Weight reduction: Running out of ideas.

This supports the heater on the trans tunnel, or at least it did on my 73 vert body. Very heavy!

I started scraping out the sound deadening material and it is up to 0.25" in places. That stuff is everywhere. I'll bag it and weigh it when done, but there must be 8 lbs of it.

It cuts down on cowl shake by triangulating the birdcage. It was not there to just hold up a heater core. George
 
This supports the heater on the trans tunnel, or at least it did on my 73 vert body. Very heavy!

I started scraping out the sound deadening material and it is up to 0.25" in places. That stuff is everywhere. I'll bag it and weigh it when done, but there must be 8 lbs of it.

It cuts down on cowl shake by triangulating the birdcage. It was not there to just hold up a heater core. George

I'm putting in a 14 point cr-moly cage, I don't think I'll need it. But you are right, in the vert it had cross brace bars to the sides. Those went first.
 
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There might be another not in the photo, none are going back in. Two tied to the bracket in earlier post. I'll see if I can find a scale.
 
A little more progress on aluminum muffler

Had a couple hours to play around with the new muffler. The old Dynomax muffler (and the stainless tip I put on it) got chewed up a bit on the last track day after a bracket broke after a few sessions of bottoming out on a dip in one of the corner's apex. I figured as long as I had things apart I'd just try to make a little progress. Here's a picture while test fitting things. The current plan is to make it a three chamber setup (only two are tacked together at the moment).



All three chambers will have slots/holes drilled in them, and surrounded by fiberglass muffling material. An item I'm still trying to decide on is if all three chambers will flow exhaust gas, or if the first two chambers will be just pressure surge volumes, and all the mass flow will occur at the outer chamber hooked to the yet unpolished baloney-cut tip.
 
The aluminum muffler has potential, might want to study Borla's design.

For the record, I scrapped out most of the spray in sound damping material, it weighed 9 lbs 12 oz. A heat gun is needed to soften it up.

The plate under the heater weighs 4lbs 9oz. The cross bars weighed 1lb 9oz.
 
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This supports the heater on the trans tunnel, or at least it did on my 73 vert body. Very heavy!

I started scraping out the sound deadening material and it is up to 0.25" in places. That stuff is everywhere. I'll bag it and weigh it when done, but there must be 8 lbs of it.

It's my understanding that that piece is only used on convertibles, not coupes. Please correct me if I'm mistaken.
 
image_3.jpg


This supports the heater on the trans tunnel, or at least it did on my 73 vert body. Very heavy!

I started scraping out the sound deadening material and it is up to 0.25" in places. That stuff is everywhere. I'll bag it and weigh it when done, but there must be 8 lbs of it.

It's my understanding that that piece is only used on convertibles, not coupes. Please correct me if I'm mistaken.

Most likely. I took the heater out of my coupe a long time ago, but never saw this.

That sound damper material might be thicker on a convertible too. There sure was a lot, I'm cutting out the battery boxes, so left it in there. Easily over 10lbs total.

I did an image search on Borla's and they have a new style called "multi-core" that looks a lot simpler than their old multi chamber design.
 
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FWIW, I need to pull the heater core out of the car one of these days. It started leaking several years ago and it's presently just bypassed. As long as it's not doing anything productive, and the car is only driven in the summer, I might as well just get rid of that dead weight. I've never pulled a heater core out of a C3 so I'll have to do a little bit of reading I guess.
 
I ripped out all of my heater assembly, controls and everything, a long time ago with no regrets.

I consider my Vette a 4 wheeled motorcycle; if you don't need it on a motorcycle, I don't need it on my Vette. :thumbs:
 
26 lbs. is what comes to mind when I removed & weighed the heater core, fan cage & box, hoses, coolant amount, duct work, blower motor etc. on my 73.
 
Here's another for guys with convertibles. I just picked up another hardtop and I swear it is half the weight of the red one I have on my old car. I'll weight it and update this. I've heard that mentioned on other forums, so maybe one is earlier or aftermarket.

The recent one has spiderweb cracking so the plan is to do/try carbon fiber skinning with low temp epoxy. I got it really cheap.
 
Okay My attempt to go light. An aluminum AC bracket for my '69. Had the iron piece cast and polished. George
 

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Small foundry in So Cal. Use to be a lot of them to support aerospace. 70 for the two pieces. Free cast.
 
Okay My attempt to go light. An aluminum AC bracket for my '69. Had the iron piece cast and polished. George

Cool!
I've been tempted to cast a few items like that also, but just haven't had the time to set up a micro-foundry kind of thing. My dad used to cast aluminum parts for his race car back in his youth. It looks like an interesting thing to try.
 
Making a little more progress.

Got the outer housing initially shaped, with a bit more tweaking to do yet. It's 1/16" for strength, but that also makes it a bit tougher to bend and shape. I've got three chambers in it. The first chamber is primarily a surge volume/attenuation piece, while the other two are primarily attenuation pieces, similar to a pair of glasspacks in parallel. Below is a test fit.

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I've drilled a couple hundred holes in the tubes, along with a few dozen slots to allow noise/vibrations to interact with the fiberglass and SS packing material around the tubes. Still have a similar number of holes and slots to cut yet before I can start to weld the end caps on. I also need to polish the exit pipe so it looks similar to the stainless tip on the other side of the car.

Right now the weight is 7 1/2 pounds. My target is 10 pounds (six less than the muffler it's replacing).
I was looking on ebay and found some inexpensive sound dB meters. I'm going to order one, and then hopefully be able to make a reasonable judgment on the comparative noise reduction capabilities of this and the other side muffler.
 
did you see the guy on ebay selling fiberglass replica bumpers & bumperettes?

No I hadn't. I did talk to a guy last summer who had them/similar pieces on his '69. There's probably 15-20 pounds that could come off the car with those pieces, but I'm still a bit shy about making these C3 antiques any less safe than they already marginally are.
 
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