely than with drilled rotors. I personally use regular rotors because there isn't much performance benefit to drilling/slotting/dimpling rotors, and I don't care about bling.
You don't want ceramic rotors, at least not at their current state of technology. The ones on Porsche GT2/3s are not "lifetime rotors" like some the early press indicated and replacement costs are in the many thousand of $ range. People are wearing them out after 4-5 days at the racetrack, and are understandably very unhappy.
Eric
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EWT wrote:I've seen those crack at the racetrack too, but it is a lot less likely than with drilled rotors. I personally use regular rotors because there isn't much performance benefit to drilling/slotting/dimpling rotors, and I don't care about bling.
You don't want ceramic rotors, at least not at their current state of technology. The ones on Porsche GT2/3s are not "lifetime rotors" like some the early press indicated and replacement costs are in the many thousand of $ range. People are wearing them out after 4-5 days at the racetrack, and are understandably very unhappy.
Eric
yikes!
I could go for some 11.9's front and back on the T Bird though (and some 17 or 18" Cobra R's to fit around them:D)
The Ceramic does have the benefit of near non existant fade though, but good lord I'd be mad if I killed them in a few runs...
Basically what I've got from this thread so far is this:
Most places out there don't make cross-drilled rotors that are good enough quality to accomodate a Q45. The ones that do are going to charge an arm and a leg. Therefore, the best deal for the money is solid, thicker rotors if you want to do an upgrade.
Am I reading this right?
Nick
Most places out there don't make cross-drilled rotors that are good enough quality to accomodate a Q45. The ones that do are going to charge an arm and a leg. Therefore, the best deal for the money is solid, thicker rotors if you want to do an upgrade.
Am I reading this right?
Nick