That piece is not a side intrusion element. It is simply a way to connect the pedal box (& passenger) back to the chassis.
The arrangement is supposed to protect our lower legs in the event of an offset (or full?) front crash, by keeping wheel & tire from encroaching.
Yes, I've grown attached to my feet....
For that longitudinal member (hidden in rocker panel) to give us intrusion protection, we'd need to be on a go-kart track....
Right, I get that it's going be totally ineffective unless you're hitting a wall or something, but they do call it that so I did for convenience's sake. "Protects both driver and passenger against side and wheel intrusion"
Didn't want to intrude on other thread (fiberglass repairs).
The battery tray in Elan trunk began to break.
Before fixing the f/g, I put a few bits of dowels in the tray's rounded edge and glassed over those. It was quite sturdy. Never showed any cracking after that.
Mine isn't a cracking problem... basically, every once in a while, my wife would notice something drip on her feet. The botton of the airbox (around the trumpets) had been slowly, over the years, cutting a groove underneath to the point where there were some small holes, and I assume she'd get a little gas once in a while dropping down.
I found out a few years ago that the root cause was that the engine mount on that side was wrong, that side needs a mount that moves the engine up a little higher to keep the airbox off the fiberglass, which I promptly put in. Since the engine's out, I figured that I might as well build up the glass in that area again to prevent future drips. Really, I could probably just put in some filler and be done but I thought I'd try to do it right with some fresh fiberglass.
Oh, and my battery is still behind the passenger seat so no trunk problems with it.
I do plan on moving it to the trunk some day but that'll be another project.