Unibody stiffening

[azopelnut]

I am going to be doing some repair to the frame rails on my Ascona 4 door (midwest car) and was wondering if anyone has any ideas on adding additional bracing to the undercarriage to create a stiffer (better handling) car without putting roll bars into the interior

[saxybiker]

I had a "frame builder" add some supports to my GT. They run diagonally fron the inner frame rail, next to the tranny, to the rear jack point. They really stiffened it up A LOT.

Allen Gage

[RallyBob]

Depends on how involved you want to get. I used to make frame connectors from the front-to-rear, as there's about a 12" space they left unsupported between the front frame rails and the rear ones. I used to recess these into the rear floors.

You could also add an inner rocker panel gusset of sorts...kinda like the '71-'73 Manta inner rocker supports (they didn't get a 'B' pillar until '74).

Or you could get brave and cut open the rocker panels and weld in a length of rectangular tubing. This tubing makes a huge difference BTW.

Bob

[azopelnut]

Anyone have any photos of their reinforced undercarriages???

[baz]

have a look in the gallery theres a few pics of some reinforcing
1 option is to seam weld the rockers to stiffen the floor

[saxybiker]

Here are a couple of pictures of the 2x2 rectangular tubing I had put under my car for frame stiffening. If I can remember how to attach them.

Hope this helps.

Vickie

[GoinManta]

Not sure how well it will stiffen it up, but I think at least a bit.

Where on the driver and passenger the frame rail runs front to back. The front jack points go between the frame rail and rocker at the front. The rear jack point isn't near as strong as the fronts. So it looked to me as if I added 2 extra 1"x1" square tube cross braces between the rocker and frame, evenly spaced between the Front and rear jack points on both sides, it might stiffen it up some.

I am doing this because I cut my floor boards out (leaving the rails in place) and noticed how thin they are and figured it wouldnt be hard to do at this point. I will take pictures and show tonight.

I also thought about maybe making up a tower brace for the rear shock towers.

Charles

[azopelnut]

(Charles said)I also thought about maybe making up a tower brace for the rear shock towers.

I like that idea a lot.... anyone do that to the front shock towers also??

[GoinManta]

The the Manta/Ascona body had front shock towers..

All it has is a nut protruding from the top of the frame rail down low. Hard to even find a picture with it.

Not to mention the hood almost already touches the engine. So doubt there is room.

Charles

[RallyBob]

This is a bit radical as far as street cars goes, but you get the idea. I cut the entire inner rocker panel out and welded in 2 x 3 rectangular tubing. Sorry about all the rust, the car sat outside for a while.

[jeff denton]

There's a stiff floor! But what's with the muffler? You're not doing a "seat warmer" too, are you?

[RallyBob]

Originally Posted by jeff denton There's a stiff floor! But what's with the muffler? You're not doing a "seat warmer" too, are you?

Nah....that's just my defunct hillclimb car. It's now a parts-storage container for a lot of junk. I have mufflers in it, wheels, tires, new rocker panels stacked on the roof, fender flares, etc. One of these days when I actually get back to working on one of my own cars again, I'm gonna rethink the whole thing and start over probably. This car was a circle track car that I gutted out in preparation to build a better cage and suspension.

Bob

[RallyBob]

Originally Posted by RallyBob It's now a parts-storage container for a lot of junk. I have mufflers in it, wheels, tires, new rocker panels stacked on the roof, fender flares, etc.

Just in case you thought I was kidding....

[azopelnut]

Originally Posted by RallyBob This is a bit radical as far as street cars goes, but you get the idea. I cut the entire inner rocker panel out and welded in 2 x 3 rectangular tubing. Sorry about all the rust, the car sat outside for a while.

Very cool ....and I am certain that it would be VERY strong Bob!
This makes me wonder if any Opelers out there have replaced their frame rails with some 2x3 square tubing? That would be possible ....right??? Could you cut and weld square tubing to match the bend at the front of the rail where it goes up to the firewall. Seems like a no brainer. This novice would like to know. I would think that would make the car very stiff.

[RallyBob]

Originally Posted by azopelnut This makes me wonder if any Opelers out there have replaced their frame rails with some 2x3 square tubing? That would be possible ....right??? Could you cut and weld square tubing to match the bend at the front of the rail where it goes up to the firewall.

I've made my own front framerails from scratch (for a rusted car) from 2" X 2" tubing. If I recall correctly, 1.5" x 2" is close to stock size, while 2" x 3" would be pretty darn big! I used to have a jig for this and I just cut and notched the tubing to fit the profile. The critical dimensions were the suspension location holes...hence the jig.

Makes me wonder what I ever did with that jig in fact???

Bob

[heimue]

Here's my idea of preparing a body (in my case a Rallye Kadett) for today's hard driven roads. When I started the car, I planned on taking the road in a topless Kadett. Putting in a visible subframe was not an option for me, but I wanted to make sure that the body had at least the stiffness as before, but more would be better. Well, the plan of building a convertible went down the drain (I just made up my mind), but some pipes and sheet metal made it's way down under (or in) the frame. For further clarity, crosscheck the colors on the pics:
I started with 2 different size rectangular pipes inside the rocker panels, (green and dark blue), that were welded together to form one solid section. In the front, I added a bent 2.5 mm sheet metal (red) to connect the pipes to the front frame and to the special made lower A-pillar (gray), also bent from 2.5 mm sheet metal (actually hidden under the A-pillar). At the rear, there are two connections (gusset plates, not visible anymore) between the pipe section and the sheet metal (medium blue), to tie back into the original frame sections and the wheel well. Additionally, there is a new (violet) cross member added, made out of, you guessed it, 2.5 mm sheet metal. The last goodie is an outer cardan shaft tunnel (orange), but if I remember that right, only made out of 1.5 mm sheet metal. There is some damper material between the two cardan shaft tunnels to keep noise down to a minimum.
I furthermore planned to tie a pipe between the upper ends of the lower A-pillar, inside the instrument panel area. The last thing would have been a bent sheet metal below the lower end of the rear window. Both parts were already prepared when I discontinued my convertible-idea and were never installed. I did this frame conversion as part of my study of automotive engineering, and did some finite elemente (FE) calculations on it (back in the early nineties, when FE software had to run on 386's computers...). Anyway, it promised to be real effective, although I don't have any nice pictures to prove it. Calculations at this early stage of FE calculations were output in page-long tables of numbers...
I'll include the original photos as well as the colored ones, so you can see more details.
Have fun with copying it,
Dieter

[heimue]

the other pics:

[heimue]

and the last ones:

[baz]

Originally Posted by RallyBob Just in case you thought I was kidding....

bob we call them sheds here when they get like that
and if you add just a little more we call them skips