My new C63 coupe

[the///Mthree]

Originally Posted by devo

That's really uncalled for.

Seems like Ateam woke up on the wrong side of the bed this morning

Clearly he didnt understand I was trying to tell him that this C63 has more cross sectional area than it appears in these pictures.

Next time I will try not to be so blind and dumb when I post.

[CSanto]

I just priced a C63 on the amg website, damn these things are getting expensive. 80k was my sticker with performance pack.

Gently used 12 GTR for 84-85?

I go GTR. What do you guys think?

[IND-Distribution]

Originally Posted by SchnellM3

Nice new car, love that interior

Interior is sharp, love those seats.

[bruce.augenstein@comcast.]

Originally Posted by Ateam

I have had trouble understanding this in the past and these brakes are a perfect example. Perhaps the overall diameter of the rotor is the same as the M3 (I did not know until you told me) but the "cross sectional" area of the rotor face is a lot less on this car and other cars with large diameter rotors. Another one that comes to mind is a g37-the diameter is quite large but the actual rotor face has much less cross sectional area. That is the problem with stating rotor measurments in diameter, it does not take into account how much rotor area is available.

Do you know what I mean? Its like a donut that is equal in diameter only has a center hole that is 3 times larger, meaning there is a lot less "donut" even though the donut is the same in diameter! mmmm donuts-need to go get some now

That is the part that looks odd-its the rotor material is skinny, even though they might be very large diameter?

Speaking of that, to me you are losing a lot of material that can participate in heat dissipation. Something I have been wanting to understand so if someone or gthal can explain this I would be grateful!

Would be fun to have both this and an m3! Now that would be fun times

In spite of your subsequent nastiness, since you've asked for some enlightenment, here it is:

Ignoring brake pad material and rotor material, the overall capability of a disc brake is dependent on (in rough order of importance), its weight, surface area of the pad(s), and the overall swept area between rotor and pads.

These factors all govern temperature, and temperature is the enemy.

Weight of the rotor is important because it acts as a heat sink, so with an equal amount of braking, a heavy rotor will heat up less than a light rotor. Surface area of the pads is important because if they're small, the surface of the pad will heat up more with a given amount of braking.

Swept area is important because even if the pads have a good deal of surface area, if they're narrow (measuring from the outside of the rotor to the inside of the rotor), the swept area across the rotor will be reduced, and since heat dissipation isn't instant, that area of the rotor will heat up more, thus driving pad material temperature up, thus...

Rotor diameter has some importance also, since a larger rotor weighing the same as a rotor with a smaller diameter has more surface area to dissipate heat, both on the outside, and with "hollow" finned rotors, from the inside as well.

Back on point, my overall impression of the brakes on the C63 is that on track they work better, overall, than those on the Bimmer, regardless of the details of construction.

Track rats will run out of brakes in the M3 in no more than five laps or so, while C63 drivers tend to report more gradual softening of the pedal under duress. As a detail, my belief is that pad material largely dictates this particular discrepancy.

Bruce

[Mr. ///M3 RD]

Originally Posted by gthal

Hi all,

I am excited to say that I picked up my new C63 coupe yesterday! Specs as follows:

Heath, Congratulations and all the best to you ... enjoy this fine automobile... also much success in your new professional live.

Thanks for writing this great review

[Ateam]

Originally Posted by bimmerj

Very simple, I will measure my rotors tomorrow with a digital calipers and get the area of the annulus. You do the same and we will compare them.

Think I will be banned shortly. Apparently multiple posts of mine are getting selectively deleted.

People need to chill out here. Its an internet forum. Sucks it has been sucked down to the level of being so heavily moderated. No forum for FREE discussion anymore. WHy is there mods looking over everyone's shoulders on a internet chat board. You let the comments stand for themselves and the people that read and comment then reply and if they do not like something they will speak, as they usually do.

So anyway-if I could measure the surface area I would but have no clue how-not as taleneted as the physics masters here!

[bimmerj]

Originally Posted by Ateam

Think I will be banned shortly. Apparently multiple posts of mine are getting selectively deleted.

People need to chill out here. Its an internet forum. Sucks it has been sucked down to the level of being so heavily moderated. No forum for FREE discussion anymore. WHy is there mods looking over everyone's shoulders on a internet chat board. You let the comments stand for themselves and the people that read and comment then reply and if they do not like something they will speak, as they usually do.

So anyway-if I could measure the surface area I would but have no clue how-not as taleneted as the physics masters here!

Ok, just measure the length of the exposed area. The diameter of the rotor is known, will say this is D. Multiply the length of the exposed piece by 2 and subtract the diameter of the rotor from it, this will give d. The exposed area will be A=(3.14/4)*[(D)^2-(d)^2)].

I always thought the back rotor of the C63 is slightly smaller than that of the M3, but I could be mistaken.

[Ateam]

I am not seeing how that equation would give you the area of the exposed rotor? I can do that but I am thinking something is not right there.

I think an easier measure would be simply to measure how tall the actual piece of the rotor is. ie-like you would measure how tall the profile of a tire is. If the rotors are the same overall diameter than this will tell us which one has more actual rotor material. Ill go do that

[TonyTone]

Congrats looks great!!!!

[Ateam]

Ok for the-

rear-2.5 inches of rotor material from "donut hole edge" to outer edge.
Front 2.8 inches

[bimmerj]

Originally Posted by Ateam

I am not seeing how that equation would give you the area of the exposed rotor? I can do that but I am thinking something is not right there.

I think an easier measure would be simply to measure how tall the actual piece of the rotor is. ie-like you would measure how tall the profile of a tire is. If the rotors are the same overall diameter than this will tell us which one has more actual rotor material. Ill go do that

Sorry, meant how tall the exposed area is. The formula will give us the area of the annulus. I know we don't have to go through this, but out of curiosity, I like to find out the difference.

George

[Ateam]

I illustrated which part I am measuring

[bimmerj]

Originally Posted by Ateam

Ok for the-

rear-2.5 inches of rotor material from "donut hole edge" to outer edge.
Front 2.8 inches

Please keep in mind, this is a very rudimentary calculation and done just for curiousity.

[Onurleft]

Nice article. Love when people do stuff like this, it really adds lots to the forum.

The torque really is addictive for DD usage. It makes negotiating traffic and errands that much easier to cope with when you really want to hustle.

Some things I want to point out though...
If you translate the Supertest Article with the E92 M3, the car was tested on PS2's for the Ring and the Cup tires for the independent performance tests and small tracks. This is stated in the article. You might want to adjust that in your write up it is mis-leading everyone who reads it!
Also a SportContact 3 is far from anemic, even compared to an RE-11. While it is more of an "all-arounder" vs. a competition autocross tire, it's an incredibly capable tire, especially @ temperature (track temperature). They hold together even when there's excessive weight on top of that heat unlike others which have de-laminating issues, one being the PS2

[Ateam]

Originally Posted by Onurleft

Nice article. Love when people do stuff like this, it really adds lots to the forum.

The torque really is addictive for DD usage. It makes negotiating traffic and errands that much easier to cope with when you really want to hustle.

Some things I want to point out though.
If you translate the Supertest Article with the E92 M3, the car was tested on PS2's for the Ring and the Cup tires for the independent performance tests and small tracks. This is stated in the article. You might want to adjust that in your write up it is mis-leading.

No doubt torque is fun! But come on folks-this is sounding like the 335 tuned crowd. Its not not like the m3 is not capable of enough around-town torque and power! I don't know about you guys but I have never struggled to do anything around town or on the freeway that involved speeding up, passing, maneuvering etc. I think once you are at 400 hp, you have ample power at all times to have "adequate" DD capabilities! Anything beyond is indeed a hell of a good time but the arguement that it is a "better" daily driver is absurd! I think the more accurate statement would be its easier to feel the acceleration and have fun with compared to having to purposely rev the motor in the s65.

[Ateam]

Originally Posted by bimmerj

Please keep in mind, this is a very rudimentary calculation and done just for curiousity.

This is not really rudimentry. If you just measure what I did and compare them-it will tell a lot.

Although i do not know the math to convert the measurement I made to the total area of the rotor space, it will be directly proportional to that area, therefore a larger diameter measurement for this peice of the rotor will indicate more surface area-the missing piece is exactly how much.

If you could measure yours and post that would be interesting. I am not sure if they are the same or not but would be itneresting

[bimmerj]

Originally Posted by Ateam

This is not really rudimentry. If you just measure what I did and compare them-it will tell a lot.

Although i do not know the math to convert the measurement I made to the total area of the rotor space, it will be directly proportional to that area, therefore a larger diameter measurement for this peice of the rotor will indicate more surface area-the missing piece is exactly how much.

If you could measure yours and post that would be interesting. I am not sure if they are the same or not but would be itneresting

That's what I exactly mentioned about the area. I say rudimentary, because we are not taking the material the pads are made of as well as the area covered by the pad. I know our initial project was the exposed area and we will go with that. I will do the calculation tomorrow. And next time use a system that is not archaic (use mm), just kidding.

[Ateam]

Per AMG website

C63 brakes

Front rotors overall is 14.2
Rear overall diameter is 13

M3
front- 14.2
rear 13.8

So the m3's overall is bigger as well

[Ateam]

Originally Posted by bimmerj

That's what I exactly mentioned about the area. I say rudimentary, because we are not taking the material the pads are made of as well as the area covered by the pad. I know our initial project was the exposed area and we will go with that. I will do the calculation tomorrow.

Your killing me! Just bust out the tape measure and lets see the raw data!

[Its_lobelt]

Great car man. The new C coupes are gorgeous IMO.

[bimmerj]

Originally Posted by Ateam

Your killing me! Just bust out the tape measure and lets see the raw data!

lol, I don't have the car now. My wife will get back tomorrow.

[Ateam]

I was not paying attention to the wheels but those 18s look fab! I would have just kept those-They look pretty sweet!