Dartht33bagger

I've wanted to get subframe connectors for years. Luckily, I've finally got enough money from my internship this summer to get them. I've searched around for a while and decided that the Spohn SFC look like they are the best ones out there. I also know that I want to go with the weld-in versions and not the bolt-in version.

My research on how to actually install them haven't gone nearly as smoothly. I've seen people saying that you need to remove the carpet and gas lines, to people saying that you need to support the car with the suspension up on jack stands, to people saying that you need the car on a perfectly level drive-on lift, to people saying that you need the car to be on a jig so that the body is 100% straight. With all this conflicting information, I don't have a clue what to do.

Is this a job that could be done at home? I don't know how to weld, but my grandpa does. Would we be able to install these at his house, or would I be better off finding a shop to do it for me?

RedLeader289

iTrader: (2)

Subscribed. These are questions I wouldn't mind knowing the answer to as well.

Base91

iTrader: (1)

I've read the different opinions too and think that the arguments for having the frame straight before installing SFCs make the most sense. You can do it with jack stands. Figure out where to support the frames and get the front jack stand tops level with each other and the same with the rears. If the frame doesn't sit evenly then it could be twisted. Weight the relevant corners so it sits on all 4 stands then fix the SFCs in place. Should lock the frame straight for a good suspension foundation.

toomany

It's best to do it with the suspension loaded. Jackstands under the rear axle and under tue front a-arms works. You won't need to completly remove the carpet, just pull it back along the edges where the welds will be. Same for the fuel/brake lines. Use some common sense, if they look close...move them out of the way.


Having said that. I welded my UMI SFC's in without the suspension loaded. And haven't seen any ill effects.

nosajwols

iTrader: (1)

The safest way is with the suspension loaded. Before welding anything in I also recommend making sure the doors open and close right and that the gaps all look right. Just to make sure the car is "straight" before welding or you can screw it up. As long as it is level the suspension will let the frame relax in a straight position (for lack of a better description).

It can work with the suspension unloaded and the frame on stands or a lift BUT you run a greater risk that the chassis is tweaked a little before welding. It is also much harder to make sure it is right since the frame is not "relaxed". If it is off the SFC will lock the car into the tweaked position. Now you have a "bent" car that the doors etc. do not line up properly (and more importantly, it is bent...).

Just as a reference, during assembly of my car recently (entire car was disassembled for body work) we had tonnes of trouble getting the doors 100% right (out about 1/4 to 1/2 inch out). Then we noticed the stands in the front were on the frame not suspension! Put them on the A-arms and the doors dropped right into place 100% perfect. They (stands) were set to the same height just not on the suspension. This is a car BTW that has SFC AND a 6 point (but t-top) it is much stiffer than most, still makes a big difference. BTW SFCs and 6-point were welded in ~20 years ago with the car on suspension...

Base91

iTrader: (1)

The argument for doing it while the car is essentially sitting on its wheels may make sense for a new or refreshed suspension set up but on many older cars, like mine, with original suspension the car is no longer straight. Every spring has sagged a different amount. If you can't guarantee the frame is straight when sitting on the wheels the only fixed reference is the frame its self not moveable suspension components. It is of course much easier to do sitting on the wheels and few people would probably notice the difference. But better.....?

midias

I put mine on 4 ramps and welded them in. Seemed to work well.

nosajwols

iTrader: (1)

The suspension by design has "give" and is supposed to flex before the car chassis starts to deflect and bend. Now under extreme loads (cornering, hard acceleration) as we know the car chassis will flex otherwise we would not be trying to stiffen it. Sitting still should not be an issue.

Even worn suspension will do this (let the chassis be neutral). In-fact the softer the suspension the more flex it has the better in this case. Sitting still on a relatively level surface there should be near zero chassis flex when sitting on the wheels/suspension. If someone's suspension is so bad that level parked it is causing the chassis to flex enough that is causes a problem, I suggest they address that before anything else!

If you support the car on the frame/body, now the only thing that can flex to take up any minor imperfection is the chassis itself. Any error (floor not perfectly flat and level, stands not exactly the same, resting location not on frame in the exact spots, etc.) will result in chassis bend which will result in potential problems.

If you have a frame machine and take exact measurements and have the frame exactly in the factory specs, that will do the trick and will be better than on the suspension, not too many have that so resting on the suspension is the best (yes best) option.

toomany

FWIW: When I did mine, it was just a shell. No interior and no body pannels. No suspenssion or anything else. As bare as the car could get. I had just gotten done installing new floor pans and 10pt roll cage. All of my gaps are correct, didn't take any more adjustments than usual when re-assembling a car.

camarotucker

iTrader: (2)

https://www.thirdgen.org/forums/susp...-overload.html

https://www.thirdgen.org/forums/susp...on-thread.html