BUILD-OFF CHALLENGE: Tygaboy's '75 LS3, It seemed a good idea at the time... Options

[tygaboy]

Here's the latest thinking on the chassis stiffening design.
1. It's a "race rod". This is a term I'm claiming defines a car that has elements of race car-ness but is clearly a "hot rod".
2. Given #1, above, I'm not trying to build something that will pass tech or be the stiffest ever (or even close) cage. I am after something that will be a big improvement over stock and help handle the motor.
3. Bonus points if it's a bit unique and makes me smile.

Initial mock up meets my criteria! (IMG:style_emoticons/default/biggrin.gif)
(note the tubes are not positioned exactly, exactly, but you get the idea...)

I'm going to plate the seat belt retractor area and land the angled bar top at that spot. On the back side, I'll remove the factory anchor bolt, plate that side and run a tube from there back to the suspension tower.

This saves me trying to fab a complex, multi-bend compound tube and eliminates having to deal with another hole in the firewall.

[tygaboy]

Keeping with the race rod approach, I'm going to stay with the stock, 3-point retractable seat belt.

With the cage location, I need to move the seat belt retractor. I talked with Seat Belt Planet and they can add the needed length to the belt so I can relocate the retractor to the base of the firewall.

So long as the retractor mechanism is mounted in the same physical orientation as stock, I'm good to go.

The retractor is just sitting there, not attached. I still need to fab the mounting location but again, you get the idea.

[tygaboy]

Mock up of the location for the shifter.

Feels like I'm making progress again. (IMG:style_emoticons/default/cheer.gif)

[tygaboy]

I want to do some additional "triangluation" for the angled bar so I stated playing around with what a perforated panel might look like. This is the first hack/sketch so...

It'd echo the engine compartment panel design but I think this time I'd use 2 mirror image pieces and seam weld together the inner edges of the dimpled holes, making a hollow panel about 1/4" thick. Plenty strong.

And worst case, I can always use a tube to triangulate.

The saga continues.

[csdilligaf]

I like the plan. It will be way better than stock but still give you easy enough access. Good choice.

[tygaboy]

Chris I've nothing to add really but to say this is one damn cool build.
Enjoy your creativity and fabrication work.
Those seats are really cool.
Would individual style hoops work per seat. Styled like the Audi TT.
Just a thought. Have at it.

Dion - Great minds... I've bent up a pair of "roadster hoops" that are, for lack of a better description, 90 degree bars that run from the seat belt retractor location, behind the seats, right behind the head rest supports, then down, paralleling the shape of the seats. They form the rear-most part of the tunnel design. I'm just not sure I like it.

I'm trying to be sure I don't back myself into a corner with things like being able to create an access panel in the firewall, etc.

This build is really forcing me to think as many steps ahead as I possibly can.

The whole side-to-side bar is turning into a big challenge. I need as much room as I can get inside the car for seat adjustment and safety. And I need room in the engine compartment for the induction system I'm contemplating.
So it's not a slam dunk as to where it'll best fit or what design will work best. Then there's the whole "do I really even need it?" question.

But hey, if this stuff was easy, what fun would it be? (IMG:style_emoticons/default/laugh.gif)
I'm really enjoying the challenge!

[Cracker]

I really like the direction you are going...only one design element to consider (given your point #1 above). The horizontal bar over 4th he rocker does not have to be that high...not even close. Consider positioning it at 1/2 the current height or keep the rear height the same and taper it down to the front. Can you "mock" it up like this repost pictures? Looking great Chris!

T

[tygaboy]

I really like the direction you are going...only one design element to consider (given your point #1 above). The horizontal bar over 4th he rocker does not have to be that high...not even close. Consider positioning it at 1/2 the current height or keep the rear height the same and taper it down to the front. Can you "mock" it up like this repost pictures? Looking great Chris!

T

Tony - Thanks for the encouraging words. I appreciate all comments and especially from those with experience. And as always, your wish, sir, is my command. (IMG:style_emoticons/default/pray.gif)

Obviously, I didn't have the correct length supports.

Looks wise? I happily admit, I really like it!

I think I'll bend up a new tube that runs all the way from the from to the back and see how that looks. It'll soften the look at the transition angle and better match the shape of the seat.

Now, if I could just convince Rudy to work up his math on the difference in stiffness between these two designs...! (IMG:style_emoticons/default/lol-2.gif)
(seriously, though Rudy, that's impressive stuff to us who don't know a cosine from our elbow.) (IMG:style_emoticons/default/aktion035.gif)

[Cracker]

Double post...

[Cracker]

Hey Chris...have you ever thought about something like this??? (IMG:style_emoticons/default/stirthepot.gif)

Tony

[tygaboy]

And in the spirit of full disclosure:

I've said it before - mostly you see the end result in the pics, not the gaps in knowledge or experience, or the 'n' number of attempts at getting things to work out. So, it's only fair I pay tribute to those parts and pieces that sacrificed themselves to the cause. These are the latest examples of my learning as I go.

Put these in the "Don't" column:

- You can't expect a good result unless you have thought ahead and allowed for enough tube length so that the front part of the die doesn't run off the end of the tube and totally gack the part. (Yes, that is a rip in the tube...)

- given a particular radius die, there are limits to how close you can bend two radii. If you think you can outsmart physics and magically get them closer, you are wrong.

- as with all things in life, the facts are the facts and no amount of lube will make any difference.

I should start a website called "FabFail.com".

I'd be a regular contributor...

[Cracker]

Much better Chris... (IMG:style_emoticons/default/beer.gif)

If Patrick Motorsports would build a "race car" with such a cage (which I don't agree with btw) - it is perfectly fine for a "Race-Rod"! Regardless of the loss of stiffness... biggrin.gif

T

[tygaboy]

Hey Chris...have you ever thought about something like this??? (IMG:style_emoticons/default/stirthepot.gif)

Tony

Which part(s)?
Dropped floor? right hand drive? the pedal box? a bolt in roll cage mount? orange? working on my build outside?
(IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/happy11.gif)

[Cracker]

LOL!

Which part(s)?
Dropped floor? right hand drive? the pedal box? a bolt in roll cage mount? orange? working on my build outside?
(IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/happy11.gif)

[tygaboy]

Hack in MS Paint V2.

Maybe like this. But the bend would be a bit larger radius.

[Andyrew]

Mock up of the location for the shifter.

Feels like I'm making progress again. (IMG:style_emoticons/default/cheer.gif)

Looks like the exact same location mine is in! I believe I tilted mine a hair as well, in practice I dont think that was necessary.


I like the door bars too, I've been contemplating seriously doing a hidden cage on my car and your door bar design has always been on the back of my mind

[Curbandgutter]

[/quote]
Now, if I could just convince Rudy to work up his math on the difference in stiffness between these two designs...! (IMG:style_emoticons/default/lol-2.gif)
(seriously, though Rudy, that's impressive stuff to us who don't know a cosine from our elbow.) (IMG:style_emoticons/default/aktion035.gif)
[/quote]

No no no, no more calcs. (IMG:style_emoticons/default/hissyfit.gif) They are summarily disregarded based on anecdotal experience. (IMG:style_emoticons/default/stirthepot.gif) I'll play along. (IMG:style_emoticons/default/slap.gif) Anecdotally I can say that your current design delivers all of the loads to the weakest point in the long. Do your self a favor and tie your front hoop up to the strut tower. If you do that, then you're on to something. Alternatively, do one of your awesome gussets and tie that vertical front hoop bar into the vertical sheet metal area behind the A pillar. Otherwise, it's a very good looking design without adding much structural integrity to bending forces in the longs. (IMG:style_emoticons/default/chair.gif) It does look really good though. Especially that gusset back to the firewall. My 0.02 $.

[Curbandgutter]

This is what I mean

[ablesnead]

You said race rod ...so in that spirt lose the gusset idea...does nothing but add weight....and even though the fabrication looks cool , it crosses the line of extraneous ....my opinion of course...but I am cursed with excellent taste (IMG:style_emoticons/default/smile.gif).......

[tygaboy]

[quote name='Curbandgutter' date='Jul 26 2017, 02:29 PM' post='2510405']
[/quote]
Now, if I could just convince Rudy to work up his math on the difference in stiffness between these two designs...! (IMG:style_emoticons/default/lol-2.gif)
(seriously, though Rudy, that's impressive stuff to us who don't know a cosine from our elbow.) (IMG:style_emoticons/default/aktion035.gif)
[/quote]

No no no, no more calcs. (IMG:style_emoticons/default/hissyfit.gif) They are summarily disregarded based on anecdotal experience. (IMG:style_emoticons/default/stirthepot.gif) I'll play along. (IMG:style_emoticons/default/slap.gif) Anecdotally I can say that your current design delivers all of the loads to the weakest point in the long. Do your self a favor and tie your front hoop up to the strut tower. If you do that, then you're on to something. Alternatively, do one of your awesome gussets and tie that vertical front hoop bar into the vertical sheet metal area behind the A pillar. Otherwise, it's a very good looking design without adding much structural integrity to bending forces in the longs. (IMG:style_emoticons/default/chair.gif) It does look really good though. Especially that gusset back to the firewall. My 0.02 $.
[/quote]

Rudy -
My explanations and execution are always behind the plans in my head.
Yes, I already had plans to tie the front hoop into the chassis, I was thinking the gussets would be a lot simpler to execute than tubes to the front towers but we'll see which I end up liking best. I am a slave to fashion, don'tcha know!

I also plan to tie the front hoop in as part of center tunnel/console. It will run to the front of the floor and up the inside of the front bulkhead. That should help add a bit more "twist resist".

Always appreciate your input, my friend!