Welding on a long cover, Is this a mistake? Options

[obscurity]

Just thought I would ask what peoples thoughts are on welding a cover over the corrugated inner dogleg replacement panel. It looks more factory(kind of) but it also may just look crappy. Just looking for some opinions. It does go a good bit forward and add strength at the expense of some weight

[targa72e]

I added another layer of sheet metal reinforcements on my -6 conversion when I removed the -4 mounts as some said it added strength. figured it cant hurt.



John

[Superhawk996]

I contemplated doing the wrap like you have and then decided against it.

See my thread post #478 (page 24) & #483 (page 25 primered) for alternate approach to dealing with the corrugations to smooth them and to add some additional bending stiffness without all the weight.

http://www.914world.com/bbs2/index.php?sho...5209&st=460

[rick 918-S]

If it was mine I would cap it.

[Superhawk996]

Let me offer up a little more rationale on the reason I chose the path I did.

The secret of unibody construction isn't in simply adding more material. Strength comes from the geometry of the section. This is what gives us light weight with more stiffness than old school body on frame construction that was so popular with domestic OEM's right on though the 70's. Unibody construction delivers more stiffness with less weight.

In this case of the 914 longitudinal, the bulk of the strength comes from the closed out box sections not the metal thickness. The aftermarket reproduction C section with the corrugations is roughly the same thickness as the OEM dual layer C-Section was inclusive of the inner corrugated layer that is spot welded to the outer.

By closing out the corrugations, it essentially makes makes smaller vertical box sections, closing out the little corrugated c-channels. So now we have an overall geometry that is the same as OEM. A larger overall box section (the Long) with the smaller vertical box sections along its length. Gaining strength with minimal weight add.

Might want to consider taking time time to watch this little video. Very dated but the demonstrations on section geometry is useful. That starts at about the 2:46 mark.


https://www.youtube.com/watch?v=8Ob2tVP5miE

[Root_Werks]

If you look at the inner long kits, there are holes you weld to an already solid long skin. It seems adding just a wrap over and welding along the outside wouldn't do much to strengthen.

[930cabman]

Let me offer up a little more rationale on the reason I chose the path I did.

The secret of unibody construction isn't in simply adding more material. Strength comes from the geometry of the section. This is what gives us light weight with more stiffness than old school body on frame construction that was so popular with domestic OEM's right on though the 70's. Unibody construction delivers more stiffness with less weight.

In this case of the 914 longitudinal, the bulk of the strength comes from the closed out box sections not the metal thickness. The aftermarket reproduction C section with the corrugations is roughly the same thickness as the OEM dual layer C-Section was inclusive of the inner corrugated layer that is spot welded to the outer.

By closing out the corrugations, it essentially makes makes smaller vertical box sections, closing out the little corrugated c-channels. So now we have an overall geometry that is the same as OEM. A larger overall box section (the Long) with the smaller vertical box sections along its length. Gaining strength with minimal weight add.

Might want to consider taking time time to watch this little video. Very dated but the demonstrations on section geometry is useful. That starts at about the 2:46 mark.


https://www.youtube.com/watch?v=8Ob2tVP5miE

Once again, +1 Phil.
Thanks for sharing, it's all numbers in the end