Strengthening BadDog rails

[dimsum]

I spent last night examining my new BadDog rails (front and rear) and how they fit on the car. I wish the front and rear pieces came as one piece, instead of two, so they were a little more rigid.

 

After looking at the rails, I tried to think of ways to make them stronger, like Pete's. I thought about adding a long, steel box, sandwiched between the BadDog rails and the floor pan. If this long box ran the entire length of the car, it would eliminate the seam between the front and rear sections.

 

I drew up some crude pictures that are not to scale, but should hopefully clarify what I was thinking.

 

Cross section of rail and additional box:

 

Side view:

 

 

This wouldn't make the rails as strong as Pete's design, but it would be an improvement.

 

I'm not a metal worker, only have rudimentary statics knowledge, and am basically thinking out loud here. Please provide comments and thoughts.

[JMortensen]

Weld the two pieces together at the seam and then they're one piece. Personally I think what you've got there is just extra weight. The floor pan will be the top of the "box", so you don't need to add another piece in there. If you wanted a top for the box that was .120 like the rest of the rail, then you really only need a top piece which is .120 across the flanges on the top of the BD rails.

 

If you want extreme overkill then you should sell the BD rails and do a larger box tube like Pete did. But I think the BD parts are already a huge step up from stock since they connect the subframes and they're 3x as thick as stock (if not more), so the question is how far do you really need to go, and are you going to rely on your subframe connectors for ALL of the structural improvement, or are you going to beef up the rockers to, or do a cage, or a roll bar, etc.

[Bartman]

Are these BadDog frame rails designed to be installed over the factory frame rails or do you have to remove the factory ones? Perhaps they can be installed either way. From the drawing dimsum posted it looks like you have no factory frame rails.

 

These may be a nice improvement for my car and it doesn't look like it would be too difficult to install.

[Pop N Wood]

I agree with Jon. Just use the bad dog stuff or do a variation of Pete's design. Either one will be leaps and bound stiffer than the stock stuff.

[JMortensen]

Are these BadDog frame rails designed to be installed over the factory frame rails or do you have to remove the factory ones? Perhaps they can be installed either way. From the drawing dimsum posted it looks like you have no factory frame rails.

 

These may be a nice improvement for my car and it doesn't look like it would be too difficult to install.

They're designed to fit right over the existing rails. I removed the originals on my car due to TC rod changes and the fact that mine were all bent up and the BD parts would no longer fit over the originals.

[Bartman]

They're designed to fit right over the existing rails. I removed the originals on my car due to TC rod changes and the fact that mine were all bent up and the BD parts would no longer fit over the originals.

Do you have any pic's that you could post of the Bad Dog frame rails installed?

[JMortensen]

Sure do. I think around page 2 or 3.

http://forums.hybridz.org/showthread.php?t=106974

[dimsum]

so the question is how far do you really need to go, and are you going to rely on your subframe connectors for ALL of the structural improvement, or are you going to beef up the rockers to, or do a cage, or a roll bar, etc.

 

The car will mostly be street driven with a little track time, so I don't think a full cage is practical. I have a roll bar in there right now bolted to the rear wheel wells. I have been reading up on strengthening the rockers, but so far everything seems beyond my abilities.

 

It sounds like the additional steel would just be extra weight. I was thinking they would strengthen the frame rail walls. That way, if I jacked up the car by the rails, the rail walls wouldn't crush.

[JMortensen]

The rail is already 1/8" thick. I wouldn't hesitate to put a jack under one.

[Bartman]

Sure do. I think around page 2 or 3.

http://forums.hybridz.org/showthread.php?t=106974

Thanks Jon, it looks like you did a great job on your car. I may have to go the Bad Dog rail route...but it won't be easy welding them in without a rotisserie.

 

Dimsum, let us know how your install goes.

[Careless]

im goin with what the mortmeister said here. putting a part inbetween will be just too much added weight.

 

one thing you have to remember is that when you put a steelbar there, you're going to have to fasten the baddog rail to the chassis first with some small stitch welds, or the baddog rail first with some rosette welding.

 

if you fastened the steel box frame to the car, you're ognna hvae to figure a way to get the baddog rails to meet the floor pan at the same height, and also meet the frame rail so that you can tie them together, or else i't just extra weight.

 

now, if you fastened the box frame to the rail, then you'd have to make sure that the frame rail and the box frame are level so that you can drill holes into the baddog rails and rosette weld them to box frame once you've made small stitches to tie the box frame to the floor pan.

 

if the inside box frame is shorter, your floor pan will not tie into the box frame, or will not tie into the baddog rails, they have to be flush on both faces... if not, they're just added weight.

 

if the baddog rails don't sit level with both the floor pan and the box frame faces, then you'll be welding it on either only the floor pan, or only the box frame, thereby defeating the original idea.

 

a better solution i see that is much more effective and also much more lightweight, and easier to do, is to cut small rectangular steel pieces and weld them into the baddog rails every 6 to 12 inches, all the way around (tough to get a welder into there)

 

this will act like a ribbing for your baddog frames, and if you'd like to inquire about a way to tie those small ribs into the floor pan, i'd be glad to illustrate it for you when i get home using photoshop and some concept drawings.

 

let me know if you wanna see it, i have some time this weekend (aside from working on my Zee), and I'll let you know.

 

I takes some primitive methods, a bit of sponge, and some paint that you can apply to metal using sponges. and a drill bit. lemme know =)

[dimsum]

Careless,

 

If you have time, I wouldn't mind seeing what you have in mind. I think I can picture it in my head, but I just want to make sure.

 

Can you also explain the "primitive methods?" That kind of work sounds right up my alley.

 

Thanks.

[Careless]

Careless,

 

If you have time, I wouldn't mind seeing what you have in mind. I think I can picture it in my head, but I just want to make sure.

 

Can you also explain the "primitive methods?" That kind of work sounds right up my alley.

 

Thanks.

 

well i crushed my hand in between a door yesterday, so im typing with one hand, and i can't draw in paint with my other.

 

but here goes:

 

take your baddog rails. take some metal that is just as thick. getting the same type of metal would be ideal.

 

measure the inside width and height of the rail, every 6, 8, 10, or 12 inches (depending on how much welding you want to do later, and how much of your floorpan you want to tie in)

 

now insert those pieces into your baddog rails and weld them into the rails so that the top of each rib sits flush with the mounting face of the baddog rails... the part where you weld it to the floorpan.

 

this has to be flush so that you can later tie them in to the floorpans for added rigidity.

 

now. in order to properly calculate where you would have to drill holes and make small rosette welds, you would have to devise a way of marking where the holes will fall.

 

one "primitive" method of doing that is getting a hot glue gun, and dabbing a small bead of glue on the middle of every rib, on the side where it would touch the floor pan. after there is a small bead of glue on every one, take a paint marker and colour the bead of glue in a bright colour so you can see it.

 

carefully prop up the baddog rail, and once you get it in place... use a jack to compress it to the car tightly for a couple of seconds so that the glue paint rubs off the glue, and leaves a circle imprint on the floor board.

 

check with another colour to be sure. make some markings JUST OUTSIDE the rail with a drill bit or something sharp, so that when you use the second colour to check accuracy, you know where to align the rail, and you will resist smudging the paints.

 

once u remove the rail, you now have little indicators of where to drill holes. drill them out, and put the frame rails on again, using a jack. and from the top, see if the ribs line up with the holes... if they do, then you can thinly slot the holes horizontally (if you're sitting in a drivers position), and then rosette weld a small bead across the floor pan and the little ribs.

 

this is like a ladder frame inside a ladder frame, and it is a bit more work than is required, and to be honest, i wouldnt bother doing it. BUT, i wouldnt bother doing a box frame in subframe design either, because that would be even harder to get perfect.

 

im going to attempt to draw somethig for you. hold on.

 

EDIT:

 

Here is the modification in step form.

would I do this to a baddog rail? No.

would I do this if my frame rails were still rusty and on the car? No.

what would I do? I'd make new frame rails and floor pans. If you're gonna go to this length, you might as well.

This is not terribly hard, but it is time consuming and there is room for misalignment and error of the paint daubs,you have to realize that this is easier with the car on a rotissierie, and that welding a box frame inside a baddog rail is just not going to do much but add weight.

 

this is a Ladder-Frame within a Frame-rail type of deal, and it is not as strong as a box frame, as far as I'm concerned. Heck, if you want to cut out some of the small squares in or around the rails, you could then use them as small storage comparments for various items, like doobies and stuff =)

 

 

This might also be a good time to mention that you should probably coat the inside of each individual box with a light mist of some sort of rust inhibiting paint, or drench them in krown coat or something.

 

you want to make sure that all the moisture in there doesn't get trapped.

 

g'lucky!

[Careless]

another thing I forgot to mention, but if you dont tie the floor pan into the ribs with proper penetration, or you make the holes too small, or too big, they may not hold well enough if the chassis happens to twist (and it just might, in a hard turn), you will probably here some of those welds pop free, or possibly rip the metal a little bit.

 

there is a room for error here, and it can be done.

 

advantages are questionable.

 

alternatively, you can rib the baddog rails and just NOT weld the ribs to the floor pan (make them sink in, and not flush to the weld face of the original rails).

 

That would add just about the same rigidty to the chassis.

 

if you rib the chassis with ribs in close proximity to eachother, then I wouldnt bother tying the floor pan into it, as I dont think the floor pan would be going anywhere. or poping and twisting.

 

or you could even rib them evenly, and do every 3rd or 4th rib tie into the floor pan, if you'd like. but again, the floor pan isnt really structural steel. it can hold some weight and stop some binding, but if the frames cant handle one type of force, your floor pans are going to feel the brunt of it anyways.

 

so just rib up the rails if you think they're too flimsy. that adds minimal weight, and will add enough strength that would pay off instaead of welding in a steel tube all the way down the entire rail.

[dimsum]

Thanks for the diagrams. Based on the work involved and your recommendation against doing this type of modification, I think I'll leave the rails as they are.

[alexideways]

On little thing that I would change in Careless's design.

 

I would make the ribs stick out of the rail a good 2 1/2", for 2 reasons.

 

1- With the ribs sticking out this much, it's going to be easier to line everything up. *Position your rail where you want it. *Use a scribe and mark each corner (on both sides) of the ribs. *Remove the rail. *Joint the dots with your scribe. *Cut the lines as mentioned by Careless.

 

2- Now, with that done, put the rails back on with the ribs sticking out trough the top of the floor. *hammer the ribs flat on the floor. * Weld the ribs on each side. *Weld the rail's flange to the floor.

 

This way you're sure the welds'll be strong enough and they won't pop under load. As it's really hard to weld the tip of a sheet metal part, trough a slot without overheating it. If you overheat the metal, you can be sure those wels ARE GOING to pop under load.

This way, it'll definitelly be stiffer.

[JMortensen]

On little thing that i would change in Careless's design.

 

I would make the ribs stick out of the rail a good 2 1/2", for 2 reasons.

 

1- With the ribs sticking out this much, it's going to be easier to line everything up. *Position your rail where you want it. *Use a scribe and mark each corner (on both sides) of the ribs. *Remove the rail. *Joint the dots with your scribe. *Cut the lines as mentioned by Careless.

 

2- Now, with that done, put the rails back on with the ribs sticking out trough the top of the floor. *hammer the ribs flat on the floor. * Weld the ribs on each side. *Weld the rail's flange to the floor.

 

This way you're sure the welds'll be strong enough and they won't pop under load.

This way, it'll definitelly be stiffer.

There is a bump inside the floor where the frame rail attaches. I think if you hammered the tabs flat on the inside you'd distort the crap out of the floorpan. I still think you guys are fixing a problem that doesn't exist, and although I have no doubt that the ribs would stiffen the structure, I just don't think they're necessary, and Pete's larger rails are easier to do than that would be, and still stronger.

[alexideways]

:iagree:I do agree that wider & thicker rails are the way to go, I was just trying to fix, what I saw as a flaw, in the aforementioned plan. In case he decides to go that route.

[Careless]

There is a bump inside the floor where the frame rail attaches. I think if you hammered the tabs flat on the inside you'd distort the crap out of the floorpan. I still think you guys are fixing a problem that doesn't exist, and although I have no doubt that the ribs would stiffen the structure, I just don't think they're necessary, and Pete's larger rails are easier to do than that would be, and still stronger.

 

that was my point for posting the diagram.

 

it was a rudimentary way of solving a problem that doesnt exist, or wouldnt be beneficial for the time involved in doing such a modification.

 

The ribs would strengthen the frame rails themselves, no doubt.

 

but how hard would it be to find a bar stock that is thick and wide and tall enough to fit PERFECTLY within the confines of the baddog rails, from front to back, to be welded in as a structural support?

 

I dont think that's possible to find, and would require a lot of work, and just add weight. bigggggggg minus here.

 

There's no question that ribs would make the baddog rails see less twisting, but then again, if you're going to that extent, like i had said above my posting of the short diagram:

 

would I do this to a baddog rail? No.

would I do this if my frame rails were still rusty and on the car? No.

what would I do? I'd make new frame rails and floor pans. If you're gonna go to this length' date=' you might as well.[/color']

 

Im all for the box frame rails on their own. they're thick as you want them to be. and stout as you make them. tie those into the rockers at various points, and you got yourself one helluva reinforced undercarriage.

[proxlamus©]

are the bad dog frame rails stainless steel?!

 

any problems welding these rails to the steel underbody using a mig?!

 

If it is stainless do I have to use gas? or can I use a stainless wire flux?!