Custom Subframe Connectors - worth it or pointless?

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Evil_Fiz
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Joined: Sat Aug 01, 2015 9:30 am
Location: Jacksonville, FL

Custom Subframe Connectors - worth it or pointless?

Post by Evil_Fiz » Sun Dec 10, 2017 6:49 pm

I am considering fabricating a set of 2" tubular sub-frame connectors for my resto-mod 1970 Ghia convertible. What I envision is a tubular link connecting the lower font beam tube and the rear torsion spring housing. These would either be welded to both tubes or bolted to mounts welded to the tubes. they would also be bolted to the the body mounting bolts at the corners of the Napoleon hat and at the rear pan edge. The longitudinal tubes would be connected to each other by a butterfly brace similar to those made for Miatas. My Thinking is this would improve torsional rigidity and foster better handling characteristics. I got the idea after reading FJCamper's road course setup thread and his mention of the Ghia body flex point just forward of the tunnel access cover.

I have not seen this done before so I imagine it is either a waste of time or the return on investment is not worth the effort, but who knows. I am interested in your thoughts and opinions either in favor or against. I am in the process of rebuilding the chassis so now would be the best time to undertake this effort. This car may or may not get a spirited Subaru engine, 4 wheel disk brakes, upgraded master cylinder, appropriate gas shocks, standard width beam, dropped spindles, caster shims, Delrin bushings where applicable, and maybe narrowed rear trailing arms, so please consider that when providing feedback.

Cheers,
Emil

Ian Godfrey
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Joined: Thu May 27, 2010 4:52 am

Re: Custom Subframe Connectors - worth it or pointless?

Post by Ian Godfrey » Thu Dec 14, 2017 1:47 am

I think there is definite merit stiffening the Ghia pan. In my road race ghia I have the braces that go between the napoleon hat and the front beam and they make a lot of difference particularly under braking. http://cal-look.no/lounge/index.php/topic,10938.0.html
I also gave a lot of consideration to these
http://evhcompany.com/Ghia.html
but I ended up getting a roll cage instead which stiffens the car up a lot too.

Ol'fogasaurus
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Location: Just north of Seattle

Re: Custom Subframe Connectors - worth it or pointless?

Post by Ol'fogasaurus » Thu Dec 14, 2017 11:47 am

Have you considered rectangular tube instead? Round tube has it's advantages: as I remember it survives twisting better but for up and down loads the strengths of rectangular tube has advantages. Even square tube has it's advantages too but not as much as rectangular tube and, like tube would probably require some bracing.

https://www.bing.com/images/search?view ... ajaxhist=0

An example of commercial beam supports as an idea.

viewtopic.php?f=28&t=113703&start=720

I play in the sand and currently am playing with supports for the "pickleforks" for off-road use as I don't think that much of the commercial Truss/Kaffer bars that are available (if you have IRS then maybe the Mendola's "Stiffy" might be worth thinking about as they use one other connection point). About half way down Dustymohave has a picture of the additional sub frame connector between the torsion tube and the pan that he uses. The additional support is my understanding to be something VW recommended. A few pages forward of that is what I am looking at doing for the additional support.

Will this work for you... I don't know but it might give you some ideas.
Lee

My opinion is worth slightly less than what you paid for it.

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