Drilled and Slotted Rotors

[Norm Peterson]

All drilled rotors aren't created equal

Understood. And I'll bet that the Audi rotor price point is more like Porsche's and significantly higher than typical aftermarket Mustang drilled-rotor pricing.

It would be nice to know what rated pad temperature would be consistent with your 1200° S4 rotors. I'm sure it'd be higher than 1200°, but given that I've managed to crack pads rated above 1500° I'd be intentionally dialing things back a bit on courses that are 'easy' on brakes and avoiding tracks that are brake-intensive. I could demand that of myself and make it happen . . .


Norm

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[EFI]

Well if you go by what others think it's just so Ford can sell more cars lol

Every single car manufacturer on the planet has that idea...and pretty much every decision made is for the sole purpose to sell more cars and make more money.

Manufacturers are not out there spending billions of dollars and thousands of man hours in building cars to please consumers...they are out there doing all of that to sell more cars and make money for themselves. Simple as that.

 

[Voo Doo]

Every single car manufacturer on the planet has that idea...and pretty much every decision made is for the sole purpose to sell more cars and make more money.

Manufacturers are not out there spending billions of dollars and thousands of man hours in building cars to please consumers...they are out there doing all of that to sell more cars and make money for themselves. Simple as that.

What exactly are you saying.....Auto makers are manufacturing cars with drilled/slotted rotors....just to sell more cars??? And you feel this is unsafe to the consumers?? :shrug: Not sure what it is you mean??

 

[EFI]

Auto makers are manufacturing cars with drilled/slotted rotors....just to sell more cars???

Yes, of course. They are not doing it because they are bored and have nothing else to do. And they certainly will not be doing it if it ends up costing them money.

So yes, they are doing those to make cars more attractive to buyers so more cars sell which equals a fatter bottom line for them. They are not doing it out of the goodness of their heart or just to do it. Every single thing that is done to a vehicle has some sort of ROI process to deem it worthy or not of making it to production.

 

[Norm Peterson]

What exactly are you saying.....Auto makers are manufacturing cars with drilled/slotted rotors....just to sell more cars???

Precisely that.

Unfortunately, cross-drilling rotors still hangs onto an image of racing, held over from a long-ago time when drilling was the only option for dealing with pad outgassing. These days, it's a piece of bling that lies somewhere between non-functional and anti-functional, designed mainly to appeal to those who are impressed by what they see and erroneously imagine to be true.

And you feel this is unsafe to the consumers??

At some level of use/abuse, yes.

The mfrs need only build a car that's fit for normal street driving with a fairly generous margin of safety above that. Not a comparable margin of safety above what the hardest possible use outside the car's street driving purpose might amount to.

The catch comes in the fact that the mfrs are not producing race cars. But some of us use them that way, or almost that way. The mfrs have satisfied their internal standards even though that isn't always enough for the race cars that they aren't building.


Norm

 

[Voo Doo]

Precisely that.

Unfortunately, cross-drilling rotors still hangs onto an image of racing, held over from a long-ago time when drilling was the only option for dealing with pad outgassing. These days, it's a piece of bling that lies somewhere between non-functional and anti-functional, designed mainly to appeal to those who are impressed by what they see and erroneously imagine to be true.



At some level of use/abuse, yes.

The mfrs need only build a car that's fit for normal street driving with a fairly generous margin of safety above that. Not a comparable margin of safety above what the hardest possible use outside the car's street driving purpose might amount to.

The catch comes in the fact that the mfrs are not producing race cars. But some of us use them that way, or almost that way. The mfrs have satisfied their internal standards even though that isn't always enough for the race cars that they aren't building.


Norm

Just so I'm clear......tou are saying they make unsafe braking cars.....to sell more cars ?? Right??

 

[Norm Peterson]

Just so I'm clear......tou are saying they make unsafe braking cars.....to sell more cars ?? Right??

You're not going to catch me out trying to provide just one answer to a question that needs to be divided, so you can turn around and twist the meaning of what I posted to suit some agenda.

(1) They certainly are using the visual appeal of drilled rotors in the hopes of selling more cars. Such rotors as installed as original equipment have been determined by the mfr to be adequate for street driving. Period.

(2) But those street brakes are not necessarily safe enough for track-level driving. This applies even more to aftermarket rotors for cars like the Mustang.

I'm not even going to try to find a boundary between (1) and (2) where a cross-drilled rotor becomes unsuitable for the purpose at hand.

I hope that's clear enough, because if that doesn't make it 'click' for you there may be nothing that does.


Norm

 

[Evolvd]

Which just goes to show...if you want drilled rotors for daily driving, you'll be fine if you purchase from a reputable dealer/manufacturer. Unfortunately a lot of folks think that if you're not racing your car every day then you're wasting money on buying a performance car.

(Not pointing any fingers...just generalizing)

 

[Norm Peterson]

Posted on another forum barely an hour ago.

I think you're right about the contagious bad luck. I spent a lot of time on Saturday helping my student with brake issues. (It seems that whoever last worked on the brakes thought bleeder valves should be tightened with an impact wrench.) Then Sunday he cracked a rotor (Drilled rotor cracked between the holes, what a surprise.)

Norm

 

[Norm Peterson]

Which just goes to show...if you want drilled rotors for daily driving, you'll be fine if you purchase from a reputable dealer/manufacturer.

(Not pointing any fingers...just generalizing)

At least clearly limit your usage of such things to street driving only (and say as much if you're going to discuss them online).


Norm

 

[maddawg57]

Well I guess that we need a track section and a daily driver section . Look at the first post by the OP and tell me what it says. He's not asking about rotors for a track car and clearly states that . Everybody has got an opinion . Cross drilled rotors are perfectly fine for the STREET as long as they are quality rotors . I won't give my opinion on track use because I don't track my car . I will ask one question will they pass TECH ?

 

[Norm Peterson]

Keep in mind that a "street-only" side to this topic will inevitably degenerate into a discussion where price becomes a top purchase criterion. While I'm willing to give OE drilled rotors the benefit of the doubt for street use, I'm not going to give aftermarket drilled rotors blanket acceptance.

I've had two sets of Brembo plain rotors that came through with visible thickness variation in the rotor 'cheeks'. What would make anybody think that the foundry and machine shop making drilled rotors to a price point is going to do a job that's any better than that?


I would probably still insert a warning against tracking with them.


Norm

 

[BmacIL]

Can lead a horse to water, but can't make it drink, Norm.

 

[Voo Doo]

Yes, as stated... Daily driver/shows and track cars. I concede two separate entities.

I guess I can't understand why Ford would offer up a Track Car with drilled rotors if indeed it's a bad idea ?? Certainly not to sell more GT 350R's ? Then all the track guys say they're no good? I know you're probably correct...I just don't understand. I'm really....really not trying to be a smart ass or piss anybody off.
I guess I better just be quiet and drink the water....and wonder ?? :cheers:

 

[Norm Peterson]

I guess I can't understand why Ford would offer up a Track Car with drilled rotors if indeed it's a bad idea ??

Because for most people what they're really selling is the image of having a "race car"? I doubt they expect more than a few buyers to get heat-check microcracking in the rotors even started.

For many, perhaps most people, the image is more important than the reality. Especially when the understanding of that reality can only come from independent study specifically looking for it, or attendance at one or more track days where you might hear about it from experienced entrants, or both. An engineering attitude/outlook helps, but most people probably don't even begin to think like engineers (which makes life easy for marketing/advertising).


Norm

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