Andre#4

c5 vette chassis retrofit to our cars body

I am really going to do this, and I could use any ideas or help during this planning stage. I want to have the beautiful body of a GTA convertible, and the structural integrity of a bank vault, without a roll cage. Needs to support 500hp on radials without flexing or rattling. I have been wondering what it would take to make the car chassis really strong, and I thought it might not be too bad to just get a c5 corvette chassis and attach the body to it. I just can't drive the GTA anymore, can't stand the feeling of fall-apart whenever the car moves. It is worse with the gta convertible, even with only 300hp. I included pictures of the frame and rolling chassis I am talking about. Check out how robust and strong that is. (pictures below)

I tried driving a C5 vette, and it drives great. Feels stiff and strong like a Porsche or Mercedes Benz. Just about like a bank vault. I just hate the looks of those c5 vettes. (C4's were ok but nowhere near the natural sublime flowing beauty of the GTA) Plus, I can't really grow facial hair very well, and you need a full beard (preferably grey) to own a vette. I cant get used to the modern way they make cars today with the cheap seats, silver painted plastic interiors, and unfinished bodywork. (there are open seams and cuts all over the cars these days...they don't even finish the roof to quarter panel seam...they just put a 1" wide plastic strip over it) And these 20" rims with electrical tape for tires.

Initially, I thought of trying to improve the rattletrap/bucket of bolts the factory gave us, by adding bracing to it. all kinds of frame connectors, and all kinds of wonderbars and braces and struts and stuff. But we don't even have a real frame to connect anything to. what little there is, is too thin a guage of steel.

I saw ads for places that will make a custom steel frame for any car. That got me thinking, maybe we could hook the suspension, and drivetrain to the custom frame. In other words, mount the body on the frame like in the old days. Just strip our car down to a carcass and mount it on a real car frame. And the c5 vette frame is great because it has good suspension in front and back, ls1 bolts in, and it is a hugely strong frame, stronger than any car frame I have ever seen. It has huge strong verticals for hanging our doors onto. (no more door rattling for us) The only problem I see is that the wheelbase is 3 inches too long, but that can be dealt with by lengthening our body, or shortening the frame. (I don't want to change our body.) I am trying to have the looks of a 1988 GTA, with the structural integrity of a bank vault. I am tired of this cheap crap, but, I am not willing to give up the shape of the GTA. I don't mind losing the rear seat or the reduced trunk space. I don't use them anyway.

Can anyone suggest a better idea than this? Or maybe add some ideas for how to do this?

My thought is just strip everything till there is just a carcass. remove front clip, fenders hood, doors, hatchback, suspension, motor, rear end, interior, etc. Then, grind off whatever psudo-frame members are attached to it that would interfere with the c5 frame and chassis, then mount it on there with body mounts, and then hang our doors on the c5 vertical frame pillers, and piece together the front clip with whatever internal bracing needs to be fabricated or adapted from the 3rd gen. Use the suspension from the c5, the motor, trans, torque tube, exhaust, etc. The windshield pillar of the c5 will need to be cut off so the 3rd gen window frame can attach, and a firewall has to be adapted of fabricated. Make sure seat mounts tie into c5 frame and also to floorpan. Basically just rebody the c5 with our body. I would make a custom interior because I hate c5 vette interiors. I'd use the good stuff from our interiors and make the rest out of wood and leather. And wiring could be done a number of different ways. Easiest would be use our wiring and attach it to the ls1 motor the same way you would if you were putting an ls1 into a 3rd gen.

Any ideas? I can't think of any other cars that have seperate chassis that would work any better than a c5 chassis. Can you?

84redta

iTrader: (34)

Have you done wheel base measurements? 3rd gen wheel base is 101" with a length of 190.5", C5 wheel base is 104.5" with a length of 179.5. There will be moving of the rear wheel well on the body (or front fenders) (3.5" shortening overall), lengthening of the chassis (vette is 11" too short), and the configuration of a farther back passenger compartment. Sounds basically like you'll be chopping the car to pieces, taking sections here and there and customizing the rest to fit the needs, which may ruin the proportions of the car itself. I don't think it will be a modify the floor for body mounts and go kind of car. Don't take this as critisism, I'd like to see this happen, but just not sure if it's feasable, and throwing some thought to the idea that may have not been checked off yet.

hmi85z28

I want to do something similar. but what about making a rear frame section for the camaro instead of taking the corvette frame then fab your own suspension mounts??

Andre#4

84redta, these are the kinds of responses I am looking for. Thank you.

I am not willing to change any of the body proportions or measurements of the body. Interior can be altered, that is mostly plastic anyway and getting replaced with metal, wood, leather and wilton wool carpets.

If you have alternative ideas that would be easier, I am open to ideas. I want to do this the easiest way possible, but I am definitely doing it, no matter how hard it is. Worse people than me have done harder things than this.

I know about the wheelbase and length concerns. I am figuring it is easier to change the length of the corvette frame than building a new frame from scratch. Stronger too, and will have replaceable parts and standard mountings for suspension. I know people have shortened and lengthend frames before. I would do it properly. Instead of just cutting frame and welding back together, I figure I would put an insert and or sleeve, made of high strength steel that fits exactly, and weld that in. Sort of like the idea of a retractable radio antenna, except welded to the proper length. I could shorten the part between the wheels, and lengthen elsewhere. The other possibility, if there are too many changes, is to use the stubs of the c5 frame and make a custom center section that would conform to the proportions of our body. So the door is the proper distance from the front wheel, the rear wheel, and so the firewall and window frame are in the right spot. But using frame stubs, you could use possibly from another car, one that has the transmission bolted to the motor. But it seems that this is getting harder than adjusting frame dimensions of the c5 frame, which is a much stronger frame design than just about any other, and will still have plenty of strength after an alteration.

hmi85z28,
how do you plan on joining the rear and front frame sections together? what would you use for the front subframe? the factory one is a joke and does not attach to anything except the floorpan.

Random thoughts:
I can't think of another modern car that has a separate frame and chassis. Everything is monocoque. I thought of using a modern Supra chassis, a Porsche 928 chassis too, both of which have proper wheelbase, but those are monocoque cars. Their bodies are the chassis, and I am not using the body part. If there was a monocoque car that had a body very similar to ours, it could MAYBE be reskinned with our body, but I dont think there is, and I like the seperate frame idea. When I look under our car, all I see is a body with suspension parts mounted too it. And that is why it is a flexible flyer. Even the front control arms have only one of the bushings attached to the crossmember. the other attaches to sheet metal.

I have 8 hides of leather to cover most every surface of the interior. I plan on keeping the GTA seats (and putting beechwood leather on the plastic seatbacks) and keeping the general design of the interior. On first glance, I want it to look factory, except with genuine materials attached in a sturdy fashion (not snapped together like a childs toy). If sizes need to be adjusted, that is ok. I would prefer a larger foot area, which should be feasible with the rear mount transaxle. I might use orthopedic seats from a Porsche 928. I also might change my mind about the factory look of the interior and use a rolls royce interior that I have, if the dash width is correct. I can decide that part later. I always enjoy my time in a rolls royce, and the seats are orthopedic and comfortable. I figure that a custom interior of the trans am design would be just as enjoyable though. I always loved the airplane look of the dash and the general design, just hated the materials of everything except the leather seats and steering wheel. And hated the fact that the dash and console and assorted bits were black and grey when the rest of the interior was beechwood.

hmi85z28

i dont know if it would work or not, but i was thinking of doing a rear section to mount and then do a front clip, then create my own sfcs from there ive been looking to see how others are doing it but cant find anything for the camaro, so im trying to combine the ideas of how all the other retrofits would work for us

sailtexas186548

iTrader: (2)

this is already being done by someone on TGO

https://www.thirdgen.org/forums/fabr...-z06-long.html

BlackenedBird

iTrader: (5)

What about the torque tube? You think about doing that part? It would need shortening or lengthening.

84redta

iTrader: (34)

With enough money, that should be able to be overcome, but this is coming from someone that honestly has never seen the inside of a torque tube so.

Anyways, you need to measure proportions from the back of the car to the wheels, which i believe the 3rd gen will be longer, but if you can lengthen the frame in the middle, i think that would yield a better result as far as location of everything else, but it's going to be interesting changing interior cabin of a 3rd gen to accomodate the torque tube tunnel alone with changing it into a 2 seater configuration.

Andre#4

I will check the thread. It would be nice to see someone who is already doing this.

What's the big problem of shortening the tube?. I know a shop that can shorten the drive shaft. They can do the tube too, right? Anyway, to answer the question, yes, I am using the torque tube. Mechanically, everything the corvette chassis has to offer will be used. A little cutting or lengthening of the corvette chassis is not the real problem here. The worst area will probably be in the fitment of the 3rd gen body to the c5 chassis, particularly the windshield pillars and their attachment and integration into the c5 firewall provisions. Right? And maybe the hanging of the doors on those c5 pillars.

While I have not seen the inside of a torque tube, I have never needed to. They are relatively trouble free. They are simpler than a standard drive shaft. We are discussing some involved fabrication here. I hardly think a driveshaft in a tube is a major concern.

I am not trying to waste anyone's time here. I am really doing this. I have already disassembled and restored every nut and bolt of a modern coachbuilt Rolls Royce Corniche, (made by hand, not the regular production model) with 4 brake systems, 16 brake cylinders, 2500 psi accumulators, 2 pumps, and a hydraulic height control and body roll control system. Not to mention 2 heating and ac units with 784 different electrically servoed control settings, activated by 8 Lucas servoes, and controlled by twin Lucas pinecone matrix switches, and relays for each circuit. and ALL LUCAS ELECTRICAL PARTS. I mean, just to see the inside of the trunk lid, you have to remove 70 screws. And there is nothing in there to see. To change the plug wires is an 8 hour job. So imagine what is involved in actually servicing something of consequence. Compared to that, this third gen stuff may as well be powered by a rubber band.

I am certainly capable of building what will essentially be a hot rod with american mass production car parts. I have 30 cars (I don't like to mention that because it makes people think I am trying to get attention, but I assure you, owning 30 cars is NO PICNIC...can you imagine? 30 batteries, 120 tires threatening to flat spot, 30 tanks of gasoline in various states of degradation, the maintenance on the garages, the taxes on the real estate for the garages, not to mention the cars themselves! It turns you into a slave.)

Before I buy the corvette, I thought some other minds could contribute some things I did not think of. And I know some people on here have done some good fabricating and would maybe have some ideas relating to this project.

If that torque tube comment was meant as some kind of a hit, (and I am not even saying that it was, because I don't want to say anything that might be inflammatory), I hope this thread does not turn into a girly personal bickering venue like some threads do. That has never happened in any thread I have started. If I had any tolerance for that type of thing, I would have a live-in girlfriend again. At least that had some benefit. Bickering via internet has none.

Andre#4

lengthening the frame in the middle won't work because the wheelbase needs to be shortened. If rear overhang of 3rd gen is longer, c5 frame can be lengthened on the rear extensions. OR JUST LEFT ALONE> (3rd gen has no frame anyway. If it can support the overhang without the c5 frame, it can do it better with it, right? even if it is not full length, it is better than the current situation wherein there is no frame at all back there) I don't think a few inches of rear body overhang will make any problem of structural rigidity even if the c5 frame is not lengthened. More important back there will be facilitating a strong mounting situation for the rear bumper support so it is strong in an accident, while maintaining the standard attachment points for the bumper cover. Perhaps a situation of lengthening the c5 frame as long as possible while still leaving enough room to adapt it to the existing rear bumper support mechanism

I think the problems with the stock 3rd gen arise from mounting the suspension and engine to a body without a frame or a roof that was designed for 88-150 horsepower and 15x7 inch wheels. The rear frame extension will be one of the easiest things to do. Just a technicality. Shortening the middle will be more involved, because the whole car fundamentally depending on it.

As far as the floorpan goes, floor pans are easy to make. Not worried about that. It has to accomodate the torque tube and the exhaust. I want to make the bump in the floorpan narrower in the front, since the transmission will no longer be there, and I want more room for my right foot. to relax on long trips.

marolf101x

Here's what's in a torque tube:


There are now many places that can address this part of the project.

Rear Frame Rails:
The rear frame rails are the least of your worries. Like you stated, it's just metal hanging off the frame holding up the body. The front and rear "extensions" are easy to fabricate and capable of holding the body.

Trans tunnel:
The stock vette tunnel is slightly wider than the camaro tunnel, even though the torque tube is there instead of the trans.

Why is this?
The way the corvette is set up the rack sits in front of the engine (in front of the harmonic balancer, actually). So if you leave the steering stock you have to push the engine and firewall way back to get the front wheels to sit in the wheel wells correctly. This in turn pushes the trans tunnel further back into the car.
This is not a problem at all, and is "easily" accomplished. You just need to know what you are getting into.

The vette parts actually line up with the camaro quite well. You can see some pics here:
http://projectawdcamaro.com/3rdgen.html

BlackenedBird

iTrader: (5)

Andre#3...Why did YOU make such a big deal out of a simple question? Your not even the OP, yet you talked about my question about the torque tube over a& over.

My question was exactly what it was. A QUESTION!

I have never even RIDDEN in a torque tube 'vette, much less looked inside one in any way. Soi I have NO clue what they are, except that they aer (apparently) part of the "frame" that makes up a 'vette.

Don't try to read stuff inside simple text over the internet. Take it for exactly what it, not what you think it might be.

Besides....The question was for the OP, marolf101x, not you or anybody else. But you seemed to take it personal & if it was directed towards you.

marolf101x

Just so we're clear, Andre#4 is the OP.

I'm just here trying to help out a fellow 3rd gen owner.
No need for anyone to get their panties in a twist, we're only talking about cars not politics or religion.

Now, get back on the subject of putting a vette under a camaro. . .

BlackenedBird

iTrader: (5)

My apologies then. I recognized your user name and thought I was in YOUR thread, https://www.thirdgen.org/forums/fabr...-z06-long.html.

But it was still just a question about the torque tube, nothing more. Just a question, still my understanding of them are that they are the "frame" of the 'vette.

marolf101x

The torque tube is not the "frame" of the vette. It adds some structural rigidity as the entire drive line is "solid", but the engine and rear end are attached to the actual chassis by rubber mounts, so they are allowed to move.

The vette has hydroformed frame rails that run down both sides. The upper suspension points attach to this. The lower suspension points attach to an aluminum "cradle" that is bolted to the frame.
The trans tunnel is also very heavy and well braced, so it adds to the overall structure as well. It's acts as a "backbone" as the original design was for the convertible, to have a chassis as stiff as they could get with no top.

Andre#4

I wonder if it will be possible to use 0 offset wheels, with the deep dishes, that the third gens use. The c5 uses front wheel drive style wheels, with very high offset. I want gta wheels or BBS RS wheels, and the deep lip looks good to me. The c5 track width is about 2" wider. The only way to have a proper track width is to have narrower wheels, and/or even higher!!! offset. Seems these wheels will have no outer lip at all. That will not look right for third gen. The polished lip is muscular/sinister looking, especially on the front where it is deeper.

Or narrow the track width of the chassis somehow, so such high offsets would not be needed.

From my preliminary calculations, the offset would have to be 70mm on a 7.5" wide wheel to fit the width of the body (Front wheel). On an 8.5" wheel, the offset would need to be 83mm, but that would put too much wheel inside and might scrape steering knuckle and so forth. In other words, we have to loose an inch off the outside edge of each corvette wheel.

Stock c5 8.5” front 58mm offset
Inside hub 166mm / outside hub 50mm
108 centerline
Third gen body on c5 chassis 8.5” 83mm offset (will probably interfere on inside dimension)
Inside hub 191.4mm /outside hub 24.6 mm
108 centerline
Third gen body on c5 chassis 7.5” 70.65mm offset
Inside hub 165.9 / Outside hub 24.6mm
95.25 centerline


Blackened bird, I had no problem with your suggestion of the torque tube. It is a valid concern. If I did not mention it previously it is because I was not concerned about it. (I figured I would have that part done professionally...they have been lengthened and shortened before and tooling is already made for just that purpose) it is a good strong design and I am incorporating it, and the rear transaxle. Porsche has used them for 35 years.

The more of the c5 I keep, the closer to a c5 my car will drive and feel. Plus, the less possible problems I will have. If everything mechanical is stock c5, the only problems will be body/electrical/fit and finish/leakage/ etc.

Like I said before, I am not getting into personal stuff or she said/she said with a stranger. This is a car venue, not an elementary school girls chat room. These personal things are so stupid. My dad and his brother have not spoken to one another for 45 years because of one of these things. I am not getting involved.

Andre#4

Too bad about the trans tunnel having to be wider. I hope it is not too much wider.

n33d4sp33d

nice project. how did it turn out? i am building a 69 camaro and used a shop in Alabama to modify torque tube. shop is gamel street rods. went with c6 and they built the chassis. pleased with their quality and expertise.