Well with all of the sfc's I have been seeing I havent seen anyone throw out the brand I am running (which may be a bad thing LOL). Im running CGS chassis SFC's they were a bolt in then welded them but you can get them just as weld ins if you like. I have been running them for almost 3 years whithout a bit of problem. Just thought I would toss out another company to think about.

I'm going to jump on the TGO bandwagon, and vote for Spohn. I love my SFC's, i need to sand them down and coat them w/ por 15 though, as to the fact i cheaped out on the powdercoating, haha.

Anything as to the suspension, I turn to Spohn first.

Brandon

I've welded in quite a few pairs of subrames........I have the SSM lift bar setup, and i love the subframes, but unfortunately they arent available anymore.

the hotchkis ones are nice, and fit very well for the most part...and im a fan of the attachment points as well.

the spohn ones have given me nothing but trouble, they only fit OK even on a really straight car, and they are a real bitch to weld to the rocker seam because they're round.

i've got the Hotchkis weld-on ones (had them for about 5 years now and they aren't installed yet.)
probably install them this weekend.

I had the SSM SFC welded under my '86 IROC-Z and they really stiffened the chassis. As mentioned they blot & weld to the rear sub-frame, weld to the front sub-frame and tac-weld along the rocker panels.

My only problem was closeness of the Edelbrock front Y to the RH SFC, though it did clear enough to not rattle.

Since the SSMs come in a kit I think you will be quite satisfied with the resulting stiffness to the chassis.

Does anyone know the weight difference between most of these subframe connectors? I have a set of SSM connectors and they feel pretty heavy, but I have nothing to compare them to.
I have never seen any manufacturer post this info-any help would be appreciated.

i just bought the Alstons a month ago, and have had them installed for 2 weeks, .. they are really awesome, not as low as my 3" hooker cat-back, follow the body close underneath, relativley easy to drill and install. made the car real tight... got them from TDS, about $180 powdercoated black .. might weld them up in a month or so

Maybe it's just me...

I can't see charging $200, for $50 MAX worth of material! I can understand R&D time...machine costs for bending...construction welding time, but still!

The profit margin on SFC's just seem like overkill! Hell, R&D is almost a moot point, with 14+ years worth of R&D with others to copy. It's not like it's brand new R&D

I want SFCs, but...I just can't bring myself to spend that much. I think I'm gonna build my own. With my metal building experience, it won't be THAT difficult. I't's not like we're trying to push 1000hp cars through them.

I'm sure I'll get flamed for this...Oh well...It's just my opinion.

my first set of SFC's were comp eng ones, two pieces of 2 x 2 with one of them having a useless/pointless bracket on one end that I paid plenty for (summit + truck ship) that I had to weld. wwhen I could have just bought some 2 x 2 and cut it myself.

the second set I bough 1 x 2 thickwall and did just that.

Where could one purchase the Kenny Brown set up?

the closest i've seen to thier design is the umi's which i will be running. i'd love some kb's but there are defunct until kenny recovers and starts over.

UMI has the best design hands down. Installation ws easy, and makes room for virtually any exhaust system.

wat would be the be the best SFC for true dual setup?

After looking at the UMI set, I think I'm going to be going with those.

Ask for ryan.... and tell them Cale Bradley refered you. They will probably give you a discount of some sort. Or you can email me and I will talk to him.

Does UMI have a website? I would like to check out there sfc's.

UMI website

To me, the UMI set looks like a homemade set, with the stepped bar being 2 pieces welded together. That would be an easy way to build a set at home.

Damn sure not at $200 for a set!

MAC make awsome connectors
just google mac performance parts

Ive seen alot of square tube LCA! edelbrock lakewood metco hotchkis

i love my Comp engineering, bolt in then weld em up.

I have been looking at these also. What type of exhaust are you running?Any clearance problems with the exhaust? Thanks

its time for this thread to die, people just keep bringing it back!

So I guess you never had any questions about products when you started your project. I have had my car since new. It is in original condition with a few engine mods. Now I am starting to tear my car apart to do serious mods. First thing I did was ordered my crate motor. A 383 with Fastburn Vortec heads. Now I am planning other things . This is a winter project . So I will probaly be starting alot of the older threads back up after I read them to get some opinions. There is alot of good info here that i have seen so far. So to all the people that have already done your mods

alot of people need the info and get it but have a few more questions. "NEVER SAY DIE"

I am going to have to run side exit through the front fender well and back under the rocker. I will use chambered tubes for the mufflers.

Right on that sounds like an interesting project.Show us some pics when you are done . I will not be going that root so i , will look at alternative styles. Thanks for the reply

My vote is for Spohn, had them for five years now and the car is better now then when it was new. My opinion.

Hi,I have a stock 1989 Formula 350 with T-tops,which is the best sfc to use for T-top cars?
I'd really like to make mine as solid as possible.
If any third gen owner out there has experience with this I'd appreciate the advice!

I have Spohn SFC's .......great fit and were easy to weld in.

I'm going to throw in my

I think that both Spohn and UMI make a good quality piece that will help strenghten the car. You can't go wrong with either piece and both are very popular.

My preference is UMI. I have UMI for all my suspension and I am very impressed both with the quality and service I have received.

Good luck..........

Regarding the round tube vs square/rectangular tube debate, they both have advantages. Square tube will be more resistant to deflection only at right angles, where the walls 'align" with the stress loads, however they will be less resistant to bending stresses if the stress is at 45 degrees to the walls, and they tend to be heavier per wall thickness. They are also much easier to weld to the floor pans. Just "stitching" them to the floorpans every 5 inches or so will substantially increase the stiffness of the car.

Round tubing distributes angular loads better, and will be more resistant to deflection or crushing if the stress does not align in perfect angles to the part, and will be lighter for a given size/wall thickness. They also bend better and distribute stress over a bent area MUCH better. However, round also tends to be an energy conduit as well, so they can "ring" like a bell, and wind up like a spring, which the square tubes are much less prone to doing.

So which is better for SFC's? For straighter shots, square tube, for more complicated shapes, round. Either will work fine, really .

TA

This has turned into an awesome SFC thread. Alot of information in here.

Update: My Alstons feel great and have been working nicely for about a year now. Pretty easy install also.

im using the alstons right mnow and they are great. the only issue i had was the fuel line. the fitment was great and it barly took a hour to have them welded on. they also closed up some fender gap and quited down some of the squeaks too.

well i'll jump in too

i have alstons, just welded them in 2 weeks ago, everything went well. Just wondering, did you guys with alstons weld them in as they were? I ended up cutting up the mounting cups a bit so i could get a good angle to weld at, its kinda tight up under the car.

I have Alston's that I bought from Alston and had them installed buy Alston. I like them ...how they compare to others I don't really know. The car definitely rides different. It seems to rattle much less. When your wife tells you they made a difference IT MUST BE TRUE. I also added a Wonder Bar.

my , i haven't got any yet but... i am going to get the alstons and then weld them in, but to compliment them alstons also work with the tubular type so you have even more rigidity. i think the seconds will be spohn.

I've heard lots of good things about UMI's SFC. My concern with it would be that it weighs more, but if thats what you need to keep from bending... I would say, with very little doubt that the square tubing would be very significantly stronger than round.
Reason being, consider what you are working with. The floor pan of your can can be considered a flat plat with tires on each corner. The engine in the center is applying a twisting moment, yes, but if you take a flat plate and twist it, the edges where the SFC are undergo nearly pure bending. Additionally, the tires apply the force to the road attempt to lift the front of the car, a very significant pure bend.
In fact, you can think of your SFC's as forming a solid square with your front cross-member and rear. So even cornering pressure on front wheels is attempting to put the SFC in a bending, rather than torsional situation.
There is no debate, from a mechanical design viewpoint that square tubing, along with I-beams, have the HIGHEST resistance to bending per cross-sectional area. To put a significant torsional loading on the SFC, you have to load it from the center rather than from a corner of the square.

If square is better than round, then why are alltube chassis round tubing not square?

Take a square tube, and try to twist it...now try that with round tubing...That proves my point. Round tubing is MUCH more resistant to twisting, therefore stronger..

Cardboard tubes dont twist very easy!

ROUND cardboard ones don't. Square ones do like twigs.

Tube chassis arent all made of round tubing.

And you're talking about a circumstance that doesnt apply in practice, like a bunch of others. Rather than concentrate on a single element, you need to concentrate on the entire chassis as a whole and consider the motion it is in, not a single element. Round is only stronger in torsion, given the same area. It is not stronger in bending. Thats why buildings are made with I beams not round tubing.

Then build your cage from I-beams.

Even in side impacts, not torsional, round is still stronger than square, or drag cars, race cars, pro streeters, etc., would have square tube chassis.

No, it isnt.

Tell the NASCAR guys they are all wrong then...you'll save countless lives.....

What for? They already know.

http://www.hendrickmotorsports.com/t...360.asp?bhcp=1

Check out all that square tubing on the frame.

If you dont have a background in structural engineering, might want to step out of the argument before you get hurt.

pwnd.

Actually, I do. I built structural things for years. Degree? No, just experience. NOTHING I've built has failed structurally, so I'm confident.

You threatening to take this physical? Grow up.

Ok. Post factual math proof that its stronger. Good luck. It wont happen because its false.

People take misconceptions way too far. Field engineering isnt going to work in reality. Go find 2 pieces of tubing, one round, one square, same area of steel. Break both in bending, measuring the force required to do so. You'll find your error. Fact is that the reason they make buildings out of I beams is to place the largest area of steel as far away as possible from the neutral axis. That would be the point right in the middle of the beam. Why? Because when you bend an object, the highest forces are in the area furthest away from the center, and in the center there is no stress at all. Compression on top, tension on bottom, zero in the middle. So technically you dont need any material in the middle, in fact its basically useless in pure bending. You want your area away from the axis, thats why the beams are in the shape of an I and are oriented to keep the web vertical. It doesnt differ with tubing. A square tube has more area further away from the neutral axis than does an equal area or equal OD piece of round tubing. Thats not guessing or assumption, thats fact. It can be calculated that way, or you can break it and measure the force required and get the same answer. I've done both. Look up second moment of inertia, look at the formula, calculate the I, drop that into the bending equation, and see what comes out. You're looking at ~5% stronger with same area, and ~40% with same OD.

Please people, if you cant back up your opinion with proof, dont post it. Round is not stronger than square. Thats one of those old wives tales or myths or whatever that has zero basis in reality. There's a positive use for each, and each has its downfalls. You have to choose the correct application for each and making a generalized assumption will just get you into trouble.

You bring up I-beams, when that wasn't even part of the discussion.

Only because you dont know how it pertains to the subject at hand. Its ok though, you arent the only person confused about what is really going on with how structural members work in use.

Here's a diagram for you. Tell me which piece has more area where the stress is the highest? This is why square is stronger than round in pure bending. This is also why round is sometimes preferred, because it doesnt matter how its oriented to the force, it provides the same strength in any direction.

The crosshatched area is the stress from bending, T is tension, C is compression. If you look at any diagram for concrete and reinforcing you'll find that the steel is placed on the tension side because concrete fails in tension and is excellent in compression. And why that matters to you is to explain that the stresses arent in the middle, but rather the extreme ends.

LOL and my diagram is wrong anyway. C and T mixed up. Fixing...
Fixed.

Just buy Alstons and bolt/weld them in, then buy some UMI SFC's and get those installed also, as you are able to have Alstons and another sfc installed together. As Alstons are more towards the center of the car you can fit that second pair of SFC's in there.

So there you have it, round tubing alongside square tubing, NOW you have the best of both worlds.