What would you make your car out of?

Wrecked944 · 10-25-2002, 09:34 AM

Okay, after the CIS -> EFI project is complete (and assuming "sanity" has not yet reared its ugly head), I plan to begin experimenting with weight reduction on my 911SC. And since I don't have a sliver of common sense, I am thinking of fabricating my own lightweight body panels. So here is the question: If you could fabricate body panels for your 911 made from any material (i.e. aluminum, carbon fiber, fiberglass, kevlar, titanium, ect ad infinitum), what would you choose? Feel free to assume that time, difficulty, and price are not limiting factors in this project. Only functionality, durability, weight, etc. are important...oh yeah, and don't forget "coolness factor"

So seriously, what are the pros and cons of each material?

Superman · 10-25-2002, 09:46 AM

Carbon fiber, of course. Some kevlar parts, I suppose, and some titanium, but mostly carbon fiber. half as heavy as aluminum, twice as strong as steel.

Lothar · Lothar's Garage

If I could do it any way I wanted, I think I would go for the thermoformed plastic panel approach. I think that's what they do for cars like Saturn. This would be highly impact resistant and can be painted. Fiberglass and carbon fiber are too brittle and crack easily. Alluminum is very costly and fabrication would be difficult as it is much stiffer than steel.

Planter91C2 · 10-25-2002, 09:47 AM

how about royalex, the stuff they make good canoes out of.

island911 · 10-25-2002, 09:59 AM

Milk chocolate . . ..eewww. semi or dark for me.

otherwise, titanium honeycomb.

Super, next get-together remind me about material "strengths." (carbon fiber doesn't win)

it's all timing, eh Planter

emcon5 · emcon5's Garage

Chicken wire and Spackle.

JavaBrewer · JavaBrewer's Garage

Stucco, you can just fog out the stone chips.

Chuck Moreland · 10-25-2002, 10:26 AM

All Porsche parts are made from $100 bills.

ChrisBennet · ChrisBennet's Garage

Unless you are using metal doors, you really need a cage. Poof, there goes your weight savings.

Wrecked944 · 10-25-2002, 11:20 AM

"how about royalex, the stuff they make good canoes out of."

Excellent idea. I'd never heard of Royalex so I did a search. It seems this stuff is a layered material made of sheets of vinyl, abs plastic, foam (for buoyancy), abs plastic, and vinyl. There is an excellent analysis of the pros and cons of royalex, kevlar, and various combinations on the mad river canoe website at...

http://www.madrivercanoe.com/design_and_construction.shtml

Their conclusion is as follows:

"(Kevlar is)...much lighter and more efficient to paddle than Royalex® or polyethylene.
Lighter, more flexible, and more durable than fiberglass. Best strength to weight ratio of all available materials. The choice for expeditions!"

Perhaps kevlar is also the choice for lightweight cars? I did some more research and found that Ruf's famous Yellowbird was made from kevlar body panels. This would seem to be a credible endorsement.

So carbon fiber and fiberglass are too brittle? I had no idea...but then again, I think I read somewhere that Corvettes tend to shatter in accidents. I guess that woud be a bad thing, right? Is aluminum a dead end? If I recall, the original Shelby Cobras had aluminum bodies (as do some ferraris I think?). I don't mind going through some serious suffering for this project. So difficult materials are okay. Again, time and money are no object here. I have never before heard of thermoformed plastics. I guess I don't drive Saturns much. So Saturns have plastic body panels? Amazing. I will continue researching this material...

"I would make my Porsche out of semi-sweet chocolate."

There is precedence for this mod. Pictured below is a rare example of an original Gemballa 911S (S for "sweet") - also called the "YummyBird". This car was successfully raced by the Nestle team which won the famous Mille Wonka and the Hershey 500. I understand the components were easily formed using regular injection molding, but they weren't very heat resistant and had to be kept away from small children - especially during the Easter season.

Neilk · 10-25-2002, 11:36 AM

Janus,

Contact Williams or McLaren. I am sure they could build you some nice carbon composite body panels. If price is no object, who cares about durability?

As for Corvettes, anybody see the "wow" Dish network commercial. A Corvette's door gets ripped into pieces by a passing bus. I am not sure if the door was weakened by the effects people, but the door looks like it exploded into hundred of little pieces.

82SC · 10-25-2002, 11:39 AM

start with a tubular space frame for a 911

hang all CF panels on it.

it would be a pure race car

look like a 911

and weight very little

nostatic · nostatic's Garage

Titanium baby...

Jeff · 10-25-2002, 12:00 PM

Back when I lived down by the river I used to have a van that was made of royalex.

Nostatic, nice ride.

pbs911 · pbs911's Garage

What was that Ceech and Chong movie, Up in Smoke?

cegerer · cegerer's Garage

No financial constraints?

OK, I would go with a one-off turbulent-management surfaced Mylar or Kevlar sheeting stretched over a polystyrene framework (with carbon fiber bracing, of course). The Mylar would resemble shark skin using micron-sized surface structures - shark skin is said to be the ideal aerodynamic structure. This car would slice thru the air like no other ever has!

-- Curt

Wrecked944 · 10-25-2002, 01:15 PM

"If price is no object, who cares about durability?"
"it would be a pure race car"

Sorry, I should have provided a better explanation. My 911 is a daily driver/street car. So while I am willing to blow lots of time and money on crazy and ill-advised fabrication schemes, I am hoping to have these body parts last once they are installed. Sorry about that confusion. Sometimes I assume that everybody is psychic and knows what I am thinking.

So through a process of elimination, I suppose I can rule out the following...

Fiberglass - Too brittle
Carbon Fiber - Too Brittle
Steel - Too Heavy
royalex - Too heavy
Chocolate - Too fattening

This leaves...

Kevlar - Seems cool. I like the Ruf Yellowbird connection. I can tell people my car is "bulletproof".

Titanium - Everybody seems to fear this stuff. How expensive/difficult could it be if they make bicycles and golf clubs out of it? The connection to the SR-71 provides major coolness. Would it actually be "better" than kevlar or aluminum ("better" = lighter, stronger, sweeter tasting)?

Aluminum - Probably a bear to work with but that's okay. It isn't like I have a lot of hobbies or anything (Chris Bennet can attest that I am a glutton for automotive punishment).

And some I've never heard of before today...

carbon composite (or is this carbon fiber?)
thermoformed plastics

Any other ideas or preferences? I must admit I am genuinely surprised that there is no obvious consensus. With all the racers and RS spec wannabees (like me) I'd have guessed that there would be a commonly recognized "gold standard" for light weight body panels...heck, we could not even agree on dark or semi-sweet...

BlueSkyJaunte · 10-25-2002, 01:19 PM

Simple: adamantium.

cegerer · cegerer's Garage

So through a process of elimination, I suppose I can rule out the following...

Fiberglass - Too brittle
Carbon Fiber - Too Brittle
Steel - Too Heavy
royalex - Too heavy
Chocolate - Too fattening

And experimental Dupont Kevlar sharkskin too, I suppose?

-- Curt

nostatic · nostatic's Garage

Quote:

Originally posted by JanusCole
Titanium - Everybody seems to fear this stuff. How expensive/difficult could it be if they make bicycles and golf clubs out of it? The connection to the SR-71 provides major coolness. Would it actually be "better" than kevlar or aluminum ("better" = lighter, stronger, sweeter tasting)?

Depends on the application. My knowledge is from the bicycle world, but for some things, Ti is king (frames), but for others (cranks, chainrings, etc) there are better choices. One difficulty with Ti comes in welding. You need an inert environment, and since thin tubes tend to be used (due to its strength), it's easy to screw up. Also, depending on the alloy, machining and forming can be very difficult. CP is fairly well behaved, but harder/strong alloys (like 6/4) check up machine tools.

Ti is great because it is strong, light, and deals with flex well (bend, not break). This is unlike aluminum, that can be strong and light, but is prone to catastrophic failure when flexed. I believe my ME friends talked about low modulus of elasticity.