Hey all. It's been a while, but thats how life is...

Anyway, I have a few questions. I'd like some input from the experts on a couple ideas that I had.

1) Has anyone considered using Carbon fiber for the body shell, dash, etc? Obviously, it would be a pricey and not very practical thing for the strreet, but has anyone ever dreamed up ideas like this?

2) Tube frame - I know that it has been done and thought about, but has anyone put any serious thought into the daily practicality of this, as well as the price? What would be the idea tubing to use?

3) Carbon or fiberglass - Has anyone ever vacuumed(?) the air out of a mold to improve the strength of whatever they made? I know that the aviation and boating industry do this, but would it be hard for an amateur with a shopvac to do this? I have no glassing experience, but I don't see why it shouldn't be easy to do. Just need a shop vac and a giant plastic bag.

4) What about a diffuser tray running the entire length of the car, ending at the rear bumper. Think along the lines of F1 and Grand Touring/Le Mans style bottom tray, starting at the front bumper, going to the sides of the car, and going all the way to the back. There are some very challenging engineering prospects to work around with this, but I think it would be possible. What I have in mind is something that can provide easy routine maintenance through jacking points and such. Anyone have any idea what a good material would be (plastic, fiberglass, aluminum, carbon fiber{not very practical at all])
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[This message has been edited by 85FieroGT3.4 (edited 02-24-2008).]

No one's ever heard any of this being done? I know practicality limits, but still, these are some good "What if?" ideas.

They're GREAT "what if" questions...But not very practical questions.

1) I'm sure MANY people have considered it...Then priced it, and immediately STOPPED thinking about it. Someday I would like to do a 1-off curvy carbon dash, but right now I can't spare the money and definitely can't spare the many hours that would be required for this.

2) Daily practicality depends on the extent of your build. Count on spending thousands upon thousands of hours to do a "daily practical" tube frame that has things like door seals and the like. Ideal tubing would be post-weld heat-treated 4340 steel tube. Practical tubing would be DOM mild steel. Tubing diameter would vary by frame location.

3) Again, not rocket surgery but it takes alot of time. If you tried using a shopvac, though, you'd likely burn up the motor as the vacuum needs to be held for at least an hour, depending on epoxy used.

4) Thought about making aluminum panels under the car, it would be fairly easy, I'm suprised more peoplke haven't done this one.

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My Web page | The Turbo Super Duty Build.
You know that little voice that says it can't be done? I duct-taped its mouth shut and pushed it down a flight of stairs. (Leader of the Insurgency)

4) I believe Steven Snyder had used plastic sheet sunder his car, and Blacktree had made himself a "diffuser" style bumper, but it didn't look like any actual fluid analysis was used in the design.

quote Originally posted by FastIndyFiero: They're GREAT "what if" questions...But not very practical questions. 1) I'm sure MANY people have considered it...Then priced it, and immediately STOPPED thinking about it. Someday I would like to do a 1-off curvy carbon dash, but right now I can't spare the money and definitely can't spare the many hours that would be required for this. 2) Daily practicality depends on the extent of your build. Count on spending thousands upon thousands of hours to do a "daily practical" tube frame that has things like door seals and the like. Ideal tubing would be post-weld heat-treated 4340 steel tube. Practical tubing would be DOM mild steel. Tubing diameter would vary by frame location. 3) Again, not rocket surgery but it takes alot of time. If you tried using a shopvac, though, you'd likely burn up the motor as the vacuum needs to be held for at least an hour, depending on epoxy used. 4) Thought about making aluminum panels under the car, it would be fairly easy, I'm suprised more peoplke haven't done this one.

That was basically the whole idea of the post - what if. I know that practicality dictates function before form in everyday life, but think about how cool it would be to have a carbon body, tube frame chasis Fiero. Especially if you make the frame yourself, then you would have the opportunity to put any engine and tranny in it you would want.

As for the vacuum, I think that it varies. I was watching "How its Made" and they use a vacuum for only a matter of a couple minutes. But, that was for a helicopter.

quote Originally posted by FieroWannaBe: 4) I believe Steven Snyder had used plastic sheet sunder his car, and Blacktree had made himself a "diffuser" style bumper, but it didn't look like any actual fluid analysis was used in the design. Also, placing the tray under the engine compartment would block required airflow through the engine compartment, creating a lot of extra heat. The air flow there is required for cooling capacity.

As for the diffuser in the back, that is one of the things that I think would have alot of practicality if incorporated into a true body tray. As for the heat frfom the engine - that was one of the design challenges that I was refering to. Maybe incorporate a honda radiator into it, in a nice compartment, so it can get its nice cool air flow, and provide nice cool fluid. This would be a fun design challenge.

I’m sure you could do all of this, a carbon fiber body requires a mold to lay up the carbon fiber, to do exact replacement body panels would be a lot of work for weight loss that would be in my opinion to minimal to warrant the work.

As far as the tube frame goes, there have been a few tube frame Fiero’s made, like the IMSA cars. a member here recently made one, I forget who, so its been done, it takes a lot of time designing and even more building.

Next you spoke of vacuum bagging your carbon fiber, if your going to put in all the work to make a carbon fiber body panel in my opinion it would be silly not to bag it. I don’t know how familiar you are with the process of vacuum bagging, but basically you lay up your carbon fiber and resin, then you lay a layer of perforated plastic over the carbon, and then on top of that you lay a layer of basically cotton batting, and finally your plastic vacuum bag, the cotton absorbs the excess resin and can cut weight rather substantially. A vacuum cleaner wouldn’t cut it, the motor would over heat, shop vacuums use the air they are sucking to cool the motor, when vacuum bagging there isn’t air flow, also though a shop vac moves a lot of air it doesn’t create a lot of vacuum from a pressure stand point, you would need a dedicated vacuum pump.

Now in my opinion doing all this is going to make a car fairly impractical for street use, because if your going to make your own tube frame your going to spend a lot of time developing your own suspension that will allow you to easily mount wider tires, and if your going to do all that your probably going to put a lot of extra power in the Fiero too. So that would be the point I would consider a carbon fiber body and under tray, you would need to do research as to a different way to get air to the engine if your closing off the bottom, most likely through large side scoops.

If your thinking about doing all this do your self a favor, spend a lot of time doing research, that’s a huge idea you have, and there’s nothing wrong with big plans, but start small, there are lots of online sources about working with carbon fiber as well as books on the subject. Before you make a body I would start small, make a center console, or something along those lines to get some experience.

You should do the same with your idea of a tube frame, read about suspension design and chassis design, learn how to weld if you plan on tackling the project.

Realistically, as a one man project, assuming you already know enough about chassis design and what not to start tomorrow and you could weld and had all the tools necessary, your going to spend a lot of money and a ton of time, I would guess 2 years minimum.

quote Originally posted by FieroWannaBe: 4) I believe Steven Snyder had used plastic sheet sunder his car, and Blacktree had made himself a "diffuser" style bumper, but it didn't look like any actual fluid analysis was used in the design.

Yeah.. as far as materials go I just used some 3/32" ABS sheet. I wanted to smooth out the underbody, not necessarily generate more downforce. I just made it flat along the whole bottom of the car to where the engine bay starts. I planned on making a rear diffuser and engine compartment belly pan (with some cool vents of course!) but didn't get around to it before I wrecked that car. If I ever do it again, I'll use slightly thicker ABS, or put some aluminum strips behind it for reinforcement. It was a bit floppy making it hard to install, but it was straight once I had it screwed in.

[This message has been edited by Steven Snyder (edited 02-25-2008).]

quote Originally posted by xxsportscar: I’m sure you could do all of this, a carbon fiber body requires a mold to lay up the carbon fiber, to do exact replacement body panels would be a lot of work for weight loss that would be in my opinion to minimal to warrant the work. As far as the tube frame goes, there have been a few tube frame Fiero’s made, like the IMSA cars. a member here recently made one, I forget who, so its been done, it takes a lot of time designing and even more building.

In all reality, i thought of the Carbon fiber as something that would be a cool thing to do. I thought of the vaccum bagging more for making my own fiberglass pieces. You know, an attempt to make good quality pieces. I know that Carbon is light, but so isn't fiberglass. There are easier ways to lighten a car up. As for the tube frame, that is something that I would like to do. I think that there could be a huge market out there for a tube frame Fiero that would use factory mounting points for anything, but allow any engine. Plus, like you said, it would have a double A-arm tube suspension (naturally ). It would be a huge challenge, but theres a reason that I want to go to school for this.

quote Originally posted by Steven Snyder: Yeah.. as far as materials go I just used some 3/32" ABS sheet. I wanted to smooth out the underbody, not necessarily generate more downforce. I just made it flat along the whole bottom of the car to where the engine bay starts. I planned on making a rear diffuser and engine compartment belly pan (with some cool vents of course!) but didn't get around to it before I wrecked that car. If I ever do it again, I'll use slightly thicker ABS, or put some aluminum strips behind it for reinforcement. It was a bit floppy making it hard to install, but it was straight once I had it screwed in.

Steven, is that the material that is used on the front of some race cars as an airdam? If so, that seems like the best bet for anything, since it is more readily available and cheaper than other materials. How hard would it have been to service the car with that on there? How heavy was it?

Not a Fiero but it might give you some idea of what's involved in building a car like that from scratch...

http://www.grabercars.com/

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Dave

www.ltlfrari.com

Cool ideas when you aren't planning on doing it can be limitless.
Why not make the entire space frame out of carbon fiber? That's how McLaren, Pagani, etc. make their cars. You could use a Lamborghini Miura drivetrain, since it's mounted transversely. Add carbon fiber body panels as well, and you'd end up with a lightweight Fiero with a Lambo drivetrain for only slightly less than the cost of a real Lambo.

But even if I hit a $300M lottery jackpot, I wouldn't spend that kind of money on a Fiero.

quote Originally posted by 85FieroGT3.4: Steven, is that the material that is used on the front of some race cars as an airdam? If so, that seems like the best bet for anything, since it is more readily available and cheaper than other materials. How hard would it have been to service the car with that on there? How heavy was it?

I weighed it but I can't remember right now. I think it was 7 lbs for the 48"x48" sheet though.
Some race cars probably use ABS as an air dam. They likely use thicker sheets though. ABS very impact and abrasion resistant and inexpensive. Servicing the gas tank would require the removal of about 10 screws holding the sheet up. The front can be accessed by removing just 3 screws and folding the sheet down.

quote Originally posted by 85FieroGT3.4: I think that there could be a huge market out there for a tube frame Fiero that would use factory mounting points for anything, but allow any engine.

I disagree. I think there's approximately zero market for that.
Kit car MFG's that build tube frame cars do not use Fiero panel interfaces.

Someday I want to build a custom chassis fiero. Keep the central fiero chassis to retain the stock windshield and door seals and build it around a late model suspension and drive train. Something like this (and it was for sale in a mall several weeks back)...

//www.fiero.nl/forum/Forum1/HTML/048610.html