Please share your removable engine compartment cross-brace tips and ideas

[beeman]

I feel that I need to stiffen up my large engine bay, obviously would like to do it with something removable.
What is the best way to do this? Steel vs aluminum? What diameter tubing? What mounts? Big "X" or another geometry?
Thanks!
Dave

[Roger Reid]

Try this type of connector. http://www.pacificcustoms.com/mm5/merchant.mvc?Screen=PROD&Product_Code=ac702000f-095&Store_Code=PC&PowerSearch_Begin_Only=&sort=&range_low=&range_high=

[beeman]

Thanks for the link, Roger.
I've seen some like that... Seems like they are all Chromoly? Any options in mild steel or do I need to have someone else TIG it?
You linked to the 1" option, is that the recommended diameter for this brace?
Thanks!

[Roger Reid]

There are many sizes and several manufacturers. You now have a name to do a search by and select what you need.

[crash]

Do you mean something like the red tube structure in this picture? It was relatively easy to make and allows much easier removal of the drive train.

4130 or "chromoly" tubing can be MIG welded with the correct wire. We use ER70 S-2. Same filler as we use when TIG welding 4130.

[beeman]

Yes Mike, but something that spans more/most/all of the engine bay. Your technique looks interesting, how did you mount it? Looks like nuts welded to the frame with a bolt at each corner? I can do that fairly easily! Did you just weld a washer into the tube ends for the bolt or is that off-the-shelf? My engine bay is even larger that the FFR setup, is 1" adequate?

I'm making the assumption that I shouldn't leave this big opening un-triangulated, right??
Thanks for teaching me guys!

http://fs5.directupload.net/images/170115/p3ocfbov.jpg

[crash]

Looks like you could easily tie into where your roof bars meet the main hoop and add a removable "V" that connects the roof bars to the already there X brace towards the rear. As far as the X brace, you can machine spuds and mating pieces to be welded to the X brace, or you can use the nut and washer method. I would think the nut and washer deal would not be as strong, but it certainly is much easier to build.

I have never used the previously linked tube ends, but have seen them used plenty of times and they seem to work will in certain situations. I might put those at the X brace end of the V and then use something that looks much like your door hinges for the top where it would be 2 tubes wide.

Not to side track you, but I have rethought the entire rear of the frame on my new car and am going to make everything aft of the main hoop removable. So basically the frame will be split into a main frame section and a rear frame section to help with repairs when crash damage is encountered. I'm not recommending it for you, just letting you know that I have considered many ways to attach bracing elements in the rear of these cars, and that is what led me to the above recommendations for you.

[beeman]

Thanks!
Are you suggesting the red V I drew? In my mind I imagined an X, like the yellow. There shouldn't be any engine interference with either, right? Does an X buy me anything over a V?

http://fs5.directupload.net/images/170411/2e4myh77.jpg

[crash]

That would be a CFD question.

[LCD Gauges]

My SOTP (seat of the pants) CFD Computer says the X will produce more rigidity due to the 360 degree binding points.

The other question is, will the V suffice for what you're doing?

[crash]

Or...

[beeman]

I think either option will triangulate the bay nicely, I think the X might do a little better with the smaller triangles.
Edit : but now I see what you are talking about Crash - with my modified roof bars, I probably am better off sending that load with a V to the center of the main hoop like you suggested!
There is nothing unsexy about the Ganassi Ford GT.