[Autohome Modification School] After seeing the title, some friends may think: Upgrading the braking system is so simple. If you go to the track, just replace it with a four-piston or six-piston caliper and enlarge the brake disc. , why bother to open a special article to discuss

[Autohome Modification School] When you see the title, some friends may think: Upgrading the braking system is so simple. If you go to the track, just replace it with a four-piston or six-piston caliper and enlarge the brake disc. Well, why bother opening a special article to discuss it. But what if your upgrade budget is limited? This time we specifically discussed low-cost braking system upgrade solutions, and also verified whether a low-cost solution can meet the intensity of occasional track experience. As a standard, the upgrade cost of the entire braking system is no more than 4,500 yuan. What can you do with this money?

For the convenience of narration, we will not use the "image reading mode" to explain this time, so that we can use large paragraphs of text to make a more thorough description. After several days of planning and testing, my colleague Meng Huan and I present this article to you.

● Discussion on the feasibility of using the original brake system on the track

Can the original brake system be used on the track? Due to factors such as manufacturing cost and service life, the braking systems of most models are only designed for daily street driving and are not suitable for track use. Because our braking and deceleration movements are usually relatively gentle, and the braking intensity is only about 10%-30%. However, full braking is very frequent on the track. In addition to controlling the posture, almost all the braking system's capabilities are used. Although, the braking system is used much more frequently, and the heat accumulated on the braking system at this time will be dozens of times that of daily conditions.

When too much heat accumulates and the brake pad exceeds the operating temperature, its friction coefficient will decrease. This phenomenon is called "thermal decay". We will not have a physics class today to talk about the causes of thermal decay. As long as you remember that the braking system has its optimal operating temperature, the braking force will decay when the temperature is exceeded. In fact, the braking system itself has been designed with a heat dissipation mechanism to prevent excessive temperature, such as the ventilation structure in the center of the brake disc (commonly referred to as "ventilation disc"). Some calipers even have brake pad cooling fins to help dissipate heat, such as the following This is what the Porsche caliper in the picture looks like. This design is not common, but it illustrates something: braking systems hate overheating. A braking system like

has no problem coping with daily use and more intense driving, but track driving is a completely different concept. In order to give everyone a more intuitive understanding, we will not list the data and directly use pictures to illustrate the problem. The picture below is a scene of a Lamborghini racing car braking when it was taken from the competition. It can be seen that the brake disc is red. This is a scene that is impossible to see in daily driving. Moreover, the greater the output power of the engine, the more it can push the car to higher speeds. When decelerating, more energy will be released on the braking system, and the requirements for the braking system will be higher.

Please look at the picture above. When a modified high-horsepower street vehicle brakes on the track, the upgraded competitive braking system performs its duties well, converting the vehicle's forward kinetic energy into heat and releasing it, and the brake disc does the same. Red light was emitted. What is the temperature of the brake disc at this time? According to the general rules of steel after being heated, it will appear slightly red at 600°C, orange-red at 700°C, red at 800°C, and red and yellow at 900°C. The front brake disc temperature of the white vehicle in the picture above is obviously 800°C, and the temperature of the flame in the furnace is no more than that.

Let’s talk about why the brake disc turns red. We know that when an object heats up, it will emit infrared radiation. The greater the temperature difference with the surrounding environment, the greater the infrared radiation will be. When the temperature of the brake disc is much higher than the surrounding environment, the infrared rays released are too strong, and part of the infrared rays will be converted into visible light, which becomes the red light we see. The picture above is a brake disc in normal condition taken by an infrared imager. The escaping infrared rays are seen under the infrared imager.

Is the braking system of ordinary street cars really not suitable for track use? It's not impossible, but generally the heat accumulated after 5-8 minutes is already considerable. The resulting heat attenuation requires braking in advance to safely enter the next corner, which not only affects the performance but is also very dangerous.What's even more dangerous is that when you are unaware of the attenuation of the braking system and still brake according to the established braking point, the extended braking distance due to thermal attenuation will directly send you into the track buffer zone. Such as the three poor guys in the picture above.

So how does a racing car solve the problem of the braking system? The first is to enhance heat dissipation. For example, in the braking system of the WTCC racing car in the picture above, you can see the forced air duct. This air duct forces the cold air introduced from the front of the car to the central air duct inlet of the brake disc to ensure sufficient cooling air flow to the brake disc. Different racing cars have different shapes of air ducts, but most of them follow a similar idea.

Racing's solution also involves using better materials. “Better” here means brake friction materials with higher optimal operating temperatures. For example, the braking system of the formula racing car in the picture uses carbon ceramic brake discs. Its optimal operating temperature is around 1000°C, which can fully meet the most demanding braking environment. Some supercars and high-performance coupes are equipped with similar braking systems as standard or optional equipment.

Okay, enough of the obscenity, don’t forget that our topic this time is “Low-Cost Braking System Upgrade Solution”. Although the expensive and willful things above cannot be used in this case, they also point out that the braking system Ideas and directions for system upgrades: improving heat dissipation and using better materials. The budget is limited, but the general principle is still the same. For the harsher working environment of the track, we need to replace brake pads with higher operating temperatures and consider replacing brake discs with higher heat dissipation efficiency.

By the way, I would like to mention the multi-piston braking system. They are not selected in this upgrade plan. The limited budget is only one factor. On the other hand, the improvement of the caliper structure is only the basis for performance improvement. The actual performance will be affected by the superposition of many factors. If the design is not good, some seemingly powerful multi-piston braking systems may be just an illusion... We will talk about this in the next issue.

As this test platform, we used a modified Subaru BRZ - the same car that was previously tested in the "Subaru BRZ Modification Log" (For previous stories, please click here: Track Test + Analysis Subaru BRZ Modification log Part 9). The vehicle was modified with coilover shock absorbers, CUSCO anti-roll bars, and 245mm wide AD08 R high-performance street tires. In terms of power, only the high-flow exhaust middle and rear sections have been replaced, and the braking system is completely original. We will use this car to alternately replace the original and upgraded braking systems and drive them on the track for a period of time. During this period, the vehicle will simulate a "track day" state and run at full speed to ensure that the braking system is under as high a load as possible. to check the difference in their durability and reliability. Next, let’s introduce this brake upgrade plan.

● Introduction to the brake upgrade plan: brake pad part

This upgrade plan is to replace the brake pads and brake discs based on the original calipers. The brake pads are HAWK's HP PLUS and HPS models, and the brake disc is the T2 brake disc from the dba brand street series. Of course, there are many optional brands for upgrade plans. We have only chosen two of them to illustrate. Other brands also have products of similar levels and prices, and their performance is also very similar. Friends can choose according to their personal preferences.

first introduces the first upgrade solution, HAWK HPS, which is positioned as a "high-performance street upgrade product". The manufacturer claims that its characteristics are "stronger braking force", "larger friction coefficient under high and low temperature conditions", "better braking progressiveness" and "longer service life". We can understand that this is a product that has a slight upgrade in braking power compared to the original product, but does not affect its service life.

This brake pad does not look "fierce", with a smooth surface and moderate hardness. The slot in the middle is to enhance the friction toughness, relieve the pressure on the brake pad, and like the slot on the brake disc, it can remove the dust generated during the braking process and ensure the perfect fit of the friction surface.

There is also a chamfer on both sides of the brake disc.This design can also be seen on many other brands. Its function is to reduce the vibration between the edge of the brake pad and the brake disc, reduce braking noise, and improve driving comfort. Of course, this is to reduce the number of brake pads. In exchange for the effective contact area. It can be seen from this point that HPS brake pads are still a product that focuses more on comfort and durability, and the performance may only be a small upgrade. Considering that its retail price of 885 yuan/set is only less than 5% higher than the 849 yuan of the original Subaru BRZ, if the test performance is good, it may be used as an original substitute for daily driving.

has an interesting question. The friction material of the brake pad looks like "sticking" to the metal base. How to ensure that the lateral friction of the brake will not pull the friction material off the base? It turns out that there is a layer of "mechanical retention system" on the base, which is a dense collection of small hook-shaped protrusions. These protrusions are integrated directly into the brake pad when it is formed, like countless little claws holding the friction material and the base firmly together. There is a layer of lining between the mechanical retention system and the friction material to strengthen the connection strength between the two, and also acts as a heat insulation to prevent the heat of the friction material from being transmitted to the brake caliper to prevent the brake fluid from overheating.

There is also a heat insulation pad on the back of the brake pad to further prevent heat from being transferred to the caliper. It also acts as a sound insulation to prevent the noise from the friction surface from being transferred to the caliper, making the driving experience more comfortable. The thermal insulation pad is fixed on the metal base using a thermal bonding process. This principle is a bit like the sound insulation and vibration pad attached to the inside of the steel plate of a car.

Another alternative product is HAWK HP PLUS. The product positioning is a "brake pad that can take into account both track and daily driving." Its optimal working range is slightly wider than HPS, but it is a medium-low temperature model in the track series, so that it can take care of daily use. The friction coefficient is said to be not much higher than that of the original factory, and the service life, noise and impact on the life of the brake disc should all be within the acceptable range.

The material of the brake pads looks slightly rougher and should have a higher friction coefficient. There are still grooves in the middle for stress relief and dust removal. HP PLUS does not have chamfers on both sides, which may sometimes produce some noise, but it ensures a larger effective contact area and therefore can provide higher braking force.

By comparing the two brake pads together, it is easy to distinguish the HPS with chamfers and the HP PLUS without chamfers. From the above observation, we can also see that the friction surface of HP PLUS is slightly rougher than that of HPS, and it looks The former contains more metal components, which should be helpful in improving braking force, but brake pads with more metal components may shorten the life of the brake disc.

We carefully measured the initial thickness of each set of brake pads and made a rough estimate of the wear based on the changes after the completion of the subsequent testing sessions. Although it is not the main performance indicator, we also hope that the brake pads can have a longer service life. Longer service life means higher cost performance. The price of this HP PLUS brake pad corresponding to the BRZ model is 1,177 yuan per set, which is approximately 38.6% higher than the original price of 849 yuan. It is said that it is not expensive, and it will be even more cost-effective if it happens to be time to replace the brake pads.

● Introduction to the brake upgrade plan: brake disc part

Another component of the brake system upgrade is the brake disc upgrade. What we chose is the T2 series brake disc of the dba brand. T2 belongs to the street driving orientation in the dba product line and is an upgraded product of the same size as the original factory. According to the manufacturer's propaganda, the T2 brake disc has better heat dissipation performance, lower braking noise and more stable braking torque than the original one.

The surface of the brake disc has some symmetrical curve-shaped grooves, which are said to reduce braking noise and improve braking sensitivity. Generally, the grooves on the surface of this brake disc are used to scrape off dust and improve the contact efficiency between the brake pad and the brake disc. The above curve is symmetrical, does not distinguish the direction of rotation, and can be used universally on the left and right sides.

Looking at the middle ventilation duct from the side, it seems that there is nothing special about it. In fact, the DBA in the middle of the brake pad uses a patented structure called "kangaroo paw", which uses dense small pillars to replace the blades of the traditional brake disc.It is said that it can provide more heat dissipation area and stronger brake disc structure, which can effectively resist thermal attenuation problems and improve reliability... Oops, it has become an advertisement. The nominal name is the nominal name. How about the specific performance? It depends on subsequent tests for practical verification.

Continue to look at the back of the brake disc. The center of the disc is the inlet of the cooling air duct. Indeed, the special ventilation structure of the brake disc cannot be seen from the outside. Generally speaking, this kind of upgraded brake disc has a higher mechanical hardness than the original disc and can withstand the friction of harder brake pads, which means it has a longer high-load working life. The retail price of this set of brake discs is 2,900 yuan, so the total cost of the two brake pads is 3,785 yuan and 4,077 yuan respectively, which does not exceed the budget of 4,500 yuan. So whether it is worth the money depends on the following. How did the test perform?

● Introduction to the test process and preparation work

Let’s talk about the test process to be carried out. We will test it at the Ruisi Circuit in Huairou, a small track in Beijing. The track is very small, with a single lap only 1.3km long. It is especially suitable for racing novices to practice car control. We simulated a track experience as ordinary enthusiasts to compare the performance of the original and modified braking systems on the track. What's the experience like?

Wait a minute, testing will be introduced in the next issue. There is still some preparation to be done before testing. We must first "open" the brake pads, that is, let the pads and discs run into each other to achieve the maximum contact area. So we need to install two sets of brake discs on the car respectively, and first complete the "skin opening" operation.

The operation of replacing the brake pads is not complicated at all. Loosen the two floating screws on the caliper, remove the piston, and you can directly replace the brake pads. This is the same as ordinary maintenance steps and is not complicated at all. Interested friends can even DIY it by themselves. In order to compare the effects, we will use two sets of brake discs to compare the performance of three sets of brake pads (original factory, HPS street version, HP PLUS track version), so we will start with the original brake discs. piece.

Comparing the race-used HP PLUS and the removed original brake pads together, we can find that the surface of the race-used brake pads is rougher, and without chamfering, the surface area of ​​the race-used brake pads is relatively small. Bigger too.

By stacking the two brake pads together, you can see that the racing leather is indeed longer than the original brake pad, and the contact area is larger. This distributes the braking pressure to a larger effective contact area, providing higher braking force and working stability. After

is installed, the appearance looks no different from the original one. The advantage of this small-scale upgrade is that it is low-key, but the disadvantage is that the appearance does not look very "beep". Okay, let’s drive out and get ready to peel the competitive leather.

● Brake pad "skinning" and running-in

In order to ensure safety and not cause trouble to other traffic participants, we chose an open space specifically for the purpose of skinning the brake pads. According to the manufacturer's instructions, the process of skin opening is to first brake slowly from 50-55km/h to 10km/h and repeat 6-10 times, and then brake hard from 65-70km/h to 10km/h and repeat 2-3 times. , until the black heat dissipation film adheres to the surface of the brake disc... What does the black heat dissipation film look like? Give it a try first.

The process of driving is actually quite boring. It means accelerating to the specified speed, depressing the brake pedal and decelerating to about 10km/h, turning the car around and accelerating again, depressing the brake pedal again to decelerate...and so on. According to the manufacturer's requirements, the braking force gradually transitions from light to heavy. Throughout the process, there was no obvious change in braking feel. Halfway through the peeling process, we stopped and took a look.

As can be seen from the picture above, there is indeed a dark mark on the inner ring of the brake disc. This should be the "heat dissipation film" left by the brake pad on the disc. Then as long as the heat dissipation film continues to be laid Just fill the brake disc. Some friends may think that this is like the mark of the brake disc after high temperature. In layman's terms, it is "blurred". However, after testing with an infrared thermometer gun, the temperature of the brake disc at this time was only about 95°C, so it was definitely not a trace of high temperature. Come on, let's continue.

continued to go around in circles, kept going around in circles... and finally ran out of the predetermined number. Finally, the brake disc is covered with a black thermal film. When the test is completed, the temperature measuring gun shows that the surface temperature of the brake disc is about 203°C. After sufficient cooling, the first round of testing can be carried out. We will introduce the details of the test part in the next issue.

This time we discussed a low-cost upgrade plan for the braking system for "track days", that is, within a budget of 4,500 yuan, the braking system of an ordinary car can be upgraded to handle ordinary track driving. Let’s talk about the theoretical part first. Next time we will conduct a field test to verify whether 4,500 yuan can obtain stable braking performance and whether the performance improvement brought by the upgrade is worth the money. At the same time, the original brakes should also be used as a reference. Experienced the same baptism on the track. Trust me, this is going to be one hell of a test. Let’s talk more next week, so stay tuned. (Text/Car Home Xu Yunhe)

[Car Home Modification School] In the last issue, we designed a plan for upgrading the braking system that costs no more than 4,500 yuan, which includes two HAWK brand brake pads and one A dba brand brake disc. To see how much of an upgrade effect this combination can have compared to the original brake system, we will conduct a test session in this issue. Let me tell you in advance, this is one hell of a test.

In the last issue, the BRZ equipped with track version HP PLUS brake pads and original brake discs has completed the skin opening work, so let’s start the first round of testing immediately. Since it is to test the adaptability of the braking system to track day driving, the test is naturally conducted on the track.

We chose this track, which is located at the Ruisi Circuit in Huairou, Beijing. It is 1.3km long. It takes about 1 minute for the BRZ to complete a full lap. Although it is very short, its maximum speed can still exceed 130km/h. There will be a total of three places where emergency braking is required from above 120km/h to about 60km/h, and one place where emergency braking is required from about 100km/h to 60km/h. h is about 4 times per minute, which means that the braking system needs to perform emergency braking 4 times per minute, during which there is only a short breathing cooling time. Calculated according to the time of a regular track day, each session is 10 minutes long. Whether the braking system can survive 40 times of emergency braking without thermal degradation is one of the main purposes of our test.

This worry is not unfounded. In the previous Turbo BRZ track test, the YELLOW six-piston braking system experienced severe thermal decay on the 5th lap, accompanied by thick smoke. The scene was tragic. Therefore, we infer that a 10-minute track drive can run about 8 laps, which should make the original brake system appear weak, so that the performance of different brake pads will be more intuitively different.

● The first round of testing: original brake disc, original brake caliper + HAWK HP PLUS brake pads

A set of HP PLUS brake pads includes two front brake calipers, a total of 4 pieces, excluding labor and modification costs The cost is 1,177 yuan, which is 38.6% higher than the cost of replacing the original brake pads. According to reports, this set of brake pads can provide a higher friction coefficient and wider temperature adaptability.

There is a special issue to note here: Many friends believe that upgrading the braking system can directly shorten the braking distance. This statement is one-sided. Under normal use, the original brake system can activate the car's ABS anti-lock braking system during emergency braking. This is where the problem lies. The reason why ABS is activated is that the wheels have a tendency to lock. The tendency to lock is because the braking force exceeds the endurance range of the tires. At this time, if you replace the brake pads with greater braking force, the ultimate deceleration effect will not be much different from before. , because when the tires have a tendency to lock, the bottleneck in improving braking force is actually the tires.

So what’s the point of upgrading the braking system? In addition to better foot feel and more linear controllable range, the most important thing is to be compatible with higher operating temperatures. Even after the temperature rises sharply under continuous heavy load operation, the braking force can continue to be maintained without attenuation - or attenuated. less.

In order to minimize the braking force bottleneck caused by tire performance and subject the braking system to the most severe test, we used AD08 R high-performance tires with a width of 245mm.The wider tires allow the braking system to work with greater load, simulating the most severe track driving conditions. 245mm is already a very wide width for the BRZ. Wider means better grip, and more grip means more torture for the braking system. For the BRZ's braking system, it is rare to encounter a harsher working environment than this.

There is another problem. What we are looking for is to find brake pads that can take into account both track and daily use. While meeting the needs of the track, the braking effect in daily use must not be sloppy at all. Many high-temperature brake pads designed for track use will suffer from poor braking power due to low temperatures when dealing with daily use at much lower temperatures, so we specially arranged a cold braking test. As you can see in the picture above, the brake disc temperature was only 8-9°C when the test car set off. We immediately conducted a 100-0km/h braking test in this state.

The result is that the braking distance is surprisingly good - 37.96 meters, which is better than the original 38.73 meters. Of course, the 245mm semi-hot melt tires also play a big role. After the first braking step is completed, the temperature of the brake pad rises to 55°C. At this time, the formal track test begins. In order to evaluate the performance of the braking system under different temperatures, we will do a 100-0km/h braking in the middle of the 2nd and 7th laps, and the initial low temperature state just now. The braking data below are put together and compared to give a comprehensive evaluation of the braking force under different conditions.

While running, I recalled the first braking step, and there was already a slight intervention of ABS. As we just talked about, this is a sign that the tire is approaching the edge of maximum grip. This shows that the low-temperature braking power of HP PLUS brake pads is not bad at all. And as the test continues, the braking force seems to have improved slightly. Every braking point when entering the corner is very confident, and the braking distance is almost as expected.

After running for 2 laps, the subjective feeling of braking from 0-100km/h for the second time was not much different from the first time. The brake disc temperature increased to 316.5°C, which is considered high for a mass-produced braking system. The operating temperature has reached 2. It has only been 2 laps. The load on the braking system of track driving is really not comparable to that of daily driving. Whether you can handle it or not depends on how you perform later. Let's continue to sort it out.

This set of brake pads always has a discernible slight friction sound when decelerating. If I have to describe it, it is like the sound of a stone grinding a stone, indicating that this brake pad is still a hard one. This is an improvement. The friction coefficient and durability must be sacrificed, but I don't know if it will be hard enough to accelerate the wear of the brake disc.

On the 6th lap, the GoPro camera on the front of the car captured the reddish disc surface during braking. This is a surprising thing and shows that the brake pads are really resistant to damage. The reason why most civilian braking systems do not have the fiery red brake discs on racing cars is not that the vehicle speed is not enough, but that the optimal operating temperature is too low. Before the brake disc temperature reaches the point of glowing, the brake pads have already Severe thermal attenuation occurs, more braking force cannot be provided, and the temperature will no longer continue to rise.

The 7th lap was completed. The brake disc temperature measured immediately after the car stopped was 612.5°C. The high temperature caused the brake pads to immediately start to emit flames. This was the anti-corrosion black paint on the surface of the brake pads burning. Here to remind everyone, the parking in the picture is a last resort to collect the brake disc temperature. In actual intense track driving, you must not stop immediately. You must first drive at a constant speed of about 60km/h for a few minutes to allow the braking system to It must be fully cooled, otherwise it will easily cause damage to the braking system, and it is also very dangerous.

Let’s talk about the final data.The performance of HP PLUS brake pads is still remarkable. The initial low-temperature braking, thermal braking and final limit braking distances are shortened in sequence, to 37.96 meters, 37.54 meters and 37.19 meters respectively. In addition to the AD08 R tires gradually warming up and entering the state, the braking force also performs better and better as the temperature increases.

was not happy and soon encountered something unhappy. We found that the brake disc was severely damaged. It seems that the brake pads are still more inclined to the formula of competitive models, using relatively high hardness in exchange for friction coefficient and durability, so the requirements for the brake discs become higher. It seems that this brake pad is best used with an upgraded brake disc.

The burnt paint on the back of the brake pad shows that it has really been exposed to very high temperatures. If normal post-race cooling procedures are carried out, the high temperature of the braking system will be quickly carried away by the air, and there will be no persistent flames. The surface material burned and melted due to high temperature has adhered to the surface of the caliper, and the friction surface of the brake pad has also shown slight signs of melting. However, the objective performance is that the braking force is great. This thing is completely broken and swallowed. , who was forced to finish the test.

Let’s put aside the matter of replacing brake discs later. Let’s first see how the HPS brake pads corresponding to the street perform. The HAWK HPS street brake pads were first replaced on site, and after the same opening process as before, the second round of testing began.

● Second round of testing: original brake disc, original brake caliper + HAWK HPS brake pad

On the road between the opening location and the track, I compared the performance of the two brake pads Driving experience. The foot feel of HPS used on the street is more linear, especially during frequent low-speed start and stop, it is always very supple, very close to the driving feeling of the original brake pads. Looking back at the previous HP PLUS competition films, I often felt unexpected braking force rushing towards me when braking at low speeds. Although it is not scary, this unexpected deceleration still makes people feel a little uncomfortable. In addition, HP PLUS competition tablets will make a squealing sound when braking to a stop. As someone who is used to the screaming of competitive braking systems, it doesn't matter to me. The volume of the screaming is not high, but some people must feel uncomfortable. It would be nice if there was no sound at all.

HPS street leather test method is still the same, three 100-0km/h braking test comparison, respectively, at low temperature, after 2 laps on the track and after 7 laps on the track. The brake disc is subjected to low-temperature braking testing starting from an initial temperature of 4°C.

The low-temperature braking result is slightly worse than the HP PLUS competition skin, 38.14 meters, but it is not bad. The temperature of the brake disc after stopping is only 37.8°C, which is lower than the 55°C of the competitive leather, indicating that the braking power of the braking system is relatively smaller. When the braking system remains unchanged, it can be inferred that the brake pads The friction coefficient is lower.

The lower friction coefficient also explains the less abrupt feeling during daily driving. If the braking feeling of HPS street pads is compared to a hardwood block, then the feeling of previous HP PLUS competition pads is like cobblestones. Although it was all hard friction, there was still something different under the heavy pressure. In comparison, HPS brake pads require more forceful depressing of the brake pedal to achieve the same braking force as the previous HP PLUS. This has some impact on the choice of braking points and confidence when entering corners, and there is a little difference every time. I was anxious and worried about whether the car would be able to stop as expected.

After two laps of track driving, the braking performance improved, and the 100-0km/h time was shortened to 36.26m. The brake disc temperature measured by the temperature measuring gun is 106°C, which is much lower than the 316.5°C of the competition disc, indicating that the load on the braking system is really small.

One thing to note is that the difference in vehicle performance is not directly proportional to the difference between the brake pads. Because the braking force to slow down the vehicle is completed by three sets of systems: front braking components, rear braking components, and engine braking effect. When one of these three systems weakens, the load on the other two systems will increase accordingly, so the actual braking effect will not degrade as much as expected.

In the next few laps of driving, you can clearly feel the attenuation of the braking system.For track driving, the driving route is very sensitive to changes in braking distance. Extending even 1 meter will cause the vehicle to deviate from the original driving route, and the vehicle that is already in critical control at this time has no ability to return to the original route. Yes, unless you compromise by slowing down and sacrificing speed, you will sacrifice lap speed and safety.

I was on pins and needles during the few laps when I couldn't find the exact braking point. When I finally completed 7 laps, the final 100-0km/h test stopped far beyond the expected distance. According to the test data, the final braking The distance has increased from 45.52m to 45.52m, which is 9.26m longer than the previous best result and nearly two car lengths. This is quite unsafe for safe driving. When decelerating to the original stopping point of 36.26m, the vehicle speed is still 37.18km/h. If you stopped just right against the obstacle before, the speed of the car after the brake fade is enough to knock it away.

The braking system also turned into a "small torch" after stopping, but the brake disc did not turn red during the entire test. It can be inferred that the operating temperature throughout the process was not high, and the low friction coefficient of the brake pad itself was one factor. , another factor is that after heat attenuation, the braking force is further reduced, and the heat generated is much less. The track test of HAWK HPS street brake pads ended in a "tragic" way.

Looking at the replaced brake pad, there is no sign of melting on the surface. The brake pad really looks like a hardwood block, has little braking power and is not resistant to high temperatures. The good news is that based on the observation of the brake disc, this set of brake pads has almost no damage to the disc. It can be used with confidence for daily driving. It should be a good solution. Anyway, the price is about the same as the original brake pads, right? So the question is, how much worse will the performance of the original brake pads be?

● The third round of testing: original brake disc, original brake caliper + original brake pad

Let’s just let the data speak for itself. The car was loaded with original leather and started to conduct three 100-0km/h braking tests of low temperature, normal and extreme. Before the first low-temperature braking, the brake disc temperature was 5.3°C.

The low-temperature braking distance is 39.61m, which is more than 1 meter farther than the 38.14m of the street film and the 37.96m of the competitive film. No comments here, let’s continue reading.

The feeling of driving on the track is particularly interesting. After passing the uneasy street brake pads just now, the original brake pads actually give people a very solid feeling. The braking force is just right, not as good as the HP PLUS competition pads. It's powerful but still gives people enough confidence. The braking distance after two laps reaches 37.5m, which is better than the low-temperature braking performance and is comparable to HAWK's two upgraded brake pads. The brake disc temperature is 197.5°C, which is between the two HAWK brake pads.

Everyone is more relaxed next, just wait for the original brake pads to complete 7 laps, and finally measure how much the braking distance increases due to thermal decay, then call it a day and go home. The accident happened at this time, and the original brake pads gave us a small surprise.

During the subsequent driving, the original brake pads actually performed stably. Every braking operation was no different from the previous lap. Even during the process of braking and decelerating from 130km/h, the on-board camera captured the appearance of the brake disc. There was a trace of red light. This is simply amazing, indicating that the braking system can withstand high operating temperatures without any thermal attenuation. Braking from 100-0km/h after 7 laps gave a score of 37.95m.

After this, the test results of three sets of brake pads with original brake discs are released:

at the test site There was no time to think about it carefully. Since the original brake pad had no obvious attenuation, we first found out its limit, so we came up with a more severe "hell-style test": driving for 2 consecutive knots on the Ruisi track, and it was also It is 20 minutes, without stopping in the middle. In order to give the braking system a chance to breathe, the 100-0km/h braking test is not performed in the middle, and the 125-70km/h braking into the corner of a typical section of the track is directly collected. performance changes and compare them.

In actual driving on the track, the car does not have many opportunities to use 100-0km/h braking. Instead, the performance in the distance from braking at the highest speed in the straight line to the speed at which the car enters the corner is of great reference value. The shorter the braking distance in this section, the further back the braking point can be, which means a faster lap speed in the timing lap, and a more active advantage in the competition.

2 session of 20 minutes of track driving is equivalent to the intensity of a junior car race. Except for endurance races, the junior car races we usually come into contact with seldom exceed 25 minutes. On the continuous and multi-turn Ruisi track, the braking system has to operate under a continuous high load and there is almost no chance to breathe. If you can withstand this 20-minute "hell test", you can directly use it to participate in a game.

The first 10 minutes passed by in a blink of an eye, and the braking system was still strong. After setting a braking distance of 40.31m from 125-70km/h on the second lap, the subjective driving feeling has not deteriorated much. That's when the on-board camera captured some interesting footage.

Starting from the 10th minute, the brake disc began to show obvious red light, which did not fade much even on the road. The instantaneous temperature of the braking system at this time is estimated to be higher than 700°C, so the pure original braking system of this BRZ transformed into the Ghost Rider, flying on the track with two flames on the left and right. There was some attenuation in the braking force, but as I continued to torture it, the amount of attenuation did not increase further.

When this "Hot Wheel" finally completed the 20-minute experience, the deceleration distance from 125-70km/h was extended to 47.4m, 7.09m longer than before. That is to say, when the 20-minute race is about to end, you already need to advance the braking point by about 7 meters to ensure the original cornering route.

The test based on the original brake disc comes to an end here. HAWK HPS street brake pads were directly eliminated with miserable test results. HP PLUS competition brake pads performed well, but considering the greater wear on the original brake discs, we will use upgraded dba brakes the next day The disk undergoes its 20-minute "hell" test. The original brake pads that were supposed to be used as cannon fodder ended the test with very satisfactory results, and their performance can already surpass the upgraded products of third-party brands for street use.

It was completely dark when the brake disc was opened for dba. We had to huddle next to the steaming brake disc to keep warm. Guo Feng, the editor of the event channel who came to reinforce the photo shoot, immediately caught a cold. In the second Tainan, he just lay down and rested - this is a story for another day. On an empty venue at night, we continued the previous steps of accelerating and braking to ensure good contact with the brake discs and pads to ensure optimal transmission efficiency, and then let the car cool down sufficiently to ensure durability for the next 20 minutes. Get ready for the test.

Back in the office, I took up the removed original brake disc and brake pads and looked at them carefully. The surface of the parts that had been exposed to high temperatures had begun to turn white.I'm thinking that the reason why the BRZ's original braking system has withstood such a test is because the manufacturer is kind enough to prepare a higher-level racing braking system for this model that is positioned as an entry-level sports car.

The surface of the brake pad has broken and fallen off at the edges due to continuous testing, and the middle has melted and adhered together at high temperature. The heat insulation patch on the back panel has also fallen off. It is no longer recommended to continue using such brake pads. Despite this embarrassment, the previous test results still proved that the specifications of Subaru's original brake pads are very high.

● The fourth round of testing: dba brake disc, original brake caliper + HAWK HP PLUS brake pads

The 20-minute "hell test" on the second day was mainly aimed at HAWK HP PLUS racing brake pads. It can be seen that the results of the opening the night before were quite good. A layer of fine lines was formed on the surface of the brake disc to fit the brake pads. So without further explanation, let’s start the test directly.

The working conditions in the first 10 minutes are similar to those of the previous day. Our main focus is on the last 10 minutes. How will the durability of this braking system be under continuous high-load operation? If you can survive the entire 20 minutes, you can even use it directly to participate in high-intensity regular car events.

After about 10 minutes, the dba brake disc also appeared the same fiery red light as before, but the braking feeling at this time did not feel attenuated at all. The same braking point can be used in every lap, and every deceleration is the same. The deceleration effect is about the same as expected, just like this, round and round, without any fatigue at all. In this section of the test, due to the shorter braking distance and better controllability, I was able to delay the braking point significantly, which also made some contribution to the lap time. So BRZ set its best lap time in two days: 1 minute, 0 seconds and 10 seconds. The other two sets of brake pads failed to achieve this lap time no matter how hard they tried, and ended up in 1:01.3 (original pads) and 1:01.4 (HPS street pads) respectively.

At the end of the test, the brake disc temperature was measured at 666.5°C, which was slightly higher than the test temperature of the previous 10 minutes. The braking distance from 125-70km/h changes from 39.2m at the beginning to 40.5m at the end. There are two points to note here: First, after replacing the DBA brake disc, the improvement in braking stability directly reduced the braking distance by about 2m, and secondly, after the 20-minute hell test, the braking distance was only extended by a few meters. The staggering 1.3m has little impact on the line.

After continuous testing for twice as long as before, there are only some normal wear marks on the surface of the dba brake disc, which is completely within the acceptable range. In other words, this brake upgrade set with a total price of 4,077 yuan can fully cope with high-intensity track days and can successfully complete an entire race.

But the story is not over yet, we have to consider the last indicator: durability. The original pads and HP PLUS competition pads have already gone through a 10-minute and a 20-minute durability test, so the street pads that have been eliminated also need to undergo another 20-minute durability test in order to estimate different brake pads based on their respective thickness changes. wear rate. Under the same working conditions, less wear means the brake pads are more durable and more cost-effective.

It is really a waste of time to continue testing for 20 minutes, because after yesterday's overheating, the performance of the brake pads has been greatly attenuated. During the entire test, the previously mentioned best braking result of 125-70km/h was 44.46m, which was about 3m longer than before, and the result after thermal attenuation was even worse. Judging from the screenshots of the video, the scattered sparks during braking indicate that the structure of the brake pad has been damaged at high temperatures and is rapidly disintegrating under heavy-load braking.

As can be seen from the table, after a total of 30 minutes of track driving, the HAWK HPS street skin consumes the fastest. Fastest, the original leather is second, and the HP PLUS competitive leather is the slowest. If the retail price and durability are considered together, and the price of the original brake pad is 849 yuan, the HP PLUS brake pad with the least wear is actually equivalent to the price of 897 yuan, and the HPS brake pad with the most wear is equivalent to The price is 1518 yuan. Careful friends may notice that the consumption in the 30-minute continuous test is more than three times the consumption in 10 minutes. This is because when used continuously at high temperatures, the brake pads become fragile due to the influence of temperature, and the wear rate is doubled. has grown.

Let’s summarize our entire test. If so, a total of two feasible modification solutions are given. For the BRZ car specifically, the original braking system itself can also be used as a third solution for use in relatively low-intensity environments. Friends can follow Choose based on your own needs. Again, HAWK and dba brands are not the only choices. We are just using these two brands as a modification example. You can choose other similar brands and models according to your own needs and preferences. For general track experience, brake pads with a maximum operating temperature between 600-800°C are sufficient.

Let me mention YELLOW’s six-piston braking system, which is the one used in the previous BRZ modification series. After digging through the test data at that time, we found that the braking distance of the 125-70km/h braking system was 47m at its best, and even exceeded 60m after thermal attenuation. No wonder blue smoke frequently appeared during the test at that time. The vehicle almost ran off the track due to the excessive braking distance. This is not to beat the six-piston braking system to death with a stick, but to tell you that not all six-pistons can provide better braking effects than the original calipers.

When the last serial was released, many friends asked about how to purchase HAWK and DBA brake discs. Here is the contact information of our agents.

We have talked about the topic of upgrading the braking system for 4,500 yuan. In the end, we found a very easy-to-use and cost-effective upgrade package for less than 4,100 yuan. After actual testing, it is very suitable for those who want to have both street and track day experience. Friends, even if you use it directly to participate in entry-level competitions, there is no problem at all. Regarding this topic, everyone is welcome to discuss it with us in the message area, and you are also welcome to leave your suggestions and opinions. If you are still undecided about some modification and upgrade plans, please feel free to tell us, and we will select appropriate content and compare it with actual tests similar to this article. This concludes the discussion about this brake upgrade.