Structural sills, no torque boxes

[Geoff]

https://www.studebaker-info.org/AVDB2/AvantiRQA/67QA0151/67QA0151x07112018/67QA0151x07112018b.jpg
https://www.studebaker-info.org/AVDB2/AvantiRQA/67QA0151/67QA0151x07112018/67QA0151x07112018.html
https://www.youtube.com/watch?v=1n5Oq_yyG_o
https://www.youtube.com/watch?v=CaAAdalko50
and has done away with torque boxes. That car's frame has also been 'sturdied' as seen in one picture.

Normally what, the frame bolts to the torque boxes and the torque boxes are adhered to the body, yes? If the torque boxes are omitted, the frame must bolt to something. The quest then becomes to create that something. What hits me right off the bat is, I would borrow a page out of the C5 & C6 'Vette book, sandwiching balsa wood between two fiber mediums. Or just sandwich three to five fiber mediums together, oriented in different directions. The final creation also needs threaded inserts or similar solution, to anchor the bolts.

My basket case needs some underside work and I too may omit torque boxes.

Edited December 7, 2022 by GeoffC312
I think my text hid some details. I extricated the links and killed my text.

[Kodjo]

It's not that simple. A torque boxes is called torque box because it has to make the car stiff. They are not there just to keep the distance between frame and body.

[mfg]

The torque boxes or " hog troughs" also lend  support, and anchor the rollbar..such as it is!

[Dwight FitzSimons]

The roll bar "such as it is" isn't too bad.  A local person flipped his nearly new '64 Avanti on a peaked (sharp) hill on a narrow road.  The car slid, nose first, on the pavement into a pole.  The windshield header was pushed down maybe 2 inches and roll bar not at all (that I could discern).  He was going probably well over 60 at the time.  So, it did its job at street speeds.

--Dwight

[mfg]

29 minutes ago, Dwight FitzSimons said:

The roll bar "such as it is" isn't too bad.  A local person flipped his nearly new '64 Avanti on a peaked (sharp) hill on a narrow road.  The car slid, nose first, on the pavement into a pole.  The windshield header was pushed down maybe 2 inches and roll bar not at all (that I could discern).  He was going probably well over 60 at the time.  So, it did its job at street speeds.

--Dwight

The stamped steel " roll bar" found in original Studebaker Avantis is more substantial than what is found in later Avanti ll's (with moon roofs)

[pantera928]

5 hours ago, mfg said:

The stamped steel " roll bar" found in original Studebaker Avantis is more substantial than what is found in later Avanti ll's (with moon roofs)

I hope never to have to test that statement!

[Geoff]

So I should have clarified in the beginning: I know I'm not just applying a filler between the body and frame. It somewhat is, though I know said filler needs to be of a certain conformity. I'm also aware the roll bar attaches to the torque boxes. I am also contemplating replacing the factory stamped steel bar with DOM steel, like an actual roll bar.

This has already been done, and the car to feature it sustains road course beatings. I'll picture it here, but this pic. and more are linked in the initial post. I'll stop posting links inside of my written text. Maybe that hid too many details?

Carbon fiber is strong, as this segment shows, https://www.youtube.com/watch?v=hjErH4_1fks. Also, I read about Chevrolet sandwiching balsa wood between composite materials. That made the floor 10× stronger than using composites alone, plus balsa filters out noise and vibration.

Okay, so culminating all of the above: I am taking aim at creating a rustproof substitute for stock torque boxes. I may use chopped mat fiberglass, I may use carbon fiber, I may include balsa wood, I may pick everything listed above, and some materials unlisted. I just want to recreate "structural fiberglass sills in place of hog troughs" as seen below.

Now that it's better explained, and better visualized, how do you suppose this was done?

Edited December 7, 2022 by GeoffC312
Nuked links; just typed out URL addresses

[mfg]

Sounds real interesting...probably stronger than original.

PS...The Grantellis installing roll cages in Bonneville #8 & #9 is an indication they didn't have complete confidence in factory 'roll bar'.

Edited December 7, 2022 by mfg

[Avanti83]

It would be nice to see a few more shots of the underside, particularly with the body on frame, but it looks like they did exactly as you described. They apparently boxed in the rocker panels and other areas under the body and then mounted it to the frame. Exactly where the mounting points are located is not all that obvious. 

They could have used wood or even foam in the areas like the rocker panels to fill the void and provide rigidity.

It must work as the cornering shots in the video look like the car handle very well. 

The early corvettes didn't use hog troughs so they probably just used more box sections than the Avanti's.

https://www.rkmotors.com/blog/Corvette-Bones-Growing

Good luck on your project and keep us in the loop.

[Geoff]

I'll definitely be documenting my progress with my basket case, both in stills and in videos. There is so much I want to do to it, and don't mind at all making my alterations publicly available. I have reached out to the owner of the Targa Tasmania car, to learn more about it. As you say, it would be great to see more shots of the frame and body together.

[Geoff]

I found an update to this inquiry. Here's the Targa Tasmania Avanti's frame. I notice those extensively modified mounts. I even see some tabs amended outside of the 'driveshaft valley' on the X.

I'm leaning towards tearing down and rebuilding my car on a Titan rotisserie; I have this internal monologue speaking to me about working smarter not harder. Other tasks are at the top of my list but I hope to be at the frame modding stage later this summer.

[Desert Driver]

I think you're going in the right direction with this project. Those hog troughs were a quick solution to securing a wider chassis to the narrower Lark frame While providing structural rigidity. The outriggers on the frame shown in the photo look quite substantial. Couple that with reinforced fiberglass, and you've got something better than what Studebaker engineers came up with for the Avanti. Those guys were under the gun to get the car into production while saving money to keep the auto division alive. Working smarter beats working harder every time!

[Geoff]

I'm hoping so. My goals are to make that area lighter and more durable (stronger and rust resistant). The torque boxes are known rust items and I don't want to rely on scheduling repairs every so often.

I will mount a belly pan to the bottom of my frame and I'll be storing my car circa Thanksgiving, bringing her back out circa Tax Day each year but I have heard how labor intensive it is to remove and replace torque boxes. I don't mind spending more time on it once and being finished with it.

[Zedman]

On 2/14/2023 at 10:09 AM, GeoffC312 said:

I'm hoping so. My goals are to make that area lighter and more durable (stronger and rust resistant). The torque boxes are known rust items and I don't want to rely on scheduling repairs every so often.

I will mount a belly pan to the bottom of my frame and I'll be storing my car circa Thanksgiving, bringing her back out circa Tax Day each year but I have heard how labor intensive it is to remove and replace torque boxes. I don't mind spending more time on it once and being finished with it.

Hi GeoffC- I have my Avanti II body completely off the Chassis and a new one nearing completion & paint very soon. I would direct your attention to this Blog- http://hogtrough.blogspot.com/

It entails the whole operation with lots of commentary and diagrams. The added benefit is that it stresses there is no need to cut fibreglass.

I will be utilising this Blog very soon and believe the whole job to be much easier still, because the Body is already up. Likewise, you have already done the hard part !

I already have the replacement two-piece Torque Box kit. Funnily enough, when I ordered these from Classic Enterprises, I specifically chose mild steel ('cos here in Australia- we don't get snow and salt combinations!), but they charged me extra and sent Stainless steel anyway- (Duh... read guys, please!).  In any case - Stainless would eliminate the corrosion problem in your case and they aren't all that heavy either.

Would it be expedient to just renew the old ones?

Edited February 18, 2023 by Zedman

[Geoff]

My existing frame and torque boxes are gone-zoh. Well to be fair, a lot more than that is toast. My poor car was sitting for longer than two decades, getting acquainted with plant life. And the sunroof leaked, so there's that. If I recall correctly last she was road worthy was 1998.

This picture the prior owner took just after she was removed from living the plant life. The section of the tires buried in mother Earth is visible; lots of the low metal pieces were taking dirt naps. An '84 or '85 "on the dismantler's doorstep" was what I wanted to start with. I found one!

I like the idea of no torque boxes, and that this route can be made more durable.

[Zedman]

On 2/18/2023 at 5:04 PM, GeoffC312 said:

My existing frame and torque boxes are gone-zoh. Well to be fair, a lot more than that is toast. My poor car was sitting for longer than two decades, getting acquainted with plant life. And the sunroof leaked, so there's that. If I recall correctly last she was road worthy was 1998.

This picture the prior owner took just after she was removed from living the plant life. The section of the tires buried in mother Earth is visible; lots of the low metal pieces were taking dirt naps. An '84 or '85 "on the dismantler's doorstep" was what I wanted to start with. I found one!

I like the idea of no torque boxes, and that this route can be made more durable.

Hi Geoff- My apologies if you thought I was treading on your toes, I don't mean to- you have got far more guts than I !   I just believe you may well get your Avanti on the road and driving a lot quicker by going the factory route. I am well down that track already and it is a significant opus I can tell you.  What are you doing with the existing Chassis?  Are you going to repair it or opt for another one?  Good luck with this project and have fun.

 

Edited February 20, 2023 by Zedman

[Geoff]

You're good, and I appreciate the clarification.

I have a replacement frame already, in good condition. Everything going on the car which can benefit from a rust inhibitor will get a coat or two. Nearly every item in the car now is getting removed and given away, trashed/recycled, or sold. I'll be taking the car down to the fiberglass body and starting from that phase.

My optimism would love to have the car up and going by October this year but realistically I should extend that another six months, using next winter to finish up, bringing it out April of next year. I want to take the finished product to shows and events all over the country.