reducing unspung weight
10-09-2012, 06:24 AM
#1
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reducing unspung weight
Reducing un-sprung weight is a great way to improve handling. Lighter wheels help as do PCCB's, which by the way is my first but perhaps out of the budget choice. Short of that mod I would ask are there any iron rotors for the 997 that are lighter than the factory drilled rotors?
The real answer is probably go to PCCBs and gain not only the lighter weight, longer wear but also far less brake dust.
A question for those with PCCB's have any of you had any rotor damage from rocks etc dinging the rotors? Thanks
The real answer is probably go to PCCBs and gain not only the lighter weight, longer wear but also far less brake dust.
A question for those with PCCB's have any of you had any rotor damage from rocks etc dinging the rotors? Thanks
Last edited by f4 plt; 10-09-2012 at 08:04 AM.
10-09-2012, 10:01 AM
#2
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2-Piece Brake rotors from Girodisc seem to be what some of the track guys are using and they also say that these rotors are a cost affective alternative to PCCB's.
http://www.rss.rpmware.com/girodisc/...e/g-58130.aspx
http://www.rss.rpmware.com/girodisc/...e/g-58130.aspx
10-09-2012, 11:40 AM
#3
Three Wheelin'
Sorry, this is a partial hijack - but the initial question was about un-sprung weight and handling. I'm wondering, with all the expertise out there, if better handling is the goal, and reducing un-sprung weight rather expensive, could you also get better handling (at less cost) using some other option (I don't know, which is why I'm asking, like thicker sway bars, better control arms, etc.).
10-09-2012, 12:11 PM
#4
Instructor
Not had any isses with my PCCB's and damage due to rocks.
Stopping power is second to none.
Allows for great trailbraking
No grab and dive of the nose (maybe thats the car)
No brake dust
No squeals (so far)
No rust of the brake rotor.
Only problem is that they are less effective when immediately wet...but that resolves when you burn the water film out of the way and is the same with any brake....just more noticable here as they are such a good brake.
In short, the brakes are phenomenal and, though I used to ba a naysayer and would not have had them on any of my prior 3 porsches, with this one, I'm delighted and I'll never have anything other type of brake if I ever trade this car...which I won't!!!
Stopping power is second to none.
Allows for great trailbraking
No grab and dive of the nose (maybe thats the car)
No brake dust
No squeals (so far)
No rust of the brake rotor.
Only problem is that they are less effective when immediately wet...but that resolves when you burn the water film out of the way and is the same with any brake....just more noticable here as they are such a good brake.
In short, the brakes are phenomenal and, though I used to ba a naysayer and would not have had them on any of my prior 3 porsches, with this one, I'm delighted and I'll never have anything other type of brake if I ever trade this car...which I won't!!!
10-09-2012, 02:35 PM
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How much lighter are PCCBs than say aftermarket 2 piece rotors?
How much does retrofitting PCCBs cost?
The point I would make is that reducing unsprung weight is good stuff, but reducing rotational weight gives a more noticeable improvement. And many people have found that their suspension valving was poorly sprung for dramtically lighter wheel end weights (on other forums, not here that I'm aware of). Do the PCCB cars come w/ different spring rates or shock valving?
Moment of Inertia is a factor of the distance the weight is from the fulcrum. The fact is that losing 10# at the hub makes not nearly the difference that losing say 10# off the barrel of the rim or even running lighter tires makes. Think about this: Sit on a spinning bar stool w/ your legs sticking out and have someone spin you around while taking note of your current speed. Now pull your legs in while spinning and you will instantly and greatly accelerate. This is a perfect example of having the exact same weight overall, but you get more acceleration just by reducing the MoI.
I'm not certain what it costs to retrofit PCCBs, but whatever it is you will feel more performance difference w/ some lightweight forged 18" wheels and by being very selective about your tires actual weight (tire weights available on Tirerack.com under specs).
~ take care
How much does retrofitting PCCBs cost?
The point I would make is that reducing unsprung weight is good stuff, but reducing rotational weight gives a more noticeable improvement. And many people have found that their suspension valving was poorly sprung for dramtically lighter wheel end weights (on other forums, not here that I'm aware of). Do the PCCB cars come w/ different spring rates or shock valving?
Moment of Inertia is a factor of the distance the weight is from the fulcrum. The fact is that losing 10# at the hub makes not nearly the difference that losing say 10# off the barrel of the rim or even running lighter tires makes. Think about this: Sit on a spinning bar stool w/ your legs sticking out and have someone spin you around while taking note of your current speed. Now pull your legs in while spinning and you will instantly and greatly accelerate. This is a perfect example of having the exact same weight overall, but you get more acceleration just by reducing the MoI.
I'm not certain what it costs to retrofit PCCBs, but whatever it is you will feel more performance difference w/ some lightweight forged 18" wheels and by being very selective about your tires actual weight (tire weights available on Tirerack.com under specs).
~ take care
10-09-2012, 04:21 PM
#7
Rennlist Member
Thread Starter
Well after much research and an extended conversation with the lead tech at the local dealership ( he also is a PCA member, tracks his car and is a Porsche Master tech) I have decided to fore go putting PCCB's on my C2S. what i'm going to do is put stainless steel break lines and the GT3 master cylinder on the car. When the rotors wear down I will replace them with lighter gyro disc rotors. I already run lightweight forged wheels so I have reduced some unsprung weight. Next Porsche WILL have PCCB's
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10-09-2012, 04:32 PM
#8
Poseur
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Porsche advertises the PCCBs at 50% of the weight of their iron counterparts.
The only detractor of the PCCBs is the price, however, we're getting a bargain compared to what a Ferrari owner pays for the same brakes--about $22,500.
The reduction of unsprung weight has never been an inexpensive undertaking, but for those who have done it, the pay off is quite remarkable. In a word, it makes the car feel more nimble.
I've never had any issues with stones are anything impacting the rotors that could jeopardize them. Apparently, neither has Porsche since they are starting to put them even on their SUV models which should be encountering that stuff a lot more.
The only detractor of the PCCBs is the price, however, we're getting a bargain compared to what a Ferrari owner pays for the same brakes--about $22,500.
The reduction of unsprung weight has never been an inexpensive undertaking, but for those who have done it, the pay off is quite remarkable. In a word, it makes the car feel more nimble.
I've never had any issues with stones are anything impacting the rotors that could jeopardize them. Apparently, neither has Porsche since they are starting to put them even on their SUV models which should be encountering that stuff a lot more.
