Basically eye candy these days, as pad meterials are much better. Most race cars use solid rotors as well, sometimes slotted, but drilling is not as common anymore, unless the race is in heavy rain.
Drilled or slotted rotors still relevant?
- Thread starter J. A. Rizzo
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Originally Posted By: artificialist
Why do S-Class Benz cars leave the factory with drilled discs?
Why do people buy low-profile tires? Roads are a lot worse than they were years ago. The reason is style (or the perception of performance).
Why do S-Class Benz cars leave the factory with drilled discs?
Why do people buy low-profile tires? Roads are a lot worse than they were years ago. The reason is style (or the perception of performance).
I remember that Porsche Racing removed the fancy street rotors and used plain ones for track days.
What does that tell you?
What does that tell you?
check NASCAR. All solid rotors. Or go to the road course with me sometime. All the serious cars are smooth rotors these days.
Every stocker you see with drilled rotors already has hugely over-designed brakes already.
Thus they can afford to trade mass for eye candy.
Every stocker you see with drilled rotors already has hugely over-designed brakes already.
Thus they can afford to trade mass for eye candy.
It's also possible M-B doesn't use ceramic pads on the S-series but some other pad compound that would benefit from the slotted/drilled rotors. Maybe they have such giant discs that the surface area is sufficient that the slots/holes don't reduce performance. I dunno. Just wild speculation here.
Checking on the 2010 Porsche 911 Carrera 4S, it ships with drilled rotors, but I don't know the pad compound or the rotor diameter, pad surface area, etc. to make a judgment on whether that supports or discredits the original question.
Checking on the 2010 Porsche 911 Carrera 4S, it ships with drilled rotors, but I don't know the pad compound or the rotor diameter, pad surface area, etc. to make a judgment on whether that supports or discredits the original question.
Minor point: I know that at least on some Porsches with carbon ceramic rotors, the rotors are made with the holes already in them so they don't have to be drilled. This greatly reduces the chance of stress fractures around the holes.
Not sure if all of Porsche's perforated rotors are made that way, but I thought I'd throw that out there FWIW.
Not sure if all of Porsche's perforated rotors are made that way, but I thought I'd throw that out there FWIW.
Good point d00d. Wonder if Porsche makes a set of perforated carbon ceramic rotors for my Honda Pilot?
Originally Posted By: J. A. Rizzo
It's also possible M-B doesn't use ceramic pads on the S-series but some other pad compound that would benefit from the slotted/drilled rotors. Maybe they have such giant discs that the surface area is sufficient that the slots/holes don't reduce performance. I dunno. Just wild speculation here.
Even the entry level C-Class with relatively small brakes comes with drilled rotors nowadays. As was stated above, it's all about the looks, just like the 19" or whatever rims and super wide tires - nobody needs them, but if it looks good, manufacturers will be happy to sell it to you.
It's also possible M-B doesn't use ceramic pads on the S-series but some other pad compound that would benefit from the slotted/drilled rotors. Maybe they have such giant discs that the surface area is sufficient that the slots/holes don't reduce performance. I dunno. Just wild speculation here.
Even the entry level C-Class with relatively small brakes comes with drilled rotors nowadays. As was stated above, it's all about the looks, just like the 19" or whatever rims and super wide tires - nobody needs them, but if it looks good, manufacturers will be happy to sell it to you.
I have grooved std size rotors on my saab. They definitely are an improvement over the old ones, braking feel is firmer and they do grip somewhat more. Under hard braking they make the typical sound but it's not too loud. The pads are also non-std so I'd think it's the better pads that are making the difference in the end.
How about the amount of unsprung weight saved by cross-drilling, slotting, etc ...
It's probably not worth the trouble in an endurance race ... but what about something like an SCCA 20-lap event?
It's probably not worth the trouble in an endurance race ... but what about something like an SCCA 20-lap event?
The unsprung weight savings was very noticeable on my TL immediately. I wasn't even looking for it, I just noticed the car seemed to handle better especially when going over bumps mid corner and couldn't figure out why at first. After half a day I remembered the unsprung weight savings.
I think I saved around 7lbs per corner going from the stock brakes with iron calipers to the 13" 4pot aluminum calipers.
I think I saved around 7lbs per corner going from the stock brakes with iron calipers to the 13" 4pot aluminum calipers.
i recently upgraded to slotted/drilled.
i got it because it looks cool
seriously, i got better braking out of mine and it really does cool the brakes off. sometimes they are completely warm to touch.
i got it because it looks cool
seriously, i got better braking out of mine and it really does cool the brakes off. sometimes they are completely warm to touch.
I'm betting on a typical FWD that a substantial unsprung weight reduction is a GREAT mod.
I was looking at TL's, and unfortunately I could not escape the 'wrong wheel drive' issue!
I was looking at TL's, and unfortunately I could not escape the 'wrong wheel drive' issue!
Originally Posted By: SteveSRT8
I'm betting on a typical FWD that a substantial unsprung weight reduction is a GREAT mod.
I was looking at TL's, and unfortunately I could not escape the 'wrong wheel drive' issue!
Same thing here. But then I figured the FWD will save me from being me, I like going sideways too much. I still have some regrets though.
Be glad you didn't get one, besides the turbo kit that just came out, they're pretty much unmoddable power wise.
I'm betting on a typical FWD that a substantial unsprung weight reduction is a GREAT mod.
I was looking at TL's, and unfortunately I could not escape the 'wrong wheel drive' issue!
Same thing here. But then I figured the FWD will save me from being me, I like going sideways too much. I still have some regrets though.
Be glad you didn't get one, besides the turbo kit that just came out, they're pretty much unmoddable power wise.
Originally Posted By: d00df00d
Originally Posted By: BuickGN
The unsprung weight savings was very noticeable on my TL immediately.
How much of this was from the rotors, though?
I knew I would kick myself for not weighing them... The vast majority was from the calipers. The 13" rotors felt about the same weight as the stock 11.8". Mine are 1pc. Knowing what I know now, I would've gone with the 2pc.
Originally Posted By: BuickGN
The unsprung weight savings was very noticeable on my TL immediately.
How much of this was from the rotors, though?
I knew I would kick myself for not weighing them... The vast majority was from the calipers. The 13" rotors felt about the same weight as the stock 11.8". Mine are 1pc. Knowing what I know now, I would've gone with the 2pc.
I just purchased SAE paper 2006-01-0691 "The Effect of Rotor Crossdrilling on Brake Performance". It looks extermely interesting so far and covers everything I've ever heard mentioned from the loss of mass, wet braking, brake wear rates, high speed cooling, low speed cooling, pad glazing, brake fade, and much more. I just printed the 28 pages so it will be bedtime reading material. This screen hurts my eyes staring at it for too long.
I'll post a summary tomorrow. Anyone know what I can and can't post? I signed the license agreement and I'm not going to violate it but I think a brief summary in my own words would be ok, right? Is anyone even interested before I go to the trouble?
I'll post a summary tomorrow. Anyone know what I can and can't post? I signed the license agreement and I'm not going to violate it but I think a brief summary in my own words would be ok, right? Is anyone even interested before I go to the trouble?
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