brakes brakes brakes....
Don't ya just hate it when your sap gets runny.
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Joined: May 2005
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From: Center Point, AL
Senior Member
SL Member
Joined: Oct 2004
Posts: 309
From: S.F. Bay Area, CA
I'm sorry for being frank, but you are just waisting your money if your going to install brake ducts to improve your braking for mountain road driving. Brake ducts may help to a degree, but they are only bandage fixing the real problem.
This "mushy" feeling your getting on the backroads (In cas e you don't know) is brake fade. There are different types of brake fade,
If after you've done your mountain driving, are your brakes still "mushy" feeling? Do you feel like you've lost pressure in the peddle and can go to the floor easily, or more easily that before/or should be able too?
If so, then it's likely that you've got air in your brake fluid, and that feeling your getting is you compressing the air in it. (I'll go into more on how this may have happened later)
If not, and you have good peddle pressure, but the car just doesn't slow down, then it's likely you've over heated your brake pads, which may also be a possibility. I don't think this is likely unless you get El'cheapo pads. Different brake pads have different operating temperatures. El'cheapo brake pads will have a much lower peak operating temp than say a good Performance Friction pad, Hawk, or Porterfield pad. Now, on the flip side, a REALLY high peak temp pad is terrible at low temps, so higher temp is not always the best alternative.
Finding a pad for the temp range your are driving is the best pad. Light cars like ours run a typically lower temp than say Corvette's or 300ZXs, which are much heavier, and are on the brakes more because they are slowing down that heavier weight from higher speeds,
Carbon fiber rotors are not for cars as light and low horsepower as ours. You will never reach the temps needed to make those work best for you.
My personal recommendation for a pad would be a Porterfield R4-S. I personally run these have have put mine current set through 4 race track events w/o any fade. That's full throttle then slamming HARD on the brakes till ABS kicks in, and doing that a few times per lap, for 20min straight, for 4-5 20min track sessions in 90F+ temperatures.
Regarding the fluid fade, bubble will get in your break fluid 2 ways.
1. Either the fluid in your resovour is too low or there is some leak somewhere in the system to allow air or bubble to get into the hoses.
2. Moisture in the air seaps into your fluid over time. Over time, more and more moisture gets into your fluid. When you get your brakes really hot, and your fluid really hot, it can be hot enough to boil any water that is now mixed with the fluid. This boiling creates the bubble you know have.
The only way to prevent this is,
A. Replace your fluid with higher boiling point fluid.
Example of what I used for my 300ZXTwinTurbo on the race track: http://www.buybrakes.com/store/MOTUL-8069HC
But I think this would be overkill for our cars. I haven't even bothered to put it in my own xA, and I still get good performance.
B. Bleed all the fluid out of brakes more often.
Below is a story of the first time I took mine out on the track,
(never mind, looks like the ScionLife gods have deleted it)
I've found below a previous writeup I did on brakes for the xA on ScionLife. Please take a look.
https://www.scionlife.com/forums/vie...659&highlight=
1. Bleed out and fully replace all of your brake fluid. A full 2-3 flushes should replace everything. I noticed you live in Hillsboro,OR, so with all the rain you get, you might have to replace it every time you change your pads, or more often.
2. Upgrade your pads.
3. Don't touch your rotors unless your looking for more bling. Trust me, slotted won't do anything for you. If you've got 40k+ miles on your rotors and they warped, or severly damaged, then sure get the slotted, but I wouldn't recommend them simply to improve breaking response on our light cars.
4. No need to upgrade your calipers, unless money is burning a hole in your pocket and you need something to impress your friends.
5. Don't bother with brake ducts unless you like to tinker and have time to kill. They will bring down the average temp of your rotors, but that also means you better not get a brake pad with too high an operating temp. I wouldn't recommend R4-S if you duct your front rotors. If anything, I'd recommend trying to REDUCE cooling to your brakes with R4-S pads. They LOOOVE heat.
FYI, I've driven about 30-40 race track events and 30+ autox's over the years. Most of them in my 300ZX TT, 4 in my xA, and a few in rental cars if it was out of town. Actually just last Thursday, I rented the Hertz Shelby GT-H and took it around Portland International Speedway (just down the road from you).
Good luck.
This "mushy" feeling your getting on the backroads (In cas e you don't know) is brake fade. There are different types of brake fade,
If after you've done your mountain driving, are your brakes still "mushy" feeling? Do you feel like you've lost pressure in the peddle and can go to the floor easily, or more easily that before/or should be able too?
If so, then it's likely that you've got air in your brake fluid, and that feeling your getting is you compressing the air in it. (I'll go into more on how this may have happened later)
If not, and you have good peddle pressure, but the car just doesn't slow down, then it's likely you've over heated your brake pads, which may also be a possibility. I don't think this is likely unless you get El'cheapo pads. Different brake pads have different operating temperatures. El'cheapo brake pads will have a much lower peak operating temp than say a good Performance Friction pad, Hawk, or Porterfield pad. Now, on the flip side, a REALLY high peak temp pad is terrible at low temps, so higher temp is not always the best alternative.
Finding a pad for the temp range your are driving is the best pad. Light cars like ours run a typically lower temp than say Corvette's or 300ZXs, which are much heavier, and are on the brakes more because they are slowing down that heavier weight from higher speeds,
Carbon fiber rotors are not for cars as light and low horsepower as ours. You will never reach the temps needed to make those work best for you.
My personal recommendation for a pad would be a Porterfield R4-S. I personally run these have have put mine current set through 4 race track events w/o any fade. That's full throttle then slamming HARD on the brakes till ABS kicks in, and doing that a few times per lap, for 20min straight, for 4-5 20min track sessions in 90F+ temperatures.
Regarding the fluid fade, bubble will get in your break fluid 2 ways.
1. Either the fluid in your resovour is too low or there is some leak somewhere in the system to allow air or bubble to get into the hoses.
2. Moisture in the air seaps into your fluid over time. Over time, more and more moisture gets into your fluid. When you get your brakes really hot, and your fluid really hot, it can be hot enough to boil any water that is now mixed with the fluid. This boiling creates the bubble you know have.
The only way to prevent this is,
A. Replace your fluid with higher boiling point fluid.
Example of what I used for my 300ZXTwinTurbo on the race track: http://www.buybrakes.com/store/MOTUL-8069HC
But I think this would be overkill for our cars. I haven't even bothered to put it in my own xA, and I still get good performance.
B. Bleed all the fluid out of brakes more often.
Below is a story of the first time I took mine out on the track,
(never mind, looks like the ScionLife gods have deleted it)
I've found below a previous writeup I did on brakes for the xA on ScionLife. Please take a look.
https://www.scionlife.com/forums/vie...659&highlight=
1. Bleed out and fully replace all of your brake fluid. A full 2-3 flushes should replace everything. I noticed you live in Hillsboro,OR, so with all the rain you get, you might have to replace it every time you change your pads, or more often.
2. Upgrade your pads.
3. Don't touch your rotors unless your looking for more bling. Trust me, slotted won't do anything for you. If you've got 40k+ miles on your rotors and they warped, or severly damaged, then sure get the slotted, but I wouldn't recommend them simply to improve breaking response on our light cars.
4. No need to upgrade your calipers, unless money is burning a hole in your pocket and you need something to impress your friends.
5. Don't bother with brake ducts unless you like to tinker and have time to kill. They will bring down the average temp of your rotors, but that also means you better not get a brake pad with too high an operating temp. I wouldn't recommend R4-S if you duct your front rotors. If anything, I'd recommend trying to REDUCE cooling to your brakes with R4-S pads. They LOOOVE heat.
FYI, I've driven about 30-40 race track events and 30+ autox's over the years. Most of them in my 300ZX TT, 4 in my xA, and a few in rental cars if it was out of town. Actually just last Thursday, I rented the Hertz Shelby GT-H and took it around Portland International Speedway (just down the road from you).
Good luck.
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Joined: Jun 2005
Posts: 403
i am not sure that i have ever experienced heat fade in my xa. there was once when i thought that i did when i was starting to get a clue, so i bet that i was completely mistaken.
i have been VERY impressed by the stock brakes. i have about 20k miles, four days at the pocono raceway, and many autocrosses on this car but the brakes are still good. i think that the pads will need replacing soon though.
i was thinking about getting a big brake kit until i saw the prices posted in this thread. i would sink that much money into some silly engine swap before i bothered fixing what ain't broke!
by the way, i use konig helium rims when doing performance driving. they are VERY open, so maybe they are allowing the brakes to cool down a lot.
i will definitely get some better pads and maybe those slotted rotors soon.
thanks for the info.
i have been VERY impressed by the stock brakes. i have about 20k miles, four days at the pocono raceway, and many autocrosses on this car but the brakes are still good. i think that the pads will need replacing soon though.
i was thinking about getting a big brake kit until i saw the prices posted in this thread. i would sink that much money into some silly engine swap before i bothered fixing what ain't broke!
by the way, i use konig helium rims when doing performance driving. they are VERY open, so maybe they are allowing the brakes to cool down a lot.
i will definitely get some better pads and maybe those slotted rotors soon.
thanks for the info.
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SL Member
Joined: Oct 2004
Posts: 309
From: S.F. Bay Area, CA
Glad to see somebody else hitting the track sometimes with their xA. I think we're the only 2 people in the whole USA that's hit the track with their xA. Ha..
Something else, most people for their everyday braking, and I might also have to say with most mountain corner carving, you don't really stomp on the breaks very often to the point where you trigger the additional "panic brake" booster. At the track, I hit that point very very often... Even more likely to overheat the breaks, but I actually have never felt fade yet with these brakes. Suprising no fluid fade either yet, knock on wood...
Good luck,
Something else, most people for their everyday braking, and I might also have to say with most mountain corner carving, you don't really stomp on the breaks very often to the point where you trigger the additional "panic brake" booster. At the track, I hit that point very very often... Even more likely to overheat the breaks, but I actually have never felt fade yet with these brakes. Suprising no fluid fade either yet, knock on wood...
Good luck,
Senior Member
SL Member
Joined: Oct 2004
Posts: 309
From: S.F. Bay Area, CA
Something else I forgot to mention. And this is something that is likely mentioned in the links to the SE-R brake pages.
Regarding the high end brake fluid, you may notice that they list a dry and wet boiling point. The dry is considered new fluid. Fluid that has seen minimal to no air/humitidy.
Wet boiling point is referincing the boiling point of the fluid that's older and/or been introduced to air/humity for extendede periods of time for water moisture(lower boiling temp) has mixed with the fluid.
On our Z's that we regularly hit the track with, we used to bleed out the entire brake system before a track day to make sure we never got fluid fade (very common in these cars at the track). We would also only use fresh sealed bottles of Motul brake fluid. If we didn't use an entire bottle, we'd toss it in the trash, not even using it for later to top off. Once the bottles been opened, even if you reclose it, it's performance will be lost as it sits and the new air you introduced in the bottle gets absorbed into the fluid. Just to give you an idea of the extreme cases.
Regarding the high end brake fluid, you may notice that they list a dry and wet boiling point. The dry is considered new fluid. Fluid that has seen minimal to no air/humitidy.
Wet boiling point is referincing the boiling point of the fluid that's older and/or been introduced to air/humity for extendede periods of time for water moisture(lower boiling temp) has mixed with the fluid.
On our Z's that we regularly hit the track with, we used to bleed out the entire brake system before a track day to make sure we never got fluid fade (very common in these cars at the track). We would also only use fresh sealed bottles of Motul brake fluid. If we didn't use an entire bottle, we'd toss it in the trash, not even using it for later to top off. Once the bottles been opened, even if you reclose it, it's performance will be lost as it sits and the new air you introduced in the bottle gets absorbed into the fluid. Just to give you an idea of the extreme cases.
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