Uni-body homemade convertible?

[maxsideburn]

Well my first post on these forums. I'm part of several automotive forums that are dedicated to the type of cars I own, but I felt that I should join some place that was a little more about cars in general.

Anyway, first post, something crazy. First off, yes I know that generally sawing the roof off of a unibody car is bad, bad, bad. But let's just say for a moment that I really, really want a convertible (or t-top/targa), but can't afford one. I do; however, have a 1990 Honda Accord coupe sitting in my yard that I think would look interesting topless.

1.) Well obviously just sawing off the roof is not an option. From what I understand it would make the car's structural integrity comparable to a cup of Jello. But what if the doors were welded shut? Would that make ANY difference, of would the whole "sawing off the roof" thing just be totally unfeasable?

2.) T-bar style. Let's say I removed the metal frame around my windows, cut most of the roof out, t-top style, then had some metal welded down the middle under the headliner (because I know that thin metal won't do anything to hold anything up by itself)

3.) Targa style. Now let's say I remove everything from the windshield to the back of the doors, that would leave me with something that resembled a targa top. Now I know this would leave the car nearly as wobbly as the "saw off the roof" method, but it should still help with stability just a little bit since the rear part of it is still intact. However; I know that the biggest structural problem would be the car wanting to "fold" in half. So what if I were to have some little 1" diameter metal rods or something welded in to cross the gap, you know one above each door, like a support. It wouldn't be totally open top, but should help a lot with structural issues.

4.) Huge motherforking sunroof. Now, seeing as how most things will negatively affect the integrity of the car I came up with one final solution. What if, instead of hacking away at any pillar or supports I just took a sawzall to the middle of the roof, you know, the part that's just sheet metal. In essence I'd be removing all of the thin roof metal, but leaving everything else. This wouldn't be nearly as fun as a convertible/targa/t-top, but it would definately open up the roof without doing much to harm structural strength. This option would also be the easiest to fabricate a top for. I could simply make a canvas rectangle the size of my roof, possibly with some sewn-in ribs with plastic or metal supports for strength at high speed. I could then attach the whole thing to the top of the car with either button-snaps or industrial velcro.

Well those are my ideas, and yes I'm determined to have an open-top car by this summer, lol, one way or another. I've got the Eagle Talon TSi AWD that I'm spending money on, so no money to waste on a real convertible, unless I could trade the Accord for one, which is unlikely.

So any insight would be helpful. Also if anyone here has actually done a roof chop before I'd like to know how your experience with it was.

[curtis73]

Without having access to the original design files from Honda that were made by 400 MIT PhD engineering graduates on a computer that costs more than all the land in Guam, there is no way to know. Some cars you can't even put a sunroof in because the glass will break from flexing. I've also helped a friend (it was a college drunk thing) saw off the roof of his Reliant K. One night we sawed it off over a case of beer and in the morning we went out to find it laying on the frame in the middle. It just bent in half under its own weight.

Welding the doors might help a little. Keeping a targa bar, Ttops, or reinforcing the roof won't do a thing. It will be one tiny single support piece when what is required is complex triangulation of support.

If the car is TRULY disposable, meaning you don't mind hauling it off to the junker the very next day, cut the roof. It might be fine for a while, might be fine for a few hours. Even if the car doesn't self-destruct, you have completely thrown away every penny you spent on it. No one will buy it, so its market value will be $0. Instead, why not sell what you have and buy a convertible. I've bought BMW E30 convertibles for $2000. Not only do you get a flawlessly designed piece of German engineering, you get a sexy drop top that is supposed to be a drop top.

Do an Ebay search for convertible and you'll find TONS of convertibles with wasted tops and great engines for $500. Here's one that even has a good top: http://cgi.ebay.com/ebaymotors/1992-...QQcmdZViewItem
Its currently at $200 with no reserve and only 9 hours left.

[maxsideburn]

Notice also that it's in Canada....and I'm in Louisiana. I've been looking for over a month now, I just can't find a single car with an open top that runs that I can afford. And being down here you pretty much can't find ANYTHING. So I'm stuck with not being able to find what I want unless I drive 500 miles, which I simply won't do, because I don't trust driving home a cheap car that far.

Hence why I'm so determined to figure out a way to open the roof on my car, because it could be a year before I find a convertible for sale around here I can afford and that's not acceptable.

[curtis73]

The ebay link was an example.

You just sound hell-bent on cutting your car, which is fine, but I think its a very poor idea. Think of it this way. Let's say you spent $1000 on your current car to purchase it. Then you cut the top off. It is now worth $0; either because it collapses, or simply because no one will ever buy it from you. So you now have no money, no car, and you threw away $1000. Not to mention if it does collapse you'll be responsible for any fees for disposing of it.

OR... ditch this car and buy a convertible. That way you haven't spent anything and you still have a car with value.

The only other thing I can suggest is to buy any full-frame car and chop the top. It will still be worthless, but at least it won't collapse. I understand the desire to modify what you have, but cutting the top off of an Accord is just (in my opinion) ridiculous. You have to be realistic in your expectations of your car. I'm all for modding, but if I'm building a high-MPG project, I don't start with a motorhome, and if I'm building a tow vehicle I don't start with a Tercel.

The other thing is, if you're going to not take my suggestions, at least tell us some information... how much money can you spend, how much money is your current car worth, what kinds of cars do you like

There is no way to make your Accord a cheap chopper. Period. If you cut the top off, just know that you'll be wasting money... which is the exact example you cited for not buying a convertible.

Here's one that's 170 miles from you. Item number
250090754546, an RX7 convertible for $550

I'm just trying to tell you that cutting your roof will be a complete, 100% waste of your entire investment. Doing it "right" (in quotes because there really isn't a right way) would require a complete teardown to the bare unibody, expert welding skills, extensive fabrication, and chassis stiffness test equipment. The whole time, the unibody would have to be secured in a jig so no movement took place between the cutting and the reinforcing.

Whatever you decide; keeping the same or buying different, enjoy your new convertible

[maxsideburn]

yeah that RX7 is decently close, but it's almost up to $600 and it has 3 days left, it will go for more money than I have. I can GET more, by selling the Accord, but I can't time selling the Accord with when I'll find a convertible. Also I don't like buying cars far away, what if they break down when I'm still 100 miles from home.

And, no I don't mean to be in such a rush to do something dumb to the Accord.......but I've been saying I'm going to get a convertible for like 5 years now, enough is enough. My only options around here are 2000+ models that I cannot even come close to affording. My Accord 'might" be worth $2000 if I'm lucky, so anything I buy would have to be a cheaper than that for certain.

Thing is I'd be perfectly happy with a dented up little Metro convertible or something, like I said it doesn't have to be nice, just run. I have the Talon which is a nice, fast car, I just want a little open-top car for pretty much nothing (other than modding or selling the Accord) so I can enjoy some air during our hot Louisiana summers.

[gouldie1903]

my suggestion is to add in a sub frame, square steel tubing connecting the front of the car to the back of the car. this will add strength to car and help stop flexing. next i would weld in some temporary braces in the inside of the car, like when people chop the top on an old school car.

once the sub frame is in and strong and the braces are in i would go ahead and and cut the roof off. once the roof is off i would build a roll cage, it will add strength to the body. once the roll bar is in tie in any corners that you find necessary.

pretty much add a crap load of steel triangulate, gusset, and have fun.

my friend and i have are planning on doing it to his car, 94 subaru 4 door sedan fwd.

let me know how it goes

[Blue Bowtie]

And after adding SFCs, a cage, and all the necessary braces and harmonic dampers, you'll have a car that probably weighs almost as much as one with a real frame (and would be suitable as a drop-top), and that barely pushes all that steel around with the Mountain-Dew-sized displacement engine.

The other kick is, aren't Accords a sedan? There is a perimeter frame of metal around the door glass which all but precludes the option of installing a soft top.

[mazdatech177]

just fix the air conditioning that probably doesnt work. its so nice not to sweat...

[umpazump]

"Top Gear" the other day chopped a minivan in England. They made it into a convertible with ragtop.

[ScrapGoldBass]

I used to want to make my own covertible too. I isnt worth it-I thought about it for a long time. Its better to get a moped,scooter, or motorcycle and feel the sun on your face that way.

[MagicRat]

Good posts on this thread.

If you really want to cut the roof off a cheap vehicle, go for something that already has a strong frame, such as a pick up truck (they get almost zero rigidity from the roof) or a pick-up based SUV, like an older Bronco or Blazer (either a compact or full-size)

Compact pick-up trucks are very cheap when used, it seems.

Even the unit-body Jeep XJ Cherokee makes an good convertible, because its unitbody has an excellent subframe component.

[Blt2Lst]

I wanted to do this on my 71 Caddy Coupe Deville which had tons of rust on it. Never did do it though.
I removed the 472 and front bench seat which is now in our living room before sending her off to the big crusher in the sky.