http://www.umiperformance.com/2400.aspx They look pretty good. What do you guys think?

 

Ok, but tubular is the way to go. Got a weight on them?

Ed

 

I'm willing to bet that they are heavy as hell.

Kat

 

The SFC's look to be well-designed. And the price is very competitive at $200 with powdercoated finish.

I would be curious as to their weight as well. Spohn's first design used square tubing and that was considered a decent product.

Ed, do you have the weight figures on the present Spohn tubular design? One of these days I want to add them to my '92.

 

im gonna get those, thanks for the link , i dont like the spohn tubular ones and doesnt it even say on umi website that since their square they are better torsional ridgidity . ? or did i read wrong.

edit :

When strength is a concern, square tubing has greater torsion resistance over tubular designs. Subframes do not effect ground clearance and weld-in style requires no bolts to tighten ever and less chance of flex compared to bolt-in types.

Our subframe connectors for the third generation F-Body is, by far, the strongest set-up on the market. This unique design utilizes a 3 piece set-up, allowing (3) major weld points through out the chassis of the vehicle.

 

I looked at those at the GM Nationals, and was very impressed. They're quite beefy. Yes, they're heavy, but that's the price you pay for strength.

My question is whether they'll work ok with LCA relocation brackets.

 

LCA relocation brackets go on the axle, not the frame.

 

has anyone bought these and have them on their car? ive been thinking about buying them for a few weeks now.i just wanted to know how they compare to the otheres that are out there.

 

If you are looking for something that is designed just as well if not better and do not weigh a ton, you might want to check out Kenny Brown. They get my vote.

http://www.thunderracing.com/catalog...&vid=6&pcid=36



Note: If you are looking for a lower price I know of one place but it is not that huge of a price difference. I think it would boil down to shipping rates. PM or email me for details.

 

The spohn sfc were almost 25 pounds and the lca were about 5.

 

Those don't look to bad need to find out how well they fit and what the weight. Keep us posted on how well these work

 

what about verts?or will they work on non verts like most

 

I'm with soulbounder, I got the KB Super-Subs, excellent build with tabs and very light for SFC's.

 

Evidently UMI Performance isn't aware of the boxed sheet metal reinforcements that were installed behind the GFX on ASC (aka "factory") convertibles. No these would not fit a convertible unless you removed these reinforcements, (which I don't recommend).

Lon

 

Someone please correct me if I'm wrong, but I'm under the impression that round tubing offers better torsional resistance. Square tubing provides better bending resistance.

 

a roll bar makes a good sub frame connecter ... IMO... tao

 

so what's better, sphon or umi sub frame connectors?

 

2" round tube, .1875 wa:
3.61 lb / ft, moment of inertia 44.82
(most compact, least torsional strength)

2" square tube, .144 wa:
3.61 lb / ft, moment of inertia 45.42
(better torsional strength than 2" round, but not as compact)

2.828" round tube, .126 wa: (same OD as the distance across the corners of hypothetical 2" square):
3.61 lb / ft, moment of inertia 46.72
(better torsional strength, depending on what room you have, may be as compact as 2" square)

2" square tube, .1875 wa:
4.60 lb / ft, moment of inertia 57.70
(best torsional strength, extra weight, just as compact as other 2" square)

Given equal section areas (=> equal wt. / ft), a tube gets torsionally stronger as you move material further away from the axis. The 2" square .144 outperforms the 2" round because the material making up the corners and most of the sides is further away from the axis. Likewise, the 2.828 round is better than 2" square. So, if you have a square-ish channel to run your subframe connector in, you should make the subframe connector as large of a square (or rectangle) as you can fit in the channel, and then optimize the wall thickness to get the strength you want. If the channel is round shaped, then you won't be able to fit a very big square in there, and will be losing out on torsional rigidity for the material that you are using.

The connections to the body are pretty important too. A 2" solid bar with poor connections won't help much.