928 GTS Weight Savings Significant
11-21-2010, 10:23 AM
#1
Rennlist Member
Thread Starter
928 GTS Weight Savings Significant
While the GTS is in for paint and many items being deleted earlier & in the process of being deleted, it has come to my attention that the weight savings are really becoming significant for this street based GTS. I pulled a lot of these weights off of Rennlist from most of the racers. A lot of these parts were placed on bathroom scales for all to see, so appear to be fairly accurate. Again, I am going to say approximate, so go easy. Electric front seats replaced with manual, GT3 seats: approx: 40lbs, rear bumperettes, rear A/C delete, front headlight washers, door locks, rub strips, rear windshield motor & wiper arm, side marker lights, etc: approx 21lbs, spare tire, jack, compressor and tools: approx 37 lbs, rear muffler delete: approx 30 lbs, OEM Sound deadening material replaced by newer, lighter weight sound deadening material: approx 30lbs, sunroof delete along with sunroof motor delete: approx 10lbs, air pump delete. This looks like a weight savings of approx 190 lbs. T
Last edited by 77tony; 04-16-2019 at 03:45 PM.
11-21-2010, 02:14 PM
#4
I think there will only be 20 kgs in the engine weight department. Be careful of how things are weighed. That is with or without fluids with without manifolds etc. Porsche stuff normally includes fluids and manifolds.
11-21-2010, 02:27 PM
#5
Nordschleife Master
I think you are quite high on some of the other delete items though Tony. You are probably even on the rear seat delete and then putting your box in. The Rotor difference is minimal. Front seats did save you quite a bit of weight I would guess! Light weight wheels might save you some weight, but if you are bumping up to 18" from the stock 17" you are gaining that weight back...the stock wheels are not all that heavy.
Anyway, it would have been really interesting to have put it on the scales before you touched it and then at various time throughout this process. But in the end you will weigh it and it will be cool to see how the real, final deal compares to factory numbers.
11-21-2010, 02:40 PM
#6
Archive Gatekeeper
Rennlist Member
Rennlist Member
T, when you're done and the suspension is settled, make sure to get a good alignment and corner balance done, so that A) you get a real number for the weight savings, and B) 100-150 lbs off the nose will affect the F/R weight bias.
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11-21-2010, 03:10 PM
#8
Archive Gatekeeper
Rennlist Member
Rennlist Member
I saved 11X pounds by building a car that my wife won't drive or ride in! 
11-21-2010, 03:41 PM
#11
Rennlist Member
200lbs for an engine switch? is this true? sounds a little extreme
as far as the wheel weights, that I KNOW is a trade off going from 17s to 18s. (no weight savings or losses for near equal quality rims) remember, what you gain in weight in rim weight center being a little larger, you remove tire material, as rubber is a little heavier than aluminum.
In other words, my hoosier 17" wheel and tire package weighed near the same as the hoosier 18" wheel package.
as far as the wheel weights, that I KNOW is a trade off going from 17s to 18s. (no weight savings or losses for near equal quality rims) remember, what you gain in weight in rim weight center being a little larger, you remove tire material, as rubber is a little heavier than aluminum.
In other words, my hoosier 17" wheel and tire package weighed near the same as the hoosier 18" wheel package. Paul, maybe you missed that last line... He is getting rid of the WHOLE 5.4L Porsche engine man! Air pump nothing...he is going to drop nearly 200# by going with a SBC! Greg the weight difference between an SBC and a Porsche engine is HUGE man! I saw a guy here in Austin pull his 4.5L and put in a bored 383 (thus 406) and his car sat nearly 3" to high! It was UNREAL! I think he cut 1.5 spring turns off to get the car down to a normal looking ride height. Then of course it was to stiff (and still a bit high).
I think you are quite high on some of the other delete items though Tony. You are probably even on the rear seat delete and then putting your box in. The Rotor difference is minimal. Front seats did save you quite a bit of weight I would guess! Light weight wheels might save you some weight, but if you are bumping up to 18" from the stock 17" you are gaining that weight back...the stock wheels are not all that heavy.
Anyway, it would have been really interesting to have put it on the scales before you touched it and then at various time throughout this process. But in the end you will weigh it and it will be cool to see how the real, final deal compares to factory numbers.
I think you are quite high on some of the other delete items though Tony. You are probably even on the rear seat delete and then putting your box in. The Rotor difference is minimal. Front seats did save you quite a bit of weight I would guess! Light weight wheels might save you some weight, but if you are bumping up to 18" from the stock 17" you are gaining that weight back...the stock wheels are not all that heavy.
Anyway, it would have been really interesting to have put it on the scales before you touched it and then at various time throughout this process. But in the end you will weigh it and it will be cool to see how the real, final deal compares to factory numbers.
11-21-2010, 03:47 PM
#12
Rennlist Member
I think you are being very optimistic of the weight savings. front bumpers and rear bumpers were thought to be around 50lbs, end up being near 20.
ac pumps, windshield wiper motors, etc etc, all look heavy, but in actuality, they are not that heavy. what saves the weight is just a X-load of these little things being removed. my racer that has amost everything that can be removed, removed, and 100lbs of cage welded back in, went from 3500lbs (stock) to 2800lbs. but, thats EVERYTHING. its the same for most all 928s. Lightweight starter, and all sort of chassis cut outs (ie battery box removal) lexan windows, etc etc.
ac pumps, windshield wiper motors, etc etc, all look heavy, but in actuality, they are not that heavy. what saves the weight is just a X-load of these little things being removed. my racer that has amost everything that can be removed, removed, and 100lbs of cage welded back in, went from 3500lbs (stock) to 2800lbs. but, thats EVERYTHING. its the same for most all 928s. Lightweight starter, and all sort of chassis cut outs (ie battery box removal) lexan windows, etc etc.
While the GTS is in for paint and many items being deleted earlier & in the process of being deleted, it has come to my attention that the weight savings are really becoming significant for this street based GTS. I pulled a lot of these weights off of Rennlist from most of the racers. A lot of these parts were placed on batroom scales for all to see, so appear to be fairly accurate. Again, I am going to say approximate, so go easy. Electric front seats replaced with manual, lightweight street/racing type seats: approx: 50lbs, rear A/C and rear seat delete: approx 30 lbs, (with the new, custom built rear seat delete cabinet weight added back in):30lbs, rear bumperettes, front headlight washers, door locks, rub strips, rear windshield motor & wiper arm, side marker lights, etc: approx 30lbs, Fikse Lightweight racing rims and Zimmerman drilled rotors: appros 20 lbs, spare tire, jack and tools: approx 30 lbs, rear muffler delete: approx 30 lbs, OEM Sound deadening material replaced by newer, lighter weight sound deadening material: approx 20lbs, sunroof & sunroof motor delete: approx 20lbs, Optima Dry cell battery: approx 38 lbs. This looks like a weight savings of approx 268 lb to this point in time. If we do decide to install the LS376/480hp aluminum block & heads motor, that will save another 160lbs for a total weight savings of approx 428lbs!! Lets go! T
11-21-2010, 04:01 PM
#13
Nordschleife Master
im curious about the optima dry cell
38lbs is huge there
From past experience, optima didnt have a battery that fit the 928's compartment and allowed for the door to close fully. Can you be more specific about this battery that you used? I had to think that the original batter is not much more than 40-45lbs, ive never weighed it but im curious about this optima dry cell.
38lbs is huge there
From past experience, optima didnt have a battery that fit the 928's compartment and allowed for the door to close fully. Can you be more specific about this battery that you used? I had to think that the original batter is not much more than 40-45lbs, ive never weighed it but im curious about this optima dry cell.
11-21-2010, 04:24 PM
#14
Rennlist Member
Thread Starter
Front & rear bumpers, are staying put, who said anything about front & rear bumper weights? Not removing the bumpers, but will be swapping out the GTS rear bumper for a S4 bumper-no difference in weight there. This is a street car, not a track car. James M stated 160lbs less for the LS3, not 200. I went to O'Reillys today and they had Optima batteries that did not feel very light to me. My guy at O'Reillys asked me to get the part # so we can order these lightweight dry cell batteries? T
11-21-2010, 04:28 PM
#15
Archive Gatekeeper
Rennlist Member
Rennlist Member
I think he meant that the Optima battery itself weighs 38 pounds. I'll weigh a group 48 battery tonight just for fun, my guess is ~50 lbs.
FWIW, I'm not seeing where his mods are going to bring anywhere near 268 lbs savings:
Corbeaus website says A4's are 26 lbs each, either in normal or wide. So big savings over the 118lbs that a pair of 12-way and 8 way, heated GTS seats weighs
Between the double DIN brick, amps, subwoofer magnets and all the wood framing etc, no way are you saving weight over stock rear seats and the rear A/C.
A set of 4 GTS Zimmerman drilled rotors weigh 68 lbs 8 oz, dunno what the solid factory units weigh but I doubt it's more than 72 or so.
The rear wiper motor assembly is 3 lbs exactly, and the wiper arm and blade is 14 oz.
GTS spare tire is 27 lbs 4 oz, so that's a real savings. (EDIT: a 16" spare is 29 lbs 7 oz)
Tool panel with a full set of tools = 5lbs 2 oz
Porsche air compressor in its box = 5 lbs 7 oz
I'd love to know what the real weight savings on the sunroof delete is, I have a non-sunroof panel, cross braces, headliner, and sound deadener, will get their weights.
But the only # that really matters is how much less than 3505 the finished car weighs with a 1/2 tank of gas.
FWIW, I'm not seeing where his mods are going to bring anywhere near 268 lbs savings:
Corbeaus website says A4's are 26 lbs each, either in normal or wide. So big savings over the 118lbs that a pair of 12-way and 8 way, heated GTS seats weighs
Between the double DIN brick, amps, subwoofer magnets and all the wood framing etc, no way are you saving weight over stock rear seats and the rear A/C.
A set of 4 GTS Zimmerman drilled rotors weigh 68 lbs 8 oz, dunno what the solid factory units weigh but I doubt it's more than 72 or so.
The rear wiper motor assembly is 3 lbs exactly, and the wiper arm and blade is 14 oz.
GTS spare tire is 27 lbs 4 oz, so that's a real savings. (EDIT: a 16" spare is 29 lbs 7 oz)
Tool panel with a full set of tools = 5lbs 2 oz
Porsche air compressor in its box = 5 lbs 7 oz
I'd love to know what the real weight savings on the sunroof delete is, I have a non-sunroof panel, cross braces, headliner, and sound deadener, will get their weights.
But the only # that really matters is how much less than 3505 the finished car weighs with a 1/2 tank of gas.
Last edited by Rob Edwards; 11-22-2010 at 02:25 AM.