Need help tying roll cage into suspension pickup points

[2ManyZs]

Jon, I'm thinking that with the X brace in there, the horizontal tubes from the main hoop to the crossbar between the struts are redundant and possibly not going to add much. The reason I say this is, the crossbar is already strengthened by the X and the strut towers themselves are already triangulated from your main hoop. If you had mounted the diagonal from your main hoop back to the strut towers from roof level on the main hoop, you might possibly see some benefit from those extra tubes, but yours are mounted down on the main hoop a bit lower than most.

 

With the X in there, why not take those short tubes from the floor and mount them more vertical to the leg of the X and mount them on a long pad that curves up the trans tunnel a bit and do away with the one tube from the top of the trans tunnel up to the X?

[JMortensen]

The purpose of the tubes from the hoop to the strut towers is to provide another load path for the door bars in case of a side impact.

 

I guess I'm not following the second part. Can you draw it for me?

 

EDIT--Just clicked, don't need the picture. The curved plate part had me confused because I was thinking you meant on top of the tunnel. Yeah, I suppose I could do that. I'd have to cut more holes in the rear deck, and they might be going straight through that thicker plate there. I'll have to work it all out and see where everything ends up. Thanks for the idea.

[2ManyZs]

Better idea now that I think about it would be to lay the tube down and attach it to the X where it comes thru the bulkhead. I was thinking if you made a long mounting plate, you could run it on the floor from above the suspension mounting point you want to reinforce and have it end a couple inches up the tunnel. That way, you could mount the tube closer to the curve and lay it down more horizontal to go to the leg of the X where it came thru the bulkhead.

 

I know why you want to put that extra tube in the main hoop, but if you compare your pic to the most other cages where that kicker tube to the top of the strut tower is mounted to the main hoop I think you'll understand. Yours is mounted at the bottom of the bend in the main hoop whereas most at mounted near the top of the bend very close to the roof, which means yours already has more of a load path for forces from the door bars than most other cages.

 

The only other thing I see that I would want to do is to gusset the cage to the chassis wherever possible, if it's within the rules of whatever class or sanctioning body you plan on running.

 

Sorry, I don't have a program on here that I can do drawings with.... never had a lot of use for one so I've never bothered with this computer...

[JMortensen]

Better idea now that I think about it would be to lay the tube down and attach it to the X where it comes thru the bulkhead. I was thinking if you made a long mounting plate, you could run it on the floor from above the suspension mounting point you want to reinforce and have it end a couple inches up the tunnel. That way, you could mount the tube closer to the curve and lay it down more horizontal to go to the leg of the X where it came thru the bulkhead.

That's an interesting thought. Might just do the X first, then look at both options.

 

I know why you want to put that extra tube in the main hoop, but if you compare your pic to the most other cages where that kicker tube to the top of the strut tower is mounted to the main hoop I think you'll understand. Yours is mounted at the bottom of the bend in the main hoop whereas most at mounted near the top of the bend very close to the roof, which means yours already has more of a load path for forces from the door bars than most other cages.

 

The only other thing I see that I would want to do is to gusset the cage to the chassis wherever possible, if it's within the rules of whatever class or sanctioning body you plan on running.

Good ideas here too. Gussets are definitely part of the plan, have no fear. I'm going to run open track days and play around in FP until someone bitches that I've removed the rusty drip rails or I get my V8 swap done, whichever is first. Then I'll probably be in a class that I have absolutely no chance of winning. I just want to make this one as fast as I can possibly make it. If I decide to really try to compete in autox on a higher level or start actually roadracing instead of just timetrialing, I'll get another car.