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The problem I see after taking a closer look at the design is that it is mounted above the lower control arm and in the picture the scoop would be above the lower cutout airflow from the splitter when car is resting on the ground.
The high turbulence from the wheel at speed will not guarantee airflow.
In my opinion the cool air has to be directed from the front high pressure area to the duct to be effective..
The inlet drops down below the lower a-arm. The channel in the front undertray directs air up higher and the duct is aimed to receive that air. Have a look under your car and you'll see that channel.
The inlet drops down below the lower a-arm. The channel in the front undertray directs air up higher and the duct is aimed to receive that air. Have a look under your car and you'll see that channel.
I have and it is minimal at best. It would be better served mounded on the underside of the control arm to at least have a more direct shot at cool airflow.
Would be better to modify the dust shield to accept the ducting then just blowing onto the caliper.
I guess a simple left right tire temp test to see.
You don't want to feed it where the dust shield is. That's just cooling one side of the rotor. A vaned rotor acts as a turbine which pumps air radially. To best use the vaned rotor, you want to feed it at the inner annulus to allow it to pump around cooler air. There's an opening to the inner annulus of the rotor between the knuckle and the caliper, which is where this duct directs air to.
You don't want to feed it where the dust shield is. That's just cooling one side of the rotor. A vaned rotor acts as a turbine which pumps air radially. To best use the vaned rotor, you want to feed it at the inner annulus to allow it to pump around cooler air. There's an opening to the inner annulus of the rotor between the knuckle and the caliper, which is where this duct directs air to.
The separators in the disc are not directional [correct me if I'm wrong] left and right and are not acting as a turbine, hell if they were we would not have this issue..
Check out this photo. Regardless if the rotor has directional vanes, the air flows from closer to the center outwards. You want to feed the air close to the center at the opening and not at the face of the rotor.
Fantastic job Ronac. Hoping you can come up with a excellent duct for the rear also. I’m wondering if it might be a little more difficult due to the RWS system?
Lastly thanks for making these in plastic and not CF. That will reduce costs greatly.
Looks really good Ronac. Looking at the RENNtech version from the picture, would it be possible to increase the inlet size of your design as theirs seems like it would catch more air.
2. Keep front CCM (420x40mm) but oversize the rear to 390x32mm with 4 pot calipers - This can increase the rear brake capability for a more balanced brake system.
Last edited by RacingBrake; 02-27-2019 at 03:14 AM.
I was reading around the forum and came across the video with myself... So I see that there are different perspectives on what is causing overheating issues and how to solve them. Let me try to explain what I concluded during numerous tests with flow and pressure sensors as well as flow visualization aids on GTR during solution development for my partners in Germany.
First of all, regarding the debate on rotor vanes, they all create flow whether curved, straight or multiple with slight differences in effectiveness. In this video:
you can clearly see how rotor does a great job in creating air flow. Test was done at wheel rpm equivalent to the speed of 100km/h, no forced induction to the inlet.
BUT, the problem starts when You put the wheel on. All of the stock wheels we tried block most of the hot air from going out of the wheel in between the spokes. So the hot air from the rotor is being pushed back in to the center of the wheel, towards the wheel housing. So big problem with stock setup, with aluminium heat shield with air inlets, is that the hot rotor exhaust air is being partially sucked back in to the center of the rotor, thus decreasing the cooling potential of the cold air which should come from the front diffusor.
Second is the heat shield itself. It has small inlets and big spacing from the rotor. This space between the shield and rotor surface has significant cross section surface which leads to the center of the rotor. Effectively there is almost no separation of exhaust and inlet of the rotor. There are pictures of Aston Martin in this thread with aluminum parts which are actually not ducts but separators with the purpose of blocking this hot air recirculation.
Third is the upright that has a shape which covers most of the rotor inlet, so simple big pipe solutions don't work. It is something we had to live with and just use every bit of space to guide air all around the upright.
So conclusion was: Duct which has a total inlet/exhaust separation needs to be made. Inlet has to be far away from the rotor exhaust. Front canards and fender exhausts will help additionally for extracting air from the wheel/wheel housing.
Below is how it is done on a race car, but it is on usable on regular cars with regular suspension travels and steering angles. But the point is the same, supplying the rotor with cold air only.
2. Keep front CCM (420x40mm) but oversize the rear to 390x32mm with 4 pot calipers - This can increase the rear brake capability for a more balanced brake system.
Anyone interested in this conversion for overall low maintenance cost with guarantee result.
RacingBrake offers CCB conversion not just for MB GT R, but also Aston Martin DBS, Audi RS7, BMW M3/M4, Camaro Z28, Corvette ZR1, Ferrari F430/F458, Porsche 911 etc. Not just the rotor replacement, we have caliper rebuild kit that can help your OE calipers more resistant to higher temperature and function more effectively, brake pads w/different compounds for street and track racing, CCM rotors made with continuous carbon, or even OE calipers replacement.
Besides those parts and components, we offer professional advice on how to deal with your brake issues. We are a professional brake company providing fundamental solution to brake industry for more than 30 years.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Interesting conversation. For whatever it’s worth, on my C63 track rat I have 996 GT3 Cup brake cooling ducts retrofit to my lower control arms in front to cool my big RacingBrake rotors. They’re pretty basic but effective. I’m sure they can be fit to the GT cars with little effort. And it makes a noticable difference on my 3900# pig.
One other observation on this thread. If you’re not checking all components of your wheels and brakes as the absolute first priority before going out on track, and after every session, you really have no business being out there. You’re not just putting yourself and your car in jeopardy, but everyone else out there. OP needs to do some HPDE1 with an instructor and observe the behavior of others in the pits before being so reckless again. Yes, this was all totally avoidable - relying on pad wear sensors is a total rookie move.
Here’s an example. At WGI last year I was doing my usual between session check on my car. I saw something funny with the drivers side front tire. See pic below. That’s a snapped tire cord sticking out of the sidewall of my beautiful PSC2. Tire still held air fine. Upon dismounting the tire it was found that not only was the sidewall ripped 3/4 of the way around the tire, but the other side was showing signs of the same. If I had gone back out on track like that, I could’ve been killed with some of the speeds I see there. You have to know your car and you have to check every single time out there. You never know what you’ll find.
Not even noticing that you have no pads left, and continuing to drive like that... sorry, that’s not Mercedes’ fault.
I solved the problem by selling both my AMG cars. Bought 2 Porsches instead. They have no brake cooling issues. Surprisingly AMG is poorly engineered to not provide adequate cooling to the front brakes. They also completely misrepresent the capabilities of the cars. It is complete fallacy to put a Race setting on the performance selector. I told Tobias Moers of my disappointment.
I solved the problem by selling both my AMG cars. Bought 2 Porsches instead. They have no brake cooling issues. Surprisingly AMG is poorly engineered to not provide adequate cooling to the front brakes. They also completely misrepresent the capabilities of the cars. It is complete fallacy to put a Race setting on the performance selector. I told Tobias Moers of my disappointment.
Those of us who run the GT R hard on a track wouldn't agree with you; Race is a very useful setting, and you seem to be the only owner who ****ed up his brakes from negligence. Do you think it's the car or the driver?
Enjoy the Porsches; they are great cars also; well at least the GT variants.
You are sadly mistaken if you think was the driver. Did you watch the video? A Sunday drive by someone with 100's of laps at Laguna. The only negligence is on the part of AMG and their lack of front brake cooling. Remember who started this thread, a GT R owner whose brakes looked the same as mine.
You are sadly mistaken if you think was the driver. Did you watch the video? A Sunday drive by someone with 100's of laps at Laguna. The only negligence is on the part of AMG and their lack of front brake cooling. Remember who started this thread, a GT R owner whose brakes looked the same as mine.
How in the Hell does this article from 2017, which btw has nothing to do with the higher performance AMG versions like the GT R, have anything to do with an owner getting out on track with highly worn brake pads, that then due to negligence ruins expensive rotors? I’ve been track driving for 25 years, and one: I’ll assume responsibility for not paying attention to the consumables on my car, and 2: I never run at (my) limit with ESC on; ever! This will markedly reduce the longevity of rear pads, especially those that are weighted more towards street use than track, which obviously the OEM pads have to be.
Lastly, the scenario listed in the article of the ABS/ESC system constantly applying the pads to the rotors due to low brake fluid pressure does not happen on a GT R on track, or I and fellow owners who’ve driven the car ‘in anger’ would know it.
There is no doubt that more forced air cooling would be welcome; it essentially always is
How in the Hell does this article from 2017, which btw has nothing to do with the higher performance AMG versions like the GT R, have anything to do with an owner getting out on track with highly worn brake pads, that then due to negligence ruins expensive rotors? I’ve been track driving for 25 years, and one: I’ll assume responsibility for not paying attention to the consumables on my car, and 2: I never run at (my) limit with ESC on; ever! This will markedly reduce the longevity of rear pads, especially those that are weighted more towards street use than track, which obviously the OEM pads have to be.
Lastly, the scenario listed in the article of the ABS/ESC system constantly applying the pads to the rotors due to low brake fluid pressure does not happen on a GT R on track, or I and fellow owners who’ve driven the car ‘in anger’ would know it.
There is no doubt that more forced air cooling would be welcome; it essentially always is
I provided a link to that article only for information and did not intend to imply it had anything to do with my debacle. Do realize, my pads were almost new with 2500 miles on the car. In fact when they dealer inspected the pads after the failure they were all at 9 mm, which is nearly new (approx 10 mm). You should also realize I spoke with my SA at the dealership before taking the car to the track and he said nothing about anything or concerns in doing so. Just so you have all the facts. In turn when the Porsche dealership did the safety inspection (after trade-in) the head mechanic said he found no cooling ducts at all to the front brakes.
I provided a link to that article only for information and did not intend to imply it had anything to do with my debacle. Do realize, my pads were almost new with 2500 miles on the car. In fact when they dealer inspected the pads after the failure they were all at 9 mm, which is nearly new (approx 10 mm). You should also realize I spoke with my SA at the dealership before taking the car to the track and he said nothing about anything or concerns in doing so. Just so you have all the facts. In turn when the Porsche dealership did the safety inspection (after trade-in) the head mechanic said he found no cooling ducts at all to the front brakes.
Can you send me the link here on the forum where you state exactly what happened to your car, and hopefully with pix? I ask because without excessive pad wear, you aren’t going to transmit huge amounts of heat into the CCM rotor enough to damage it. My rear pads are at about 4mm, this after about 20 HPDE sessions, with about 6 of them with ESC Sport actually on as my son was also driving the car for the first time at one track weekend. These pads will be replaced when the car comes out of its winter hibernation. Front pads still with around 60% of pad left. I am a pretty quick driver, but I am smooth on the brakes, and I burnished the pads prior to taking the car to the track the first time. Hence my pad wear might be different than yours, although your pads weren’t essentially worn at all. Therefore my confusion as to why you may have had rotor issues?
Can you send me the link here on the forum where you state exactly what happened to your car, and hopefully with pix? I ask because without excessive pad wear, you aren’t going to transmit huge amounts of heat into the CCM rotor enough to damage it. My rear pads are at about 4mm, this after about 20 HPDE sessions, with about 6 of them with ESC Sport actually on as my son was also driving the car for the first time at one track weekend. These pads will be replaced when the car comes out of its winter hibernation. Front pads still with around 60% of pad left. I am a pretty quick driver, but I am smooth on the brakes, and I burnished the pads prior to taking the car to the track the first time. Hence my pad wear might be different than yours, although your pads weren’t essentially worn at all. Therefore my confusion as to why you may have had rotor issues?
Bish
I deleted those post after all the ridicule. You buy a $231k car with a $9k ccb option and they last 21 laps. Unacceptable! They probably wouldn't have lasted 1 lap with Lewis Hamilton. Obviously, AMG never expects someone to take an SL to the track. Suckered me.
01-31-2019, 03:05 PM
So I see that there are different perspectives on what is causing overheating issues and how to solve them. Let me try to explain what I concluded during numerous tests with flow and pressure sensors as well as flow visualization aids on GTR during solution development for my partners in Germany.
