flyweight...

[Colleton]

Wait. Carbon fiber roof? Seriously?

Let me cut out one of the most important structures of the car, replace it with a fancy fiberglass, bolt it in and put up with more noise and vibration and chassis flex to save maybe 10 lbs? If you're going to spend that kind if cash for ounces (ok that's a little exaggerated), just buy a body in white and build your own car.

People, be realistic. Glad to see more intelligent people are chiming in with very realistic weight loss ideas.

The structural strength of the roof lies entirely in the frame. The roof itself is a thin piece of sheet metal that provides little, if any, structural integrity. That's why the glass roof cars are actually stronger than the metal roof cars, the glass is thicker and stiffer than the sheet metal. It adds ~ 28lbs to the weight of the car though.

JMO, but I don't see how anyone will save any weight by replacing the roof panel.

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[SVTFreak]

The structural strength of the roof lies entirely in the frame. The roof itself is a thin piece of sheet metal that provides little, if any, structural integrity. That's why the glass roof cars are actually stronger than the metal roof cars, the glass is thicker and stiffer than the sheet metal. It adds ~ 28lbs to the weight of the car though.

JMO, but I don't see how anyone will save any weight by replacing the roof panel.

You're close. The roof rails at the door are an integral part of a unibody structure. They are still there on glass roof cars. And not on verts. Which is why all verts (not sure about this one yet) come with extra bracing on the frame (subframe connectors, if you will). Drive a coupe and vert and the difference is astounding.

I guess you would replace the center part that doesn't bear as much stress with carbon fiber. But for that much money in te panel and the labor, for a very very small amount of savings....why? Lol. I think someone that does that just wants to say "I have a carbon fiber roof! YOLO!"

 

[Trevon]

I think someone that does that just wants to say "I have a carbon fiber roof! YOLO!"

God forbid it's painted, too!? All carbon fiber should be painted.

I LOVED when Bill Goldberg was having his wifes' 1973 Trans Am built and he was about the first person to have pretty much CF everything (hood, trunk, roof, fenders) and painted it all! It was so awesome. Exposed CF is for ricers and hypercars.

Nobody has even driven one yet and there's all this talk about modification; what are ya gonna do, get to work 45.7 seconds faster? Driveshafts and wheels, maybe; but hacking a body? No thanks.

I enjoy auto-x'ing but these minor weight savings aren't going to detract more than a 1/10 of a second from a good driver.

 

[WestRace]

Is there any validity to the so called "rotational mass"? Supposed you can save 4lbs per wheel. That's 32lbs total but those are rotational mass and not stationary. That means the amount of acceleration experienced by rotational mass is a lot more vs. stationary mass which ultimately affect acceleration time such as 0-60 ...

 

[tbonez3858]

God forbid it's painted, too!? All carbon fiber should be painted.

I LOVED when Bill Goldberg was having his wifes' 1973 Trans Am built and he was about the first person to have pretty much CF everything (hood, trunk, roof, fenders) and painted it all! It was so awesome. Exposed CF is for ricers and hypercars.

Nobody has even driven one yet and there's all this talk about modification; what are ya gonna do, get to work 45.7 seconds faster? Driveshafts and wheels, maybe; but hacking a body? No thanks.

I enjoy auto-x'ing but these minor weight savings aren't going to detract more than a 1/10 of a second from a good driver.

My personal answer to this would be feel...Several cars ago I put larger and heavier wheels on my car. It was a major mistake. The feel of the car instantly changed and not for the better. A while later I put some light weight RPF1s on which were a good deal lighter and the entire car changed. On paper it wouldnt seem like such a relatively small difference but what a change it made. The stop watch may have never caught the difference but every stoplight and corner I could feel it.

 

[OppoLock]

Is there any validity to the so called "rotational mass"? Supposed you can save 4lbs per wheel. That's 32lbs total but those are rotational mass and not stationary. That means the amount of acceleration experienced by rotational mass is a lot more vs. stationary mass which ultimately affect acceleration time such as 0-60 ...

Are you asking for formulas?

 

[stilesg57]

I agree with switching out the heavy mechanical stuff that more or less lines up with your already-in-place performance mod plans. CF body panels on a primarily-street car is just never really worth it.

Anyone really interested in pulling as much weight out of their car as possible needs to follow Vorshlag.

^^^This. Those guys are crazy. However...look what their wheels saved me AT EACH CORNER on my Bimmer. Guess which one was stock and which was Vorshlag:

Funny enough, the biggest improvement wasn't in acceleration. Or handling. Or even braking (though that was a close second).

It was in MPG.

I kid you not, I got an honest-to-god, consistent and repeatable 9 more miles per gallon on the highway by dropping ~11lbs off each wheel. Couldn't believe it the first time I filled up; thought my gauges were broken. I dropped decently low gears in the rear end a year later (3.07s -> 3.64s) and I'm still getting ~5MPG better with the car than I ever did with the stock wheels. They've almost paid for themselves in three years. Crazy.

 

[Don's Stang]

I agree with switching out the heavy mechanical stuff that more or less lines up with your already-in-place performance mod plans. CF body panels on a primarily-street car is just never really worth it.




^^^This. Those guys are crazy. However...look what their wheels saved me AT EACH CORNER on my Bimmer. Guess which one was stock and which was Vorshlag:

Funny enough, the biggest improvement wasn't in acceleration. Or handling. Or even braking (though that was a close second).

It was in MPG.

I kid you not, I got an honest-to-god, consistent and repeatable 9 more miles per gallon on the highway by dropping ~11lbs off each wheel. Couldn't believe it the first time I filled up; thought my gauges were broken. I dropped decently low gears in the rear end a year later (3.07s -> 3.64s) and I'm still getting ~5MPG better with the car than I ever did with the stock wheels. They've almost paid for themselves in three years. Crazy.

Yes with just a aluminum driveshaft on my 2011 mustang gained at least 1mpg then lighter wheels saved me more


so rotational weight is the most important

 

[Taneras]

Just my personal thoughts on weight reduction...

I'm not going to go out of my way to lose weight. If I happen to lose weight replacing the exhaust, getting some sporty/comfy racing seats, getting different wheels, and some weight loss on the driveshaft that's awesome. But I'm not going to start replacing body parts, removing sound deadening materials, or whatever else. There's just not a lot of weight to remove without decreasing the daily driver value/safety of the car. And what weight can be removed without sacrifice either of those items is usually expensive and doesn't really end up removing a lot of weight.

If handling is what you're looking for, focus on the tires, suspension, and doing your best to move the weight around (lower center of gravity, get as close to 50/50 balance both front and back and left and right, etc.). I think your money is much better spent there. Or just get a Miata...

 

[DivineStrike]

Anything I do to reduce weight will be standard stuff I would do anyhow. Exhaust and wheels. Although styling wise I'm perfectly happy with the PP wheels but tire options will suck and moving to 20's will save me both weight and money in tires as there are more options, but we'll see in that regard. I will however after reading this thread probably swap out the driveshaft as well.

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