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Re: Subframe connectors, which way shoul
[Re: Vert]
#962
08/20/03 03:35 AM
08/20/03 03:35 AM
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Joined: Jan 2003
Posts: 477
Clarkston,MI
Todd_DesMarais
super street
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super street
Joined: Jan 2003
Posts: 477
Clarkston,MI
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Wize, I'm with you on pre-loading the chassis. I just can't picture the "how to" with a heim setup. (limited scope of vision per se ?) a cage will ultimately make the chassis the most rigid, but the "here and now" was to at least tie the front and rear together.
I was too young to catch the wire car when it was new, but have since found Don's car to be a cool project. It's kinda like mom's cross your heart bra 'eh ??
Vert, A triangle is the strongest shape in nature, especially an equalatteral triangle. that applies to a force exerted to one side. but as for torsional strength, I haven't the brain power to figure it out. In your question, did you mean to make the connectors from triangular stock, or to triangulate the frame (ala rollcage) ??
aduC' 47
IIeredevleB 66
383 etilletaS 66
DTC 0053 MAR 50
"ssenlli latnem a dna ,ybboh a neewteb enil enif a si ereht"
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Re: Subframe connectors, which way shoul
[Re: Streetwize]
#963
08/20/03 10:11 AM
08/20/03 10:11 AM
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Joined: Jan 2003
Posts: 6,480
USA
Molloy
master
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master
Joined: Jan 2003
Posts: 6,480
USA
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Quote:
I merely looking for a way to find lateral tuning (the torque reaction of the MoPar chassis is very well understood already) and limiting/adjusting (for track conditions) torsionally what is already there.
Now I think I understand why you want to use heim joints.
Thanks,
-Molloy
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Re: Subframe connectors, which way shoul
[Re: Vert]
#964
08/20/03 10:13 AM
08/20/03 10:13 AM
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Joined: Jan 2003
Posts: 6,480
USA
Molloy
master
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master
Joined: Jan 2003
Posts: 6,480
USA
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Quote:
My question... anyone try a triangular section for chassis stiffening? I thought it would be the structure with the highest resistance to flexing. I can see difficulties in welding it to a non-flat surface. Any thoughts?
I'm confused again. Triangular cross section for subframe connector tubing?
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Re: Subframe connectors, which way shoul
[Re: Molloy]
#967
08/27/03 01:03 PM
08/27/03 01:03 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
I see what you're saying about triangular cross section connectors.
The individual subframe connectors, which are closer to the edge of the body, will likey experience more of a classic bending moment, in which case a rectangular box section will likely be best suited.
I'm way late chiming in here and I apologize for that, but I want to step up in support of Malloy's opinion.
I believe he has it right when he says that the sub frame connectors primarily experince a bending moment (rather than torsion). The further out from from the driveshaft the connectors are, the more this is true. Think of it this way: take a rectangular piece of sheet metal in your hands and twist it like a car twists when you get on the gas. See how the two outside edges of the sheet metal bends? Yes, there is a torsional component to that force, but it's primarily a bending moment and square/rectangular tube is great for that.
BTW, the best shape for pure torsional stiffness is a cylinder. Think drive shaft, torsion bars etc.
Now, back to our regularly scheduled program 
-jr
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Re: Subframe connectors, which way shoul
[Re: RedCharger]
#972
09/02/03 07:26 PM
09/02/03 07:26 PM
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Joined: Jan 2003
Posts: 17,843
S.E. Michigan
ZIPPY
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 17,843
S.E. Michigan
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Don't sanctioning body rules state they want the floor pan completely welded to the connector? I believe they do here in the states anyway.....
Molloy, yep that is a good idea and I see the potential. It will probably have to wait until later though, probably at whatever time outriggers get added/cage goes in/mount for the seat belt crotch strap gets welded to the connector. It will probably happen but later down the road.
Rich H.
Esse Quam Videri
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Re: Subframe connectors, which way shoul
[Re: RedCharger]
#973
09/02/03 09:16 PM
09/02/03 09:16 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
two separate people have told me that the welds should not run the whole length of the subframe connector it should be 2 Inches of weld then a two inch space of no weld. Apparently when people now seam weld race cars they do this also and it is better than a solid weld. What do people think ?
It may be "better" because it's (marginally) lighter....or causes less distortion....or because it's strong enough....who knows. One thing is for sure though....for a given size (cross sectional area) stitch welds are NOT stronger than full welds. BTW, aren't you worried about exhaust fumes?
-jeff
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Re: Subframe connectors, which way shoul
[Re: M_D]
#975
09/03/03 12:01 AM
09/03/03 12:01 AM
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Joined: Jan 2003
Posts: 117
Melbourne Australia
RedCharger
member
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member
Joined: Jan 2003
Posts: 117
Melbourne Australia
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Yeah I think will run the welds down the whole length of the rails. I am not worried about the exhaust cause I have made a template to follow the floor and I will trim the rails with a plasma cutter to match so I am not actually cutting the floor. I was going to get a mate to weld it with a Tig anyone use a Tig to weld them in ?
Thanks,
Mike
Last edited by RedCharger; 09/03/03 12:02 AM.
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Re: Subframe connectors, which way shoul
[Re: RedCharger]
#976
09/03/03 12:42 AM
09/03/03 12:42 AM
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Joined: Jan 2003
Posts: 477
Clarkston,MI
Todd_DesMarais
super street
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super street
Joined: Jan 2003
Posts: 477
Clarkston,MI
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Redcharger, if you cut the connector to match the floor contour, you will be loosing a good deal of the structural rigidity that a box section gives. I understand if you don't want to cut the floorpan, as I don't want to touch my pans in my cuda either. another option is to let them hang just below the pan, and angle the rear up to the frame rail.
as for welding, a proper weld is stronger than the two metals it adjoins. the best way to weld sheet metal is to "stitch weld" it. this doesn't mean leaving spaces, but to weld an inch skip an inch and so on. then go back and weld the skipped areas. the other option is to do as stated above, spot weld (small weld puddles) down the length, then fill the whole seam in.
what car are you working on? we have quite a few pics of Rich's b-body if you want 'em.
Todd
aduC' 47
IIeredevleB 66
383 etilletaS 66
DTC 0053 MAR 50
"ssenlli latnem a dna ,ybboh a neewteb enil enif a si ereht"
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Re: Subframe connectors, which way shoul
[Re: Todd_DesMarais]
#977
09/03/03 02:38 AM
09/03/03 02:38 AM
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Joined: Jan 2003
Posts: 117
Melbourne Australia
RedCharger
member
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member
Joined: Jan 2003
Posts: 117
Melbourne Australia
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Hi Todd, Thanks for explaining the stitch welding it all make sense now. The car is an Aussie Charger it appears the same as a US A body. Cheers, Mike 
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Re: Subframe connectors, which way shoul
[Re: roadrunnerreds]
#979
09/03/03 09:26 AM
09/03/03 09:26 AM
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Joined: Jan 2003
Posts: 17,843
S.E. Michigan
ZIPPY
OP
I Live Here
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OP
I Live Here
Joined: Jan 2003
Posts: 17,843
S.E. Michigan
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Brad, the 3" section is vertical.
The rear frame rails were opened at the end and had 5x9/16" or so holes drilled in each side (for a total of 20 holes).
The SF connectors were slid inside the frame rails, welded at the open end, then each of the 20 holes were also welded to close them and attach the connector to the frame rail on three sides.
There is nothing to attach them to at the top side, which again helps make the case for running them through the floor.
At the front, the connector is first welded to a flat plate which is then welded to the trans crossmember.
For a 69 B body you need two 4 foot (even) sections of .083 wall 2x43 tubing to make them, and the connectors themselves don't need any more work to fit, other than welding a plate to the front.
Rich
Rich H.
Esse Quam Videri
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