NJ-GT

I think it's helpful to post the weight of several components.

I'm quite impressed with the work Porsche has done to reduce the weight on the GT3 RS, but I have no idea why the car is heavier than the 996 GT3. It is heavier on the scales, and it feels heavier.

- Stock Hood on Aluminum (996 GT3 has a steel hood): 17.60 lbs
- Sock Doors on Aluminum (996 GT3 has a steel doors): 24.40 lbs

The rear deck lid is made of plastic. Hood, doors and rear deck lid feel much lighter than my 996 GT3.

- BBS 1 piece Mg wheels (9"): 16 lbs
- BBS 1 piece Mg wheels (11"): 17.5 lbs

These wheels will be used for autoX and Time Trials, while the stock ones will be used for DE, and an incoming set for PS2 street tires.

- MPSC 265/30R19: 23 lbs
- Front wheels: 24 lbs each (including TPMS sensor).
- MPSC 325/30R19: 28 lbs
- Rear wheels: 31.5 lbs each (including TPMS sensor).

Weight saving on the wheels: -44 lbs

I just finished the front axle brakes swap. Removed the RS29 and installed the stock Pagid yellow P90. I installed the PCCB rotors from my 996 GT3, I still have to do the rear ones.

Iron Front Rotor: 27 lbs each
996 PCCB Front Rotor: 12 lbs each.

Front axles Weight saved on PCCB: 30 lbs

CWay27

Are you going to strip its interior like you did on the 996??

BTW it's the first time I ear of someone removing steel brakes for ceramics, usually it's the other way around.

gtdrei

Changing seats would be a logical major weight loss. What do the stock sport seats weigh ?

NJ-GT

No idea yet, I'm waiting for the 997 GT2 seats to arrive. Porsche did not ship them due to a special UPS code used to transport the explosive airbags they come with. I told them "send the seats without airbags, I want the seats not the airbags".

The torax airbags in those seats are going out anyway, I have enough extra weight with 4 airbags already, I don't want six.

I will post the weights when I swap them later next week.

Additional Information:

Rear Cast Iron Rotor (OEM 350mm): 22 lbs
Rear PCCB Rotor (996 GT3): 12 lbs

Rear axle Weight saved on PCCB: 20 lbs

Total weight saving from switching to 996 GT3 PCCB: 50 lbs

Rear Center Muffler (no tips): 19.5 lbs
Sharkwerks bypass pipes (no tips): 4 lbs

Stock Battery: 35 lbs
Braille 2015: 15 lbs. 21 Ah (compared to 35 Ah for an Optima Red Top). I chose a heavier one this time. BrailleAuto has 11.5 lbs, and 6 lbs batteries.

Toolkit: 8.5 lbs

Trunk liners: Not worth it to have it removed, a total hassle for less than 8 lbs most likely. There is a heavy electronic box in the trunk, on the passenger's side. It is not an amplifier, no idea what it is.

dwishen

Does this mean that the 997 cars have front, side (i.e., in the doors), and thorax airbags? If this is the case, if you swap seats, will the front and side/door airbags still work? I've been wondering that...

Thanks

NJ-GT

Yes, 6 airbags, annoying.

The torax airbags can be disabled via PIWIS. A few folks switching to 996 GT3 Recaro seats have done it.

dwishen

Very interesting news to me. I've been concerned about that, as I like the idea of side airbags for the street, in case I put it into a tree or pole.

Don't have one yet, but this has been playing into my decision, as I would want to swap seats.

Thanks

GT2Driver

NJ-GT,

The weight of a 997 GT2 seat is 23 lbs and the undercarrige 10 lbs.

NJ-GT

- Front Stock Sway bar: 7 lbs, part# 997.343.701.91, 27mm of diameter
- Front GMG Sway bar: 9 lbs, 28.5mm of diameter

- Rear Stock Sway bar: 6 lbs, part# 997.333.701.02, 24mm of diameter.
- Rear GMG Sway bar: 8 lbs, 25.5mm of diameter


Rear upper control arms: 0.75 lbs each (2 per side)
Rear monoball upper control arms: 1.5 lbs each (2 per side)

We can confirm that the 997 GT3 RS and 996 GT3 RS have the same spring rates at the front axle. The part# is the same on both, my old car and Mooty's car: 996.343.531.95

So, the front springs are 225 lbs/in linear (40N/mm).

Installing a front sway bar is the biggest pain, the subframe, steering rack, power steering box, coolant lines, they all have to come down.

997gt3north

Interesting
- the 997gt2 bar is 25.5mm
- the factory's "information" about the gt2 bar is that it is 30% stiffer
- obviously the bars are different but the quoted stiffness numbers don't seem to match
- if the factory information is correct, not sure you would need a stiffer front bar

Yargk

The stiffness of a sway bar is not linearly proportional to its diameter. In fact I believe it goes by the 4th power.

So...

25.5/24 = 1.0625

(1.0625)^4 = 1.2744293212890625

Therefore it's 27.5 % stiffer. I guess the factory rounded up.

NJ-GT

GMG claims 30%-80% stiffness increase over the stock bar. However, I find it difficult to gain 80% stiffness just by increasing 1.5mm on diameter. I put the GMG front bar because the rear bar was too stiff (per advertisement), and GMG sells them as a kit.

I will be testing this Sunday at an autoX. If I experience the same push, I would need to make some phone calls.

Anyway, I spoke to Ira (Tarrett Eng) this week, and as soon as he has a prototype ready for the rear blade style bar, I will go for it. I don't like the resolution of the rear bar, just three holes and a wider range.

OldGuy

I am guessing most of the weight problems come from ever changing safety regulations and Porsche struggling to meet those while cutting weight. They get rid of 40lbs and then the govt requires a heavier bumper etc.

997gt3north

i know the calcs - i just round 27 to 30

C.J. Ichiban

get in line for tarret blades, mine should be here in 2 weeks.