Tiron

I've heard conflicting reports about sub frame connectors, many people online seem to say that they are one of the best things you can do, while some people I've asked face-to-face say they couldn't even tell they were on.

Are sub frame connectors worth it? Are the bolt-on versions any worse than the weld-on ones? How hard is it to install the bolt-on ones yourself ('97)?

Injuneer

All I can say is jack your car up BEFORE you have SFC's, and only one tire lifts off the ground. Jack it AFTER the SFC's and the entire side of the car will lift both tires right off the pavement. The increase in chassis stiffness it amazing.

You'll obviously notice it more on a convertible, and less on a coupe with no T-tops, but if installed correctly, they make a big difference.

You don't want bolt-on connectors. You need to have them welded.

Mystery Bird

If you can't weld them yourself you can at least get all the areas clean for the welder so he won't have to. He will appreciate it and charge less. If you're handy you can make your own, I did for about $20.

Tiron

I'm just out of high school, so I wouldn't feel comfortable welding or anything like that. Judging from both of your responses I'm going to assume that the bolt-on ones are just about worthless.

How did you make yours?

Injuneer

With bolts-ons, there will still be movement of the SFC's against the chassis attachment points. In severe cases, and I've seen this documented in a magazine specifically for a 4th Gen F-Body, the bolts through the vehicle subframes can start to tear the subframe metal. Welding eliminates all the problems.

One solution is to get the bolt-in SFC's, prep the areas where they will weld to the chassis, bolt them in, and take the car to a shop that can properly support the vehicle (sitting normally on all 4 tires) and weld the SFC's in. I doubt that very many of us have actually welded our own.

Look at what is available from sources like Spohn and BMR.

In my case, I had the SFC's installed at the same time as my 6-point roll bar. Everything is chrome moly steel for reduced weight, the roll bar goes through the floor to the subframes, and the subframe connectors attach nearby. It make for a very solid chassis, even with a swing-out side bar.

Mystery Bird

Mine are pretty heavy, I used two inch square tubing for the main beams and tied the ends with 1/4 in steel, bending, cutting, and drilling to make fit. A little overkill but most of the supplies were free. If you don't have the tools or a welder it's impossible. They look just like these: http://www.thunderracing.com/shop-by...me-Connectors/

Tiron

Are they any real strength differences between the square or the tubular SFCs? My car has been lowered far enough that it can't be correctly aligned anymore (close though), and I hit the ground all the time with it. The tubular ones all say they give better ground clearance, but are they really much different as far as strength goes?

I've got a T-top Z28 that I plan on autocrossing with, so if the square ones are stronger I'd probably go with them, and just be more careful.

I'm looking at these 2:
http://www.lmperformance.com/78664/2.html
http://www.lmperformance.com/723/2.html

JakeRobb

Anybody who says they didn't notice the difference is someone who put them on early, before the body started to get weak. I put mine on at like 80k miles, and the difference is huge.

Mine are just bolt-in. I'll get them welded someday.

calaban

My car was a hard top until 05, I bought them when I did the T-Top conversion. I didn't get them installed until 08 and couldn't tell a real difference between them; Hard Top, T-tops, or T-tops with SFC's.

mzgp5x

I have a 1997SS. Back in the day (1999) I installed a Kenny Brown Subframe system. They call the Double Diamond. Ties Motor compartment to the rear trail links and cross the pan to the rockers. Welded. I also went to the top side with the KB roll cage. Very stiff. Makes a big difference in throwing it thru the corners.
I would also reccomend Energy suspension bushings all around.
B.

4THGEN4ME

I too went with Kenny Brown's SFC's. I had them installed in his shop that he had here in Indy...before it closed due to Kenny's health issues. They made a great difference, especially at the strip...gained .3-.4 secs instantly because the entire car hooked-up better and was more solid...no flexing! They welded mine in and photographed the entire process to send to prospective buyers that were on the fence as to whether or not to purchase. This was all on my 98 Z28 hardtop too.

koolaid_kid

I doubt seriously whether you would notice any difference on a street car, even if you are autocrossing it. Especially with your car lowered like that, you don't want anything hanging down even further, which is what the square ones would do.
That UMI setup is a nice piece; I like it a lot.

TheHeadFL

I have SLP 3-point bolt-on SFCs. I installed them like 7 or 8 years ago. Never had any tearing or anything like that. They bolt into a threaded steel billet that you insert into the subframes.

They are *far* from worthless. All the aforementioned benefits of SFCs I've experienced. Jack up the car, the entire side comes up. Ride is very stiff. It was a night and day difference from stock.

I will add that I had to tighten the bolts about a dozen times in the first 2-3 months. They actually gradually changed the shape of the body because my car was not totally straight when I bolted them on. (Previous owner, front end collision, did not know about it at the time) When I bolted on the SFCs, I could only get the bolts about 2/3 way threaded in to the billet. Each time I tightened them, I got a little more in. The SFCs themselves were not deforming at all, they are thick boxed steel and are very visibly straight and true. The subframes themselves were not deforming or tearing. The body itself was 'untwisting'. (Total deformation of about a half inch) Anyway, after about 10-12 tightenings, they bolted absolutely flush and I have even removed the SFCs since then and the car retains the shape. 8 years on, the bolts are tight and I haven't touched them since. I even marked the area with chalk to see if they move at all. They don't.

Just saying...

frankzlt1

I also have bolt ons, they 3 point umis and I check them every once I a while and their still tight and no tearing. They made a huge difference on ride and handling I would recommend sfc to any body with a unibody car I even had them on my 79z28.

bills70z28

Weld the ends, then use bolts,huge washers, through the floor pan,(drilll)through the sfc's... 2nd gen f body.