Structural Rigidity- S14- Convertible

[Jimmy Up]

I started a thread in the premie section but I am looking for some very knowledgeable input on this.

So I have been doing a little bit of driving lately and putting time and money into an S14 that I have grown to love dearly. Now I want to cut that shit up.

Ive been searching all over different websites for over a month now looking for some solid information on straight-up cutting the roof off of this car, making it a convertible- forever.

My personal opinion is that with a cage added to the ride height I am rocking, the kit, wheels and whatnot. It will come together pretty sexily. But that is besides the point.

My thread here isnt about how you guys think its going to look, but rather about that structural rigidity thing that everyone keeps telling me about. I would not be cutting ANYTHING until I have a full wallet to put a nice cage in the car so I am not even considering doing this without a cage.

So do you guys think that with a proper cage built, that a convertiblehttp://images.intellitxt.com/ast/adTypes/mag-glass_10x10.gif (http://zilvia.net/f/#) S14 would have a good amount structure, good enough to still use it as a solid drift car? Or am I getting in over my head into something that is not even going to be functional when completed?


If you just want to tell me how stupid and ugly this is going to be, please spare me, Ive heard it ALL lol.

Thanks for any input and advice in advance.

[Vision Garage]

I think they would be pretty awesome.

Here are pictures to give you and idea Jimmy

http://www.deepvision.net/gallery/albums/20060708-HINORL_IAN/HINORL06-01-170.jpg

http://i32.photobucket.com/albums/d10/DROPTOPS14/Picture251.jpg

http://i34.tinypic.com/2ezgwub.jpg

I always wanted to to a Hard top version for my s14 as well. Since its hard top. Just chop off the roof from the pillars up to where the quarter windows are.

[tt99ol]

if you gusset the a&b pillars you should be fine
and weld in a strut tower bar that connects to the cage
thats all the roof skin holds together anyway
plus cages are much stronger than that flimsy crap nissan calls sheet metal

[Nismology]

oh wow that blue 13.5 is sick :O
wish i could afford the conversion. /pif

[kingkilburn]

You could look into getting the added panels from an s13 convertible, or you could look up the diagrams to see whats different and 1up what Nissan did to reinforce it.

[thefro526]

I have no doubt in my mind that you can cage an S14 and chop the top off and still retain a good amount of structural rigidity. If anything, you may end up with a more rigid chassis than stock if done correctly. I'm assuming though, that by cage, you mean some sort of a substantial cage (6/8+ point) and not a roll bar.

I would be extremely careful with how you do the chop and the cage work though. I'd suggest putting the car on some sort of a jig or welding in some sort of temporary reinforcement to keep it from flexing too much while you're chopping it and caging it. I'd be worried that if you left the car on it's wheels that you might encounter some sort of chassis shift or flexing when you remove the top from the car.

Also, I'd look into what sort of reinforcement was done on both the S13 convertibles we have here in the States and the S15 'verts over in Japan. I know neither of the chassis are identical to an S14 but they should still be close enough for some good info.

In the end, +1 for taking the road less traveled. +1000 for trying to do it right.

*edit* After thinking a bit more about the idea, I would also make sure you attach the front A-Pillars to the cage as well like what is done on pro race car cages.

[bejota180sx]

i think the cage would make it strong structuraly even without the roof , kinda like when EVOs chop of the roof and put in a carbon fiber one, the rigidity is held by the cage almost completly... same idea but different execution...

btw there are diagrams on zilvia about the structure modifications they did to the convt s13... check them out maybe you could get a idea of what could be done besides the cage to maintain the rigidity...

[kingkilburn]

eco eco eco

lol

[projectRDM]

Cage it before you cut it. Any cutting will introduce flex into the chassis, sagging in places where it's not as sound. If it's caged and rigid first you won't have that issue.

I'd also consider reinforcing the rocker panels, the S13 verts have a lot of bracing there and that's basically the only structure left to hold the two halves of the car straight. A boxed section on the inside as well as outside, plus a cap over the frame rails will be serious reinforcement.

[GSXRJJordan]

Cage it before you cut it. Any cutting will introduce flex into the chassis, sagging in places where it's not as sound. If it's caged and rigid first you won't have that issue.

I'd also consider reinforcing the rocker panels, the S13 verts have a lot of bracing there and that's basically the only structure left to hold the two halves of the car straight. A boxed section on the inside as well as outside, plus a cap over the frame rails will be serious reinforcement.

I was just going to say the same thing - YES the roof, B pillars, and C pillars are structural members, and YES a cage can and will make it stiff enough, but you have to cage first!

I wouldn't think you'd need much support along the rocker panels if you had a 8pt cage (A-pillar bars connected through a halo, and even a dash bar), but it can't hurt.

Mike, a budget of $2k can easily get this done. Make it happen!

[atutt]

lol, weld the doors shut... There's your structural rigidity. (Sorry if it was mentioned, BB's sucks for internet sometimes)

[98koukile]

So this will be a convertible with no top correct? I think that's the only way you can do this and have it look decent. Since it will be a drift car you won't need rear seats correct? I would box the cage through to the trunk and tie it into a rear strut bar setup

[Jimmy Up]

I am in debt to all of you guys.

Building the cage PRIOR to cutting the top off makes a ridiculous amount of sense and that is something I did not think of at all.

I will draw up the cage I plan on putting in this and upload pics tomorrow.

But what I was planning on doing was building a full cage, the only thing that I would WANT to do different from the good ol S2000 powered sears vert would be to make the bars connecting the a pillars to the main hoop detachable, to keep a cool look, but I am looking at a full track car and the more I think about it the better it will be to just weld those in there as well.

I will be reading through all the responses tomorrrow when I wake up.

Thanks a lot guys, more input is welcome- I will definitely be starting a thread in the near future.

[kingkilburn]

You could also look into how the hot rod and muscle car guys make roadsters out of coupes.

[DJ Silent]

How much rigidity is lost by making it a targa top? Thats what I am interested in doing

[kingkilburn]

If done properly you lose none when the top is on but you do gain a hefty bit of weight.

[GSXRJJordan]

How much rigidity is lost by making it a targa top? Thats what I am interested in doing

As soon as Mike posted this thought in another thread, Targa is what came to my mind too! Keep the rear and quarter glass, keep the B and C pillars, and loose the top!

Problem is a couple of things - one, you'd loose a shit-ton of rigidity. Targa cars have boxed B-pillars and roofs (or similar), making that little section of the roof a "rollover" protector, and chassis stiffener. This would be rectified with a 8pt or above cage (A pillar bars and a halo from the main hoop around to the windshield). By this time though, you've lost streetability.

The other one would be making the old piece of your top attach/detach, for me anyway. I still like to drive my car on the street, and in the rain, so I'd need some type of top up there. Some stretched cloth wouldn't cut it for me.

If done properly you lose none when the top is on but you do gain a hefty bit of weight.

"done properly" = cage. See Kognition's build thread for roof weight and his impression of his carbon roof - he said it's definitely noticeable.

[kingkilburn]

I've seen kits for some cars that are similar to those retractable soft tops sun roofs in the sense that you cut out the old frame to put in the new one.
http://www.windscreenhospital.ie/Images/autoglass3.jpg

[Jimmy Up]

Hey targa tops- start your own thread.

Captain Crunch Bustah

[ericcastro]

Cage it before you cut it.


I was just going to say the same thing -

Thats the only thing I was gonna say aside from it should be pretty dope man.

Hey targa tops- start your own thread.
Captain Crunch Bustahlol
Targa Tops, this isnt a VWforum

[98koukile]

You could also negate some of the weight of the cage by gutting the doors of glass, assemblies and excess metal and still keep the interior cover or replace it with a flat sheet of stainless. Losing the roof is like losing 50-75 lbs depending on sunroof or not and loosing every piece of glass save for the windshield should be double to triple that weight savings and all high up on the car

[3CL1P5]

The guy who owned my Zenki before me actually made this a show car and when he did that, he cut out the center roof support along with cutting a massive 1.25'x2'~ hole for an after market sun roof. It's absolutely flimsy and a bit concerning to be honest and so I've bought a daily since then and the Zenki is a full track only car. When I removed the sunroof there's basically no structure left on top (not that it contributed to the structure in the first place) - but as a result, I'm chopping the roof off after it's caged.

At the moment it's fully gutted, the doors will be gutted, all windows except front windshield will be removed, cage added, door bars, strut bars part of the cage will be added, it'll get end caps/plates welded where the pillars were removed...the lot. All in all, very cool result in my opinion.

With that said, it's a whole lot easier to restore structure and rigidity when it's a track only car with fancy cages and what not when you can just leave it as the most impractical car ever :). I'll definitely be sure to post quality pictures when the time comes to start documenting the process and the results.

Note: You guys are fantastic with your advice! These cars are definitely not strong cars to begin with, so caging it would be extremely beneficial before chopping the roof off.