why is the track model so heavy?
08-13-2005, 12:03 AM
#41
Originally Posted by spcemn_spiff
If they weigh less and assuming that acceleration due to gravity is constant, then mass should be less. This is based on Newtons laws of motions (2nd) if they have not been refuted lately.
And no, I think Newton is not going to be disproven any time soon.
08-13-2005, 12:20 AM
#42
Originally Posted by spcemn_spiff
The reason why most disk brakes at least on the front wheels have vents or vanes is for convection cooling, if mass were as important, some would increase mass and some would have vents. And its cheaper (manufacturability) to increase mass and not have vents. Z non-Brembos have vented rear brakes too, so the reason they went with vents instead of more mass is because of effective cooling.
Heat generated is dependant on the speed of the rotor, the more the speed, higher the speed of air flowing thru the vents because of the impeller based design of the vents, this results in better cooling at higher speeds. So mass seems to be a little disconnected from this effect. And if you think convective air flow is not a good way of cooling things, then radiators should not exist. I am not talking about infinite cooling potential either, I am just talking of keeping the temperature in the operating range, which is not infinite or impossible.
So again, we go to carbon fiber ceramic composite brakes is because of reduced mass and inspite of that better cooling, if you know Porsche and Ferrari use these rotors on their road cars, so the shift towards low mass indicates that mass is less important/effective in cooling the rotors. I have not done any calculations to analyze the heat transfer, but I know that increasing the mass to cool better is a completely wrong direction in my books.
About the 1300C quote, http://news.bbc.co.uk/sport1/hi/moto...de/3518465.stm
Its not the best source, but I cannot disregard it as being unreliable.
Heat generated is dependant on the speed of the rotor, the more the speed, higher the speed of air flowing thru the vents because of the impeller based design of the vents, this results in better cooling at higher speeds. So mass seems to be a little disconnected from this effect. And if you think convective air flow is not a good way of cooling things, then radiators should not exist. I am not talking about infinite cooling potential either, I am just talking of keeping the temperature in the operating range, which is not infinite or impossible.
So again, we go to carbon fiber ceramic composite brakes is because of reduced mass and inspite of that better cooling, if you know Porsche and Ferrari use these rotors on their road cars, so the shift towards low mass indicates that mass is less important/effective in cooling the rotors. I have not done any calculations to analyze the heat transfer, but I know that increasing the mass to cool better is a completely wrong direction in my books.
About the 1300C quote, http://news.bbc.co.uk/sport1/hi/moto...de/3518465.stm
Its not the best source, but I cannot disregard it as being unreliable.
08-13-2005, 06:46 AM
#43
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Originally Posted by kcobean
I think he mistakenly said 'mass' when in fact he meant to say 'volume', which for the purposes of this discussion would equal surface area.
And no, I think Newton is not going to be disproven any time soon.
And no, I think Newton is not going to be disproven any time soon.
I understand the effect of mass, but increasing the mass is not a good approach in my opinion and not used in cars from what I can see. Because chances are you will be running into heavy masses to absorb heat effectively.
There are two things that need to happen if mass approach is used and forced air convection is absent. One is increased mass will go on and absorb all the heat, now the temperature of the rotors and pads goes up. Second you need to cool the absorbed heat! You dont have convection, effects of radiation are minimal and for conduction there is not good enough thermal path.
So in essence theoretically there is no way of cooling the mass, all you are doing is absorbing the heat and not dumping it. That is not desired.
08-13-2005, 03:43 PM
#44
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While the conversation on ceramic brakes is lively, it doesn't appear to contribute to this thread. There's little doubt that ceramic brakes offer some sizable advantages, the COST is out of this world as well. Porsche and Ferrari can offer the properly engineered brake application on cars that cost about the same as a nice piece of real estate. For those of us that WORK for a living and want the best braking on our Z's, steel and iron still offer the best bang for the buck.
08-15-2005, 05:49 AM
#45
Back from Tremblant...
Ah guys, stop being closed minded ! mass, airflow, conductivity and so on ALL contribute to brake performance. Stop trying to find one single source for everything, it's ridicule...
The mass argument (my argument anyways) applied to brake fade resistance. A heavier caliper will store more heat and keep brake fluid to a lower temps and resist boiling longer.
Mass of the rotor will play a role. Airflow cooling will certainly be a major factor in disc temperature and cooling. Surface area, vanne design and so on. But it will never cool the disc faster than heat is generated from braking (duh, obvious) and thus does not help much against temperature spikes and subsequent heat treatment while cooling. It will bring the temps down faster between turns.
Don`t compare F1 technology with amateur track applications unless you have a real knowledge of why things are this way in F1. Regulations do not care about what is the best/most efficient ways of going around a track... Did anybody ever wonder WHY they don`t use other disc brake material than carbon ? Why not ceramics? The answer is in the regulations (www.fia.com).
Ah guys, stop being closed minded ! mass, airflow, conductivity and so on ALL contribute to brake performance. Stop trying to find one single source for everything, it's ridicule...
The mass argument (my argument anyways) applied to brake fade resistance. A heavier caliper will store more heat and keep brake fluid to a lower temps and resist boiling longer.
Mass of the rotor will play a role. Airflow cooling will certainly be a major factor in disc temperature and cooling. Surface area, vanne design and so on. But it will never cool the disc faster than heat is generated from braking (duh, obvious) and thus does not help much against temperature spikes and subsequent heat treatment while cooling. It will bring the temps down faster between turns.
Don`t compare F1 technology with amateur track applications unless you have a real knowledge of why things are this way in F1. Regulations do not care about what is the best/most efficient ways of going around a track... Did anybody ever wonder WHY they don`t use other disc brake material than carbon ? Why not ceramics? The answer is in the regulations (www.fia.com).
08-20-2005, 05:34 PM
#47
Originally Posted by track brembo
so what the TRACK still faster, stiffer, and look awsom with does big BREMBO gold rotors
08-21-2005, 06:39 AM
#48
Originally Posted by kcobean
The car being heavier will outweigh any aerodynamic advantage acheived by the tracks diffusers and other aero tidbits.
What hapenned to drag being a factor of speed to the power 2 ?
Anyway, the Z "feels" heavier than it is. If we take a look at many other sports car, the Z is pretty much average weight. A few pouds difference for different trim levels doesn't make a big enough difference to notice.
08-21-2005, 08:34 AM
#49
Originally Posted by Kolia
Really ? New physics at work here ?
What hapenned to drag being a factor of speed to the power 2 ?
Anyway, the Z "feels" heavier than it is. If we take a look at many other sports car, the Z is pretty much average weight. A few pouds difference for different trim levels doesn't make a big enough difference to notice.
What hapenned to drag being a factor of speed to the power 2 ?
Anyway, the Z "feels" heavier than it is. If we take a look at many other sports car, the Z is pretty much average weight. A few pouds difference for different trim levels doesn't make a big enough difference to notice.
08-21-2005, 08:45 AM
#50
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Originally Posted by kcobean
Yes, Drag increases the faster you go, but my point is that the better Cd you get with the Z isn't going to give it a performance advantage over a lighter car unless you're talking about constant high speeds, which very few of us actually do. Acceleration on either the 1/4 mile track, the street, and/or a road course is far more affected by unsprung weight than by aerodynamics.
08-21-2005, 08:59 AM
#51
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Originally Posted by Kolia
Really ? New physics at work here ?
What hapenned to drag being a factor of speed to the power 2 ?
Anyway, the Z "feels" heavier than it is. If we take a look at many other sports car, the Z is pretty much average weight. A few pouds difference for different trim levels doesn't make a big enough difference to notice.
What hapenned to drag being a factor of speed to the power 2 ?
Anyway, the Z "feels" heavier than it is. If we take a look at many other sports car, the Z is pretty much average weight. A few pouds difference for different trim levels doesn't make a big enough difference to notice.
true
But when lapping with windows down (required by most schools and +)...
Forget any aerodynamic advantage/differences
on autobahn on 500miles trip it might make a difference
08-21-2005, 09:43 AM
#52
Originally Posted by kcobean
Yes, Drag increases the faster you go, but my point is that the better Cd you get with the Z isn't going to give it a performance advantage over a lighter car unless you're talking about constant high speeds, which very few of us actually do. Acceleration on either the 1/4 mile track, the street, and/or a road course is far more affected by unsprung weight than by aerodynamics.
If we consider only the Z. The weight difference between each trim level is minimal. I don't think it would make any noticeable difference. The diffuser and mini-lip are supposed to lower drag from .30 to .29. They also help on high speed stability. Which matters more for me. (Changing my exhaust pretty much screwed that. I'll have to reproduce the wedge from the OEM silencer to fix that.)
If we compare the Z with the competition well, it's not that heavy. The steering is pretty stiff and gives the illusion of being heavier. Its overall performance level is high enough that, on a full course race track, the driver will make the biggest difference.
08-21-2005, 10:11 AM
#53
Originally Posted by Kolia
A right, I keep forgetting performance is mesured in 1/4 times.
If we consider only the Z. The weight difference between each trim level is minimal. I don't think it would make any noticeable difference.
The diffuser and mini-lip are supposed to lower drag from .30 to .29. They also help on high speed stability. Which matters more for me.
If we compare the Z with the competition well, it's not that heavy. The steering is pretty stiff and gives the illusion of being heavier. Its overall performance level is high enough that, on a full course race track, the driver will make the biggest difference.
08-21-2005, 10:17 AM
#54
Wheee, that was a lot of quote work !
Glad we're on the same side kcobean . I just like to throw different perspective in these conversations.
I'd define high speed as taking a turn at "only" 90 mph. Yeah you're right, not everybody is able or willing to do that.
Cheers !
Glad we're on the same side kcobean . I just like to throw different perspective in these conversations.
I'd define high speed as taking a turn at "only" 90 mph. Yeah you're right, not everybody is able or willing to do that.
Cheers !
08-21-2005, 07:47 PM
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Originally Posted by Kolia
I'd define high speed as taking a turn at "only" 90 mph. Yeah you're right, not everybody is able or willing to do that.Cheers !
If you can, you might have a place as a F1 driver
08-22-2005, 03:10 AM
#57
Originally Posted by Nano
Can you honestly tell the difference between taking a turn at 90mph with the stock muffler+diffuser... and tanabe muffler without diffuser?
If you can, you might have a place as a F1 driver
If you can, you might have a place as a F1 driver
The car does feel a bit different at speed. Wieght loss might be partly responsable also. I might have pictures some where, the Tanabe system leave a huge hole in the underbody !
08-22-2005, 06:07 AM
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Originally Posted by qirex
its all marketing crap...
the Z is fun, but it certainly isnt a great track car...
the Z is fun, but it certainly isnt a great track car...
with a few modifications the Z has ton of potential and can be made into a track beast.
Last edited by Nano; 08-22-2005 at 06:10 AM.
08-23-2005, 02:22 PM
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Alright, so you guys want to know where a bunch of that extra weight comes from on the track...
Well yes it has manual cloth seats... but it has AIRBAGS in both... which weigh more than you think. The track model also has curtain airbags as well... airbags and all the crap to make them work actually weighs a bit. So there's the x-factor that you guys weren't thinking of.... i win
Well yes it has manual cloth seats... but it has AIRBAGS in both... which weigh more than you think. The track model also has curtain airbags as well... airbags and all the crap to make them work actually weighs a bit. So there's the x-factor that you guys weren't thinking of.... i win
