911R Weight Reduction
02-27-2020, 01:34 PM
#496
Addict
Rennlist Member
Rennlist Member
02-27-2020, 09:23 PM
#498
Thank you but I have never done anything for publicity. Truthfully, I am surprised that I have continued to post on Rennlist (as I am sure you know, I do not post on Facebook, Instagram, etc.). I have continued to so do because it has seemed that people are interested. As to magazines, although, without use of my name, certain cars I have have appeared upon occasion, it is certainly nothing I seek. What I do, with some examples, though candidly not the best examples, appearing in this thread, is done not for show or notoriety but simply to improve the particular vehicle. And, to be sure, in all that I do or have ever tried to do in the various areas of life through which I walk, the guiding principle has always been and will always be to do the best that can be done and that anything less is simply not acceptable. A friend, a retired United States Army Four Star General, often talks about "what right looks like" and I believe one should do right and, if you do, the results look the part.
I've always wanted to see what the facility you operate out of looks like.
02-27-2020, 10:58 PM
#499
Rennlist Member
This thread goes beyond Porsches. Engineering, design, functionality, materials, experimentation, innovation. Speaks dearly to my heart, and my passion for engineering when I entered college. Plus...Porsche. Thanks for keeping us in the loop Bob.
02-28-2020, 12:04 AM
#500
Rennlist Member
That sounds fantastic. I would have preferred a manual car, but have a left leg injury that keeps me in a PDK.
Would be very interested in your top two "bang for the buck" recommendations for further weight loss in a PDK 991 GT3 that was otherwise built at light as possible with LWB, PCCB, radio delete and already had the 3 standard aftermarket weight modifications (lithium battery, mag wheels, side muffler delete) .
02-28-2020, 09:25 AM
#501
After lightweight battery, exhaust system, magnesium (or carbon) wheels and composite brake discs with aluminum bells (hats), other than occasional big wins such as a carbon fiber chassis, carbon fiber body panels or a carbon clutch, which, by themselves, for high quality components, are very expensive, the process of weight reduction is pound by pound, sometimes even gram by gram. In other words, to truly reduce significant amounts of weight is very time consuming, engineering intensive and horribly expensive (e.g., in F1, the cost of weight reduction, particularly at the margin, can exceed $50,000 per pound), and, generally, the cost for every incremental pound is higher than the previous pound. Though I suspect I could generate a many, many page list of things to target for weight reduction, the truth is that, after the four items mentioned above, unless you reduce the weight of your car by at least 50, preferably 100 pounds, other than perhaps in your mind, you will not feel it when driving nor will it have any substantial effect upon how the car handles. And, given how well a GT car is engineered by Porsche (thank you Dipl. Ing. Preuninger and team), the cost of reducing from 50 pounds to 100 plus pounds on a one-off basis (i.e., unlike Porsche, that can amortize research, development, engineering, tooling, etc. costs over thousands of cars and can drive finished parts costs down by volume purchasing) could be several hundred thousand dollars to almost $1,000,000. In short, after battery, exhaust, lightweight wheel, composite brake discs, do not enter the slippery slope unless you are prepared to ride it to the finish.
The following 4 users liked this post by Robert Linton:
03-03-2020, 08:04 AM
#503
By composite brake discs I meant either PCCB or Brembo CCM-R which, if available in the size you desire, might be lighter than PCCB (and are claimed to offer better performance) and the 6082 T6 aluminum brake "hats" (bells) that come with PCCB.
03-04-2020, 11:28 AM
#504
After lightweight battery, exhaust system, magnesium (or carbon) wheels and composite brake discs with aluminum bells (hats), other than occasional big wins such as a carbon fiber chassis, carbon fiber body panels or a carbon clutch, which, by themselves, for high quality components, are very expensive, the process of weight reduction is pound by pound, sometimes even gram by gram. In other words, to truly reduce significant amounts of weight is very time consuming, engineering intensive and horribly expensive (e.g., in F1, the cost of weight reduction, particularly at the margin, can exceed $50,000 per pound), and, generally, the cost for every incremental pound is higher than the previous pound. Though I suspect I could generate a many, many page list of things to target for weight reduction, the truth is that, after the four items mentioned above, unless you reduce the weight of your car by at least 50, preferably 100 pounds, other than perhaps in your mind, you will not feel it when driving nor will it have any substantial effect upon how the car handles. And, given how well a GT car is engineered by Porsche (thank you Dipl. Ing. Preuninger and team), the cost of reducing from 50 pounds to 100 plus pounds on a one-off basis (i.e., unlike Porsche, that can amortize research, development, engineering, tooling, etc. costs over thousands of cars and can drive finished parts costs down by volume purchasing) could be several hundred thousand dollars to almost $1,000,000. In short, after battery, exhaust, lightweight wheel, composite brake discs, do not enter the slippery slope unless you are prepared to ride it to the finish.
much appreciated, Brian
03-04-2020, 05:36 PM
#505
Brian:
First, in truth, even if you change to a lithium battery, a lightweight exhaust, PCCB and magnesium or aluminum wheels (the "Four"), the weight savings is barely enough for you to feel the difference (except, of course, in your mind and in your bank account). As such, if the Four are the only weight reduction modifications that you will do to your car, then the extra money for BBS Magnesium Wheels over BBS Aluminum Wheels for an additional approximately six pound weight (albeit rotating weight) saving cannot, rationally, be justified. Of course, I would argue that, even together, the Four cannot be truly justified vis-vis real (vs. imagined) performance. In other words, save your money and simply enjoy the car. On the other hand, many people make these and other modifications not because of performance but because, often under the guise of performance, (a) they simply like doing it, (2) want to, verbally or on forums such as Rennlist, show (i.e., at Cars and Coffee) and/or tell others what they have done, (3) post pictures on Instagram, Facebook, etc. and/or (4) are sold into doing it by a shop and/or a manufacturer. On the other hand, if the weight reduction is about achieving real gains in performance, you will have to go after many, many more weight reduction targets and this will be very time consuming and very expensive (particularly because, in most instances, each incremental pound of weight saving will cost more, in some cases, very significantly more, than the previous pound of weight reduction) -- and, if the goal is substantial weight reduction, then that approximately six pound reduction for approximately $11,000 additional is reasonable as there are few big wins after the Four. But, I say again, do none of it and enjoy the car.
First, in truth, even if you change to a lithium battery, a lightweight exhaust, PCCB and magnesium or aluminum wheels (the "Four"), the weight savings is barely enough for you to feel the difference (except, of course, in your mind and in your bank account). As such, if the Four are the only weight reduction modifications that you will do to your car, then the extra money for BBS Magnesium Wheels over BBS Aluminum Wheels for an additional approximately six pound weight (albeit rotating weight) saving cannot, rationally, be justified. Of course, I would argue that, even together, the Four cannot be truly justified vis-vis real (vs. imagined) performance. In other words, save your money and simply enjoy the car. On the other hand, many people make these and other modifications not because of performance but because, often under the guise of performance, (a) they simply like doing it, (2) want to, verbally or on forums such as Rennlist, show (i.e., at Cars and Coffee) and/or tell others what they have done, (3) post pictures on Instagram, Facebook, etc. and/or (4) are sold into doing it by a shop and/or a manufacturer. On the other hand, if the weight reduction is about achieving real gains in performance, you will have to go after many, many more weight reduction targets and this will be very time consuming and very expensive (particularly because, in most instances, each incremental pound of weight saving will cost more, in some cases, very significantly more, than the previous pound of weight reduction) -- and, if the goal is substantial weight reduction, then that approximately six pound reduction for approximately $11,000 additional is reasonable as there are few big wins after the Four. But, I say again, do none of it and enjoy the car.
The following 2 users liked this post by Robert Linton:
911Jetta (03-09-2020),
ForeverCar (03-04-2020)
03-04-2020, 07:13 PM
#506
Brian:
First, in truth, even if you change to a lithium battery, a lightweight exhaust, PCCB and magnesium or aluminum wheels (the "Four"), the weight savings is barely enough for you to feel the difference (except, of course, in your mind and in your bank account). As such, if the Four are the only weight reduction modifications that you will do to your car, then the extra money for BBS Magnesium Wheels over BBS Aluminum Wheels for an additional approximately six pound weight (albeit rotating weight) saving cannot, rationally, be justified. Of course, I would argue that, even together, the Four cannot be truly justified vis-vis real (vs. imagined) performance. In other words, save your money and simply enjoy the car. On the other hand, many people make these and other modifications not because of performance but because, often under the guise of performance, (a) they simply like doing it, (2) want to, verbally or on forums such as Rennlist, show (i.e., at Cars and Coffee) and/or tell others what they have done, (3) post pictures on Instagram, Facebook, etc. and/or (4) are sold into doing it by a shop and/or a manufacturer. On the other hand, if the weight reduction is about achieving real gains in performance, you will have to go after many, many more weight reduction targets and this will be very time consuming and very expensive (particularly because, in most instances, each incremental pound of weight saving will cost more, in some cases, very significantly more, than the previous pound of weight reduction) -- and, if the goal is substantial weight reduction, then that approximately six pound reduction for approximately $11,000 additional is reasonable as there are few big wins after the Four. But, I say again, do none of it and enjoy the car.
First, in truth, even if you change to a lithium battery, a lightweight exhaust, PCCB and magnesium or aluminum wheels (the "Four"), the weight savings is barely enough for you to feel the difference (except, of course, in your mind and in your bank account). As such, if the Four are the only weight reduction modifications that you will do to your car, then the extra money for BBS Magnesium Wheels over BBS Aluminum Wheels for an additional approximately six pound weight (albeit rotating weight) saving cannot, rationally, be justified. Of course, I would argue that, even together, the Four cannot be truly justified vis-vis real (vs. imagined) performance. In other words, save your money and simply enjoy the car. On the other hand, many people make these and other modifications not because of performance but because, often under the guise of performance, (a) they simply like doing it, (2) want to, verbally or on forums such as Rennlist, show (i.e., at Cars and Coffee) and/or tell others what they have done, (3) post pictures on Instagram, Facebook, etc. and/or (4) are sold into doing it by a shop and/or a manufacturer. On the other hand, if the weight reduction is about achieving real gains in performance, you will have to go after many, many more weight reduction targets and this will be very time consuming and very expensive (particularly because, in most instances, each incremental pound of weight saving will cost more, in some cases, very significantly more, than the previous pound of weight reduction) -- and, if the goal is substantial weight reduction, then that approximately six pound reduction for approximately $11,000 additional is reasonable as there are few big wins after the Four. But, I say again, do none of it and enjoy the car.
03-05-2020, 02:43 PM
#507
One of my favorite threads on Rennlist. Thank you for sharing, Robert. More of a general question, but when adding up weight reduction, do you simply subtract the weight savings of a rotating or unsprung piece as told by the number on a scale? Or do you multiply by a factor (some use 4 for example on rotating items)? Assuming it's the former but would love to hear your thoughts.
03-08-2020, 04:49 PM
#508
There are various theories, opinions and complex formulas about rotating and/or unsprung weight, but. as a conservative rule, I would use 1:1 with but a few possible exceptions: (1) for axle weight savings, I would multiply actual savings by 1.2; (ii) for wheel savings, I would multiply actual savings by 1.6; and for, e.g., a carbon clutch, I would multiply actual savings by 1.5. One could argue for more or less, and one could add other items but I would leave these at 1:1 and know that you have a bit of margin.
