928 Technical discussion - Theories, experiences, physics, and solutions.
12-01-2015, 03:37 PM
#47
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And as far as driving goes (ego time! )... well, lets see you run as fast as MA with 50 less HP, no motons, no suspension mods, etc etc..
https://rennlist.com/forums/928-foru...l#post12797613
12-01-2015, 03:40 PM
#48
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Thread Starter
So here are the calculations to show that by adding weight you actually increase the themal load on the brakes. (based on the simulation above)
KE start 307,247 light car
KE start 270,969 heavy car
both at near 43mph
KE end based on simulator at 1840ft down the track before braking at the same point:
KE end 1,991,956 Light car at 120mph
KE end 2,085,914 Heavy car at 114mph 4% more KE before braking
both cars have same force on the wheels and to the ground through the tires and slow to the same speed that they started out at :
Total KE to slow: 1,684,709 for light car
(1,991,956 start before slow - 307,247 J to orig speed)
Total KE to slow: 1,814,945 for heavy car
(2,085,914 start before slow- 270,969 J to the orig speed)
Heavy car with 15% more weight will slow at 15% slower rate and take 15% longer time (if at the same speed) but, its going 5% slower before its decel
we can call it 4 seconds for lighter car and then 4 seconds plus 15%-5% = 10% = 4.4 seconds.
this is 421,177 Joules for light car in 4 seconds or 564HP/sec.
this is 412,487 Joules for heavy car in 4.4 seconds or 552HP/sec
difference of 2% more power/second for the lighter car
In the end, i think at worst case, the effect on braking would be near the same with the extra weight.
If you have some comments on the calculations.. lets hear 'em
Ive made only a few minor approximations, that i think in the end , they would not be huge factors at all. the limits are easy to see.
( the decel distance for the heavy car is approx'ed at 4.4 seconds. ill plug it into the formula and see the exact time it would take to decel, assuming the decel rate is 1g for the light car and .85g for the heavy car)
KE start 307,247 light car
KE start 270,969 heavy car
both at near 43mph
KE end based on simulator at 1840ft down the track before braking at the same point:
KE end 1,991,956 Light car at 120mph
KE end 2,085,914 Heavy car at 114mph 4% more KE before braking
both cars have same force on the wheels and to the ground through the tires and slow to the same speed that they started out at :
Total KE to slow: 1,684,709 for light car
(1,991,956 start before slow - 307,247 J to orig speed)
Total KE to slow: 1,814,945 for heavy car
(2,085,914 start before slow- 270,969 J to the orig speed)
Heavy car with 15% more weight will slow at 15% slower rate and take 15% longer time (if at the same speed) but, its going 5% slower before its decel
we can call it 4 seconds for lighter car and then 4 seconds plus 15%-5% = 10% = 4.4 seconds.
this is 421,177 Joules for light car in 4 seconds or 564HP/sec.
this is 412,487 Joules for heavy car in 4.4 seconds or 552HP/sec
difference of 2% more power/second for the lighter car
In the end, i think at worst case, the effect on braking would be near the same with the extra weight.
If you have some comments on the calculations.. lets hear 'em
Ive made only a few minor approximations, that i think in the end , they would not be huge factors at all. the limits are easy to see.
( the decel distance for the heavy car is approx'ed at 4.4 seconds. ill plug it into the formula and see the exact time it would take to decel, assuming the decel rate is 1g for the light car and .85g for the heavy car)
12-01-2015, 03:44 PM
#49
Nordschleife Master
12-01-2015, 03:47 PM
#50
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12-01-2015, 04:31 PM
#51
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Actually Mark the amazing thing is YOUR ability to offend, denigrate and ridicule just about everyone on any thread. People tend to give up on any of your "debates" simply because you are so unpleasant to deal with not because you are right or wrong and of course you ALWAYS have the last word. That perhaps you believe is winning....which is about all the winning you actually do given your racing record. Yes they have more power, more money, new tires......still makes you an also ran most of the time. And Mark I have no delusions that I am a great driver...now a great actor perhaps
So my polluted mind with all the common thoughts has known for many years how convoluted your thinking can be.... can be quite amusing at times
So my polluted mind with all the common thoughts has known for many years how convoluted your thinking can be.... can be quite amusing at times
12-01-2015, 04:45 PM
#52
Rennlist Member
Thread Starter
Actually Mark the amazing thing is YOUR ability to offend, denigrate and ridicule just about everyone on any thread. People tend to give up on any of your "debates" simply because you are so unpleasant to deal with not because you are right or wrong and of course you ALWAYS have the last word. That perhaps you believe is winning....which is about all the winning you actually do given your racing record. Yes they have more power, more money, new tires......still makes you an also ran most of the time. And Mark I have no delusions that I am a great driver...now a great actor perhaps
So my polluted mind with all the common thoughts has known for many years how convoluted your thinking can be.... can be quite amusing at times
So my polluted mind with all the common thoughts has known for many years how convoluted your thinking can be.... can be quite amusing at times
just use the example yesterday about your correction of my quote out of my physics book. if you have a comment to make, make it clear. read the post. be polite , and try not to be such an *** as well. Im trying to help here as much as i can.. its fun to discuss the technologies and lots to be learned both ways here. in this example ..... just exposing a major misconception about weight. many folks haven't dug this deep in the problem of brake issues. this is a way to find out that maybe the problem is not the brakes, but the technique. again, just trying to promote good conversation, and help. sorry if i come across in an arrogant fashion..... its not my intent. but usually the challenger of common thought (right or wrong) is looked upon that way.
an Jim, i have plenty of success in my racing over the years... the main success, besides the wins, has been in the fun factor, for which the car has exceeded all expectations. its known by all that race against it for the 100s of races ive been. I'm proud to own such a car with such capability but performance as well.... all while having HUGE limitations on the money and resources i can toss at the car. this list has helped me along the way in many ways.... on occasion,
i try and share the success so others can as well. You dont see it that way, but thats the way i see it.
12-01-2015, 05:27 PM
#54
Rennlist Member
Thread Starter
12-01-2015, 05:48 PM
#56
12-01-2015, 06:58 PM
#58
Rennlist Member
Thread Starter
Yes , work or energy (commonly used interchangeably). not power.
so, even though the KE is the same for two cars during a decel.. the rate at which it decels (rate of change of KE), can create greater temp rises in the components slowing the car. even though the heavier car might need more energy to slow, if the rate is increase on the lighter car, the temps of the brakes can be higher. this is due to the brakes ability to dissipate heat. if there was no dissipation, then there would be no difference. there is, so there is.
so, even though the KE is the same for two cars during a decel.. the rate at which it decels (rate of change of KE), can create greater temp rises in the components slowing the car. even though the heavier car might need more energy to slow, if the rate is increase on the lighter car, the temps of the brakes can be higher. this is due to the brakes ability to dissipate heat. if there was no dissipation, then there would be no difference. there is, so there is.
12-02-2015, 01:34 PM
#59
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Thread Starter
Im laughing just picturing Daniel working on King David's Genitals in photoshop.... reducing.... scaling..... fillling in.......
