a) D$#@ Those doors do have side impact beams in there don't they.

b) You are right. I forgot about that part.

c) I think if anyone of us flip in our vettes, unless there is a proper roll bar, or cage, we are pretty much screwed.

5) I wouldn't want to replce my firewall with steel. What I was thinking of was much thinner fiberglass with a polyurethane coating. Problem is polyurethane is a fire hazard. Scrath the firewall idea... not worth it.

I don't need an engeneering degree to know that carbonfiber needs to be thick (IE multiple layers) to be strong, and that in certain locations, like between 6 & 8 the carbon fiber would be too thick to conceal.

No need for engineering course work. I am a fairly rational person, let the engineers be engineers, I'll just stand on the shoulders of giants. That is if you engineering folk (yes you too Norval) don't mind me picking your brains.

Yeah, that car is the Greenwood car. A real flopy jalopy from what I've read.

After all this, and looking at the bircage pic a bit more I think
6) part 3 could be entirely replaced by a tubular steel panel. That would be more rigid, and possibly lighter and
7) to hell with the loop portion completely. The car would be better off with a roll bar. Yes I know it adds weight, but if the car weighs the same (or slightly more) after replacing part 3 and ditching the loop, but with a roll bar that increases frame rigidity and makes the car legal for the track, then why not?

Sorry for the poor sentance structure.

 

MikeC-

Plug them holes up with epoxy. Actually for what I was thinking, I would probably go with tubular steel, and then fabricate a sheet of fiberglass to cover up the hole.

I have an 81, so no problem there.

 

HOnestly replacing part 3 with steel tube and fiberglass sheet would weigh more. Honestly the birdage is not the place to save weight. Its only around 100lbs.

Heavy parts are where you want to save-- transmission crossmember - go tubular, you'll probably save 5-10lb. Rear end crossmember( go tubular and you'd probably save 5-10lbs. With these items you are reducing weight and probably increaseing rigidity and thus safety.

Go carbon fiber or alum. driveshafts and halfshafts. put lightweight racing seats in it, put bare minimum for carpetting and interior panels(remove all insulation)


Search the archives there was a great post on weight loss, many pages long with suggestions

 

look at all the holes the general put in there, one being in a very bad spot (access hole for steering power ram bracket on drivers side).


Twin Turbo that is a very bad bad hole and mine was plated over years ago. If you ever have a control valve ill adjusted and watch the frame where the ram bolts on you will see it flexing back and forth and wonder how why it doesn't fatigue with normal use.
Plate that section of the frame over and go right around the bend.

I agree with Mike there are lots of places to save weight and still not compromise safety.
Places that the weight will really come off.

 

I think that my last post is
- possibly around the same weight
- much safer
- more rigid
- track legal

 

Norval, I plated that hole, it was immediately apparent that that was a very bad spot right there. The whole steering box arrangement puts a lot of stress on the frame, much more than a rack would.

 

I am also adding the gussets to the lower A arm mounts and the motor mount as recommended by GM in the manual on how to prep the corvette for racing.

 

Pirates. I guess this is what it feels like. :p:

 

MikeC-

Ok now that I'm off the defensive, I may not even touch the birdcage. (See, I can listen to reason).

I still want to shave weight though (I know there are other areas, and there is nothing saying I wont do those too). How about speed holes in the side impacts beams? :smash: :eek: :crazy: :jester

No seriously, how about a composite polyurethane carbon fiber material? My issue with that however is, how the heck to you attach something like that? Couldn't weld it, and adhesive would break too easily in the event of a collision.

 

I'm gonna do that too, also seam welding my frame is only a little bit of work, somehow the later frames are 90% welded through, very strange.
Also thinking about plating up the rear crossmember/pinion mount section.

 

Also thinking about plating up the rear crossmember/pinion mount section

What area are we talking about. The pinion mount is a projection welded to the frame with a big hole in it or are we talking about where the 4 screws pass through the removable crossmember?
I never really looked at the pinion mount before.

 

I mean this:


the crossmember on the left, to which the pinion mounts.

 

Apple here's the thread I was talking about: http://forums.corvetteforum.com/zerothread?id=326967

IMO, its easier to do the cheap and sleazy stuff before getting into exotic stuff. Then if you get down to the weight you want you don't have to go to Carbon fiber, etc. unless you want to loose more weight.

I don't doubt with a little thought and little investment, you can get the vette into the low 3000lbs

 

MikeC-
Yeah, I've read that one before. Alot of good ideas. I've mentioned Gkull's front end before, quite a weight savings. I can only imagine the weight reduction came from better laid fiberglass thus allowing less material. I wonder if there is anything we could do to lighten up the pieces our cars came with. May have to read up on fiberglass.

Aside from the cheap and sleazy stuff, what are your thoughts on carbon fiber polurethane side impact beams?

 

Hi Norval,

Any chance you could post a photo of this? I've read about it somewhere (VIP?) but would like to actually see it done.

TIA

 

arrow marks the spot

 

Norval-

Wow that is a bad hole.

Any comments on the composite side impact beams?


[Modified by applevette, 1:31 PM 12/10/2003]

 

MikeC-

Come on Mike, I am not trying to be difficult. I am heeding your advise on the birdcage thing. I realize you are an engineer and know more than I do about certain things; that's why I ask.

 

The only problem with the composite side impact beam would be the bonds to the door steel. Without extremely good bonds there the impact beam will be useless. Just make sure the new beam is of same strength or better and figure out a way to effectively bond it to the door skin and front and rear door steel sections.

Once again, I implore you not to screw with the safety aaaspects of a car. Its a dangerous proposition and there could be legality issues when you remove/change safety items from your car.

I have heard of people sanding the baackside of fiberglass panels to lighten the car but you can only do that to so many areas with the body on the car..... even when the body is off of the car there are still areas you won't be able to get to.

Seriously consider the simple stuff, ie. bolts ons. Fiberglass rear leaf tubular transmission crossmember, tubular a-arms, aluminum heaad and rad, aftermarket hood or front clip. If you have a 78-82 see about getting the rear window replaced with lexan(check for legality). Possibly replace the popup head light assemblies with stationary ones. Aluminum or Carbon Fiber driveshafts. Figure out whether you can use an 80-82 rear end gear case(they are aluminum- but not as strong)if you are an earlier car.

 

Mike Lexan rear window?? How much does a stock window weigh? I have sheets of lexan here at work.
Never thought about that one but if I could save a few pounds :) :) :)