The point to installing the SFC is to induce a camber into the car before welding. That way, when you set the car back down on the ground, it will be preloaded straight.
I built the first set of subframe connectors back in the day. I had been putting subframe connectors on Mustangs for years when I decided to build up a set and put them on my own car. I was amazed at the results.
My normal ritual when leaving the shop was to turn out of the parking lot and ease it up to about 4000rpm in first gear, then smack the throttle and spin the tires to 6500 until they hooked and off I'd go.
Well, one Sat., while messing around at the shop, I decided to weld up a set of connectors and install them on the car. I was hoping for a little better handling and some rigidity in the chassis. I put the car up on the lift and started welding.
When I got done, I took it for a drive. I turned out of the parking lot, eased it up to about 4000 and smacked the throttle like I always did, but this time, the tires didn't break loose. They stuck hard and bit without spinning. I was shocked! I tried it again. Same thing. The car hooked hard and wouldn't break the tires loose from a rolling start. The car also handled better. Less body roll and it felt like the rear of the car was more connected to the steering wheel.
When I got back to the shop, I tried to analyze the problem. As I did, I came to understand FWD Unibodies even more. Think about the engine and how it drives the front wheels. As you put power down, the engine and subframe lift up on the core support and push down on the firewall. This causes the chassis to bow in the middle and lift the front end of the car, thus lightening the front tires. When you raise the car on a chassis lift (twin post or equivalent), you bow the car in reverse and induce a negative camber into the chassis. As you weld the connectors to the bottom of the car, you fix this camber that you induced by lifting the car. Then when you put the car back on the ground, it preloads the chassis straight. It prevents the torque of the engine from bowing the chassis under load. Since my original design incorporates a taper in the mounting locations, it also triangulates the bracing and prevents the chassis from twisting as well. This makes the rear sway bar more efficient. As you run the car thru turns, the rear sway bar is trying to resist the roll. When the chassis twists, it negates any effect the sway bar has. By making the chassis more rigid and resistant to twist, the bar does a much better job.
Incidentally, I gave this idea to Vadim while having lunch in a restaurant in Detroit during the Detroit convention....back in the day.
So the point is to lift the chassis (not the wheels) when welding in the connectors. And if you don't have them yet, give us a call. We designed and built them in the first place. Ours are two pieces of 1x1 box tubing (.083 wall) welded together, powder coated and have beveled end caps.
