Of Curb Weights and why this car will not weigh under 2600lbs

[Sony]

Originally Posted by chulooz

Unless you are moving the engine over 6" you may as well just skip a meal and drinks to save the same amount of weight.

Even a foot or more... a 3" diameter driveshaft like what is found on this car weighs what? maybe 2 or 3lbs per foot? Bet you the shaft weighs about 20lbs total, if that. If you replace the driveshaft with CF that's one thing...reducing 15 lbs I can see being significant. However you could take a dump before you race and reduce the weight more than you would by cutting a foot off your stock OEM driveshaft. The change in weight distribution would affect the cars handling far more than the drop in weight.

[serialk11r]

Sorry for interrupting the intense conversation, but typically what body panels can you switch out? And is fiberglass or something like that usually available as a cheaper alternative to carbon fiber?

[Sony]

Originally Posted by serialk11r

Sorry for interrupting the intense conversation, but typically what body panels can you switch out? And is fiberglass or something like that usually available as a cheaper alternative to carbon fiber?

Yes, usually fiberglass is cheaper than CF and can be found more readily. Usually the hood, roof, trunk lid and quarter panels can be switched out to lighter materials. Typically you don't want to replace the doors with lighter weight materials unless you are adding rigid crash bars as part of your roll cage behind the door panel...otherwise you would be pretty boned in a crash.

[Sully]

CF driveshaft is especially useful because it's less rotating mass. Changing the curb weight isn't really the goal, a more robust/responsive engine is.

Driveshafts are pretty light anyway.

[Matador]

Originally Posted by Sully

CF driveshaft is especially useful because it's less rotating mass. Changing the curb weight isn't really the goal, a more robust/responsive engine is.

Driveshafts are pretty light anyway.

Maybe on newer cars...........

[tripjammer]

Originally Posted by Sully

CF driveshaft is especially useful because it's less rotating mass. Changing the curb weight isn't really the goal, a more robust/responsive engine is.

Driveshafts are pretty light anyway.

This car might have a CF reinforced plastic Drive shaft...the 350z/370z has one...so does the LFA...and other cars...its not too expensive for them to include it in the FT-86.

2700 pounds is light enough for a loaded FR 2+2....

And just think they are not even using aluminum suspension components...well they might we just don't really know yet until there is a breakdown of the components. Pictures don't tell us crap.

[Gardus@Supersprint]

It's almost pointless to change components with carbofiber items aside from the hood (and the boot, but less so, as some weight in the back can help to put the power down), which in a car with a mid/front mounted engine can be heavy if it's not alumium.
The roof is more complicated but as it's on top you get less pitch and rollif it's lighter...BMW M3s and M6s have a carbonfibre roof for this reason..Some Lancer Evos have an alluminium roof.


Instead fitting ligher, non suspended parts, like the wheels, can do miracles both on the performance but also on the handling.
Some very light but strong wheel, like the OZ Alleggerita, can reduce the total wheel weight by 3-4 X4 kg= 12/16 kg and that's A LOT both for the flywheel effect and for the supension control.

The driveshafts have some flywheel effect but this effect is directly proportional to the distance between the weight and the centre of rotation, so even it weights as much as a wheel or two, the total effect it's much lower.

The flywheel itself is larger in diameter so if you change it with a lighter one you'll feel the effect much more.

Lexan or thinner glass windows can help, light seats even more.
Usually on a medium road car you can get 80 kg froma "mild diet" of carbon fibre and glassfibre components, fixed seats, lighter wheels, less sound proofing and maybe the removal of the rear seats (which I don't like)

[Sully]

Originally Posted by MatadorRacing_F1

Maybe on newer cars...........

I only have experience with newer cars.

edit: I'm only considering sport-y cars here, really. Not trucks, or RWD luxury yachts, obviously. I mean, if it's a 4,000 lb car or a truck with a 20,000 lb towing capacity, or rock crawler with gobs and gobs of torque with insane gearing? Yeah, the driveshaft is a bit porky-and for good reason!

[Dave-ROR]

With an aluminum hood it's basically pointless to switch except for this who like the cf look.

Oz alles aren't that light. 3-4kg = 6.6-8.8lbs per wheel even with the extremely overweight stock 20lb wheels you won't see that loss with one of those wheels. 2kg is more like it (1-1.5kg loss for most stock 17s on other cars). Some forged wheels you MIGHT see 3kg or slightly more though.

And then there's always that testing that has shown heavier wheels to be faster due to the reduced strength of lightweight wheels but that testing hasn't been anywhere near in depth enough yet.

[Matador]

Originally Posted by Sully

I only have experience with newer cars.

edit: I'm only considering sport-y cars here, really. Not trucks, or RWD luxury yachts, obviously. I mean, if it's a 4,000 lb car or a truck with a 20,000 lb towing capacity, or rock crawler with gobs and gobs of torque with insane gearing? Yeah, the driveshaft is a bit porky-and for good reason!

No. This is why there is a market for aftermarket drive shafts. S12-15s, Supras, GT4 Celicas and the list goes on.

[chulooz]

Originally Posted by Dave-ROR

With an aluminum hood it's basically pointless to switch except for this who like the cf look.

Oz alles aren't that light. 3-4kg = 6.6-8.8lbs per wheel even with the extremely overweight stock 20lb wheels you won't see that loss with one of those wheels. 2kg is more like it (1-1.5kg loss for most stock 17s on other cars). Some forged wheels you MIGHT see 3kg or slightly more though.

And then there's always that testing that has shown heavier wheels to be faster due to the reduced strength of lightweight wheels but that testing hasn't been anywhere near in depth enough yet.

If you are going to be saving 8lbs per wheel for a total loss of 32lbs you are doing great. That is unsprung AND rotational mass, it will certainly be a noticeable difference.


Testing that has shown heavier wheels to be faster???

[Dave-ROR]

Originally Posted by chulooz

If you are going to be saving 8lbs per wheel for a total loss of 32lbs you are doing great. That is unsprung AND rotational mass, it will certainly be a noticeable difference.


Testing that has shown heavier wheels to be faster???

I wasn't saying 8lbs. I was saying the wheels he mentioned will say about 2kg not 4. It was a correction to his post. I agree that 8lbs is huge and noticeable.

As for the testing I'll find the links and post when I'm back at a computer and not using my phone. Grassroots did some I believe as did others. I'm mentioned this testing before and also that IMO the testing isn't was flawed but it's worth considering. The main thing was strength the lighter wheels flexed more wasting energy and in some cases the extra force of the heavier wheels inertia could potentially be helpful to a low powered car. Anyways I'm not convinced its accurate myself based on the limited testing.

[fatoni]

Originally Posted by Dave-ROR

I wasn't saying 8lbs. I was saying the wheels he mentioned will say about 2kg not 4. It was a correction to his post. I agree that 8lbs is huge and noticeable.

As for the testing I'll find the links and post when I'm back at a computer and not using my phone. Grassroots did some I believe as did others. I'm mentioned this testing before and also that IMO the testing isn't was flawed but it's worth considering. The main thing was strength the lighter wheels flexed more wasting energy and in some cases the extra force of the heavier wheels inertia could potentially be helpful to a low powered car. Anyways I'm not convinced its accurate myself based on the limited testing.

looking forward to those links because that kinda sounds like nonsense. i mean width vs weight yeah but just weight difference? crazy

[Dave-ROR]

Ill find them tonight when I get home.

And that post had a typo I mean that I believe that the testing was flawed not "isn't was flawed"...