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Discussion Starter #1
hey everybody, im new here. i realized that you guys are into alot of the same stuff as me, like custom fabrication and cool cars, so i decided to tell you about my idea. or at least thats all it is so far. its about this car i want to build. i would however hesitate to call it a hot rod since one of the ideas behind this car is that it needs to get at least a little bit good gas milage. and it uses a tiny little 2.9. or thats the engine im thinking of so far. i havent learned to weld yet but im taking a class next quarter.
i got some pictures...



the best idea i came up with for the body was taking 1x1 (or so) beam and making a frame and then just welding on panels. straight lines all flat, nice and simple. then i would jsut make a frame from 2x4 and mount it to the body. so far i think my front suspension/steering is goign to be the hardest part...
what do you all think so far?
 

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Brian Martin,Freelance adviser
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I think you designed a 1948 Crosley! :)



Brian
 

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A small, light car with a 2.9L will deliver plenty performance and get good mileage. Sure it can be a hot rod! Hot rods started out with warmed up four cylinder Model A Ford engines. Power to weight ratio is the key! Many modern builders are going to hi-po fours to power cruising rods. Nothing you want to brag about on the drag strip in most cases, but great for cruising. Many modern EFI fours have nearly as much power as 50 and 60s small to mid sized stock V-8s.
 

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Hey (insert name here)!
I have to give you credit. You are actually dreaming AND working to achieve that dream. Most of the 16 year olds I know don't know how to open a hood let alone start designing their own car.
Take your voc courses, get some additional knowledge and experience and keep dreaming and doing.
If you want to pursue the CAD design try to get into one of the higher end programs like Unigraphics or Catia.
This is some of the stuff I am designing for my Bad Ast Astro Van project...



Of course I have 20+ years on the design end and 35+ on the doing side.
Mark
 

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Building up a whole new body from scratch (and sheetmetal) seems like alot of work, and welding.

What I've kind of...been looking into, is building a car from pieces of other ones. I used a sawzall to cut a 10-inch strip from the middle of a late 70's Ford truck hood, turned each side with the cut side up, and well...that was about it.

But its already made, slightly curved, decent sheetmetal. And what I started to build would actually have resembled an early roadster if I had ever completed it.

Just look around for pieces of cars that you could saw up, and put back together into a decent (and still, pretty light-weight) body. Its less fabricating and trouble than building a slab sided body.

This is a good thread to look into Scratch Built Hot Rod
 

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Instagram: partsretriever
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I think 1x1 square tube frame isn't going to be strong enough- safety first!

That aside, I think starting from a good rolling chassis/old sandrail/dune buggy will give you a good base to start from, as with having the complexities of suspension design, brake design, and some other things relatively established (since your vehicle is lightweight, and say you start with an old cop car frame, it'll ride really stiff- for example)

I think starting with a 2wd S10 or Ranger frame would work pretty good.

A 2.9 isn't too small. The first car I turned a wrench on in the name of speed was a twincam Saturn coupe with 1.9 liters (116 cubic inches). Now I have a jeep with a 4.0 six, which is slower than even the singlecam saturns!

But that's okay, Jeep does not (usually) equal speed.
 

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Try using round stock for your chassis build. Such as 1.5"OD round tube in parallel for your exterior, with smaller 3/4" round tube fashioned as interlaced X members in between your upper and lower tubes. You can build a lite weight chassis out of chrome molly tube and save on the weight compared to standard 2" x 4" tube, or 3" x 5" tube for your heavy critical points. You can find designs on the web of chassis renderings using round tube stock.
Good Luck.
 

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Discussion Starter #9
thank you guys for all your input so far. for my first ever car i think im going to do something based around a small pickup frame for simplicity (and cheapness) of starting out. someday though, this car will see the road. by the way your cad's are amazing, especially that steering nuckle. very impressed. my program was 25 dollars
 

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My nephew designed and built a car when he was in high school. He used a 2.8 front drivetrain and mounted it midships. He designed all the front suspension and steering, something I wouldn't reccomend. I think you might be happier with your first project being a little less ambitious, like maybe using an existing front suspension. Try to use the same wheelbase as the car it came from so you don't have to worry about tinkering with ackerman angles and such. An old Fiero might be a good donor car for those parts, or a Chevette which basically uses the same stuff, nice and light.
 

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Caterhams are a good example of how IFS can be done on fenderless cars (but, expensive Sports Cars though).

Now, look at these pictures below.










The car's body is pretty minimal, enough sheetmetal to cover the frame and rollbar. The front-suspension is exposed, but done tastefuly, and the engine is set back to the point that its not dumped over the front wheels. From the front, the car has an pretty wide track, which, is something that you would find on most "donor" vehicles, but it still manages to make it look pretty good.

The only problem i could see, would be trying to find a frame that dosn't look like crap, and setting the engine back enough.

Hood wouldn't be too hard to make actually, use a radiator as a grill or something, your body could still be made out of flat sheet metal, and a small engine (like your four cylinder) would push this around pretty good actually.
 

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The Caterham and other Lotus 7 derivatives ("Super Seven", etc.) use a 1" square tubing frame. They aren't rail frames though, the sides are actually trusses with triangulated bracing. I wouldn't use less than 2"x3" 10 gauge tubing for a light, small engine rail frame, 2"x4" 10 gauge (or 2"x3" 8 gauge) for a small block V-8 of medium power (say 400 hp or less). The more power, the heavier the frame needs to be if rail type. A truss type frame will hold up to a lot more power if braced right, and be a lot lighter. You can't just plop any body down onto it though!

The body and frame structure need to be tied together. The Lotus 7 (et. al.) body is basically a frame with sheet metal attached, forming more or less a unit body. Think of it as a sand rail dune buggy with sheet metal riveted to the frame. It's practically the same thing! The sheet metal skin isn't stressed, but does help provide a little rigidity.
 

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Accidentally posted twice ! deleted second post.
 

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i was suggesting that he build something similair to a caterham, but their actually a pretty interesting car.

But, more of a Caterham copy would be acceptable. A pretty skinny frame, with some decent engine set-back, and a flat sheet metal (except for corners) body thats build from tubing would pretty much nail the "look". And, its pretty much what he was going to build anyway.
 

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Discussion Starter #15
i definatly like the looks of this catheram thingy. another idea i was toying around with would be making somthing from a mini pickup by setting the cab back and such. i made some paint chops its kinda cool :



this would be someone in my generation taking the cheapest things possible and putting whatever engine you can in it. less stylish though.
 

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I kindo like thjose little trucks, especially the old Datsun king cab. The little fin treatments on the side are a nice element. The first one would need the bed dropped a bit.
 

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I've thought about the mini truck idea. Take the cab and set it back 2-3', just enough to have the radiator just in front of the crossmember (to hide it, kind of like boys rod), and shorten the bed. Would look kinda like a T truck. The only problem is that hideous front suspension! Now build tubular arms for it and it wouldn't look so bad. A universal tubular arm MII kit would look okay, or even a straight axle, but if you're going that route it would just about be easier to build a complete frame, or cut the truck frame in the middle and build a front half. That might be a good compromise situation -- utilize as much of the truck as possible yet make it look decent in front...

A mini truck cab chopped or with the top off would still make a good tub for a T style frame, and be a lot more comfortable than a real T bucket. Would sit higher though. It's a lot of work to section one and still have opening doors and all the room! An early Toyota "extra cab" would provide lots of leg room though, and a little room to recline the seats.
 

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Here is a few pictures of the Model-T tub i made from two sides of a Ford Truck hood. Not completed, but with about 30 dollars of sheet metal and some channel steel, it would be a good body. It took one sawzall blade, and some spray paint to get it this far.
 

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The mini truck ideas are just cool enough that you should try it! Would really bring on lots of looks. Set teh motor back with the firewall, maybe stick a straight six under the hood (or a straight eight.... don't know if the hood is THAT long though!!). A Datsun truck with a 280Z straight six and maybe the IRS would look really cool and be fast! Extending the hood and fenders will take the most work, but would be worth it! Leaving the grille where the factory put it takes care of the ugly front suspension real nicely! Now if you use a short engine and set it back (like the 2.9L V-6), set the radiator back too so there's more weight on the rear end.

About the first idea in this thread.... it's ambitous to say the least! But if you don't make something that's reasonably attractive, you won't like the results. To boxy won't look all that good. Check out sites about body building the easiest way to do it is similar to what you're doing, but using styrofaom panels covered with fiberglass. Easy to make curved shapes and such. Check out http://www.rqriley.com/frp-foam.htm. Also look at the designs at http://www.rqriley.com/plans.html. Something that looks sort of like the "Urba Car" but bigger and powered by a larger engine would be easy enough to build using tubing and even steel panels. Several of the wedge shaped designs could be done that way, though the foam and 'glass method would ultimately be cheaper and lighter. The Tri-Magnum body shown on the foam construction page is the hardest of the bodies ot make. The flat panel ones should be much easier.
 
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