Hawk brake info
01-03-2010, 08:53 AM
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Hawk brake operating temperature Chart and how to reduce your lap times
The following chart was put together by a Hawk brake distributor to NASA, a two time NASA National Champion, RX-8 co-driver for my Grand-Am team, fast guy and close personal friend----Jay Andrew. Jay and I have been RX-8 testing brakes (and suspension, tires, engines.....) for the past two + years. The chart below was created in conjuntion with Hawk Performance engineers and other qualified Hawk people in the know. Jay stocks several compounds for the RX8 and more importantly knows what he's talking about---the ENTIRE braking system. Not just the brake pads. You may find pads for a cheaper price (or maybe not) but you won't find help like that which Jay can provide. I'll betcha a shiney nickle that we have more brake data than anyone else in the U.S. Part of this reason is because we have a Hawk team sponsorship and have volunteered to test many different compounds. Several
Our team is scheduled to attend several NASA events in 2010 to drive our various RX-8's in enduros and sprint races. Jay is under contract of sorts to present brief Technical brake seminars for NASA South-East, Mid-Atlantic and NASA Great Lakes for 2010. Please feel free to come up and introduce yourself to talk shop, hang out or whatever.
Below is the brake compound chart. How someone would use it properly is to have recorded data on pads and rotors during on-track driving. This is out of the huge majority of people's budget. The next best bet is to snag a hand held infra-red laser thermometer. You'll want one that at reaches 1,200 F however I think you'll find that it's difficult to get your stock car's RX-8 brakes that hot. This is most likely due to the fact that the car is very well balanced and the rear brakes also bear some of the load which reduces the sole braking burden on the front brakes and therefore there is less heat acheived in them.
If a car had a big, heavy V-8 way up front their front brakes would easily achieve higher temps. These temps are frequently seen in Mustang HPDE track cars and in about all Mustang race cars. Adding more tire grip and/or suspension mods gives you the opportunity to move up in your braking compound choices. More grip = stronger braking opportunities = more heat.
If you think you're a brake pad upgrade candidate or not, you'll want to confirm your brake operating temps. More often than not people will stick with a brake pad they are comfortable with and not experiment with alternate compounds. This is usually seen in an HPDE 3 driver status. He is faster than a beginner but may not yet to tap into his/her brakes to find lap time reductions. A typical brake pad compound switch generally comes from a experiencing a brake problem. An example would be driver feedback of "my brakes don't work as good after 10 or 5 or XXX laps". Our RX-8's mask brake compound upgrade opportunities because IMHO the RX-8 stock brakes are fantastic. The brakes are so good that people often leave a lot on the table. Upgrading pads allows for deeper track braking and slowing down the car over a shorter distance. This allows for reduction in lap time. You have to experiment and their is a big difference in the beginner and novice (and some HPDE Expert) ranks in driver pad preference. This is often described in "feel". This feel can often be directly related to the initial foot application of the brake pedal. Some people "stomp", others have an initial touch of the brake pad more like a gentle touch followed by a deeper press of the pedal. The lap timer is the true measurement.
OK. Here we go.
The common mistake people make when measuring their brake pad and brake rotor temperatures (usally with an infrared gun) is taking temps after the brakes have cooled to much. You want hot brakes. HOT. You can't get them too hot. Typical HPDE teachings have engrained the benefits of a cool down lap for the last lap of the session and I'll suggest to you that they are generally as slow as molasses during an Ice Age and totally useless for temperature data. The proper way to collect this data is later in the afternoon when your driving skills may be their best, track grip is better than the early morning sessions and you're obtaining solid tire temps. You will want to drive a zinger lap and quickly pull into pit lane. Don't worry about how accurate you are using the brakes to mirror what you think you're doing on the track. Put a ton of heat in them instead. Run into pit lane as fast as you can without getting in trouble and see what these dudes read. See how hot you can get them. Trust me you won't have huge spikes that will make this data irrelevant. More often than not people perform this exercise and have cooled many of these temps away. You want a friend to be waiting for you at the FRONT of pit lane----that closest to pit entrance or pit-in. Several tracks you could capture your data at are not data friendly either for brakes, rotors or tires. This is generally due to two things: A long straight that precedes pit entrance which allows the brakes to really cool down, a long pit lane entrance that allows the brakes to cool down.
Examples of these tracks where collected brake and rotor temps (and tires) are inaccurate are:
-Road Atlanta, Road America, Daytona
A list of tracks that aren't too bad are:
-CMP, Mid-O and Putnam Park.
There are several that are neigher good nor bad. The proper way the big boys collect data is with sensors touching the brake rotors and a thermocouple installed in the actual pad----totally not cost effective for the weekend warrior. This recording method tells you what the brakes are actually doing on various parts of the track.
What you're looking to do is to confirm you are cooking your brakes or not getting enough heat in them. It has been my experience as a RX-8 driver and instructor that too often than not HPDE RX-8 drivers leave tons of opportunity on table with the brakes. I see this in our data when I have a new driver run our race cars. The data will reveal that many of these fast and experienced race drivers (often local, regional or national champions) brake too early and too gently. Part of this is due to the nature of our cars---the suspension setup is dialed in, there is solid grip (usually supported by Grand-Am hoosier/R6 compounds at 225/17 or 245/17 tire) and our wonderful cars that have a great weight balance. Several race cars don't have ABS to fall back on and this is a blessing and a curse. Those drivers prominently drive ABS cars have a fall back position and when they switch over to non-ABS cars they can often lock up a tire which may result in flat-spotting. Many a pro-driver I know keeps a variety of cars in their test schedule to hone thier skills. A non-ABS spec miata is often in their stable of race cars. We measure brake system pressure which essentially is how a driver applies pressure to the brake pedal. We also measure where on the track (measured in distance---1,535 feet or 1,578 feet from a fixed point on the track---usally start and finish) along with speeds. All of these data points tell you a ton of info about how much, when, where and how fast a driver uses the brakes. When comparing data you can segment a section of the track (the same things that trackmate, AIM and racpak can do) to evaluate comparable time reductions or additions. Some drivers brake a little later, some overbrake, some underbrake but retain a high minimum rolling speed into the following corner. Lots of "styles" that require close analysis to see the differences.
So what does all this mean? It means that most drivers of the RX-8 are leaving time on the track. Why? Typically I find that the low spring rates in the front support the rear end getting light and this can be felt when small steering inputs are applied. Aggressive trail braking with too much steering input will reveal this in a stock car. The end will become light and a driver will often back down and brake less deeply over the following laps. So what's the fix? Brake in a straight line. Brake hard. Brake harder. Stomp on those stoppers. Get into the ABS. Experiment with this process by choosing a braking point on the track where you are carrying a fair amount of speed. Ideally you are traveling in 4th or 5th gear and then enter a corner requiring a downshift to 3rd or 4th gear speeds. Brake in a straight line. Do a lap. Repeat process. Brake a few feet later each time. If you choose a braking zone that has easy to read braking markers in your line of sight, this makes it a little easier. Choosing a turn that has lots of safety margin (flat grassy run off) adds an additional margin of error. Going off the track after a braking zone into a large, dry, flat grassy run off is a helluva lot less forgiving than a tire wall. T1 at VIR is great for this. The braking zone at the end of the backstraight at VIR is a KILLER place for this. T10 at Road ATL. T1 at Putnam. I'd avoid Roebling Road, Mid-Ohio and Lime Rock. Choose a track that has a high margin of error and push it. Push it hard.
Using your left foot for braking allows you to carry your higher speed for a longer period of time over a longer distance as you don't have to lift off the accelerator and then move to brakes. Most HPDE drivers do this very gingerly. They "coast" between throttle and brake if you will. Everyone does it. Congrats, you're normal. If you're an HPDE driver and try to convince that you don't do it then your lying to yourself. You are denying yourself the opportunity to become a better driver. There is opportunity for lap time savings here because.........there are typically several braking zones per track. Let's pretend a track has 10 turns. A 1 tenth of a second lap time savings per corner will yield a one second lap time reduction. Great theory however this is often not the case. Generally I see the majority of time in the HIGH SPEED braking areas. Call this 2 or 3 turns which offer 80% of potential lap time reduction due to better braking (usually less overbraking). Why is this?
Because you are carrying so much speed (and therfore distance) during these high mph straights, braking earlier increases your time over these longer distances. This makes you slower over these longer distances. This adds lap time. Generally these type of braking zones lead to people over-braking and our low torque RX-8's don't pull hard to help reuperate from this lower speeds. THIS is where the time REALLY is. Especially when these high braking corners lead to longer straights. T1 and T5 at Road Atlanta are great examples. T1 at Mid-O another. T10 at VIR is huge. The famous Kink at Road America. This is where time reduction exists and a person should work on tapping into it if you are measuring your lap times. This is generally where I drive a students car and scare the crap out of them.
This is where your lap time reduction resides and where you can add more heat into your brakes. Exposing more weakness in your braking system is a good thing. Its a good thing because it usually means your going faster!! Congrats!!! You are faster. This is a great thing.
More heat in your brakes (because --congratulations--you're going faster) will put more demand on your brake pads. This is the time you want to quickly pull into the pits before your session ends and your data becomes useless . Now look at your temps and refer to the chart below. Are you a hotshoe braking expert that is pushing the limit of your street or street/track pads? It is easier to do with these cars because the brakes are so wonderful AND most people don't take full advantage of them.
Remember to brake in a straight line when using stock suspension and remeber to offer very little steering input. For those of you that have increased your front spring rate you are great candidates for this braking exercise. Higher front spring rates = less front nose dive and less dramatic weight transfer (which is generally the rear end of a stock car "lifting" up and makes the rear end a little squiggley). The rear end is squiggley because the rear tire contact is less and your using less of your rear tires to help slow the car down. The ABS takes care of avoiding rear brake lock up in these situations however the net effect is this limits the cars ability to be more aggressive with your brakes.
Happy braking and see you at the track.
Our team is scheduled to attend several NASA events in 2010 to drive our various RX-8's in enduros and sprint races. Jay is under contract of sorts to present brief Technical brake seminars for NASA South-East, Mid-Atlantic and NASA Great Lakes for 2010. Please feel free to come up and introduce yourself to talk shop, hang out or whatever.
Below is the brake compound chart. How someone would use it properly is to have recorded data on pads and rotors during on-track driving. This is out of the huge majority of people's budget. The next best bet is to snag a hand held infra-red laser thermometer. You'll want one that at reaches 1,200 F however I think you'll find that it's difficult to get your stock car's RX-8 brakes that hot. This is most likely due to the fact that the car is very well balanced and the rear brakes also bear some of the load which reduces the sole braking burden on the front brakes and therefore there is less heat acheived in them.
If a car had a big, heavy V-8 way up front their front brakes would easily achieve higher temps. These temps are frequently seen in Mustang HPDE track cars and in about all Mustang race cars. Adding more tire grip and/or suspension mods gives you the opportunity to move up in your braking compound choices. More grip = stronger braking opportunities = more heat.
If you think you're a brake pad upgrade candidate or not, you'll want to confirm your brake operating temps. More often than not people will stick with a brake pad they are comfortable with and not experiment with alternate compounds. This is usually seen in an HPDE 3 driver status. He is faster than a beginner but may not yet to tap into his/her brakes to find lap time reductions. A typical brake pad compound switch generally comes from a experiencing a brake problem. An example would be driver feedback of "my brakes don't work as good after 10 or 5 or XXX laps". Our RX-8's mask brake compound upgrade opportunities because IMHO the RX-8 stock brakes are fantastic. The brakes are so good that people often leave a lot on the table. Upgrading pads allows for deeper track braking and slowing down the car over a shorter distance. This allows for reduction in lap time. You have to experiment and their is a big difference in the beginner and novice (and some HPDE Expert) ranks in driver pad preference. This is often described in "feel". This feel can often be directly related to the initial foot application of the brake pedal. Some people "stomp", others have an initial touch of the brake pad more like a gentle touch followed by a deeper press of the pedal. The lap timer is the true measurement.
OK. Here we go.
The common mistake people make when measuring their brake pad and brake rotor temperatures (usally with an infrared gun) is taking temps after the brakes have cooled to much. You want hot brakes. HOT. You can't get them too hot. Typical HPDE teachings have engrained the benefits of a cool down lap for the last lap of the session and I'll suggest to you that they are generally as slow as molasses during an Ice Age and totally useless for temperature data. The proper way to collect this data is later in the afternoon when your driving skills may be their best, track grip is better than the early morning sessions and you're obtaining solid tire temps. You will want to drive a zinger lap and quickly pull into pit lane. Don't worry about how accurate you are using the brakes to mirror what you think you're doing on the track. Put a ton of heat in them instead. Run into pit lane as fast as you can without getting in trouble and see what these dudes read. See how hot you can get them. Trust me you won't have huge spikes that will make this data irrelevant. More often than not people perform this exercise and have cooled many of these temps away. You want a friend to be waiting for you at the FRONT of pit lane----that closest to pit entrance or pit-in. Several tracks you could capture your data at are not data friendly either for brakes, rotors or tires. This is generally due to two things: A long straight that precedes pit entrance which allows the brakes to really cool down, a long pit lane entrance that allows the brakes to cool down.
Examples of these tracks where collected brake and rotor temps (and tires) are inaccurate are:
-Road Atlanta, Road America, Daytona
A list of tracks that aren't too bad are:
-CMP, Mid-O and Putnam Park.
There are several that are neigher good nor bad. The proper way the big boys collect data is with sensors touching the brake rotors and a thermocouple installed in the actual pad----totally not cost effective for the weekend warrior. This recording method tells you what the brakes are actually doing on various parts of the track.
What you're looking to do is to confirm you are cooking your brakes or not getting enough heat in them. It has been my experience as a RX-8 driver and instructor that too often than not HPDE RX-8 drivers leave tons of opportunity on table with the brakes. I see this in our data when I have a new driver run our race cars. The data will reveal that many of these fast and experienced race drivers (often local, regional or national champions) brake too early and too gently. Part of this is due to the nature of our cars---the suspension setup is dialed in, there is solid grip (usually supported by Grand-Am hoosier/R6 compounds at 225/17 or 245/17 tire) and our wonderful cars that have a great weight balance. Several race cars don't have ABS to fall back on and this is a blessing and a curse. Those drivers prominently drive ABS cars have a fall back position and when they switch over to non-ABS cars they can often lock up a tire which may result in flat-spotting. Many a pro-driver I know keeps a variety of cars in their test schedule to hone thier skills. A non-ABS spec miata is often in their stable of race cars. We measure brake system pressure which essentially is how a driver applies pressure to the brake pedal. We also measure where on the track (measured in distance---1,535 feet or 1,578 feet from a fixed point on the track---usally start and finish) along with speeds. All of these data points tell you a ton of info about how much, when, where and how fast a driver uses the brakes. When comparing data you can segment a section of the track (the same things that trackmate, AIM and racpak can do) to evaluate comparable time reductions or additions. Some drivers brake a little later, some overbrake, some underbrake but retain a high minimum rolling speed into the following corner. Lots of "styles" that require close analysis to see the differences.
So what does all this mean? It means that most drivers of the RX-8 are leaving time on the track. Why? Typically I find that the low spring rates in the front support the rear end getting light and this can be felt when small steering inputs are applied. Aggressive trail braking with too much steering input will reveal this in a stock car. The end will become light and a driver will often back down and brake less deeply over the following laps. So what's the fix? Brake in a straight line. Brake hard. Brake harder. Stomp on those stoppers. Get into the ABS. Experiment with this process by choosing a braking point on the track where you are carrying a fair amount of speed. Ideally you are traveling in 4th or 5th gear and then enter a corner requiring a downshift to 3rd or 4th gear speeds. Brake in a straight line. Do a lap. Repeat process. Brake a few feet later each time. If you choose a braking zone that has easy to read braking markers in your line of sight, this makes it a little easier. Choosing a turn that has lots of safety margin (flat grassy run off) adds an additional margin of error. Going off the track after a braking zone into a large, dry, flat grassy run off is a helluva lot less forgiving than a tire wall. T1 at VIR is great for this. The braking zone at the end of the backstraight at VIR is a KILLER place for this. T10 at Road ATL. T1 at Putnam. I'd avoid Roebling Road, Mid-Ohio and Lime Rock. Choose a track that has a high margin of error and push it. Push it hard.
Using your left foot for braking allows you to carry your higher speed for a longer period of time over a longer distance as you don't have to lift off the accelerator and then move to brakes. Most HPDE drivers do this very gingerly. They "coast" between throttle and brake if you will. Everyone does it. Congrats, you're normal. If you're an HPDE driver and try to convince that you don't do it then your lying to yourself. You are denying yourself the opportunity to become a better driver. There is opportunity for lap time savings here because.........there are typically several braking zones per track. Let's pretend a track has 10 turns. A 1 tenth of a second lap time savings per corner will yield a one second lap time reduction. Great theory however this is often not the case. Generally I see the majority of time in the HIGH SPEED braking areas. Call this 2 or 3 turns which offer 80% of potential lap time reduction due to better braking (usually less overbraking). Why is this?
Because you are carrying so much speed (and therfore distance) during these high mph straights, braking earlier increases your time over these longer distances. This makes you slower over these longer distances. This adds lap time. Generally these type of braking zones lead to people over-braking and our low torque RX-8's don't pull hard to help reuperate from this lower speeds. THIS is where the time REALLY is. Especially when these high braking corners lead to longer straights. T1 and T5 at Road Atlanta are great examples. T1 at Mid-O another. T10 at VIR is huge. The famous Kink at Road America. This is where time reduction exists and a person should work on tapping into it if you are measuring your lap times. This is generally where I drive a students car and scare the crap out of them.
This is where your lap time reduction resides and where you can add more heat into your brakes. Exposing more weakness in your braking system is a good thing. Its a good thing because it usually means your going faster!! Congrats!!! You are faster. This is a great thing.
More heat in your brakes (because --congratulations--you're going faster) will put more demand on your brake pads. This is the time you want to quickly pull into the pits before your session ends and your data becomes useless . Now look at your temps and refer to the chart below. Are you a hotshoe braking expert that is pushing the limit of your street or street/track pads? It is easier to do with these cars because the brakes are so wonderful AND most people don't take full advantage of them.
Remember to brake in a straight line when using stock suspension and remeber to offer very little steering input. For those of you that have increased your front spring rate you are great candidates for this braking exercise. Higher front spring rates = less front nose dive and less dramatic weight transfer (which is generally the rear end of a stock car "lifting" up and makes the rear end a little squiggley). The rear end is squiggley because the rear tire contact is less and your using less of your rear tires to help slow the car down. The ABS takes care of avoiding rear brake lock up in these situations however the net effect is this limits the cars ability to be more aggressive with your brakes.
Happy braking and see you at the track.
Last edited by EricMeyer; 01-03-2010 at 11:09 AM.
01-03-2010, 09:29 AM
#2
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Hey, that's a cool chart, Eric. Thanks! I have the HP+ on my RX-8. With the street tires in STX, I find them a little easy to overdrive. If I leave the braking a little too late and jab the pedal too much initially, I can overwhelm the tires easily. The brake pedal gets very wooden and numb and it seems to take forever to get slowed down.
That happens rarely, and it's my fault when it does. Other than that, I'm totally happy with the pads. They feel pretty ferocious on street tires.
That happens rarely, and it's my fault when it does. Other than that, I'm totally happy with the pads. They feel pretty ferocious on street tires.
01-03-2010, 11:20 AM
#3
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Thread Starter
Many a brake pad reseller still follows the old school thought of Hawk Blue is the preferred street/track pad. I'm here to tell you this is no longer true. Hawk Blue technology is older and Hawk has since developed better compounds and you should be using them. What are they? HT-10's if you ask me.
Notice that the minimum operating range is higher by 50 F or so but the ceiling is much higher. This does not reveal the biggest benefit of these pads which is the initial "bite" when the pad first contacts the rotor surface. The Hawk Blues are like an on/off switch. It's part of their compound characteristics. This pad is often someone's first efforts to aftermarket pads. I've found they think they have arrived at a destination and this is what pads are supposed to feel like. After a season or two a driver will entertain another compound or pad manufacturer and they will adapt their style to this new pad. Happens all the time. Congrats, your normal.
For those of you using the ever popular (and old technology Hawk Blue), try the HT-10. The intial bite is less teeth rattling, the pedal modulation (what happens when you apply more brake pedal pressure) is easy to feel and the wear is very nice. This is more of a track pad which means it takes some heat in it to operate effectively (which is why the pads to the left on this chart are street pads----because they cool off frequently and/or don't retain heat).
Since this is a Hawk thread and our team has extensive use of their products I am suggesting the blue users (or HP+) give a shot at the HT-10's. A nice combination would be HT-10 front and HP+ or Black in the rear.
We run 60 Front and 10 rear for those tracks that you need to barely brush the brakes (like LimeRock and Mid-O) and 60/60 for heavier braking tracks like Road Atlanta, Daytona and VIR.
Happy rotoring.
Notice that the minimum operating range is higher by 50 F or so but the ceiling is much higher. This does not reveal the biggest benefit of these pads which is the initial "bite" when the pad first contacts the rotor surface. The Hawk Blues are like an on/off switch. It's part of their compound characteristics. This pad is often someone's first efforts to aftermarket pads. I've found they think they have arrived at a destination and this is what pads are supposed to feel like. After a season or two a driver will entertain another compound or pad manufacturer and they will adapt their style to this new pad. Happens all the time. Congrats, your normal.
For those of you using the ever popular (and old technology Hawk Blue), try the HT-10. The intial bite is less teeth rattling, the pedal modulation (what happens when you apply more brake pedal pressure) is easy to feel and the wear is very nice. This is more of a track pad which means it takes some heat in it to operate effectively (which is why the pads to the left on this chart are street pads----because they cool off frequently and/or don't retain heat).
Since this is a Hawk thread and our team has extensive use of their products I am suggesting the blue users (or HP+) give a shot at the HT-10's. A nice combination would be HT-10 front and HP+ or Black in the rear.
We run 60 Front and 10 rear for those tracks that you need to barely brush the brakes (like LimeRock and Mid-O) and 60/60 for heavier braking tracks like Road Atlanta, Daytona and VIR.
Happy rotoring.
01-03-2010, 01:44 PM
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Can we discuss why you would want to run a less agressive pad in the rear vs the same compound front and rear?
I've been running Carbotech XP8 and later the XP10 for the whole time I have been tracking the car. I started out trying to run a less agressive pad in the rear and this seemed to make the car wiggle in the rear even more. When I switched back to using the same pad front and rear then the wiggle went away. I did my initial testing when I was running HPDE and haven't experimented since. So far I have gone with the "If it ain't broke, don't fix it" approach. I'm now running in NASA Time Trials and am probably much more agressive with the brakes than I was back in HPDE and I've progressed to a much smoother application of the pedal.
The only thing that has made me think about experimenting a little bit is I won one of the certificates for a free axle set of Hawk pads from Jay in December and was thinking of giving them a try. What would you suggest I try in a Hawk pad? Same compound front and rear? Different compound front and rear? I've also heard rumors that Hawk pads can be "harder" on the rotor than other brands. I know the Carbotechs have been very rotor friendly. Any truth to that or just rumor?
I've been running Carbotech XP8 and later the XP10 for the whole time I have been tracking the car. I started out trying to run a less agressive pad in the rear and this seemed to make the car wiggle in the rear even more. When I switched back to using the same pad front and rear then the wiggle went away. I did my initial testing when I was running HPDE and haven't experimented since. So far I have gone with the "If it ain't broke, don't fix it" approach. I'm now running in NASA Time Trials and am probably much more agressive with the brakes than I was back in HPDE and I've progressed to a much smoother application of the pedal.
The only thing that has made me think about experimenting a little bit is I won one of the certificates for a free axle set of Hawk pads from Jay in December and was thinking of giving them a try. What would you suggest I try in a Hawk pad? Same compound front and rear? Different compound front and rear? I've also heard rumors that Hawk pads can be "harder" on the rotor than other brands. I know the Carbotechs have been very rotor friendly. Any truth to that or just rumor?
01-03-2010, 02:36 PM
#5
Power!!
eric,
What are your thoughts on those DTC30's? They seem like they might be a better fit than the HT-10's for AutoX folks that need good cold temp performance for that first run and bad weather and higher operating range +higher friction coef.
What are your thoughts on those DTC30's? They seem like they might be a better fit than the HT-10's for AutoX folks that need good cold temp performance for that first run and bad weather and higher operating range +higher friction coef.
01-03-2010, 02:52 PM
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I actually just asked Rishie about the DTC-30's based on that chart and they don't appear to offer them for the RX-8. I need new pads soon though, so Rishie is looking into how much he can get them for. Racing Brake is running a sale now though and he wasn't confident that he was going to be able to beat them with free shipping.
01-03-2010, 04:07 PM
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Thread Starter
Can we discuss why you would want to run a less agressive pad in the rear vs the same compound front and rear?
I've been running Carbotech XP8 and later the XP10 for the whole time I have been tracking the car. I started out trying to run a less agressive pad in the rear and this seemed to make the car wiggle in the rear even more. When I switched back to using the same pad front and rear then the wiggle went away. I did my initial testing when I was running HPDE and haven't experimented since. So far I have gone with the "If it ain't broke, don't fix it" approach. I'm now running in NASA Time Trials and am probably much more agressive with the brakes than I was back in HPDE and I've progressed to a much smoother application of the pedal.
The only thing that has made me think about experimenting a little bit is I won one of the certificates for a free axle set of Hawk pads from Jay in December and was thinking of giving them a try. What would you suggest I try in a Hawk pad? Same compound front and rear? Different compound front and rear? I've also heard rumors that Hawk pads can be "harder" on the rotor than other brands. I know the Carbotechs have been very rotor friendly. Any truth to that or just rumor?
I've been running Carbotech XP8 and later the XP10 for the whole time I have been tracking the car. I started out trying to run a less agressive pad in the rear and this seemed to make the car wiggle in the rear even more. When I switched back to using the same pad front and rear then the wiggle went away. I did my initial testing when I was running HPDE and haven't experimented since. So far I have gone with the "If it ain't broke, don't fix it" approach. I'm now running in NASA Time Trials and am probably much more agressive with the brakes than I was back in HPDE and I've progressed to a much smoother application of the pedal.
The only thing that has made me think about experimenting a little bit is I won one of the certificates for a free axle set of Hawk pads from Jay in December and was thinking of giving them a try. What would you suggest I try in a Hawk pad? Same compound front and rear? Different compound front and rear? I've also heard rumors that Hawk pads can be "harder" on the rotor than other brands. I know the Carbotechs have been very rotor friendly. Any truth to that or just rumor?
My gut says you initially ran too little of a rear pad which made the delta between the front and rear too great. This had the front doing more of the work. This makes the nose dive more which leads to faster (and more) weight transfer to the front. This makes the rear of the car rise a bit. This leads to the wiggle feeling. So my gut says (without asking you about your car -- which is a key part of the equation and could you share these details below) that your rear pad was too weak and/or your front too strong for the rear pad. Does that make sense?
Hawk: I would try a 60/10 because Cobetto's HPDE program is pretty good and if you're a student of Mid-Atlantic in TT then you've probably got some great driving skill set foundation.
Hawk vs. Carbotech. I too use to run the Carbotechs on the RX-8. 10 Rear and 12 Front. I liked them. Danny Pushkar (one of the principals of Carbotech) is an awesome guy and still a great friend even though we have been sponsored by Hawk for the past 2 years. Here is how I would describe the difference. Keep in mind that we often tune our cars in the braking zones by selecting various pads/combinations so the more you try different pads on cars the more feedback you get and the more you can tell small differences.
The Carbotech's have a very gentle initial bite and require more pedal travel to get them to work. The benefit is you get a better "feel" for the brakes---the more you press on the brake pedal the more the car brakes. It is a wonderful pad to use your brakes because the pedal travel is looonger. This gives you what I think are more choices for the novice/intermediate because the pedal is not a sensitive "on/off" switch. Rotor wear---agree. Carbotechs had less rotor wear however I found (using stock RX-8 rotors) that the pads wore out more quickly. I have never done any back to back testing however I think the cost of the additional Carbotech's and using your rotors longer is about the same as using Hawks longer and having to purchase a set of rotors a little earlier. Cool air ducting to your front brakes on the RX-8 can have a very positive effect on front brake pad and rotor life. Keep in mind that it can cool your brakes so the initial stab on the brakes may take a few tiny moments to generate heat. This is particularly true in the rain where brakes have a hard time retaining heat.
If we were running a race and new it was going to rain and/or it was very cold we would run a less aggressive pad that quickly could generate heat. We have run a limited production run set of DTC-30's in the rain before with much success. Unforunately for longer enduro races you can't predict that it will rain all the time and usually fall back to something conservative like a 60/60. Keep in mind we are running a very aggressive suspension setup which allows for higher grip than most RX-8's out there so the 60/60 MAY be too much for a less modified suspension car. Share your car mods and we can figure this out.
Eric
01-03-2010, 04:09 PM
#9
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Jason@Andrew-Racing.com
I will send him a link to this forum and perhaps he can jump in.
01-03-2010, 04:18 PM
#10
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I actually just asked Rishie about the DTC-30's based on that chart and they don't appear to offer them for the RX-8. I need new pads soon though, so Rishie is looking into how much he can get them for. Racing Brake is running a sale now though and he wasn't confident that he was going to be able to beat them with free shipping.
Thus far we tend to migrate toward:
60F/60R for several tracks when we run 245 front grip
60F/10R for several tracks that may require less braking and/or we run the 225 tire
70/60 for Daytona as you are braking like a freakin' **** from about 140 mph in the shortest distance possible. You could tell the advantage of this combination. The initial bite was stronger however you could stand on that brake pedal and she would hunker down like nobodies bidness.
60F/Black Rear
60F/Blue rear
In both the cases above the rear pads were to weak for the fronts and we experienced what OnRails refers to above---less than optimum performance. Actually, there is a funny story about that. The guys accidently put some blacks on the rear w/60 fronts and I was smoking the rear tires. Couldn't figure out what the heck was going on. Did a few laps, got on the radio and asked what kind of pads they put on, they checked the box and figured out the issue. Pitted, swapped pads and good to go.
01-03-2010, 04:52 PM
#11
For what I've been doing the last few years...I have been running HT10/10's and have found them to be good for what I do....
You have to swap them out if you're going very far on the street....they don't work very well cold
I have found they have about 4X the wear of the HP+ and that they don't wear the rotors out any different. I have a set of Racing Brake 2 pc rotor rings that I have run 6-7 sets of pads through...and they still are in spec and true...gotta love those rotors
You have to swap them out if you're going very far on the street....they don't work very well cold
I have found they have about 4X the wear of the HP+ and that they don't wear the rotors out any different. I have a set of Racing Brake 2 pc rotor rings that I have run 6-7 sets of pads through...and they still are in spec and true...gotta love those rotors
01-03-2010, 05:26 PM
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My suspension mods are very modest. I run the Tein S-Tech which are advertised as 207 front and 145 rear. I've paired them with a set of Tokico D-Spec adjustable shocks. I run the factory sway bars front and rear.
01-03-2010, 07:11 PM
#13
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Thanks for the info, I was getting ready to buy another set of blues but I'm going to get the Ht-10's instead.
Do you have any examples of ducting to the front brakes or links where I can look at purchasing a setup?
Do you have any examples of ducting to the front brakes or links where I can look at purchasing a setup?
01-03-2010, 08:13 PM
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Here is a link to a few pictures of the brake ducts (note: you could take your existing front backing plates off (or rock guards or whatever you want to call them) and have a large boss welded to them. Removing these backing plates or rock guards from the front and rear is the smart way to go. Your brakes will retain less heat without them.
http://gallery.me.com/meyermotorspor...lack&view=grid
You will need to purchase some hose and pick up air at the front of the car. For those running stock oil coolers I beleive there is some space on the inside portion of these coolers (at least there is with the MazdaSpeed nose). You can pick up air just about anywhere. Cut a hole in the black belly pan and run a duct from there using the air that the front nose receives.
The trick SpeedSource brake ducts are MazdaSpeed p/n: 0000-03-8301 and approx. $250 for both R and L fronts. Generic metal hose clamps will help you get where you want to go near the brakes and ducts. Zip ties and drilling some holes will allow you to mount hoses to plastic parts. You can also purchase some NACA ducts made of black ABS plastic. Running cool air ducts are your car year round and on the street is not a big deal. It's a fun little installation project that you pretty much can't F up. The benefits your looking for are longer pad life but more importantly longer rotor life. Rotor cracks are a sign of heat cycles and with good pads they usually "crack out" before they develop grooves. Small cracks are fine. Chunks falling off is......not good. For all of you---don't fear the small cracks. This is normal for any performance car or rotor brand. $400 rotors do this just as much as el' cheapo's.
Here is a link to hoses and ducts that you might want to consider:
http://www.hrpworld.com/index.cfm?tp...ction=category
Natuarlly you'll want a set of front stainless steel brake lines (also avail from MazdaSpeed and several other vendors) and to replace your brake fluid. The Castrol GT LMA brake fluid comes in small containers and runs about $6. Use a little bit of in and throw the rest away. Buy 5 or 6 of these dudes and they will last an HPDE guy an entire season.
If you guys REALLY get on the brakes and have upgraded suspension and tires then I would be bleeding your brakes at LEAST before or after each event. Gentle open track and HPDE driving with a stock car will not require frequent brake fluid bleeding in these cars.
You can spend much more on brake fluid but the main thing you need to do is bleed them. The mega expensive Castrol SRF for $70+ a pint works as sucky as the cheap stuff if your brakes require bleeding. Learn how to bleed them with a friend.
Two open ended 8 mm wrenches (one for an extra spare) are great to have. Get a good one as you'll be using it as long as you own and track your 8.
See you guys at the track and make us all proud and pass people in the braking zones.
01-03-2010, 10:46 PM
#16
Power!!
01-03-2010, 11:00 PM
#18
I don't think I'd use the HT10's for autocross after driving them on the street going home from the local track.......they are close to useless unless you really stand on them...they kinda give you a shock the first time you use them when they are cold
01-04-2010, 06:54 AM
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I have tried HPS, HP+ and DTC-30's (test set) on my stock class RX-8 over the last 3 years of National Solo competition. I have always switched back to the HPS because they are very consistent from low temps and the initial bite is not overly aggressive. In Solo competition, one corner of the car is often unweighted when you are blending braking and cornering, an overly aggressive pad will engage the ABS/Ice Mode more easily and produce less consistent reactions to driver inputs.
It is possible to adjust to a more aggressive pad, but the risk of upsetting the car becomes higher. Not to mention the increased noise and dust if you are not changing pads at the event site.
Brake fade has never been an issue on Solo courses in the RX8, even with a two driver car.
Chris Harvey
aka Trent@TireRack.com
It is possible to adjust to a more aggressive pad, but the risk of upsetting the car becomes higher. Not to mention the increased noise and dust if you are not changing pads at the event site.
Brake fade has never been an issue on Solo courses in the RX8, even with a two driver car.
Chris Harvey
aka Trent@TireRack.com
01-04-2010, 09:10 AM
#22
I'm running RacingBrake ET800s for street & solo work in my STX RX-8. They are very consistent & easy to modulate. Fantastic right out of the starting line, and have great bite when hot. Never had a problem with them either being inefective when cold, or overly aggresive when hot. Excellent all-around pad.
Supposedly, they have a good track-day pedigree as well, although I have not used them in that context and I don't know what their heat range is. I can say that I have used them on the street in well below freezing temps and have had no problems.
For somebody who does not care about track use, the ET500s would probably be a better choice for solo work since they are cheaper.
Supposedly, they have a good track-day pedigree as well, although I have not used them in that context and I don't know what their heat range is. I can say that I have used them on the street in well below freezing temps and have had no problems.
For somebody who does not care about track use, the ET500s would probably be a better choice for solo work since they are cheaper.
01-04-2010, 01:28 PM
#23
1% evil, 99% hot gas.
iTrader: (21)
I've been using HP+ pads on the track, and the stock brakes on the RX-8 are so good that I've never experienced any fade on R-compounds with a lightly-modified suspension. I bought a set of Blues as a "just in case" set when I first put the R's on, but the HP+ just won't give up even hauling it down from 128 MPH at T1 on VIR. I don't think I need Blues or HT-10's. I'm not sure I could keep them hot enough!
I have gotten an important point from your chart and follow up posts, Eric: I'm not using enough pad in the rear. I'm using "premium" ceramic stock street pads in the rear, and get a little wiggle. I figured I probably needed more, but struggled with which pad to use. Looks like HPS might be the way to go. Might even go Blacks up front and HP+ in the rear. (Just hate locking the rears before the fronts run out of brake.)
Also, funny how people talk about the pedal feel. To me the best pedal feel is one that moves maybe an inch initially, and then doesn't move at all (or very little), but is easy modulated by pressure on the pedal. I also run a Spec RX-7, usually with Blues/Blacks F/R. I tried the Carbotechs and hated them. The pedal was mushy as hell, hard to modulate, and had less ultimate braking IMHO. This was a champion's car, so they might know something I don't, but I switched back to Blue's pronto. Once of the best improvements (and most surprising) on the RX-8 was a master cylinder brace. Firmed the pedal right-up.
01-04-2010, 01:35 PM
#24
1% evil, 99% hot gas.
iTrader: (21)
Disregarding the low temperature problem for a moment, the other factor is HT-10s are $150+, while the HP+ are $95 delivered. I get at least two weekends (16+ hours track time) out of the HP+, how long will the HT-10's last?
01-04-2010, 04:16 PM
#25
I've used SRF for years and don't consider it a waste at all even though I mainly autox. Since it is autox use my brakes rarely get hot enough to require constant flushing. But the car does sit for periods of time and the low moisture absorption properties of SRF mean I don't hardly ever have to flush nor do I need to worry about the opened bottle going bad though since it is plastic I keep the air squeezed out before sealing the top. I dropped $70 on a bottle doing a full flush & fill and then another $70 on a second bottle that lasts for several years. So it's not like I'm going through a bottle or two per weekend, plus it's less work. It's a win-win for me.