I am thinking of ways of reducing the weight of my 996TT. Ideas that come to mind are:

GT3 seats
Replacing the motorized rear wing with a fixed unit
Aftermarket exhaust (already done - Fabspeed sport)
Light weight Brembo kit from Beastpower (12lbs per corner I believe)
Removing the rear seats
Removing the spare tire
Lighter weight wheels (already ordered, HRE 540Rs)

I'd appreciate the input from anyone/everyone who can give me some insight regarding weight savings of the above. Also, any other ideas for weight savings (excluding Watt's inevitable suggestion, "buy a GT2") would be welcomed.

Thanks in advance,
-Donn

 

You could remove the front driveshaft, diff, and axle shafts.
Sort of an erzatz GT2. It's been done before. Saves over
100 lbs and lots of rotating mass.
Hoosier tires are much lighter than most other tires.
I'll bet several of the CF body parts for the GT3-RS would fit.
remove the air conditioner compressor and condenser.
Lighter-weight battery, maybe mount it where the spare tire
was.

 

Interesting ideas. Thanks Joe. I think the only viable one for my mostly street driven car (in weather that is >100 degrees five months out of the year) is the lower weight battery and CF body parts.

Any ideas how much the battery might save?
What CF body parts are available?

With 640 HP on tap, I'd like to retain the AWD system. Also, the results of the Audi's in Trans Am (and their subsequent banning) many years ago suggest to me that the AWD system works to my advantage (with proper suspension tuning), in spite of what may be a 100 lb weight penalty.

By the way, the drive shaft you can lift with your pinky. It weighs next to nothing. It is definitely < 5 lbs. Not sure how much the front transaxle weighs though.

-Donn

 

Racer, if you´re looking for carbon-fiber parts you should look at the Manthey racing bodykit, pictures of which are posted in one of the earlier threads. It saves 63 kilograms, equivalent to 140 lbs and helps improve the car´s aerodynamics tremendously. Its only downfall is the price - 22.000 EUR.

https://www.6speedonline.com/forums/...&threadid=1613

 

Racer 63, I am looking at the same thing. I am pulling the rear seats, adding a roll bar (oops more weight), considering the brembo brakes but am waiting to make a decision on 19" wheels or not.

What are the weights of your HRE's versus the stock 18" hollow spokes? Are you going to look at different shocks (valving) with the lighter unsprung weight?

I also want ot keep the AWD - sorry to say but it really seams to work well (although no track experience yet).

How much weight does a fixed wing save?

You might look at odyssey or other dry cell batteries for light weight, but definitely lower the damn thing.


Tim

 

gee Donn,

it is an obvious beginning...

but i considered building a TT lightweight. imagine 2600# with 550 HP, Ruf suspension and 4WD. here's what we came up with:


- Spare tire, and trunk junk (-20 lbs.)
- Carbon Fiber Hood from performance products(-25 lbs)
- Recaro Carbon Fiber Seats(-100 lbs.)
- Performance Project V7.0 Exhaust from turbo-exhaust.com(-50lbs)
- Carbon Fiber quarter panels, doors, bumpers, rear wing and sunroof (-250 lbs. I am probably off on this)
- Carbon Fiber interior (-30 lbs.)
- Carbon fiber intake Scargo (-10 lbs.)
- side and rear window in lexan, light front window (-50lbs.)
- Sound proofing, rear seats+hardware light carpets, unnecessary electronics and AC (-100 lbs. Could this be -150lbs.?)
- GT2 carbon brakes from Porsche or brembo (-44 lbs.)-
- light wheels from Fikse or similar(-15 lbs.)
- Light weight battery (-5lbs)
- Personal Diet (-20 lbs.)
-remove interior, airbags, etc ?? 50 lbs???

This adds up roughly to 771 lbs. +/- 50 removed. Of course, then you have to add the roll cage, harnesses, and other safety goodies. i would leave the a/c in myself for street car

this would be a fun car where it rains and snows, a multi surface rally meister

 

Personal diet is often overlooked, good points there watt..

 

Very funny. I weigh 170 and am 6'2. I already look like a friggin scare crow. If I lose any more weight, I'll blow away at many of the winder tracks in the region. Also, totally off topic, but my Tae Kwondo would probably suffer too from any additional weight loss.

-Donn

 

Precisely what I was looking for! Thank you VERY much Watt.

Cheers,
-Donn

 

They are only slightly lighter, 23 rear and 21 front. I'm a little leery of going too much lighter on an 18" wheel. Also, the race rubber should save weight. Not sure how much yet.

Had not though about different valving... Will discuss with Todd.

Historically it has worked very well. Examples include Trans Am in the mid 80s, Australian Touring Car in the mid-to-late 90s, and World Challenge (until this year). The trouble is that the sanctioning bodies seem to ultimately do everything they can to make them equal in performance to the RWD cars. Trans Am was never able to make them equal, forcing them to carry more weight and run skinnier tires. It didn't work, so they were banned.

Not sure. I think Watt's post may have addressed that?

-Donn

 

Hey Watt -

Just noticed that you did not specifically break out the weight savings for various body panels. Do you have that by chance? Specifically, as Tim asked, what's the weight savings of the fixed (say fiberglass or CF) wing vs. the stock, mechanically actuated wing?

 

racer - just saw you r getting brembos in your sig...which ones??

 

i do not.

stopped my research project, which i did after i sold my first, slower, seal grey gt2 to a beginner driver, Josh, the busman, ofstein, and you'd never figure this out -- decided to buy another GT2 . i investigated building a 3.8 RSR clone as well.

but i realised a gt2 is almost my perfect hotrod from factory... and bought another... Sorry, but it's TRUE!!!!!

PS. if this is a street car, one of my english gt2 buddies strongly advises against carbon panels. he has seen a carbon bonnet --shot as a lethal projectile -- right thru the windshield like a plank, not crumpling like steel in a major shunt...

so you do denigrate numerous saftey issues... not so bad at slower speeds... but since i started road racing, i'm into steel and airbags and anything that might incrementally improve my chances.

 

They are the titanium, racing inspired units. For 18" wheels (so I can run the race rubber).

-Donn

 

I agree. That's why I was hoping to see what the weight savings from the rear spoiler alone was. Not so sure I want to run a street car, with no cage, and only CF body panels.