JohnnywantsaTA

I've seen different type of sub-frame connectors,and was wondering which is better. Tubed or boxed???

Thanks

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"A musclecar, by definition, is a powerful and sporty vehicle that must be able to spin its tires at will. The Firebird Trans Am is capable of laying down twin black streaks of rubber several hundred feet long. We wanted to be sure it could, so we did it a half dozen times in the name of automotive science."-MotorTrend

MikeS

I would think that there are too many factors to simply pick boxed over tubed or the other way around. Wall thickness, tubing diameter/dimensions, and material type play a role in stiffness as well. So, geometry is not the only concern. Seems like the stiffest setup would be one that welds down the entire length of the car, rather than just at points on the front and rear subframes. That leads me to vote for boxed or rectangular tubing. But this is just my opinion. I could do some calculations or whatever to figure what is the stiffest, but dimensions would be pretty arbitrary, so I'd really rather not have to go through all that. Gut feeling says rectangular, although i'm not saying anything against round. Just my opinion here, so take it for what it's worth. I have never had sfc's on either of my thirdgens, so no practical experience with them. Just theory from school coming out here.

89rsragtop

All things the same tube is stronger than boxed. Far and away the most important things are design and installation.

ede

tube is stronger but the box is easier to work with and on a third gen works better i believe, especially if you want to weld it along the full length of the rocker panel.

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ICON Motorsports
1st & 3rd
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89rsragtop

ede is right tube or boxed is not as important as being able to weld them along the rocker panel. I was lucky on my conv. this area is boxed. When I installed my Kenny Browns SFC they were very tight to the rockers so I could weld them together in a few places along the the lengh of the car. KBs are a tube design and not easy to weld to the rocker so I got help from a pro welder. Bottem line get a design that lays tight to your rocker panel. p.s. Don't get bolt on they are not worth it.

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1989 rs ragtop LO3 KB subframes & towerbrace to hold it together but bone stock

JamesC

iTrader: (5)

I've got the Global West tubulars. They welded in fine. E-mail me for pic, if you'd like.

JamesC

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