Sub-frame connectors... Please build them correctly!
The first article is interesting, but it's really no better than the discussion here. Who wrote it? What qualifications does that person have? Data?
Yes, taller connectors resist twist better. Pushing them out to the rockers helps as well, as being wider on the chassis will also help to resist twisting. But how many people are going to cut their doors down to increase the height of the rocker and make the step over height 5 or 6" taller? And, is it necessary anyway? If you need that kind of chassis stiffness, you are probably in need of a full cage. Not to mention that a lot of racing rulebooks don't allow for those kinds of modifications to the rockers. And, because of the extensive modification to the rockers, the execution of the installation would be very important. If that installation was done poorly you could actually weaken the structure of the car. With the standard tubular connectors or the weld to floor connectors poor execution just limits your improvement, you would have to work pretty hard to compromise the structural integrity of the chassis. If you start by cutting apart your rocker boxes, you have a lot of ground to cover. The end result could definitely be stronger, but if it's done incorrectly it could also be catastrophic. The application seems very limited to me. If you have a full chassis shop to make those kinds of modifications, you should just make a full cage. If you're doing it at home, you're biting off a REALLY big chunk.
You can use basic engineering principles to argue for any of the types of subframe connectors discussed so far. But without an actual test, and without actual data, it's really just speculation. Sometimes informed speculation, sometimes not. And ultimately there is a limit to how stiff
any connector can make the chassis, because they're only one component of the chassis and they're still connected to the rest of the chassis. At some point you have to go to a cage. Which is why it would be interesting to see actual torsion tests. My own speculation is that the type of connector isn't as important as people make it out to be, because there's a limit to what any type of connector can add to the chassis. But that's just my own personal speculation, and I absolutely could be wrong.
