LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

why do the brakes suck in the rian

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Old May 27, 2003 | 09:30 AM
  #31  
treyZ28's Avatar
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From: looking for a flow bench so Brook and I can race
Originally posted by treyZ28
ACTUALLY rich-

I asked this question a week or two ago from my boss (I'm a currious pissant huh around here

The reason is that the the wheel will lock easier and hence slower stopping-

why? yes the pad/rotor is wet- but thats not the real reason. a lot of the water will dry right off due to the insane heat they see. If your trying to stop in a puddle thats one thing but just on a road- there isn't much water on the rotor after a few rotations due to the pay tightening and brushing it off and the heat.

Real reason is that the road is "pushing" the tire. (thats what i got from it) With less friction on the road/tire surface, you have less rotor to pad friction before it will lock up.

There is a chart here from braking theory class (i cant go to the class because my boss thinks i'm a dumbass and its over my head )and it shows the max decel in g's vs road - tire friction coefficient.

Your max decel is DIRECTLY related to tire:road friction and i think the max total Force of friction is derived from the that frictional coefficent.


more to come... its early and might as well be monday. Im tired- too much offroading and hanigng out with escaped circus clows this weekend (pics in sig
some of this might be herecy so let me double check the info
ok-
I had the right idea- TERRIBLE way of explaining it. The best way I can correctly explain it is kinda technical and hard to explain without a pen and paper- but i'll try to break it down and see what i can explain without paper and pad. Hopefully I wont take too much away from it and hopefully rich or fred or someone will explain it better than me- i'm a chitty teacher

The road is pushing on the tire (or tire on road) and there is a force and therefore a torque. Concider this torque to be a positive tq.

The brake pad is pushing against the rotor and then creating a torque in the opposite direction- a neg tq.

Now, when then torque - is more than the tq +, the wheel locks up. (it obvously wont start spinning the other way since its a frictional force- just a resitance to motion)

Now the road is icy. less friction between road and tire, less road "pushing" tire. Now the positive torque is less so the max negative torque is less as well meaning less friction before lock up. that obviously corrilates to slower stopping power.

The max torque and friction that can be applied to the rotor is the same as athe max torque/friction between the road and tire.

this is why cars have stronger front brakes. When you hit the brakes, weight goes up front, less friction in the rear (less weight back there) so it doesn't take much to lock them snmabitchs .

Trucks on the other hand (real trucks, not a escape) have near 50-50 bias for when they are loaded up. There will be more wieght out back. Thats why trucks can be virtually uneffected by weights that would severely hurt a cars braking performance. Some heavier duty trucks actually have a REAR BIAS

Clear as mud?
good

edit:
whoa, i just quoted myself
Old May 27, 2003 | 09:49 AM
  #32  
scoobysnax83's Avatar
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From: Arlington, VA
Originally posted by treyZ28
ACTUALLY rich-

I asked this question a week or two ago from my boss (I'm a currious pissant huh around here

The reason is that the the wheel will lock easier and hence slower stopping-

why? yes the pad/rotor is wet- but thats not the real reason. a lot of the water will dry right off due to the insane heat they see. If your trying to stop in a puddle thats one thing but just on a road- there isn't much water on the rotor after a few rotations due to the pay tightening and brushing it off and the heat.

Real reason is that the road is "pushing" the tire. (thats what i got from it) With less friction on the road/tire surface, you have less rotor to pad friction before it will lock up.

There is a chart here from braking theory class (i cant go to the class because my boss thinks i'm a dumbass and its over my head )and it shows the max decel in g's vs road - tire friction coefficient.

Your max decel is DIRECTLY related to tire:road friction and i think the max total Force of friction is derived from the that frictional coefficent.


more to come... its early and might as well be monday. Im tired- too much offroading and hanigng out with escaped circus clows this weekend (pics in sig
some of this might be herecy so let me double check the info
Originally posted by treyZ28
ok-
I had the right idea- TERRIBLE way of explaining it. The best way I can correctly explain it is kinda technical and hard to explain without a pen and paper- but i'll try to break it down and see what i can explain without paper and pad. Hopefully I wont take too much away from it and hopefully rich or fred or someone will explain it better than me- i'm a chitty teacher

The road is pushing on the tire (or tire on road) and there is a force and therefore a torque. Concider this torque to be a positive tq.

The brake pad is pushing against the rotor and then creating a torque in the opposite direction- a neg tq.

Now, when then torque - is more than the tq +, the wheel locks up. (it obvously wont start spinning the other way since its a frictional force- just a resitance to motion)

Now the road is icy. less friction between road and tire, less road "pushing" tire. Now the positive torque is less so the max negative torque is less as well meaning less friction before lock up. that obviously corrilates to slower stopping power.

The max torque and friction that can be applied to the rotor is the same as athe max torque/friction between the road and tire.

this is why cars have stronger front brakes. When you hit the brakes, weight goes up front, less friction in the rear (less weight back there) so it doesn't take much to lock them snmabitchs .

Trucks on the other hand (real trucks, not a escape) have near 50-50 bias for when they are loaded up. There will be more wieght out back. Thats why trucks can be virtually uneffected by weights that would severely hurt a cars braking performance. Some heavier duty trucks actually have a REAR BIAS

Clear as mud?
good

edit:
whoa, i just quoted myself
I just wanted the longest reply....

But seriously you should have stopped with the last explanation, it was more clear and made sense
Old May 27, 2003 | 09:57 AM
  #33  
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From: looking for a flow bench so Brook and I can race
ohh yea-

the fine print:

Rules subject to change on displaceable surafaces such as but not limited to sand, dirt, mud, snow and your ex girlfriends lawn...
Old May 27, 2003 | 10:01 AM
  #34  
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From: Browns Mills, New Jersey
Lt1 breaks suck period, they dont even stop in dry weather
Old May 27, 2003 | 10:04 AM
  #35  
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From: looking for a flow bench so Brook and I can race
)
Originally posted by Antz97ZNJ
Lt1 breaks suck period, they dont even stop in dry weather
try a silverado with 4 people in it and everything out of 2 (GIRLS' ) dorm.

Good thing there weren't any red lights- i woulda coasted right through every one

(j/k it wasn't that bad, but my Z28 stops MUCH better )

edit:
WTF are doing in alaska, with a Z28 none the less. shoulnd't you be driving a dog sled or be walking around with tennis raquets on your feet in -500 billion degree weather?
Old May 27, 2003 | 08:47 PM
  #36  
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From: Portage, IN
Well I hate to disagree with the dogsled driver, but LT1 brakes do not suck, they work just fine if taken care of properly. I run autocrosses with stock brakes and Performance Friction Z-rated pads, and the car stops extremely well, thank you.
First of all, the ABS system has nothing to do with the problem being described. Yes, the Camaro's ABS system isn't the best, at least it got a little better with the Bosch system that went into the 98+ cars, but its not the issue here. If you're kicking on the ABS system its because you're getting enough braking force to lock wheels, which is what ABS is designed to prevent. If you get tons of ABS in the rain then it's because your tires aren't doing a very good job of sticking to the road, either because they're worn or aren't a good design for wet weather driving, or you're just being too brutal with the pedal.
So, what's wrong with the F-car brakes? Nothing really. Poor braking performance (assuming no hydraulic problems like air in the lines or bad calipers or master cyl.) are old pads that have developed a pretty good glaze on them. If you really pushed your brakes hard on dry pavement you'd probably notice they dont work as good as they used to either. In normal dry weather driving you'll never notice a thing but put a film of water between those glazed pads and a wet rotor and it will take some good hard pushing to get the car stopped.
So, what to do? Get some new pads. Performance Friction or Hawk make excellent carbon metalic pads that will stop the car like you've thrown out an anchor, and are reasonably priced. If you do any hard driving at all get the Performance Friction Z-rated pads, or the Hawk HPS pads. The Hawk HP+ pads are more of a street-track compound, and if you do go for those only use them on the fronts, put the HPS pads on the rear, you dont need that much rear brake.
As for rotors, a rotor is a rotor is a rotor. I'd avoid the drilled ones like the plague, cracking around the holes is a fact of life with these. Slotted rotors look nice but I've yet to see anyone prove they offer any advantage in anything but an all-out road racing car. If you need rotors get good replacement ones and be done with it. Don't try to save a buck by looking for used or salvage yard ones of unknown quality. If they're warped you're going to end up buying another rotor anyway, cutting rotors anymore is almost impossible. Manufacturers make them so thin from the factory that if you get one brake job out of them you're lucky. Never, never re-use a rotor that is either under thickness specs or is warped. Cutting a warped rotor will get rid of the problem for a while, like until the next time the rotor gets hot, and then the problem will be right back. Once you're warped one its only good for a doorstop or a ultra-heavy frisbee.
Finally, don't overlook your calipers. GM single piston calipers are notorious for the pistons sticking in the bores. If you can't push the piston back in with a c-clamp easily when taking off the calipers its time to either replace or rebuild the caliper. A good complete flush of the fluid is a wise investment when doing a brake job, and good insurance against future problems. Just keep bleeding the system until the fluid runs clear.
If anyone remembers 4-wheel drum brakes, and has driven a car in the rain with those, you know that basically having no brakes in wet weather was pretty much an accepted fact of life. It sucked, yes, one of many reasons why disc brakes have almost completely replaced drums.

Last edited by DWoodAudio; May 27, 2003 at 08:54 PM.
Old May 27, 2003 | 09:40 PM
  #37  
TA Dreaming's Avatar
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From: Athens, GA
good info guys. i think ill try flushing the system next time. is there a better brake fluid out there to use on a daily driver? and with these pads like the hawks ive heard some eat up rotors and well i dont want that. so is that right or are the right ones perfectly fine for daily driving? thanks. Trey
Old May 27, 2003 | 10:04 PM
  #38  
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From: Portage, IN
brake pad selection is always a bit of a trade-off. Pads like the Hawk HP+ will dust a bit more and be a little bit harder on rotors but the benefit is better braking performance even under extreme conditions. The Performance Friction pads come in two flavors also, the regular Carbon metalic line and the Z-rated line, same thing applies here but the PF pads seem to be a bit easier on rotors. I'm using the Z-rated pads right now but I've used the Hawk pads and think they offer just a tad more braking force, but dust more.
It depends on how you drive. I autocross the car and use the brakes hard, but only in short bursts, so long periods of high-speed braking aren't an issue with me, initial response is. Also for the most part these cars have more rear brake then they really need, so a slightly less grippy pad in the rear suits my tastes.
I guess the best thing for you is to do a careful and complete analysis of your present brake system, and make sure its all in proper working order. Things like flushing the system won't fix bad brake performance caused by some other problem. Start with the most obvious things first and work your way up. If you have a firm pedal then your fluid is working ok for now. As for fluid just use a good brand, synthetic is ok but not really necessary. I use it because it seems to absorb a bit less moisture than conventional fluids and gives me a more consistent pedal feel even when the brakes are really hot.
Good Luck
Old May 27, 2003 | 10:53 PM
  #39  
95BlackTA's Avatar
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Called water..gets a lil slick.
Old May 27, 2003 | 11:24 PM
  #40  
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If you are talking about initial feel when you first hit the brakes (feels like you are on ice) when you have not used them in a while, it's just a matter of them being wet. Cars with very open wheels (where a lot of the rotor is exposed) are worse. Rotor and pad selection can make a difference. No long technical explanation needed.
Old May 28, 2003 | 03:54 PM
  #41  
scoobysnax83's Avatar
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Joined: Sep 2002
Posts: 2,481
From: Arlington, VA
Originally posted by DWoodAudio
Well I hate to disagree with the dogsled driver, but LT1 brakes do not suck, they work just fine if taken care of properly. I run autocrosses with stock brakes and Performance Friction Z-rated pads, and the car stops extremely well, thank you.
First of all, the ABS system has nothing to do with the problem being described. Yes, the Camaro's ABS system isn't the best, at least it got a little better with the Bosch system that went into the 98+ cars, but its not the issue here. If you're kicking on the ABS system its because you're getting enough braking force to lock wheels, which is what ABS is designed to prevent. If you get tons of ABS in the rain then it's because your tires aren't doing a very good job of sticking to the road, either because they're worn or aren't a good design for wet weather driving, or you're just being too brutal with the pedal.
So, what's wrong with the F-car brakes? Nothing really. Poor braking performance (assuming no hydraulic problems like air in the lines or bad calipers or master cyl.) are old pads that have developed a pretty good glaze on them. If you really pushed your brakes hard on dry pavement you'd probably notice they dont work as good as they used to either. In normal dry weather driving you'll never notice a thing but put a film of water between those glazed pads and a wet rotor and it will take some good hard pushing to get the car stopped.
So, what to do? Get some new pads. Performance Friction or Hawk make excellent carbon metalic pads that will stop the car like you've thrown out an anchor, and are reasonably priced. If you do any hard driving at all get the Performance Friction Z-rated pads, or the Hawk HPS pads. The Hawk HP+ pads are more of a street-track compound, and if you do go for those only use them on the fronts, put the HPS pads on the rear, you dont need that much rear brake.
As for rotors, a rotor is a rotor is a rotor. I'd avoid the drilled ones like the plague, cracking around the holes is a fact of life with these. Slotted rotors look nice but I've yet to see anyone prove they offer any advantage in anything but an all-out road racing car. If you need rotors get good replacement ones and be done with it. Don't try to save a buck by looking for used or salvage yard ones of unknown quality. If they're warped you're going to end up buying another rotor anyway, cutting rotors anymore is almost impossible. Manufacturers make them so thin from the factory that if you get one brake job out of them you're lucky. Never, never re-use a rotor that is either under thickness specs or is warped. Cutting a warped rotor will get rid of the problem for a while, like until the next time the rotor gets hot, and then the problem will be right back. Once you're warped one its only good for a doorstop or a ultra-heavy frisbee.
Finally, don't overlook your calipers. GM single piston calipers are notorious for the pistons sticking in the bores. If you can't push the piston back in with a c-clamp easily when taking off the calipers its time to either replace or rebuild the caliper. A good complete flush of the fluid is a wise investment when doing a brake job, and good insurance against future problems. Just keep bleeding the system until the fluid runs clear.
If anyone remembers 4-wheel drum brakes, and has driven a car in the rain with those, you know that basically having no brakes in wet weather was pretty much an accepted fact of life. It sucked, yes, one of many reasons why disc brakes have almost completely replaced drums.
hmmmm...sounds familiar...
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